# Is there any way to capitalize lithium for a reasonable price compared to lead?



## ga2500ev (Apr 20, 2008)

> I'm not going to do Lithium. I'm not. I cannot afford Lithium. It costs too much to capitailze...


This had been my argument to myself for the last 2-3 years I've been hanging around the forum. But now that I'm actually on the cusp of the build phase, because I now have a workable coupler, I have to revisit the question.

'92 Geo metro, 8" ADC _203_-06-4001 motor, trying to get into the range of 30 miles so I can fit nearly all of my daily commutes in.

My plan had always been to do the first pack fast and cheap. Something along the lines of 7 or 8 Walmart Maxx 29 Marines DC ([email protected] AH). Using a derating factor of 1.4 to account for 80%DOD and Peukert you get a usable pack energy of 7.5 kWh at 84V or 8.5 kWh at 96V. It would come in under $750 total, and as long as the Wh/mile was somewhere in the range of 270, that 30 miles is achievable on a charge.

I've been pretty good at stuffing my ears with my fingers and singing "La La La La!" to all the Lithium talk. But the prices have continued to get cheaper. But I have questions.

The first is how to best translate equivalent pack energies? What nominal voltage used because the cells seem to have a really wide range? For the discussion below I'm use 3.2V/cell. Is that high or low?

Next is what is the derating factor for usable energy in the pack? Does the concept of peukert completely disappear? Are we still talking about a safe discharge to 80% DOD (which gives a derating factor of 1.25 if nothing else is involved)?

My next question is does it make since to start with a small pack (say 40 Ah @ 90V) then see about paralleling a second pack to it later? This is one of the huge issues that I'm trying to resolve. With the lead, though it may only last 18 months, is cheap enough to capitailze the entire pack without breaking the bank. Packs are purchased serially with the entire pack energy available cheaply but not lasting long. It looks like the cheapest pack (using EVComponent prices) would be the 40 Ah cells. 28 of them would be $1232. But it wouldn't meet my range needs.

Does the concept of a test pack even make sense? Say purchase 20 cells giving a 64V @ 40 Ah = 2560 kWh (2 kWh when derated by 1.25). At 250 Wh/mile it's only 8 miles. But the capital costs is abour $900, which is within striking distance of the lead pack.

But can I add to it later? Or would I have to completely replace the pack with a larger Ah capacity. Adding 20 60 Ah cells in parallel would give a 64V * 100 Ah = 6400 kWh seems to push the range into the 20s for an additional $1300+. Or maybe even adding 90 Ah for another $2k giving 64V * 130 Ah = 8320 KWh. All in a package that weighs less than 200 lbs.

This is my first EV that I'm cobbling together. So I'm trying to go out of my way not to sink a ton off funds into a project that has no guarantees.

I'm trying to figure out where Lithium fits. It looks like a legit pack (10 kWh of usable energy) is somewhere north of $3k. Once I have a proof of concept (ike an actual running vehicle) I may be able to justify that type of expenditure. But until then I'm a bit unsure. That's 3 times more than I've spend on the car, motor, coupler, and all the electronics that I've purchased so far.

One last question: What advantage do those Headway cells have? It looks like they come in a nearly twice the price of the TS or the Calb packs (i.e. $19 for 10 Ah -> $76 for 40 Ah, TS $44 for 40 Ah, Calb $50 for 40 Ah).
Just wondering.

Any advice welcome.

ga2500ev


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## octagondd (Jan 27, 2010)

I don't think a test pack makes sense with lithiums because the value in them is the longer cycle life. I am not sure about adding to a pack later, but my guess would be you will run into balancing issues.

If you want to keep the entry price down, then LA still seems to be the way to go. You just have to keep saving money for more lead. It may be a good time to wait on better technology and price points if you don't need top speed or distance.


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## dtbaker (Jan 5, 2008)

I spent a lot of time with similar pondering.... and initially went with FLA because of the lower initial investment and lack of history with Li getting the cycles claimed. My first pack of FLA is showing signs of age, and the price of li has come down to the point I am going to switch this spring/summer.

