# Lithium vs Lead; the Great Cost Debate.



## mattW (Sep 14, 2007)

I've decided to try and work out the cost comparisons for a Lithium pack vs a Lead pack for a set range and a set number of years. Is Lead Acid actually cheaper or does is just seem that way up front? This article aims to find that out. The method is to get 10kWh of usable energy, I’ll try to get that with Lead and with Lithium and see what we find is cheaper in the long run. Assuming an efficiency of 250Wh per mile (a compact car) we should get a range of 40 miles (65km) with either pack. I’ll be using Australian prices since I’ve already researched them, but the comparison is probably close in other countries too.









The first step is to source a lithium pack with 10kWh of usable energy. The Lithium batteries I have chosen get 2000 cycles to 80% DoD and I estimate that at the 1 hr rate they will deliver 95% of their rated energy due to the Peukert’s effect. So to give our total energy we multiply our usable energy by 1.35 meaning we need 13.5kWh to get out 40 mile range with lithium batteries. If we assume a 120V conversion this means we need 112.5Ah. The cheapest Lithium batteries I have seen in Australia are Thundersky LiFePo4 LFP prismatic cells $2.50 per 3.2V per Ah. So our 13.5kW pack would take 38 3.2V cells at ~110Ah and would cost $10450 at normal prices (no group discount), without shipping or BMS. 
For a Lead Acid pack we also need to keep the batteries at less than 80% DoD and at the 1hr rate we can only expect to get 55% of the rated energy of the pack back due to the Peukert’s effect. That means we need to multiply the usable energy by 2.25 to get our total energy, in this case its 22.5kWh. Trojan T605 batteries could make up a 22.5kWh pack with 18 batteries (108V, 210Ah) at $225 each or $4050, it didn’t say how many cycles it would take on the website but let’s guess around 650 to 80%. That means we’ll need to replace our lead Acid pack around three times for every lithium pack we buy, meaning our total cost for the lead packs goes up by a factor of 3 to $12150 over 2000 cycles. 
Now I must admit that I didn’t look very hard for the cheapest batteries and I am only guessing the cycle life of the Trojans but even if it’s not precisely accurate it does show that the myth that Lead is clearly cheaper than lithium is not well founded. Lithium’s greater efficiency and cycle life makes up for its higher initial cost. I didn’t know what the results would be like before I started. The10kWh number was chosen just to make it easy to calculate, it has little influence on the result one way or the other. I thought the results would be close but not this close. Please note that the Lithium pack would require a BMS, which would cost $1270 but that still means you are going to pay around $12k whether you go with Lithium or Lead. It would also be worth mentioning that you would be paying for more electricity over that time with Lead; 36MWh costing $3600 compared to 21.6MWh $2160 @ $0.10 per kWh and recharging 80% of capacity. You would also need to water the batteries if you went with the Trojans, while the lithium’s would be maintenance free. It’s also worth mentioning that there are apparently disputed copyright issues with the thundersky cells and their previous record with customer support apparently not good, but this was just a cost comparison and the number look pretty convincing.
The total cost per km for the 2000 cycles is $15 750/ 130 000km = 12.1c per Km (19.7c/mile) for Lead Acid and $13888/ 130 000km = 10.7c per km (17.4c/mile) for the LiFePO4. These would obviously increase slightly when factoring in tire and brake wear. Just for comparison a the cost per km of a bunch of small ICE cars are listed here the cheapest being 41.44c/km but only 33.5% of that cost was for fuel and servicing (the rest being common cost for EVs as well) so that’s 13.9c/km for the cheapest ICE using fuel at $1.25/L. Clearly then EV have a price advantage over ICE’s especially now that normal unleaded is averaging $1.48/L.
In summary, while Lead Acid may be cheaper up front new lithium packs are more cost effective in the long run as well as being lighter, smaller and maintenance free. Obviously battery choices are highly dependant on individual conversions and budgets but it should not be assumed that Lead is the budget option, since it’s just not true anymore.


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## mattW (Sep 14, 2007)

But are you comparing the same range for the two packs? You can buy lithium without getting a 100 mile range, people seem to overestimate their lithium sizing and payback time. It doesn't bother me if you go with lead, that your choice, I just want people to look at the actual comparison not just 100Ah of lead costs this much 100Ah of lithium costs this much. There is more to it than that...


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## namyzarc (Mar 18, 2008)

I think one of the main things you left out of the article was a weight comparison. 18 lead batteries at about 50lbs each would weigh 900lbs. Not sure what the carrying capacity of a compact car is, but you would probably not have the ability to carry much of anything else without a suspension upgrade. What would the cost of upgrading the suspension be? What are the effects on the cars handling by adding this much extra weight? What is the weight of the Lipo's? We can't discount these factors.
Also, as someone else said, I agree that shelf-life (as well as total cycles) should also be taken into account.


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## JRP3 (Mar 7, 2008)

mattW said:


> But are you comparing the same range for the two packs? You can buy lithium without getting a 100 mile range, people seem to overestimate their lithium sizing and payback time. It doesn't bother me if you go with lead, that your choice, I just want people to look at the actual comparison not just 100Ah of lead costs this much 100Ah of lithium costs this much. There is more to it than that...


Yes that's a good point, you don't need the same amount of Lithium as lead since lithium has more usable energy, plus the fact that you are dragging around less weight with the lithium.


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## Qer (May 7, 2008)

JRP3 said:


> Yes that's a good point, you don't need the same amount of Lithium as lead since lithium has more usable energy, plus the fact that you are dragging around less weight with the lithium.


Or you could drag around LOTS of Lithium but get a serious range. 100 km or more would be VERY nice, but doesn't seem very realistic with led, at least not if you want to go at highway speed too.


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## onesojourner (May 6, 2008)

My 2 cents
is 2000 really a realistic number? what if you start having cells die after 500 or 1000? then what?


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## JRP3 (Mar 7, 2008)

Qer said:


> Or you could drag around LOTS of Lithium but get a serious range. 100 km or more would be VERY nice, but doesn't seem very realistic with led, at least not if you want to go at highway speed too.


I've seen a number of conversions on EValbum.com that got 60 mile range and 70 mph top speed.


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## david85 (Nov 12, 2007)

onesojourner said:


> My 2 cents
> is 2000 really a realistic number? what if you start having cells die after 500 or 1000? then what?


The cycle life is similar among many different companies using the same LiFePo4 chemistry. With the proper BMS, 2000 cycles should not be a problem as that assumes 80% DOD every time.


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## saab96 (Mar 19, 2008)

david85 said:


> The cycle life is similar among many different companies using the same LiFePo4 chemistry. With the proper BMS, 2000 cycles should not be a problem as that assumes 80% DOD every time.


What would that proper BMS be? While we have standardized controllers and motors and chargers for EVs, I have yet to see a true BMS "product" out there that has a published pricetag that you can just buy. It's really the missing link.


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## Weka (May 23, 2008)

The BMS is the core of the debate. The issue with lithiums is they need to have a closely coupled battery management system which is quite complex since it needs to monitor the batteries on a cell by cell basis and therefore expensive.

Over time the cost of the BMS and the lithiums will clearly reduce while the cost of oil and lead-acid batteries will clearly increase. However right now we need a good, proven BMS for lithiums to progress putting them into cars. Does anyone know of a good BMS out there?


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## mattW (Sep 14, 2007)

The BMS was included in the calculations. There is a link to it in the blog. The cost for a 10kW pack was AU$1270. $350 for the master module and $24.20 per 3.2V unit.


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## Weka (May 23, 2008)

mattW said:


> The BMS was included in the calculations. There is a link to it in the blog. The cost for a 10kW pack was AU$1270. $350 for the master module and $24.20 per 3.2V unit.


Good point Matt and quite true however I guess we are changing the argument on you from cost to availability. Can you describe your BMS supplier please, how it works, and why you think it is reliable? Don;t get me wrong, I would be delighted if you can point me to a good Lithium BMS solution


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## david85 (Nov 12, 2007)

If you go to the metric mind website you can find a good BMS system. I don't believe that prices are on the website, but you can drop Victor a line and find out.

Most contacts I have located in china supply the BMS with the battery. All it has to do is cut off voltage and amps above and below certain parameters, not very complicated.


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## mattW (Sep 14, 2007)

I haven't looked into it that much specifically- you can email him if you want more info. To be honest I just trust the person who recommended them to me. I can't really comment on how good they are because I haven't got mine yet.


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## ga2500ev (Apr 20, 2008)

Matt, I have to take issue with the most critical item in your discussion:



> Now I must admit that I didn&#8217;t look very hard for the cheapest batteries and I am only guessing the cycle life of the Trojans but even if it&#8217;s not precisely accurate it does show that the myth that Lead is clearly cheaper than lithium is not well founded.


You picked a situation that severely confounds your results. Your use of Australian Trojans at the extreme price of $225 AUS makes your comparison easy.

Trojans are expensive. Lead Acid in Australia is extremely expensive.

Let's try some US based Trojan T-105s from here:

http://www.thesolar.biz/Trojan_batteries.htm

Same voltage. Same Ah rating. Price USD is $127 each. So your pack price is now $2286 for 18 batteries. 3 sets cost you $6858 USD.

See? Just by shopping around your argument kind of falls apart.

And in the US I haven't gotten to the Eveready GC2 golf cart battery from Sams that only $75 USD each. That's a full 1/3 of the price of the T-605s that you originally quoted. Same voltage and same Ah rating as your T-605s.

From a technical standpoint Lithiums are better. There's absolutely no dispute about that. However at least in the US lead acid is definitely a fully available option on the table because lead acid packs are available at a small fraction of the cost of lithium.

ga2500ev


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## ngrimm (Oct 19, 2007)

Does anyone have a 10 year or even a 5 year old laptop with original batteries that hold a charge anything like they did when they were new? Or how about a rechargeable drill? Just curious since I have always seen a huge drop off after just a couple years. Norm


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## hardym (Apr 2, 2008)

As a Lead-acid EV owner who's joined the ranks of realization that their EV does not provide the distance that that they would like...

I've tried to create a wiki page of all the alternatives to lead-acid on this site, and for each specific option, detemrine the cost of a 10KWh pack. (10KWh is arbitray, but it would get me to work and almost back.)

The link is at 
http://www.diyelectriccar.com/forums/showthread.php?t=13351

This has been a disappinting collection of research until i found the latest lithium entry, which is:
_Ebay Ping__ is only selling on ebay, but offers a pack with BMS: 48V 20AH for $840 (10 packs = 9.6KWh @ $8400) __Ping doesn't recommend __series/parallelling of pack. Not sure of who manufacturers the cells, and no cell data. Here is a __testimonial__ on a bike._
​Note the price point: *$8400 for a 10 KWh pack*, which is a good price point. Lithim is the holy grail EV batterys. The problem is paralleling these packs for EV use. I'm working on trying to find someone who has successfully done that. If you know of any... please pass info along.

Mark.
http://www.evalbum.com/1352


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## saab96 (Mar 19, 2008)

hardym said:


> As a Lead-acid EV owner who's joined the ranks of realization that their EV does not provide the distance that that they would like...
> 
> I've tried to create a wiki page of all the alternatives to lead-acid on this site, and for each specific option, detemrine the cost of a 10KWh pack. (10KWh is arbitray, but it would get me to work and almost back.)
> 
> ...


Do the math again. That's a 10khw pack of 20ah cells. You'd need 5 of these to get good EV range which would be about double what you can find elsewhere with 100ah bricks.


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## Manntis (May 22, 2008)

david85 said:


> If you go to the metric mind website you can find a good BMS system.


He still hasn't fully completed it yet, and hand-makes each module. I enquired about 98 of them and was told it'd be months before he could ship them.


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## Manntis (May 22, 2008)

mattW said:


> The BMS was included in the calculations. There is a link to it in the blog. The cost for a 10kW pack was AU$1270. $350 for the master module and $24.20 per 3.2V unit.


If you're referring to Rod, making them for TS batteries, his are limited to a relatively low voltage - but from what I've seen his quality control is excellent and he comes across as an extremely knowledgeable and easy to deal with fellow.


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## saab96 (Mar 19, 2008)

ngrimm said:


> Does anyone have a 10 year or even a 5 year old laptop with original batteries that hold a charge anything like they did when they were new? Or how about a rechargeable drill?  Just curious since I have always seen a huge drop off after just a couple years. Norm


Lithium cobalt doesn't have the longevity as lifepo4. It's a big concern with the Tesla, for instance, because the lithium cobalt battery pack is such a large chunk of the cost of it.


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## MitchJi (Dec 14, 2007)

> The cheapest Lithium batteries I have seen in Australia are Thundersky LiFePo4 LFP prismatic cells $2.50 per 3.2V per Ah. So our 13.5kW pack would take 38 3.2V cells at ~110Ah and would cost $10450 at normal prices (no group discount), without shipping or BMS.
> 
> For a Lead Acid pack we also need to keep the batteries at less than 80% DoD and at the 1hr rate we can only expect to get 55% of the rated energy of the pack back due to the Peukert’s effect.
> 
> ...


Hi Matt,

Question:
Can you really discharge the Trojans to 80% DOD and still get 650 cycles?

Comment:
If you are going to assume the Lithium's will last 3x lead you need to be sure to purchase batteries that you are sure will last that long. This means either a reliable warranty (best) or exhaustive testing from a reliable source or an excellent track record in EV's. Otherwise you are basically purchasing a very expensive lottery ticket. There is no way in the world I would either spend $10k for a pack of Thundersky Lithiums or recommend anyone else do that either. For your comparison to hold up you need to find a reputable source with those lithium specs and prices.

Best Wishes,

Mitch


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## mattW (Sep 14, 2007)

My comparison wasn't to prove it once for all or definitively or anything, I just wanted to show that the overall price is similar long term even if the up front costs are different. People keep saying things like Lead is cheap but lithium is still ridiculously expensive which I think is a little deceptive if you think of the long term. I'm not sure about the cycle life of the trojans (or the thundersky's to be honest) I just estimated based on what I've seen.


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## Weka (May 23, 2008)

There was a previous commentator who said that MattW's calculations were wrong becuase there was a difference between Aussie battery prices and US prices. I checked - Matt specificed T605 whreas the commentator has I think made a mistake and thought they were T105. In fact the T605 battery is US249 from http://www.evwholesalers.com/about-us.html - who are pretty cheap - so we can see that MattW's calcualtions hold up very well.

In fact I think Matt has understated the commercial advantage of lithiums given the very rapidly rising lead prices. The real issue is finding a reliable commercially available combination of batteries and battery management system. I intend to write to the BMS that Matt mentioned and see what they say, the web site is not overly specific but looked promising.

Matt - how did you work out the price on the BMS? And you said you had a mate who you trusted- can you be more explicit? By the way, that is a great article you wrote.


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## mattW (Sep 14, 2007)

The batteries and BMS were recommended to me by ian from www.zeva.com.au, you may have seen his battery testing. He is using them on his Mx5 conversion.

I worked out the price as $350 plus 38 slave modules (120V) at 24.20 each ($919.60) so around $1270 total


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## ga2500ev (Apr 20, 2008)

Weka said:


> There was a previous commentator


That would be me.



> who said that MattW's calculations were wrong becuase there was a difference between Aussie battery prices and US prices. I checked - Matt specificed T605 whreas the commentator has I think made a mistake and thought they were T105. In fact the T605 battery is US249 from http://www.evwholesalers.com/about-us.html - who are pretty cheap - so we can see that MattW's calcualtions hold up very well.


I didn't make a a mistake in choosing the T-105. It's a battery with a similar configuration as the T-605. I also pointed out a site that had a much better price, nearly half.

Here's another:

http://www.bohannonbattery.com/html/golf.html

The T-605s are $92. The T-105s are $119.

Matt has gone out of his way to find the cheapest $/Ah he could for lithium. However he, and you, also seem to go out of your way to pick the most expensive price you can find for lead acid.

I pointed out, and will continue to point out, that lead acid batteries can be had for 1/3 to 1/2 of the price that you are quoting. And as long as they are available at those prices, that even with replacement, they represent good value and lower capitalization costs than lithium.




> In fact I think Matt has understated the commercial advantage of lithiums given the very rapidly rising lead prices. The real issue is finding a reliable commercially available combination of batteries and battery management system. I intend to write to the BMS that Matt mentioned and see what they say, the web site is not overly specific but looked promising.
> 
> Matt - how did you work out the price on the BMS? And you said you had a mate who you trusted- can you be more explicit? By the way, that is a great article you wrote.


I know that it seems that I'm just flat out against lithium. I'm not. I'm just being realistic in understanding that a lot of new people who flow into the electric car industry, such as myself, are specifically here because gas prices are ridiculous and are continually rising. Therefore they are here to get value for the dollars that they spend.

Lithium does not yet represent a superior value to lead acid. Right now if you compare the prices of the cheapest lithium, with suspect availability as has been pointed out in this thread, to widespread and cheaply available lead acid, the value just cannot yet be justified.

I can go today, on US Memorial Day, and plunk down $1925 USD and get a [email protected] pack that will last 2 years with proper care and deliver nearly 15kWh of usable energy on a daily basis. Even at 400 Wh/mile that's 36 mile range.

When I can do the same with lithium, even at 3 times the price, then it may be worth taking a look.

But I can't do it today. Can you?

ga2500ev


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## ga2500ev (Apr 20, 2008)

saab96 said:


> Do the math again. That's a 10khw pack of 20ah cells. You'd need 5 of these to get good EV range which would be about double what you can find elsewhere with 100ah bricks.


Actually he did say 10 packs making a [email protected]=9600kWh pack.

ga2500ev


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## mattW (Sep 14, 2007)

Well I've looked at like 6 suppliers here in Oz and I can't find any Trojan's cheaper than that $225 mark. Are they made in the US? That would explain the price difference between here and there. If you can get them for $92 then go for it. I have only seen 2 suppliers of thundersky cells in Australia and I actually used the more expensive price of $2.50 per Ah when my other supplier can do it for $2.40 normally or even as low as $1.83 for bulk orders. As I said in the blog, it would be different for different countries.


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## ga2500ev (Apr 20, 2008)

mattW said:


> Well I've looked at like 6 suppliers here in Oz and I can't find any Trojan's cheaper than that $225 mark. Are they made in the US?


Yup. There's a Trojan manufacturing or distribution facility within 5 miles of my home. I'm actually thinking about dropping in one day and seeing if they have any deals.



> That would explain the price difference between here and there. If you can get them for $92 then go for it. I have only seen 2 suppliers of thundersky cells in Australia and I actually used the more expensive price of $2.50 per Ah when my other supplier can do it for $2.40 normally or even as low as $1.83 for bulk orders. As I said in the blog, it would be different for different countries.


Understood.

ga2500ev


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## MitchJi (Dec 14, 2007)

mattW said:


> My comparison wasn't to prove it once for all or definitively or anything, I just wanted to show that the overall price is similar long term even if the up front costs are different. People keep saying things like Lead is cheap but lithium is still ridiculously expensive which I think is a little deceptive if you think of the long term. I'm not sure about the cycle life of the trojans (or the thundersky's to be honest) I just estimated based on what I've seen.


Hi Matt,

http://www.evworld.com/news.cfm?newsid=18037



> Source: Mother Jones
> [Apr 18, 2008]
> 
> _SYNOPSIS: Long-time EV experimenter Lee Hart finds the search for the perfect battery is fraught with obstacles_
> ...


Hi Matt,

Spending $13k on lithium cells some of which test out at about half their spec's isn't a good investment. 

Until you find a source for reliable lithium batteries with the price and specifications you mention IMO you have not proven that costs are currently similar, although you have shown that long term costs are closer than they seem at first glance.

On the other hand compared to Lead, using Lee Hart's Maintenance methods, Lithium might be even more expensive in comparison.

Best Wishes,

Mitch


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## MitchJi (Dec 14, 2007)

Hi Matt,

I think weak cells are likely to cause problems with cheaper Li-Ion Packs. Maybe you can get around this if you do your own testing and replace any weak cells. The following is from a company that sells much smaller (ebike) packs so there would be a higher failure rate with larger packs:

http://www.ebikes.ca/batteries.shtml


> Capacity Matching
> Reputed companies that build the battery packs will use cells that have been individually selected to have identical capacity. Then all cells in the pack will go flat together and there is little risk of cell reversal. We have found that almost all companies claim that cells in each pack are matched within 2 to 3 %, but our own testing has shown that a significant percentage (sometimes over half) of packs have at least one cell that is will outside of this specification.


http://www.ebikes.ca/store/#Batteries


> Testing and Guarantee
> We cycle discharge test every single battery pack several times before selling it to guarantee that it delivers the full rated capacity and that there are no premature cell reversals. With your battery there is an ID number and if you request we can send you the actual discharge test results. Our experience has shown that upwards of 20-30% of the batteries in any shipment will have at least once cell that does not deliver to the specified capacity and could cause problems down the road. With some manufacturers this can be as high as 50% of the packs, so keep this in mind when purchasing from suppliers that don't do independent testing.


Best Wishes,

Mitch


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## fire92658 (May 14, 2008)

matt... you forgot tax!


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## mattW (Sep 14, 2007)

Lol, for a simple comparison on paper I didn't think I'd be under so much scrutiny! Mitch the battery specs that are half what is advertised is the current rating. They only put out 3-5C not 10C as advertised. I have already designed my ReCYCLE project around the tested parameters i.e. 300A peak from my 60Ah pack. But thanks for the research.

If anyone wants to disagree with my conclusions then go ahead and do a comparison with the batteries you are considering. I just did it for the batteries I was considering, and as they were both from vendors inside Australia they already included the tax.


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## fire92658 (May 14, 2008)

Matt,
I know this may sound elementary but.. what is 3C ? is that the discharge rate? thanks


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## mattW (Sep 14, 2007)

I've never heard it explicitly explained but it is basically 3x Capacity or a discharge rate in amps of three times the capacity in Ah. SO for a 60Ah pack, 3C means a 180A discharge. A 100Ah pack gives 300A at 3C.


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## Guest (May 28, 2008)

I think shelf life needs to be addressed more than anything. It is already known that the power per weight is far better than lead. What is the real shelf life? It would not matter one bit if my batteries could be charged and discharged thousands of times if the shelf life is only a few years. And from what I have heard it is around 3 years. So if that is true then lithium is out the door before it even starts. For small products it is more likely that they will be tossed out or replaced with a better item before the battery life is gone. But with an EV needing to last 10 plus years or more then the battery shelf life as well as use life needs to meet the demand. I only hear of what kind of power they have and the shelf life is avoided in conversation. Why? Well I guess time will tell and only time will tell if it will meet the needs of the EV crowd.