I have had a 96v pack of FLA, which gave reasonable performance and about 40 mile max range in summer temps. The 185ah 20-hr rating translates to just about 100ah at 1hr rate. I have decided to bump up to 120v, but kept the Li ah rating to 100ah cells because I really don't need more than 40-50 mile daily range... so why pay for it!

I am NOT going for smaller because I think the higher C pull would be too hard on the pack and having a little extra range is very good for longer life.

The kicker for me is that IF we get predicted life cycles out of the Li, they will be less expense over a 10 year 'life' than equiv pack of FLA that would have to be replaced 3 times.


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## frodus (Apr 12, 2008)

The $19 includes customs and fees. The TS don't. It may be $44, but add another $4.40. Its almost $50..... just sayin.

Also, the discharge rates are higher for headway. 5C continuous, 10C continuous peak for like 2 minutes, and 15C pulse.

They're a little higher power, they're the same energy, and they're a bit more configurable for a pack. In my motorcycle, I could not fit the same amount of energy in the bike with TS because of the blocked style.

If you don't need the extra power, TS and SE are just fine. They're easier to assemble into a pack. They're more expensive to replace if a cell goes bad. With Headway, you replace one cell.

Also, there is better pricing for quantities of Headways. There is none with TS and SE.


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## TheSGC (Nov 15, 2007)

I went FLA because of the price, and my EV is also my proof of concept so sinking in lots of mulah for a nice pack wasn't in the menu. I actually have the MAXX29 and I have been doing lots of research into them because no real data exists. 

I have been thinking about 100 Ah LiFePO4, 8 volt FLA and Odyssey PC2150 AGM batteries as pack #2 when it comes time. I am still looking at pricing, reports of life, care/charging required, etc and what I really need out of them. However, in the long run, Lithiums seems to win out easily, assuming they meet even half their estimated cycle life.


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## dimitri (May 16, 2008)

DO NOT buy smaller cells, DO NOT believe TS claims of 3C continuous rate. You will end up throwing good money after bad.

You need to plan for 2C-2.5C acceleration and 1C or less for cruising current. IMHO, anything less than 100AH is not good even for the smallest car.

Some people will say that 3C is fine, but there is a good chance that frequent 3C will shorten lifecycle, which would again cause you to throw good money after bad. Remember, TS lifecycle data is for 0.5C , not for 3C. They are only telling you good parts, and even those parts are half true.

If you can't afford a good LFP pack, then its better to get LA pack and save up for a good LFP pack later.

After running my LFP pack for a year, I am already replacing some cells, all because I planned for regular 3C discharge.

I think its better to spend a little more on CALB cells since their datasheets appear to be closer to the truth than TS.


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## ga2500ev (Apr 20, 2008)

Looks like the answer is clear: Do and FLA for a starter pack and reevaluate Lithium in the next go round.

Glad that I asked.

Thx.

ga2500ev


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## Matthijs (Jun 19, 2009)

dimitri said:


> I think its better to spend a little more on CALB cells since their datasheets appear to be closer to the truth than TS.


Do not want to hyjack the thread but is this also true for the newer TS cells? Looking at this graph: http://evworks.com.au/tech/ThunderSkyVsSkyEnergy/ I am under the impression that those are not the newer versions that are being shipped out now.


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## dimitri (May 16, 2008)

Matthijs said:


> Do not want to hyjack the thread but is this also true for the newer TS cells? Looking at this graph: http://evworks.com.au/tech/ThunderSkyVsSkyEnergy/ I am under the impression that those are not the newer versions that are being shipped out now.


I have no personal experience with "newer" TS cells, but I have not seen any reports of "newer" cells being any better as far as C rates and voltage sag. Eric ( etischer ) got new Yittrium cells recently and he reports similar voltage sags under 3C load as I have on my "older" cells.

In fact, I have not seen any good explanation of what specifically makes new cells any better. Yes, we know they added Yittrium, but what is it supposed to improve and how and why? Admittedly I have not done deep research on this, so maybe someone can enlighten me. Until then they might as well have added "bullshittrium" to their cells, I will never buy TS cells again.