Pete : )


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## Weka (May 23, 2008)

ga2500ev et al

You are quite right with respect to the price of the Trojan batteries - there is certainly a quite incredible price difference in the United States with respect to advertised prices - in my sweep I found 8 stores all with different prices ranging from over $200 to $150 to as you say $92. I would note that postage and packing on 450 odd kilos would add quite a bit ... but the point is well made.

I guess the key item is that I perceive lithiums as the future and would not want to invest in lead batteries as I think it is now "throw-away technology". A bit like investing in CP/M (for those who remember such things) when MS-DOS first came out. The issue is that they are on the bleeding edge and as usual the pioneers get arrows in them ... sometimes through them. It would be good to get references from people using it, the link supplied by MattW is quite interesting in this respect.


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## mattW (Sep 14, 2007)

Well the MX5 should be finished in early june so I will pass on any performance reports I get.


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## Weka (May 23, 2008)

Just to coninue posting items that are off-topic (why break a habit) here's my draft budget for an electric conversion using the lithium battery price point and BMS figure you supply. Although I notice that according to the Aussie Thundersky site they are about to drop their prices 15%. Any comments? Units are Australian dollars

Budget for electric car
Mazda 5,000
Motor 2,300
Controller 1000
BMS 1300
Batteries 10450
Adapter plate 1000
Engine mounting1000
Other 1500
Total 23,550


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## kkjensen (Apr 25, 2008)

I'm thinking of going with thunderskys. In my quest for knowledge about the LiFePO4 I came across a tech.yahoo group that is quite active and swapping testing info and such. The group started when a couple group deals (for the lithium cobalt cells) in the UK and US went through and the US shipment had a bunch of bad cells (which we all hear about and fear is the norm). Aside from this one bad shipment I have had a difficult time finding anyone giving bad reviews (which are different than bad rumors) about the LiFePO4 cells. Buying in bulk (>100,000Ah) gets the price down to $1/Ah so IF the shelf life and reliability is good then they could prove to be very good. Performance wise any vehicle will run better with 300lbs of batteries vs 1500lbs.

My quest continues...


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## JRP3 (Mar 7, 2008)

> Performance wise any vehicle will run better with 300lbs of batteries vs 1500lbs.


Unless those 300lbs of batteries don't work  You might want to check out this thread, discussion about a group purchase of PHET lithiums:
http://www.diyelectriccar.com/forums/showthread.php/lifepo4-group-purchase-14074.html


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## MitchJi (Dec 14, 2007)

DIY Electric Car Blogs said:


> I've decided to try and work out the cost comparisons for a Lithium pack vs a Lead pack for a set range and a set number of years. Is Lead Acid actually cheaper or does is just seem that way up front? This article aims to find that out. The method is to get 10kWh of usable energy, I’ll try to get that with Lead and with Lithium and see what we find is cheaper in the long run. Assuming an efficiency of 250Wh per mile (a compact car) we should get a range of 40 miles (65km) with either pack. I’ll be using Australian prices since I’ve already researched them, but the comparison is probably close in other countries too.


Hi,

Check this out (scroll way down):
http://www.diyelectriccar.com/forums/showthread.php/evdl-a123-l5-battery-14296.html


> The thing about kokam that is scaring me off right now is that nasty >800
> charge cycles to 80% capacity...
> 
> Thundersky lists >2000 cycles for the same discharge level. I know you cannever be sure about specs, but that's a big difference.
> ...


Hi,

Comparing Lead from a reputable company whose batteries have a good track record with Lithium Batteries made by a company with an extremely bad reputation and whose batteries have an extremely bad reputation is not a valid comparison. Taking it a step further and stating that even though their Lithium's are more expensive they will be cheaper in the long run because they will last longer doesn't make any sense at all.

I thought about not posting this but I am concerned that:
1. Matt is going to spend a bunch of money for junk cells.
2. Someone else is going to stumble across this thread and spend a lot of money for junk cells.

I think either the thread should be deleted or the above comments on TS should be moved up to the second post on the thread.

BTW this is Victors site and he is using Kokam on his latest conversion:
http://www.metricmind.com/

Best Wishes,

Mitch


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## mattW (Sep 14, 2007)

There have been serious issues with Thundersky in the past, and a lot of the EVDL guys have been burned by them and are completely against them which is understandable. A lot of it I think had to do with Chinese vs western Quality control expectations, something I think thundersky has learnt their lesson from. I haven't heard any negative reports about the latest model of thundersky batteries. Rob from EV power has done 10,000km on them without any problems. Ian from Zeva is using them in his MX5 even after his extensive testing of lithium batteries. Trev from Foundry and Fiberglass has no problems with his new batteries. I will be monitoring those conversions up until I buy my own batteries but I think the newer batteries are trustworthy, and have not heard of a single report of bad cells of the LFP batteries.


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## david85 (Nov 12, 2007)

Actually I'm with Matt on this one. I feel most of the bad wrap that comes up against TS is rooted in the original 2003 purchace. Their newer batteries tend to get th esame feedback by default. But of those that are actually using TS batteries right now I am having a very hard time finding some one that will talk badly about them. I wonder if the mythbusters had any problems with them.


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## kkjensen (Apr 25, 2008)

mattW said:


> Rob from EV power has done 10,000km on them without any problems. Ian from Zeva is using them in his MX5 even after his extensive testing of lithium batteries. Trev from Foundry and Fiberglass has no problems with his new batteries. I will be monitoring those conversions up until I buy my own batteries but I think the newer batteries are trustworthy, and have not heard of a single report of bad cells of the LFP batteries.


Thanks for posting this info...I've been looking for a while for POSITIVE info about the newer cells since I understand it was the older cobalt ones that had probs. I'm starting to lean towards the C-LiFePO4 cells from PHET...apparently they have the patent on the process that give A123 their oomph and A123 pays them a premium, hence the higher price. If TS cells prove to be more consistent and reliable then the better price is the icing on the cake.


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## linz (May 18, 2008)

With this BMS, has anyone asked metric mind or the australian supplier whether they would sell at least the cell-level BMS circuits as kit sets? Assembling and testing of all those must take some time and really push up the delivery times.


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## david85 (Nov 12, 2007)

I know of at least one example of a conversion of TS batteries where the builder sourced a separate BMS through metric mind. No idea what the price was though.


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## Weka (May 23, 2008)

Matt

Can you clarify exactly what Thundersky battery you considered in your hyothetical battery pack? Was it the following battery or one of the bigger and heavier ones?

LFP40AHA 3.2V 40AH 120A 2000 190x116x46 1.5k

Also, what is the relationship between the BMS and the number of cells? In other words, do you need to reduce the number of BMS modules if the number of cells are reduced?


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## mattW (Sep 14, 2007)

I'm going with the 3.2V 60Ah cells, they weigh 2.2kg each so my total pack weight weill be around 53kg. Considering the engine weighed 66kg that is pretty good . You need one slave module per cell so the higher the voltage the higher the cost, but its not too bad.


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## Manntis (May 22, 2008)

I used 90aH TS cells for greater range. They're still reasonably small - my traction pack weighs approx. 294kg (647lbs).


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## mattW (Sep 14, 2007)

I didn't know you used TS manntis? What sort of current are you getting out of them? I am hoping I can squeeze 5c every once in a while but it looks like 3c is the norm.


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## Weka (May 23, 2008)

Manntis

Are you referring to 90Ah Thunderskys at 3kg each - that would indicate that you have 98 batteries nearly 30k/w of energy stored which would be the most powerful vehicle I know of?


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## Manntis (May 22, 2008)

28.2 kWh, actually


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## helloworld (Jun 18, 2008)

What?

and you guys end the thread there?
I just read this entire thread from start to finish, and it felt like I reached the crescendo plot of a novel, grinding away at the great cost debate of lithium vs lead, and then......... nothing.

OK, so Manntis has the biggest pack at 28.2kWh using lithium from thundersky

do they work well?
are the rumours of thundersky gear unfounded?
what was the cost for 28.2kWh of lithium using the 90Ah units???
where do you put 98 batteries?


and where did the lead advocates go?
does anyone have a comparable 28.2kWh setup using lead?
and what does their setup weigh in at?
what was the cost?


I think there are a good number of brilliant people participating on this forum which is what makes it such a great place to read the threads.

but now I feel blueballed after reading six pages of excellent dialogue on what I would consider the greatest bottleneck of every EV conversion.
it was a wonderful back and forth discussing the pros and cons of each, incredibly useful links and reference information, took me about 4 hours to read everything associated to this thread; with no conclusion?

and then.........


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## mattW (Sep 14, 2007)

Well where I live it is cheaper or at least just as cheap to go with lithium in the long run, assuming they hold true to their 2000 cycle life. That's not taking into account the added benefits of their smaller size and weight. It may be different for you where you live, so I suggest you do your own research, just make sure you size your pack with the usable energy not the total energy rating of the pack. You can use a much smaller lithium pack due to peukert's effect as I outlined in the blog.

Sorry there isn't a more conclusive answer but I guess its just 'It depends', I'm glad you liked the thread though


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## Manntis (May 22, 2008)

helloworld said:


> OK, so Manntis has the biggest pack at 28.2kWh using lithium from thundersky
> 
> do they work well?
> are the rumours of thundersky gear unfounded?
> ...


I don't know if I've the largest pack; I only know my pack size. Keep in mind I'm also using a 312V motor.

each 90aH LiIon battery is considerably smaller than its lead acid counterpart, so packaging them wasn't that bad. Ideally batteries should be in the same location for common humidity, etc. but in a small car like mine that's just not practical.

The main pack is where the storage bins behind the seats used to be, keeping the mass low and centered fore-aft as much as possible. The balance of the batteries are in 'saddle bag' boxes around the motor up front (an RX-7's engine bay is surprisingly large given the tiny size of engine), still keeping it between the axles as much as possible.

Even in a stock RX-7 there's almost 2 feet of dead space between the bumper and rad; with the rad gone there's a lot of space left up front but I wasn't about to a) put heavy mass forward of the front axle nor b) put very expensive parts in the crumple zone where it could get, well, crumpled in the event of a head on collision.


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## helloworld (Jun 18, 2008)

OK

so here is what I can glean from the knowledge contributed to this thread. 
there are many factors involved in the battery selection process, granted, everyone will agree to that. Leaving cost aside for a moment, trying to ascertain what is better, lithium or lead for an EV.

I am focusing on Watts/KG as a simple measure of comparison.

Manntis uses the 90AH lithium cells at 3.2V each, and 3KG per unit
3.2V X 90AH = 288AH X 98U = 28224WH of storage
98U X 3KG = 287.76KG
28224WH / 287.76KG = 95.92W/KG
(3.2V*90AH)/3KG=95.92W/KG

There was repeated mention of the T605 as a solid contender for the Lead camp, so using that as an example:
6V X 210AH = 1260AH X 24 = 30240WH of storage
24U X 22.08KG (50lbs) = 529.8KG
30240WH / 529.8KG = 57.08W/KG
(6V*210AH)/22.08KG=57.08W/KG

Now using that calculation as a base, it would be my opinion that if you are doing a small EV with a small target range on a tight budget, the lead battery is definitely the right choice.

there is also the issue of discharging that mattW brought up, most of the larger motors require a larger draw of amps, and if the lithium do not reach 10C as advertised and are truly limited to 3C to 5C as stated earlier in this thread then that would be another strike against lithium.

But if you are doing anything with larger vehicles and larger ranges, the lead acid batteries just dont scale as nicely as the smaller and more energy dense lithium packs. And there were too many excellent arguments on supply/availability/costs/management systems etc... to quote.

I have a 3/4 ton GMC I am converting with a standard payload rating of 1698KG(3847lbs)
for roughly $100 per T-605 comparable (Canada), I can fill my truck for 5K to achieve 60.48kWh of battery.

my vote goes to lead unless someone can find an error in my logic????


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## kcblkeeley (May 8, 2008)

Are you going with 300 v or 150 ish done with s/p combo? 50 or so batteries at about 80lb ea? (you said 5k at $100 each) I am very new to this but that's a lot of weight. Is the extra weight worth the volts/ah?
Curious


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## mattW (Sep 14, 2007)

Well as I worked out in the blog, Peukert's effect and DoD play a big role in the usable energy of the packs. If you go to 80% DoD with Lead Acid (and a lot of EVers prefer to stay above 50%) and assuming you get 55% of the 20hr rate at the 1hr or so you will actually use the battery at you only get 44% usable energy for Lead Acid Batteries whereas Lithium would give you 76%. Rehashing your numbers that means that:

Manntis uses the 90AH lithium cells at 3.2V each, and 3KG per unit
3.2V X 90AH = 288AH X 98U = 28224WH of storage x 0.76 *= 21450 usable Wh*
98U X 3KG = 287.76KG
28224WH / 287.76KG = 95.92W/KG = *74.54 usable Wh/kg*







(3.2V*90AH)/3KG=95.92W/KG

There was repeated mention of the T605 as a solid contender for the Lead camp, so using that as an example:
6V X 210AH = 1260AH X 24 = 30240WH of storage *x 0.44 = 13306 usable Wh*
24U X 22.08KG (50lbs) = 529.8KG
30240WH / 529.8KG = 57.08W/KG *= 25.11usable Wh/kg*







(6V*210AH)/22.08KG=57.08W/KG

So for a given weight you can have three times the energy with Lithium, or for the same sized pack your lithiums should weight 1/3 the weight.

On the discharge note, most controllers are only 500A which only requires a 100Ah battery pack which would be a pretty small range for most EVs so I don't think that's an issue, if you want higher discharges there are more expensive lithiums that can do bursts of up to 40C.

The only real advantage Lead Acid has is upfront cost, which is a big advantage I'll admit, but I don't think its worth the maintenance, weight, size and inefficiency of Lead, especially when the high cycle #'s of lithium make the lifetime cost comparatively similar (at least within the ballpark).


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## helloworld (Jun 18, 2008)

My bad, forgot the Peukert variable.

When you put it that way, the lead does not look very appealing at all.


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## JRP3 (Mar 7, 2008)

Unless you're looking at an AGM such as Hawker/Odyssey which have very low internal resistance and can put out high current, as well as take high current. They also last longer than standard lead, but cost more as well, so I don't know if the cost basis improves for them or not.


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## mark (Nov 14, 2007)

There is no money to be saved or made in this nonsense, it is pure flight of fancy to think that just because gasoline costs are spiraling out of control large corporations and the federal government will allow business/taxation models to change, so I say to you all, you are on your own. But I will also say keep an eye on A123 systems and Cobasy or should I say Chevron Technologies, there may be hope in the fields of nano tech, however I fear the price and availability to the public will be prohibitive in nature.

P.S I converted a VW to electric and currently I am commuting to work and back with it, pissing off impatient aggressive drivers everywhere. Top speed 45 mph


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## JRP3 (Mar 7, 2008)

mark said:


> There is no money to be saved or made in this nonsense, it is pure flight of fancy to think that just because gasoline costs are spiraling out of control large corporations and the federal government will allow business/taxation models to change, so I say to you all, you are on your own.


What are you talking about? This is a thread discussing the cost differences between lead and lithium.


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## mark (Nov 14, 2007)

I meant to say neither lead or lithium are adequate and effective in my opinion for the future tasks that will be required in the transportation of the masses (to convert the fleet in an effective way over the next 7-10 years). If anyone is interested there is a EV battery calculator at this site. 
evconvert.com/tools/evcalc/?s=b


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## Weka (May 23, 2008)

Mark

I think I have read your posts on the Volt site as well, or at least there is somebody there who makes very frequent posts expressing the same statements as you have made here. You are entitled to your views, but basically we are trying to get understand more about a fast-changing technology (lithium batteries) which have had a remarkable improvement in their price / performance over the last 8 years and which seems set to continue. In fact, if I could have a higher level of confidence in the Thundersky metrics, and an associated BMS with a proven track record, I would probably buy a Thundersky pack right now. I doubt if it would a completely economic decision, but it wouldn't be far off.

What I really want is a friendly person to vouch for the Thundersky batteries - or alternatively for a body of knowledge to form which provides the same outcome. Currently I think I will wait another year or so until the picture becomes clearer, but if anyone could provide sound advice on the reliability of Thunderskys / BMS I for one would be very interested.


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## mark (Nov 14, 2007)

You know it is odd you should mention Thunder sky I've been watching them as well and suggested the same thing you did,wait a year or two to see how the performance and pricing evolve. The only problem with that is there are probably thousands of other potential customers out there who are using the same wait and see strategy, and as you must know with supply and demand economics this doesn't help speed up R&D. You sound fairly well read, there is a Chinese gentleman at my place of employment who is aware of my electric car and seems amused by my exploits, he has mentioned he has a business friend in China who develops and sells the lithium chemical components contained in modern lithium batteries. I have not had the time to ask many questions and his broken English is difficult to understand at times, I will ask him however about thunder sky and get back to this blog with any important inside information that I can gather.


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## bazza413 (Jul 2, 2008)

We have been using the *TS-LCP200AHA battery on a number of different applications and I can only speak good of them. We have has very few problems and have probably have a few thousand cells in use. I think the bad rep is still carried over from the old days. On the 3.5t trucks we are developing we have 84 of each of these cells per vehicle so it is a huge investment cash wise (approx £20k sterling per vehicle) and I know the guys have done huge amounts of research to find the best overall product. I know that as we are a commercial concern money is not the key object. We are getting from a 3.5t chassis with a box body on it a range of 85 miles and using the manual gearbox we can get a top speed of 80+ mph.*

*Getting back to the original point, Lithium will become more with in the price range of the masses and BMS will come down in price. Lead batteries are in some respects old hat and lithium is the future but from an individual point of view I can see both sides of points that have been made in this discussion. With my experience of the TS product and its resilience to abuse, I would if buying for myself go with a Lithium product over a Lead product even though the purchase cost would be higher.*


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## Weka (May 23, 2008)

Bazza412

Can you be a bit more specific please? Do yuo have a website? You seem to be implying that you mave a major Thundersky project going on with 200a/h batteries - I can see that these would easily be 20k sterling - that would be by far and away the biggest lithium battery powered project I have heard of. What is it all about?


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## mattW (Sep 14, 2007)

Thanks for the feedback Bazza, its good to hear... I'm still saving up for my TS pack.


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## bazza413 (Jul 2, 2008)

The link to the company that developed the vehicle is http://www.micro-vett.it/eng/indexing.html The product we have is brand new and based on an LDV Maxus http://www.ldv.com/gb/index.asp it uses the standard 5 speed gearbox and the potential use of this vehicle in the UK espicially London is huge. At present we are starting production in the UK due to the volume of vehicles we need to produce, 1 customer requires 200, so as you see they guys in the know have faith in TS as that alone is 16800 cells. They may change the product if and when a lighter and more efficent cell becomes available.


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## DVR (Apr 10, 2008)

When this article was written the writter claimed the best price in AUS was $2.50 per A/h. I got a price today of less that $1.62 per A/h and very likely to be a low as $1.50perA/h.

This definitely swings the scales in lithiums favor!!


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## Wirecutter (Jul 26, 2007)

Well, continuing my *own* proclivity for off-topic posting, I'd like to thank the members and posters to this thread. Why?

I've read the entire thread to this point. A lot of information is presented, and a few recalculations and clarifications have been needed. But there is good info, minimization of rumor mongering, and civil discussion. So many other forums I've visited can't handle the volume of misunderstandings and clarifications without breaking down into a shouting match. Thanks to all of you.

Back on topic: I would really prefer to go with a lithium battery system for my eventual conversion. As discussed here, from a cost perspective, there are many angles, opinions, and variables to consider when deciding whether lead or lithium is cheaper. (over short or long haul)

What I care about is performance. Not just 0-60 time, but range. I once calculated that, for a given volume, lithiums provide 2-3x the energy and less than half the weight. That's holding volume constant. Hold the weight constant, and the volume goes up, and the power way up.

My point is that for an EV to be usable to me, I need rather long range and I need freeway speeds. So my vote is for lithium. I will have to pay the premium for the performance I want. I'm beginning to experiment with battery charging and management components. As info develops, I'll share it here.

Thanks again, all of you.

-Mark

PS. I'm living proof that you don't have to be "a Greenpeace activist living in a solar powered mound of dirt" to like electric vehicles. I'm not the greenest person on the planet by any means, but I think EVs are cool.


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## RKM (Jun 9, 2008)

Mark,

You and I are pretty much on the same page wrt lithium vs. lead. Lead would add so much weight to a Miata that it would dramatically affect handling and perhaps safety.

My ideal would be a 20-25 kwh lithium pack to get close to 100 miles per charge. I've been considering starting with a 15 kwh pack then possibly adding a second pack if/when cost drops. The additional cost and complication (two chargers, switching...) makes this option less appealing.

It seems that the majority of talk regarding "affordable" LiFePO4 batteries has been about Thundersky. I have serious reservations about using this brand. They have burned customers in the past (Victor et al). Therefore, I would prefer not to patronize them. Have they changed their ways regarding customer support? Have they improved quality control?

Are there enough of us keen to use lithium that we can put out a request for quotation? Define the specifications for a significant quantity and see what the responses are from a number of suppliers.

Rob


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## david85 (Nov 12, 2007)

The 2003 order is still haunting thundersky to this day. What I do know is that they were the first to take the risk of supplying large Lithium cells to end users at a reasonable price, so I do give them some credit for that. There are companies all over the world that still refuse to even talk to folks like us, let alone offer us the chance to try their product.

Thundersky's more recent LFP series of battery is supposed to be much better than the older ones and some retailers claim to have verified the specs though their own testing. The life expectancy cannot be verified except over time though.

All this means that you will have a very hard time finding real world testimonials of the new LFP cells. So far I only know of two conversions that are already running with many more in the works by others. Supposedly all of the buses used to transport people to and from the olympics will be powered by TS batteries. This stuff is still cutting edge so nothing is guaranteed yet and we will still have a while to wait before enough conversions are done around the world for us to get a fair picture of how reliable these batteries are. 

Of what little I have heard lately, it has all been good though. Even the mythbusters used them.


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## mattW (Sep 14, 2007)

Hey DVR where are you getting your batteries from? Foundry and Fiberglass or somewhere else... What are you doing for BMS? Honestly the thing was pretty skewed towards lead and lithium still came out neck and neck. You're very unlikely to get that many cycles from lead to 80% DoD.


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## DVR (Apr 10, 2008)

I'm got my quote from Robert Mason in West Aus This is the mail I got from him.

Hi Shane
The price is an estimate based on getting a bulk order of batteries. The price of larger cells, 90 Ah and up is coming down. I am reasonably confident that Aus$1.50 would be achievable by the end of August. The last shipment which included a lot of smaller cells averaged $1.62. Yes, they are Thunder-Sky batteries. Warranty is twelve months based on manufacturing faults only. Abuse of cells is not covered. The BMS made by Rod Dilkes (EV Power) is the only one I would recommend to date. Zivan chargers are very good. Again Rod has a cheaper charger which to date has given me no trouble after 2 months of testing.
At this stage, freight to Adelaide would be a bit extra.
The last shipment was 50% up front and the balance on receipt. I put up the other half since T/S wanted all their money up front.
I have done 3 orders with T/S and have found them to be very reliable.
Cheers
Rob 


As far as BMS goes I still havent found anything other than F7F's thundersky unit (too big and too expensive) and Rod Dilkes EVPOWER units.