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## dtbaker (Jan 5, 2008)

ga2500ev said:


> Looks like the answer is clear: Do and FLA for a starter pack and reevaluate Lithium in the next go round.


well, you can get up and rolling for less with FLA, but get better performance and lower cost over 10 years if you can scrape together the cash for Li.... I would suggest investing in a flow-rite or similar watering system for FLA, and insulate/heat boxes in winter for best performance and longest life....


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## green caveman (Oct 2, 2009)

ga2500ev said:


> Looks like the answer is clear: Do and FLA for a starter pack and reevaluate Lithium in the next go round.
> 
> Glad that I asked.


I have the same idea. I figure that, through ignorance or whatever, you'll end up trashing the first pack. So trash the lower cost set as you figure out how to look after a pack and then upgrade to Li.

If we're really luck, the decrease in price of Li will make the first set even more cost effective.


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## roflwaffle (Sep 9, 2008)

Is a factor of 1.4 accurate for de-rating? Most LAs are around 1.6-18 IIRC, but I suppose the Peukert exponent for the Wally's world batteries could be pretty good.


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## jlgh (Mar 6, 2010)

I guess with Li there is also the cost of the BMS to consider


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## dtbaker (Jan 5, 2008)

jlgh said:


> I guess with Li there is also the cost of the BMS to consider


If you use a BMS.... some people don't. That is the great unknown though; how often do cells get far enough out so that they need to be balanced and how good a charger do you need to have the HV setpoint such that no one cell goes over-voltage.


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## jlgh (Mar 6, 2010)

dtbaker said:


> If you use a BMS.... some people don't. That is the great unknown though; how often do cells get far enough out so that they need to be balanced and how good a charger do you need to have the HV setpoint such that no one cell goes over-voltage.


That's interesting Dan. I wasn't aware of that. From all that I've read and discussing it with those who use them, I'd understood that Li without a good BMS condemns them to a short and messy existence


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## atzi (Jun 26, 2008)

Quote: _This is my first EV that I'm cobbling together. So I'm trying to go out of my way not to sink a ton off funds into a *project that has no guarantees.

*_There is the key phrase you need to believe in your project first. I say do the lead-acid and after 12 months, if you drive alot, the heavies will be burnt up and you can buy the lithiums. By then, some of the smoke will clear about which brands are best, maybe improvements in the technologies, new technologies and prices may be lower.
BTW: 


go with as high a voltage as you can.
*Dimitri *you should copyright * "bullshittrium"™*
I have run lead acids for 8,000 miles and have ordered 160ah TS , hope the *trium works*
*


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## dtbaker (Jan 5, 2008)

jlgh said:


> ...I'd understood that Li without a good BMS condemns them to a short and messy existence


so far I have yet to see any real life logs illustrating that a multi-cell pack gets out of whack far or fast enough it cannot be brought back into line with occasional checks and manual balancing... I haven't even seen how often that might be required....

Jack Ricard and several other quietly maintain that the shunt balancers cause more harm than good, and have killed their fair share of cells....

I am planning on building wires to each cell running to a fuseblock for centralized checking and manual charge/discharge for balancing when and if required.


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## ga2500ev (Apr 20, 2008)

dtbaker said:


> well, you can get up and rolling for less with FLA, but get better performance and lower cost over 10 years if you can scrape together the cash for Li.... I would suggest investing in a flow-rite or similar watering system for FLA, and insulate/heat boxes in winter for best performance and longest life....


As I pointed out before, this is a first conversion. In addition I'm doing everything: motor controller, charger, and BMS, DIY. So for me it's a project with no guarantee of success nor any specific deadline other than ASAP. ATZI, if I didn't believe then I would even try to attempt. It's just that if it takes 9 months or a year to get a working vehicle together, is it real smart worrying about 10 year cost lifetimes?

Dimitri points out that there's no joy in starting with a small pack then upgrading. So if you're talking about 28 batteries at 160 Ah at today's prices ($176 per), then that's nearly a $5000 investment. That only makes sense if everything else is tested and working. Frankly the $750 for a 96V FLA pack is noise compared to that cost. Fact of the matter is that if an FLA pack lasts for 18 months, then the 10 year costs are equal. The difference is the capitalization costs.