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## Wirecutter (Jul 26, 2007)

RKM said:


> Mark,
> 
> You and I are pretty much on the same page wrt lithium vs. lead. Lead would add so much weight to a Miata that it would dramatically affect handling and perhaps safety.
> 
> ...


 The only information I have about Thundersky is the scuttlebutt (rumors, etc.) here and elsewhere. Some in this thread suggest that TS has/is improving. I can't speak from direct experience, but in my judgement, it sounds as if things are improving/have improved. I have _not_ put my "money where my mouth is," however, so this opinion is worth what you paid for it. 

My feeling in general about the large lithium cells is that they're still a little "bleeding edge". The quantities made are not very high, but the prices are. Availability is not a given, and it sounds like anyone serious about big lithiums would need to make contact with a Chinese factory and possibly visit one.

I'm intrigued by the system used by Tesla and others employing the AC Propulsion AC150 drive system. I'm not sure about the battery pack used in the Wrightspeed X1, but both the Tesla and the T-zero use a pack composed of thousands of the ubiquitous 18650 cells. (6831 cells per pack in the case of the Tesla) The white papers published by Tesla point out that there are billions of the 18650 made every year, so presumably people have figured out how to make them reliably. There are other reasons to make the case for this type of pack, but I digress...

I'm in the early research stages investigating the feasibility of this kind of design. I have some parts in hand and cells on order. I've picked up a battery welder, and I know how to use it. (Unitek 250 stored energy resistance welder and 132 weld head, for anyone interested.) I've also got some evaluation hardware for helping to design a battery management system. I'd like to conduct some of my own research to determine what can be done along these lines, and I may call on the folks here for feedback. But like I said, it's in the early stages, and unlike the Tesla company, I'm not going to promise anything wonderful for a while yet.  Of course, when I _do_ have something to brag on, I'll post here proudly. I'll shut up now.

-Mark


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## dimitri (May 16, 2008)

Speaking of Lithium options for us mere mortals, here is the quote from response I got from Valence:



> Unfortunately, due to the number of large projects we are currently engaged in, Valence is unable to respond to your inquiry. I apologize for any inconvenience this may cause.
> 
> Valence will keep your records on file and contact you whenever we’re in a position to properly support your request.


So we can pretty much write them off for now, although they were most expensive anyway from what I heard


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## saab96 (Mar 19, 2008)

I'm still waiting to see how people do with those medium size Headway batteries. I know people have them now, but I haven't heard any driving experiences.


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## Weka (May 23, 2008)

I've found one guy who is using Thunderskys - 30 x LPF-90 Thunder Sky batteries with a BMS unit purchased from the same place as he purchased the batteries : http://www.ev-power.com.au/

So far he has done 183 miles without trouble. His car is on http://www.evalbum.com/1715 .

The watching period gets shorter ...


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## david85 (Nov 12, 2007)

Metric mind makes/carries a BMS system that at least one TS conversion used to date.


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## mark1030 (Jul 28, 2008)

Maybe I'm totally wrong about this, but, all the cost projections are going forward. What if we go backwards? ie, instead of thinking about the costs at the end of a certain time period, think about the cost per cycle.

I can't find any hard numbers for Trojan t-105 life cycles, but somewhere here or on evdl somebody said it's 300-500 80% cycles, so that's what I'm going with.

A 144V 225AH pack of T-105's is 24 batteries. If they cost $150, the pack comes to $3600. If they get a minimum of 300 cycles, that comes out to $3600/300 = $12 per cycle. 

A 144V 200AH pack of LiFePO4's is 48 batteries (3V cells at beeps.com). Those cost $500 so the pack costs $24,000. They claim a minimum of 2000 cycles. That also comes out to $24,000/2000 = $12 per cycle.

I know there is skepticism about the claims of the Lithiums, but if the claims are true, it looks like the costs are fairly even. Will you get more than 300 cycles from the T105's. Probably. Will you get more than 2000 cycles from the LiFePO4's? There are claims that they can get 3000 cycles if you only discharge them to 70%.

So, my conclusion is that if the Lithium batteries perform as the people selling them claim, then they are a better solution, because your ev will perform better with half the battery weight, and by the time you need to replace your pack, the prices should be less than today.


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## Molle303 (Aug 12, 2008)

Regarding pro`s `n`con`s personally I will go for lead and just "wait it out" and in 3-4 years when my leads goes up crap creek i`m confident a good Lithium solution is within my reach - money wise.
I would`nt be happy if one of the TS goes bad,and should wait for a new one from freakin`China.
Nope I rather buy one from the shelf at the local HW-store.I think the potential "downtime" is to big a risk/cost at present.

And for you die hard Lithium-freaks a company in Denmark is currently developing a BMS !!

www.lithiumbalance.com

It`s in English  

just my 2c`s

Molle


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## saab96 (Mar 19, 2008)

Molle303 said:


> And for you die hard Lithium-freaks a company in Denmark is currently developing a BMS !!
> 
> www.lithiumbalance.com


It only balances up to 500amps. That may be pushing it if you have a Logisystems or Zilla. It also can only monitor up to 120 cells, although maybe you can stack them. So if you use cyllindrical cells you can't manage every single cell.

Has anyone gotten a price quote from them?


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## mark1030 (Jul 28, 2008)

Just thought I'd point out that in the last few weeks 2 of the LiFePO4 suppliers I've had my eyes on have lowered their prices. At beeps.com the 200AH cell went from $500 to $459 and the 100AH went from $250 to $225. It seems the 50AH one is no longer available. At elitepowersolutions.com the 160AH cell went from $288 to $272. Their other sizes also all went down to $1.70/AH.

So, the prices are dropping. I don't think the same can be said for lead acid batteries. Keep watching!


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## ClintK (Apr 27, 2008)

mark1030 said:


> Just thought I'd point out that in the last few weeks 2 of the LiFePO4 suppliers I've had my eyes on have lowered their prices. At beeps.com the 200AH cell went from $500 to $459 and the 100AH went from $250 to $225. It seems the 50AH one is no longer available. At elitepowersolutions.com the 160AH cell went from $288 to $272. Their other sizes also all went down to $1.70/AH.
> 
> So, the prices are dropping. I don't think the same can be said for lead acid batteries. Keep watching!


Does anyone have good data on the price of LiFePO4 (and Lead) over time? I'd like to see a graph on the price trend... it's tempting to wait a few more months to go for the Lithium on my conversion.


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## EVBug (Aug 19, 2008)

All right guys, help me out here. I'm trying to figure out how much lithium I need to do about the same job of all the lead I'm hauling around. It takes power to move mass, but if my car is so much less massive, then I don't need as much power.

I am not going for a 100 mile range, I'm just trying to build a lithium pack that does what my lead pack does: 70 mph max speed, and a solid 40 mile range.

Currently my Bug has 128v worth of 8v Energizer (Johnson Controls) batteries. Motor is an L91-4001. Attached is the rating Johnson Controls gave: 170 at the 20aH rate, 75 minutes @ 75 amps. We all know that due to Peukert factor, that the capacity isn't really what the label says.

So how much lithium do I REALLY need to do the same amout of work? Escpecially since my pack is going weigh 300-400 lbs vs. 1100 lbs.

How does this tie into the "Great Debate"? Because it helps determine if the Lithium is better in the long run. Too many people are trying to buy a lithium pack that does MORE than their lead pack would, which isn't a fair cost comparison.

Is the 60ah lithium the closest equivilant capacity to what I have now? Or is it 30? Or 90?

Then there's the issue of sag (internal resistance). What kind of voltage drops do lithiums exhibit? My nominal voltage is 135 volts...well, it's 140v when the car is fresh in the morning after charging the night before. When loaded, I drop from 135 volts to 120-115 volts. If lithium sags so much less, then maybe I don't need so many cells. If 120v is a good enough performance point for me, and the IF lithium batteries only sag 5 volts at the max, then I only need 125 volts worth of 3.2v units. That would be 39 units instead of 43 units which reduces my costs even further. I have a 500 amp controller, but I'm really only looking to pull 200 battery amps for short periods of time. My motor won't take much more and that's good enough acceleration for me.

So...if you all can help me tailor a lithium pack to replace my lead pack so I can calculate my costs, I'd be very grateful. I haven't had a lot of luck with this on the EVDL.


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## mattW (Sep 14, 2007)

What DoD do you go to on your lead pack? As far as voltage sag goes real world anecdotal evidence seems to suggest thundersky lithiums sag 0.2v per 1C of current per 3.2V cell. If you are going to 50% DoD then you have 170 x 0.55 x 0.5 = 46.75 usable Ah. If you multiply by 1.32 for the lithiums you should get around 62Ah to match your Lead pack- not counting the weight savings... if you are already doing 80% DoD then it will take about 100Ah to match the LA. 

Then you just need to work out whether they will give you enough current at 3-5C.


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## ClintK (Apr 27, 2008)

EVBug said:


> Then there's the issue of sag (internal resistance). What kind of voltage drops do lithiums exhibit? My nominal voltage is 135 volts...well, it's 140v when the car is fresh in the morning after charging the night before. When loaded, I drop from 135 volts to 120-115 volts. If lithium sags so much less, then maybe I don't need so many cells. If 120v is a good enough performance point for me, and the IF lithium batteries only sag 5 volts at the max, then I only need 125 volts worth of 3.2v units. That would be 39 units instead of 43 units which reduces my costs even further. I have a 500 amp controller, but I'm really only looking to pull 200 battery amps for short periods of time. My motor won't take much more and that's good enough acceleration for me.


I was going to give my 2 cents on the Ah equivalence, but I'd trust mattW's answer far more than mine. 

I do have a few questions on your motor though... I just picked up an L91-4003 (with no manual of course). Do you have any documentation on it? How is your motor hooked up? What are each of the A1, A2, S1, and S2 connections for? How has your motor performed with the 128V pack (heat / etc...)? I'm wondering because the motor is only rated 72-120. Are you staying under the 120V by counting on the sag from the batteries?

I've been keeping a close eye on the 128V 90Ah LiFePO4s packs for my conversion but have been worried about the extra 8V on the motor.


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## EVBug (Aug 19, 2008)

Thanks Matt, that's helpful. I run my pack between 50 and 80%. I think if I get the 60 ah units and maybe 40 instead of 39, I'll do ok. Heck, I can add some later if I have to. How do I find out if the lithiums can give 3-5C?

Clint,

I've looked at my motor and seen the connections but I forget how it's tied in right now. I'd have to look at it again. I know that one of the S terminals is tied to another terminal on the motor. The whole voltage/amperage rating is just an arbitrary point on a temperature curve. You can run higher voltages at lower amperages to meet the same temperature and duty cycle or you can run higher voltages and amperages for shorter duty cycles.

In my experience, limiting my take-off amps to 160 battery amps and cruising amps to 40-80 battery amps keeps the motor comfortably warm to the touch. On the hottest summer days (high 90's), it gets uncomfortably warm to touch. I keep the RPM's high, and the amps low to control the temperature. These amperages are in line with keeping my batteries healthy too.