Of course the hope is that prices will continue to drop. If 160 Ah prices get to about $100, then you're talking about $3000 to capitalize a pack.

I've seen discussions both on watering and insulation and will eventually take both into account. I just needed to rethink the big choice so that I can move forward.

BTW I never did get answers on the nominal voltage used for pack setup and the derating factors. I'd still like to know.

roflwaffle: you are absolutely correct. 1.8 is a better choice for derating an LA pack. Along with the 1.25 to account for the 80% DOD, the expectation should be to only be able to extract 44% of the total 20 Ah rated energy from the pack. So let's recalculate with a 96V Wallyworld pack:

96V * 125 Ah * 44% = 5280 Wh
5280 Wh / 275 Wh/mile = 19.2 miles.

Not enough. Each additional battery will contribute:

12V *125 Ah * 44% = 660 Wh.

So if we need 30 miles range @ 275 Wh/mile we would need:

30 miles * 275 Wh/mile = 8250 Wh / 660 Wh/battery = 12.5 batteries.

So in theory a 144V/156V pack will get me close. The problem is that I have not thought about tuning the motor yet. According to the seller that 8 in Advanced DC 2003... motor came out of a unit that was running off 80V and had reversing contactors. So most likely it has not been advanced.

So for testing it looks like getting a 1/2 pack of 6-8 batteries makes sense to simply test the motor in its current configuration, then look to properly advancing it at upping the voltage into that 144V range once everything is working.

So much to think about.

ga2500ev


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## dtbaker (Jan 5, 2008)

ga2500ev said:


> ...is it real smart worrying about 10 year cost lifetimes?


only if you want to make an informed decision on whether you want to start with FLA or Li... Li is not an option for some if $$ are not available up front, but it still *may* be the best choice if predicted life cycles are true.




ga2500ev said:


> Dimitri points out that there's no joy in starting with a small pack then upgrading.


very true. for a small car I would say that 96v is minimum driveable configuration, with 120v being much more mainstream performance wise in terms of keeping up with traffic comfortably. The pain of adding battery cabling, or changing major components designed for a range of voltage is really not worth starting with a smaller pack than you intend to run. The motor, controller, dc-dc, and instruments would likely not be able to handle starting with a 72v pack and then changing to 120v or 144v.



ga2500ev said:


> So if you're talking about 28 batteries at 160 Ah at today's prices ($176 per), then that's nearly a $5000 investment. That only makes sense if everything else is tested and working. Frankly the $750 for a 96V FLA pack is noise compared to that cost. Fact of the matter is that if an FLA pack lasts for 18 months, then the 10 year costs are equal. The difference is the capitalization costs.


well.... you are not quite comparing apples to apples in capacity, and distorting the cost a little.... The 8v FLA I am using have a 20hr rating of 185ah, but the curve under load drops that to right around 100ah in EV use because of peukart's. so, comparing to 100ah LiFePO4 is more of a straight comparison I'd say. I got 12 x 8v delivered to my house for $1500, and if treated right I could expect at least 500 cycles, maybe 750 cycles... so say the amortised cost is between $2 and $3 per cycle. The same capacity Li would cost 30x $110 = 3300 + 330 tarif +~400 S&H= $4000 and is *supposed* to last somewhere between 2000 to 3000 cycles depending on average %DOD... assuming proper charging, and not counting cost of BMS . This would give per cycle cost between $1.35 and $2... less expensive than FLA.



ga2500ev said:


> I've seen discussions both on watering and insulation and will eventually take both into account. I just needed to rethink the big choice so that I can move forward.


yeah.... I would HIGHLY recommend watering system if you go FLA, which will add $400 or so. Worth it just in time savings. BMS for Li I am not convinced is effective, and I am going to try without it and inspect/balance manually at first to see how it goes.



ga2500ev said:


> BTW I never did get answers on the nominal voltage used for pack setup and the derating factors. I'd still like to know.


did I answer that? my 185ah (20-hr rate) 8v batteries show about 100ah at a 1-hr rate, which I would consider normal EV load/use.

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