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## mattW (Sep 14, 2007)

The batteries can put out 3-5C bursts of current, you just need to work out your 'C' (capacity) so that you can get enough power out of them to accelerate. A 60Ah pack can put out 180A at 3C and 300A at 5C... a 100Ah pack with do 300 and 500 amps. 

If you are driving at 160A max then it sounds like a 60Ah pack will do everything you need without straining the batteries much at all and you still have some room to play with for acceleration.


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## EVBug (Aug 19, 2008)

Sounds good. Based on the figures you stated earlier (.2v sag per 1c per 3.2v unit) That would result in a drop to 120v from 128v in a 40 unit (128v) pack at 1C. So if I draw 3C, that's a sag of 24 volts which puts me at 104 volts. That's lower than I want my lowest voltage to be so I think I'm going to end up adding one or two more modules.

Wait a sec...I have a question now. Lead batteries are 2.4 or 2.5v per cell. I mean, I'm using 8v batteries but they're really at 9.6v when fully charged. Do lithiums behave this way or is "3.2 v" really the nominal, fully charged voltage?

I'll have to recrunch the numbers depending on what the answer is.


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## JRP3 (Mar 7, 2008)

The TS batteries run between 2.5 - 4.25 operating voltage, 3.2 nominal.
http://www.thunder-sky.com/products_en.asp

So fully charged a 40 unit pack might start out around 168 volts I guess. My "48" volt lead pack starts around 51 volts fully charged.


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## EVBug (Aug 19, 2008)

Holy cow. Then yes, 39 or 40 units would definitely be plenty. I never achieve those voltages even now. Between the lighter weight, and the higher starting voltage, my car would -fly- compared to how it is now.

JRP I'm a big fan of your 6-wheeler. That thing is awesome!


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## EVBug (Aug 19, 2008)

And.......here comes probably my biggest complaint about Lithium batteries: Minimum purchases. I can go to any store and buy a single lead battery. It seems like every lithium vendor has a minimum order.

I'd gladly buy a couple of units per month until I had my pack but I don't think I can do that. If I can, someone please point me in the right direction.


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## JRP3 (Mar 7, 2008)

Thanks, it is a lot of fun 
Buying a few every month till you get your pack means you end up with a bunch of older batteries in your pack. I think you'd be better off just saving up and buying at once, plus as time goes on they seem to get cheaper and by getting quantity you might get a further discount.


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## Coley (Jul 26, 2007)

The way they are trying to remove lead from every aspect of life, there may not be an argument is a few years.

Tonight in the paper they had an article about removing the use of lead in wheel weights.

That should make the price of Lithium go even higher, since one competitor will be phased out.

I really can't see the big deal about lead. We had all lead pipes going to people's homes in this small northwestern town, since the water supply was put in.

We finished removing the last lead pipe to a home, that the inhabitants had raised children and the folks lived to be in their late 80s.

Not how did we all servive with lead pipes all that time??

We also used to put lead pellets in our mouths, when hunting birds with our pellet guns.

A bullet was sometimes not removed, if it was in a bad place to operate.

Time for nickle-iron batteries....


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## david85 (Nov 12, 2007)

Nickel iron batteries are very reliable and long lived, but they are not very efficient. In the tune of only 50% by some sources. Some fuel cells or even diesel engines can do better. NIMH is around 60%, lead acid can be as high as 95% (low current charging) and lithium is even higher.

With lithium, the net efficiency of the vehicle is much higher and that means lower operating cost in addition to lower maintenance when compared to lead acid.

Not sure how the voltage sag of NiFe compares, but its probably not as bad as lead.

Incredibly tough, but alas it is an old technology that was not updated over the years. If it can be purchased for a reasonable price than its worth considering, but I still think lithium is the front runner to keep an eye on because information technology demands more performance at a lower cost every day. Indeed this battery is advancing almost at the pace of IT itself.

Where can you get nickel iron batteries?

Nickel zinc is another one, but I'm even less up to date on that one.


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## JRP3 (Mar 7, 2008)

Coley said:


> * Not* how did we all *servive* with lead pipes all that time??





> there may not be any obvious symptoms, but the lead can still cause serious health problems over time, such as difficulty sleeping or lowered IQ


http://www.nlm.nih.gov/MEDLINEPLUS/ency/article/002473.htm
Lead is a poison, like it or not.


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## DVR (Apr 10, 2008)

JRP3 said:


> Lead is a poison, like it or not.


Is that what makes guns so dangerous?


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## Coley (Jul 26, 2007)

I believe the lower IQ is a greater reflection of the gene pool....


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## aeroscott (Jan 5, 2008)

Coley said:


> The way they are trying to remove lead from every aspect of life, there may not be an argument is a few years.
> 
> Tonight in the paper they had an article about removing the use of lead in wheel weights.
> 
> ...


lead is bad heavy metal . I'm a iron worker and have been exposed to it welding on lead painted steel , it will make you week , have trouble spelling your own name , vary hard to get out of your system . We had a class on lead before you could work on it .I grew up in the 50's and with lead pipes and leaded gas . just had the last mercury filling replaced with epoxy and ceramic . I could taste metal in my mouth the next day ( coming out of the tissues ) google it


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## GKnightBC (Sep 10, 2008)

I have been pricing out some LiFePO4 packs for an upcoming conversion, and I have been surprised by the price difference if I purchase from China! 
The quotes I've been getting for a 96V 100Ahr pack, wieghing 90 kgs and less than .5 M x .2 m x .4m, including a bms and shipping, total under $4,800 USD! Compared to a similar Lead-Acid pack at $1,500 Batteries only. Anyone else had experience at dealing with overseas product?


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## TX_Dj (Jul 25, 2008)

GKnight-

Keep in mind, that price doesn't include battery management systems or the charger. It is important to have the right BMS and charger to match the battery. Yes, you CAN run them with a regular charger if it's profile has been set up to match the needs of the technology, but running them without BMS is a good way to ruin your investment.

Lets say you have 5 cells, we'll call them by number. If cells 1,2,3 and 5 are still below "full charge" but cell 4 reaches full charge, without BMS you will overcharge cell 4 to get the other 4 cells up to snuff. Doing so will kill cell 4, or even cause it to explode or start a fire.

This is why systems like LifeBatt's cells have integrated "VMS" and they sell the right chargers as well.

The chemistry may be the same between the cheap chinese batteries and the more expensive batteries, but the containment technology may not be the same, and they may be more prone to fire in an overcharge/undercharge situation.


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## JRP3 (Mar 7, 2008)

GKnightBC, what company? Do they have a track record? Warranty?


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## mark1030 (Jul 28, 2008)

TX DJ, GKnight says that price includes the BMS.


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## GKnightBC (Sep 10, 2008)

FYI I have been getting quotes from various companies through Alibaba.com, and the prices are wide-ranging. 3.2V 96Ahr for $440 each (1.43 $/Ahr) to 48v 20Ahr with BMS and charger for $680 each (~0.57 $/Ahr excluding BMS and chrgr). I am not sure why there is such a huge price variance, except maybe the old "if we can get away with charging more..." attitude. I kept digging up more and more source manufacturers for these products, but some had minimum purchases of 100+ units, for the 3.2V packs. I will keep you all updated as it progresses towards purchase.
My one issue is that I cannot do any kind of BBB research on these companies, so that is why I was asking about people's previous experience. I intend to use buyers insurance on the purchase, soas to prevent me getting completely skee-rewed if the company sells vapour, but I am sooo hopefull this works out! 
TX DJ: The price included BMS and charger. According to saftey specs, LiFePO4 will not explode, but will out-gas, decay and die if abused. I don't think they can explode or catch fire (no thermal runaway).
JRP3: The warranty is 6 months, and I have no idea about a track record. I will update as more info comes to light.


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## Coley (Jul 26, 2007)

I think lithium is going to be too high for a long time.

A better battery is the nickel/iron that has worked since the early 1900s.

And before you step on that thought, look into NiMH.......same thing only with a few kinks worked out....

Chevron might cover a manufacturer from making them, but we can make our own, (I know, sticking my neck out here).

Why do you suppose Exide quit making them in the 1970s??? Oilies maybe??


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## JRP3 (Mar 7, 2008)

NiFe batteries have their own problems, frequent watering, low cell voltage, low energy density, low charge and discharge rate, etc. Better suited for stationary power storage, not practical for an EV. NiMH has problems as well, higher discharge rates and lower energy density than lithium. They also need to be operated in a narrower temperature band than lithium. Lithium is a better battery technology, and is getting cheaper all the time.


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## GKnightBC (Sep 10, 2008)

Coley said:


> I think lithium is going to be too high for a long time.


Now I'm getting scared...
I just got my latest update from the news feed for alibaba.com regarding updates in the LiFePO4 marketplace. 24v 20Ahr LiFePO4 batteries with charger (not sure about the BMS, but I know I can buy one for each battery for about $25.00) for only - get this - $120.00-$125.00!!!!
That works out to a dirt cheap $.26 $/whr!!! If this is at all indicating a trend, they will be giving these batteries away by the end of this month... 
I am quite experienced with the hazards of 'Caveat Emptor', and fraudsters selling vapour, but if this is at all close to reality, the EV market is in for a shakeup and revitalization!
I will be contacting the company today and trying to get a corp history, etc. to determine if I should place my order for 50+ units (Minimum order), today...


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## JRP3 (Mar 7, 2008)

Might want to run the company by the EVDL to see if anyone has any info about them:
http://www.evdl.org/archive/index.html


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## Coley (Jul 26, 2007)

If NiFE batteries were no good, why are some that are over 50 year old and older still being used?

And they were used in electric vehicles with good results.

85 miles per charge, back in the early 1900s, is nothing to sneeze at.

Henry Ford and Thomas Edison were working on an electric car, way back when and the part of the plant, that they were building it in, mysteriously burned down.

There is no corrosion to the innards and nothing to wear out except the electrolyte.

Why also is China the only one making them, at outrageous prices??


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## david85 (Nov 12, 2007)

Coley said:


> Why also is China the only one making them, at outrageous prices??


Because thats what they do, Drive prices down. We'll still have to wait and see how good many of these battery companies are, but overall, china is the world's mass production facility and they will build anything they can to pull a profit. Companies in the US, canada and europe are all expecting handouts or to be bought out if they have a battery worth selling. I'm tired of waiting.

Nickel iron batteries are possibly the most reliable batteries ever made. Its one of those things that no one really knows how long they can last because some of the oldest ones are still working. The catch is the low efficiency. A mere 50%. If you can make your own power than it won't matter all that much, but even then who still makes them? The energy density isn't that much better than lead acid either.

It does make me wonder if there are still advances to be made in NiFe batteries but since I have no way of making my own batteries, I'll have to go with what is available. And LiFePo is what I am working on right now.


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## saab96 (Mar 19, 2008)

david85 said:


> It does make me wonder if there are still advances to be made in NiFe batteries


There are new offshoots. Just very little R&D being put into it.

I thought one of the new BYD electrics was going to use this but I think they are both using LifePo4 variants:

http://en.wikipedia.org/wiki/Super_iron_battery


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## saab96 (Mar 19, 2008)

Coley said:


> 85 miles per charge, back in the early 1900s, is nothing to sneeze at.


They got that range going 15 miles an hour down a dirt road. The driving cycle in the early 1900s was more like a golf cart today.



Coley said:


> There is no corrosion to the innards and nothing to wear out except the electrolyte.


I think people are looking at these again because they can't use the large-format NiMH batteries due to Cobasys. I hear wildly differing figures on how many charges you can get out of NiMH but people keep crowing about how long the Rav4EV packs are living. I think once the NiMH patent expires we may see a partial rebirth of interest in NiMH if they are seen as longer-lasting than Lithium.


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## JRP3 (Mar 7, 2008)

Coley said:


> If NiFE batteries were no good, why are some that are over 50 year old and older still being used?


I clearly stated the shortcomings of NiFE batteries, I guess you didn't bother to read the post, or ignored the reality of what I posted. Add poor efficiency to those problems as David pointed out.


> And they were used in electric vehicles with good results.
> 
> 85 miles per charge, back in the early 1900s, is nothing to sneeze at.


 As has been mentioned, moving a lightweight car at 15-20 mph for 85 miles is not that difficult. Try and keep that same car at 60mph and you'll probably get 30 miles of range. 




> There is no corrosion to the innards and nothing to wear out except the electrolyte.


Yes, they do last a very long time. That is really the only thing that's good about them.


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## EVBug (Aug 19, 2008)

JRP,

I'll buy what you said about NiFe but not about NiMh. That's just being the enemy of "good". The EV1 and (for long term testing) the Toyota RAV4-EV's have shown me that NiMh is "good enough". In fact, they're great, with Lithium being "fabulous".

Come on, a top speed of 80 mph, with a range of 100 miles and an effective lifespan of over 10 years? That's great. And that's in a mini SUV. Have you seen the going price for a RAV4 EV lately? Imagine the same energy stored in an aerodynamic commuter car, or even a small 4 door economy sedan. NiMh would have been great to bridge the gap between lead and Lithium but that didn't happen.

I'm not going to address any conspiricy theories or assign blame. I just wish they were available. Instead, I'm considering mil surplus NiCad or Lithium at a later date.


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## Coley (Jul 26, 2007)

Quote:

"As has been mentioned, moving a lightweight car at 15-20 mph for 85 miles is not that difficult. Try and keep that same car at 60mph and you'll probably get 30 miles of range."

And the bad thing about that would be?

The ingredients are so cheap and easy to get, that I am working on making one to test.

I can build one for under $20.00 in materials and less than $100.00 in labor.
22 size, 12 volt.

Time will tell....


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## JRP3 (Mar 7, 2008)

EVBug said:


> JRP,
> 
> I'll buy what you said about NiFe but not about NiMh. That's just being the enemy of "good".


I didn't say NiMh wasn't good, just that it did have limitations. Yes there are some NiMh packs going strong for years, but there were also quite a few that had to be replaced under warranty and some that are dead now out of warranty. Add to that the fact that you can't buy these in large format any longer and I still see lithium as the only real option for long distance EV's.


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## JRP3 (Mar 7, 2008)

Coley said:


> Quote:
> 
> "As has been mentioned, moving a lightweight car at 15-20 mph for 85 miles is not that difficult. Try and keep that same car at 60mph and you'll probably get 30 miles of range."
> 
> And the bad thing about that would be?


You're not breaking any new ground so why waste your time? We already know the capabilities of NiFe, we know they have to be charged with 50% more so they are inefficient. You an easily get 30 mile range at 60mph with lead at better charging efficiencies, so what are you gaining with NiFe? A longer lived less efficient battery. 


> The ingredients are so cheap and easy to get, that I am working on making one to test.
> 
> I can build one for under $20.00 in materials and less than $100.00 in labor.
> 22 size, 12 volt.
> ...


I wish you luck with that, I'd like to hear your results.


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## david85 (Nov 12, 2007)

I'd like to hear the results too. If the range and upfront cost is comparable to lead than it would be breaking new ground because you might never have to replace it again once you have the battery working. If you can live with the range limit (and we know many can), than its certainly worth it. The low efficiency is a disadvantage, but even if an EV costs twice as much to operate as one that runs on lead acid, you are still looking at some relatively minor recharge costs and battery replacement can now be removed from the total cost of ownership.

If you are able to make your own batteries and have the reliability and range of the norm, than I would certainly consider it progress.


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## Coley (Jul 26, 2007)

Well, it might just be spinning my wheels, but not much can be lost in doing some experiments. 

The fellow on the EVDL had some newer ones by Exide, to work with, but I can't seem to contact him.

The potassium hydroxide is very easy to obtain, free of charge and since it is the main ingrediant in most modern batteries, why not play around with it.

My plater can plate the nickel elements and I have a supply of iron oxide to work with as well.

If I am successful in making something, I can use in my EV, I would be very happy. Besides, it is better than perp motion.....

Some facts recently located:

This environmentally-friendly battery has been in use for over 100 years. In many cases we have documentation that the original Edison cells are still in use and still producing 100% of their battery capacity after 60 years in service -- this is unparalleled in the annals of battery history!

The benefits of using Nickel-Iron batteries for energy storage:

Longest battery life of any battery known today. 
Clean and simple. 
Time-tested (it was invented by Thomas Edison in the early 1900's). (Not actually true)
Battery efficiency stays about 80% throughout its lifetime. 
Does not sulfate. 
Does not freeze in any state of charge - ideal for cold weather use.
Green technology. 
Easily rejuvenated by a simple electrolyte change. 
The electrolyte is an alkalai - the opposite of a lead acid battery. No corrosion takes place.
No need to do frequent equalization charges as you have to do with lead acid batteries.


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## order99 (Sep 8, 2008)

This isn't the first time i'd heard of Nickel-Iron-but it IS the first time i'd heard of the performance values of NiFe vs. lead...more, please. And by all means keep us apprised of your results Coley!

I need a clarification though. By '50% efficiency vs. Lead-Acid', are we talking about half the range, or just twice as long to charge? Also, any differences in weight? Because even if the efficiency is half normal on Nickel-Iron vs. Lead, if the NiFe is light enough you should be able to recover some of that lost range with the power-to-weight ratio, right? If anyone's got some hard data please share...


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## david85 (Nov 12, 2007)

I heard the efficiency was 50% not 80%, not really sure of the source though so I would be open to any other info that may come to light. The more we know the better.

KOH is most certainly corrosive though. They use in in all sorts of stuff from drano to engine degreaser to oven cleaner and when diluted enough, hand soap. Its powerful enough as an engine cleaner that care has to be taken around wiring and aluminum parts.

*order99,* the efficiency refers to how much of the energy that is put into the cell gets converted into chemical potential energy. So for example, if you wanted to charge a battery that is 10 kwh capacity but is only 50% efficient, you would have to put 20 kwh into the battery to charge it completely.

Internal resistance also plays a role and generally most batteries become less efficient the faster you attempt to charge or discharge them. Lead acid can also drop to low efficiency as the rate of current is increased. Voltage sag known as the peukert effect causes a drop in voltage and result in poor energy return and shorter vehicle range from high current draw. Voltage sag of 50% has been observed in some racing applications, so maybe NiFe isn't really all that bad after all.

Lead acid is said to be as high as 95% efficient in low current situations (not often in an EV),
And some say that lithium polymer is close to 99% efficient. I'm not sure I completely believe that, but lithium is certainly a very eager battery type that will pump out power as much as you want even if it destroys itself. So the internal resistance is quite low as far as batteries go. Controls are strongly advised.


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## JRP3 (Mar 7, 2008)

Coley said:


> Some facts recently located:
> 
> This environmentally-friendly battery has been in use for over 100 years. In many cases we have documentation that the original Edison cells are still in use and still producing 100% of their battery capacity after 60 years in service -- this is unparalleled in the annals of battery history!
> 
> ...


Basically all that says the same thing, they last a long time, so that's one advantage. Now some negatives:
Low cell voltage. 
Very heavy and bulky. 
The low reactivity of the active components limits the high rate performance of the cells. They cells take a charge slowly, and give it up slowly.
Low coulombic efficiency, typically less than 65% 
Steep voltage drop off with state of charge 
Low energy density.
High self discharge rate. 


All of the above are exactly what you do not want in an EV battery. 

Another thing to look into, as I understand it it is very important for the nickel plates to not have a smooth surface, (low surface area), and one person described a proper nickel plate as having a surface similar to very tiny layered feathers. Might not be easy to recreate at home. Also, be very careful when working with those chemicals, they are far from safe.


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## Coley (Jul 26, 2007)

You only use a 20% KOH mixture. The charging resistence in the one I built is fairly high.
I burned up two small MA charges trying to charge the test cell. One was 6 volt and one was 9.
The test cell held a charge beter that the AIR/Aluminum I tried last.

This cell is using some nickel anodes that I used in a small plating setup.

I am making some with much more surface area.

I also have a plating rectifier, that will put more amps into the charging.


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## LeTank (Jun 24, 2008)

Well I didn't read every post since there are thousands of them, but it looks like nanosafe batteries are the new biggie to give a lot more range than the Li batteries. At 20,000 recharges and higher discharges that won't kill them. 

I heard it was mentioned on this forum a while ago, but the battery is said to have gotten better in the last month or two. Zenn is even planning on using them and has already a contract to use them. So are they really that great or is it all hype? I want to know.


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## JRP3 (Mar 7, 2008)

The Altairnano NanoSafe batteries have been independently tested by Aerovironment and seem to have high cycle ability as well as fast charge properties. However they are extremely expensive and unavailable to the public. They also have a lower voltage per cell than other lithium chemistries, which is a drawback. They look promising but you can't get them. Maybe someday.


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## david85 (Nov 12, 2007)

The nano safe battery is nothing to write home about. It has a proven 15 000 cycle life an high thermal stability, but the energy density is well below 200 wh/kg, and on par with today's NiMh batteries, so regular lithium could give a longer range per charge and at a much lower cost.

Given the cost and the fact that I am not aware of any recent contracts in the last year, I'm almost positive that nanosafe is a dead stick. The only reason the first shipment of batteries were made to phoenix motor cars was the company was heavily subsidized by federal funding. Last I heard of poenix was they were going with canadian based electrovaya for batteries. Electrovay claims to have a 400wh/kg battery.


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## JRP3 (Mar 7, 2008)

Actually Altair has shipped large scale packs to utilities for backup power, where the lower energy density is not an issue. They are also working with the Navy for ship power. The extreme life cycle and fast charge capability can make this a viable battery for EV's if the price comes down.


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## saab96 (Mar 19, 2008)

david85 said:


> The nano safe battery is nothing to write home about. It has a proven 15 000 cycle life an high thermal stability, but the energy density is well below 200 wh/kg, and on par with today's NiMh batteries, so regular lithium could give a longer range per charge and at a much lower cost.


With a 15K charge lifespan, and assuming a full charge cycle once a day, you're talking about a *41 year* lifespan. That's effectively forever, and pretty much puts the technology at the same level as EESTOR's ultracapacitors, assuming it actually delivers. I would gladly sacrifice range for that kind of longevity.


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## david85 (Nov 12, 2007)

saab96 said:


> With a 15K charge lifespan, and assuming a full charge cycle once a day, you're talking about a *41 year* lifespan. That's effectively forever, and pretty much puts the technology at the same level as EESTOR's ultracapacitors, assuming it actually delivers. I would gladly sacrifice range for that kind of longevity.


Its not unreasonable to trade range for long term reliability. They are more comfortable claiming 15 year life span more recently, but 40 year life was mentioned in earlier press releases. This revision of performance raises alarm bells for me. But in reality, when it comes to shelf and calender life, the only way to really know is to actually test it. Personally, I think anything over 10 lifespan is already acceptable.

Would be nice if the price could be driven down, but considering the high cost right from the start, it seems unlikely that the price would ever become competitive with other types of batteries. The use of titanium in the chemistry might be part of the cost problem. Its still worth keeping an eye on as long as they are still making them. You never really know what might come up in the years ahead.


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## saab96 (Mar 19, 2008)

david85 said:


> The use of titanium in the chemistry might be part of the cost problem.


http://www.csa.com/discoveryguides/titanium/overview.php

"There is more titanium in the earth's crust than there is nickel, zinc, chromium, tin, lead, mercury, and manganese combined! The ores of these metals are concentrated in large, easily mined bodies, while titanium ores are dispersed throughout the earth's crust."

Considering that titanium is used in toothpaste, I'd think there is enough of it for batteries.


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## LeTank (Jun 24, 2008)

Well I agree with you about the price and it would surely be worth every penny if it went to an affordable price. (Whatever that is. haha) 
Anyhoo, I am thinking of currently getting a few of the BatCap batteries to test them out. The extreme BatCap 9600 is not cheap, but not much more than a good battery and has almost* the same capabilities as the Nanosafe. However it is generally used for car audio, but I don't think it matters since it is behind the same concept. (BatCap is chemical with its differences.) Maybe I am wrong in this choice, but I just can't wait for Nanosafe or EEStor to become reasonably affordable. I am up for something new that doesn't die out the first year or two I use them, which I am currently using the Optima battery which I had to replace two of them in a month, which is very strange. (I didn't break it.) 

So what other choices is there that is affordable? Any ideas?


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## JRP3 (Mar 7, 2008)

I don't think a BatCap is anything you'd want in an EV. It's supposedly designed to supplement car audio systems by discharging thousands of amps quickly and recharging quickly, but long term discharge in an EV is not what it's made for.
You might do better looking at Odyssey SLA's if you're not happy with the Optima's and aren't willing to go with lithium.


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## GKnightBC (Sep 10, 2008)

I'm committed. I have finalized the pricing on some LiFePO4 battery packs from China. 48v 100Ahr with charger and BMS for $2,680 USD, and I'm going to get 2 to start, maybe a third if I can afford it. This gives me a start, at least, on my ideal. Wish me luck!


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## ClintK (Apr 27, 2008)

GKnightBC said:


> I'm committed. I have finalized the pricing on some LiFePO4 battery packs from China. 48v 100Ahr with charger and BMS for $2,680 USD, and I'm going to get 2 to start, maybe a third if I can afford it. This gives me a start, at least, on my ideal. Wish me luck!


Where did you end up purchasing from?


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## david85 (Nov 12, 2007)

GKnightBC said:


> I'm committed. I have finalized the pricing on some LiFePO4 battery packs from China. 48v 100Ahr with charger and BMS for $2,680 USD, and I'm going to get 2 to start, maybe a third if I can afford it. This gives me a start, at least, on my ideal. Wish me luck!


Another brave soul!

Welcome to the club, who did you order from?

I have a contact as well. since we are not far too from one another, it might be possible to make a combined purchace.


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## GKnightBC (Sep 10, 2008)

The Company I am ordering from is Optimum Battery;

OPTIMUM BATTERY CO., LTD
Tel: +86-755-84630787
Fax: +86-755-84630785
Website: http://www.optimum-china.com

I am currently gathering my resources to put together my budget and such, and then I will be ordering. I have to say, the sales rep from this company has been very helpful.


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## david85 (Nov 12, 2007)

Don't know this company, but I found that the company that I am working with also has very good sales reps. The chinese are different that way. Had you tried to contact some one like electrovaya or a123 systems, I would be surprised if you even got a reply let alone if they were willing to do business with you.

I'm already into testing large cells from a different company, so a combined order won't be possible, but I am still glad you are trying this because its a great help to all of us that are watching the lithium story unfold. The more chinese companies that we contact the better.


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## freddyflatfoot (Oct 6, 2008)

Firstly, let me say that I am new to this forum, and this is my first post. I have spent some time wading through some of the topics, and the 15 pages of this topic! BTW, this should be a sticky if it isn't already.
I am currently in the process of researching building an EV, to replace one of my cars as a town runabout.
Having said that, I have been using electric assist on my bikes for the last year or so. I ended up building a recumbent trike with a hub motor, to use as my commuter vehicle, in lieu of building a full size EV.
I soon ditched the lead, mainly due to the weight and the crap performance from the lead batteries. 
I went with a 36v/10AHr 'duct tape' LiFePo4 battery pack from China. Came with its own BMS and charger.
The pack only weighs 3.5 kg, and I can get the full 10 AHr from the battery. The discharge curve is fairly flat, and even though the voltage sags a bit, it is nowhere as bad as lead. Good for at least 30k's, and possibly closer to 40 k's. Don't really know as I haven't run the pack down to LVC.
These packs wouldn't be of any use in EV's though, as they are really only rated at 1C discharge, and I run mine at between 1 and 1.5C discharge.
Having said that, there are LiFePo4 packs that are rated at higher C ratings that would suitable for EV's.
Even though I cannot comment on the peformance difference between lead and LiFePo4 in an EV, I can certainly comment on their differences on an e-bike! And for me, its like chalk and cheese, and the LiFePo4 is the cheese!
Will I get my 1000 min cycles? I don't know.
What I do know, is that if/when I build an EV, I would prefer to use a LiFePo4 pack based on my e-bike experience. As long as I could get a high enough C rating! But that would depend on the setup that I will be aiming for for my purposes, but that would be a topic for another thread!


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## TexasCotton (Sep 18, 2008)

To start,
Tesla Motor and other ev start ups are using the small lithum battery packs in groups and then adding super caps and electronic controls, The prius PHEV use both lead acid or lithum. Johnson controls (Interstate Battery)has not geared up to mass produce lithum battery for automotive industry sector. Continential has justed started in Germany to manufacture lithum battery to be put in Mercedes. The cost of lithum battery for automotive application in the US is too high currently


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## sunworksco (Sep 8, 2008)

You can factor into the cost of lithium batteries that they can be sold for stationary off-grid solar PV systems use.They still have enough storage capacity for this application.
You can't build an ultrlight EV car with lead,only a lead sled.


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## mark1030 (Jul 28, 2008)

sunworksco said:


> You can factor into the cost of lithium batteries that they can be sold for stationary off-grid solar PV systems use.They still have enough storage capacity for this application.


You mean after their rated cycle life?

That's one thing I've been wondering. If a LiFePO4 battery is rated 2000 cycles at 80% discharge, what happens after 2000 cycles? Does it just have reduced capacity? On the LionEV 'upgrade to Lithium' page it refers to an 80% reduced capacity after the rated cycle life. I don't know how reliable that is, or how fast the capacity falls with each additional cycle, but even at reduced capacity the EV would still be useful for a while. I've kinda guestimated that my pack (whenever I may get it) will hopefully give me 68 miles at 80% DOD. I'd probably be able to use the car until the capacity was all the way down to 60% of the rated capacity before I wouldn't be able to make it to and from work.


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## saab96 (Mar 19, 2008)

mark1030 said:


> That's one thing I've been wondering. If a LiFePO4 battery is rated 2000 cycles at 80% discharge, what happens after 2000 cycles? Does it just have reduced capacity?


I've read that when it degrades not only is the capacity less but the power is also going down and the heat during discharge is going up. So it might work OK to retire a battery pack to off-grid backup if you don't have spikey loads but really, the batteries are starting to tell you that they are dying. It might not be safe to keep pushing them much longer. I wish it weren't so.


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## david85 (Nov 12, 2007)

The general rule seems to be that storage capacity is reduced to between 80% and 90% in all of the cycle life charts that I've seen (after 2000 cycles). I've been told by sales reps (so take this with grain of salt) that DOD of only 10-20% produces so little capacity loss that its hard to even measure after 2000 or more cycles.


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## hardym (Apr 2, 2008)

To rekindle more of the Lithium vs Lead debate, David85's pricing for Li-prismatics is working down to $.50/WattHour, of which it is ALL usable.

Lead packs have a characterisc such that you have a lot of power, but you can't use it all on each charge cycle or suffer from premature pack death at only a few hundred cycles. EV owners like to only use 50% of pack capacity to help save their packs. 

A typical EV truck battery pack is 24 x Trojan T-125 providing 200*24*6 = 28880 Watt Hours. Price for Trojan is about $140 * 24 = $3360.
Lead acid total pack is ($3360/28880) = $.11/WattHour.

If you factor in that you can only use 50% of the available power in a lead-acid pack, the price for lead goes up to $.22/WattHour. So, Lithium is now only about twice the price of lead, but gives you 4 times the number of charge cycles at 1/4 the weight.

To fan the flames... I have unsubstantiated rumors that there are other large purchases at the $.30/Wh for the thunderskys. Over the next several months I hope to be reporting more of this, if and when the orders are filled. Let's keep our fingers crossed. 

Mark.


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## JRP3 (Mar 7, 2008)

You really need to add in the cost of a fully functioning BMS with lithiums, which can be substantial.


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## saab96 (Mar 19, 2008)

JRP3 said:


> You really need to add in the cost of a fully functioning BMS with lithiums, which can be substantial.


Assuming you stay with the same battery type with each replacement pack or the BMS is particularly versatile, that's *a one time cost* just like any other fixed part of the EV (motor, controller, charger, etc...)


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## JRP3 (Mar 7, 2008)

That's a good point but it still needs to be paid for upfront if choosing lithium batteries over lead and should be added to the cost. You can eliminate it from the equation if it's your second lithium pack.


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## piersdad (Aug 16, 2008)

the lithium batteries are lighter per amp hour and this relates to less amp hours used per mile
so a true comparison would have to be in total kilometers driven by each pack.
this would take into account where a stuffed pack was just able to do the local commute befor replacment.


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## Jason Lattimer (Dec 27, 2008)

Still no comparison. 72 volts and 225 amp hours of Trojan j186a hc batteries cost about 1500 dollars. Thundersky batteries that run the same voltage and amp hours cost 9 to 10,000 dollars.

Why buy lithium when lead is so much cheaper. If I could afford that much lithium I would be building a custom starship cruiser with an AC Propulsion drivetrain.


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## JRP3 (Mar 7, 2008)

Actually you can get a little cheaper than that since lithiums have more usable ah than lead. So a 72 volt 200ah pack will cost around $8000, take you farther, last longer, and be about one third the weight of the lead pack, which will improve drive ability all around. Yes it costs a lot more but it's not a straight comparison.


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## kiwi_nigel (Mar 29, 2009)

freddyflatfoot;bt536 said:


> I went with a 36v/10AHr 'duct tape' LiFePo4 battery pack from China. Came with its own BMS and charger.
> The pack only weighs 3.5 kg, and I can get the full 10 AHr from the battery. The discharge curve is fairly flat, and even though the voltage sags a bit, it is nowhere as bad as lead. Good for at least 30k's, and possibly closer to 40 k's. Don't really know as I haven't run the pack down to LVC...What I do know, is that if/when I build an EV, I would prefer to use a LiFePo4 pack based on my e-bike experience. As long as I could get a high enough C rating!


Thanks Freddy, exactly what i was thinking  I source 36v 15Ah packs from Hong Kong for electric skateboards. The performance of the LiFePO4 compared to the SLA they replace is nothing short of amazing! Running an 800watt motor the LiFePO4 pack will happily discharge at 30Amps (2C) for up to 70mins and provide peaks of 46Amps for extended hill climbs. Range of the boards has gone from 20kms (SLA) to well over 30kms (LiFeP04). Also, because of the flat discharge curve - you can ride at top speed (30km/hr) constantly...whereas with the SLA you would be down to 20-25 km/hr after only 10mins! Cheers, Nigel


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