# I finally found a source for large format NI-MH batteries



## Technologic (Jul 20, 2008)

No... I'm not even half joking here guys, I really did.

I finally found a chinese source for larger NI-MH batteries.

I have just be quoted... no fooling here, $43USD/pc for a 12vx10AH pack (or 35 cents/wh).

Now... what to do with it...

I will supply the source when I can give you all more info from them about if they can get even LARGER.

I'm going to be double checking over the next few days to find out if other manufacturers can do the same thing for me.

Just wanted to give a heads up, since I can finally contribute something valuable outside of advice to this community (and my advice is rarely valuable )

"12V 10AH Ni-Mh battery pack is USD43.90/pc 1000pcs USD43.05/pc 10,000pcs." 

Contact information to come if it's valid (don't want people freaking losing money trying something like this out).

if it IS valid... and if they can even go larger (say to like 12v x 40AH) for cheaper? maybe it's possible, I'll be buying a sample and doing full charge/discharge tests on this pack including cycle life. I want to see where the DOD is after about 100 cycles (which will take me upwards of 3 weeks to do), I want to see if pack stability stays intact and if voltage drop starts occuring.

This company is in Henan so the chances are very good this is legit (Henan being the home of thundersky).

80% DOD shouldn't be occurring till 500+ cycles with NI-MH... I want to see what price i get for 12v x 50AH cells.... maybe $150? ... it could happen.


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## ClintK (Apr 27, 2008)

It'd be pretty sweet to collect some more battery test results on the site. Keep us posted on how it goes!


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## Zemmo (Sep 13, 2007)

So if someone would want to build a 100 Ah 144 Volt pack it would take 120 of these batteries at $43.90 USD that would be $5,268 USD. Do you happen to know the weight of each of these batteries? Just Curious.


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## engineer_Bill (Jun 24, 2008)

Any info yet?


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## Technologic (Jul 20, 2008)

I talked with the guy until I was exhausted (4am) and will pick it up this coming monday.

I'll see if he can send me some larger formats, they should be slightly cheaper (probably around 0.30/WH)

http://www.eastarbattery.com/index.asp is the company. It seems like, at least to my knowledge, a legitimate offer.

I believe the battery weighs around 2kg... at least that's what he was suggesting (I was expecting an expensive price on the quotation, not such a useable one).

Remember 85% DOD is common with NI-MH as well. for discharging...

I'll be picking up the largest pack I can get at 12v (namely so I can just use a crappy car charger) this week and I'll update the thread with more specifics... as with most chinese companies, their ability to explain something isn't so wonderful.


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## gerd1022 (Jun 9, 2008)

ah ok you changed it to 2 kg each

i was going to say, if it was 3.2 kg for a 12V 10Ah battery, its right around the energy density for lead. A 144V, 100Ah would weight like 850 lbs. 

2 kg means the same pack would be 530 lbs which is pretty good


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## Technologic (Jul 20, 2008)

gerd1022 said:


> ah ok you changed it to 2 kg each
> 
> i was going to say, if it was 3.2 kg for a 12V 10Ah battery, its right around the energy density for lead. A 144V, 100Ah would weight like 850 lbs.
> 
> 2 kg means the same pack would be 530 lbs which is pretty good


I had to go back and look at the conversation  
For some reason my mind remembered 3.2kg. He said <2kg but since battery is custom made, he didn't have an exact weight anywhere I could see.

It might be less for the larger ones? that's generally how it goes (less cases).
The attraction to NI-MH is the cycle life (possibly upwards of 1000 useable cycles) for a cheap enough price that you're not blowing the entire value of the car every replacement (lithium quotations have consistently been twice this much).

At any rate I'm still amazed I found a company that's making large format NI-MH's. Only Panasonic was doing it for years. I'm looking forward to actually being able to test this... my battery pack for 96Vx100AH would cost about $3000 this way... and I'd have to replace it after about 125,000 miles. It's only about twice as much as FLA batteries.

He did say he can go cheaper with large format packs... I don't know what that means yet though. 
Since The specific energy density for NiMH material is approximately 70 W·h/kg, his 2kg number seems about right I guess?


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## Jason Lattimer (Dec 27, 2008)

http://www.batteryspace.com/index.asp?PageAction=VIEWCATS&Category=864

Here, check out this site. They have 39.6 volt packs at 10 amp hours for $420. They also have 37volt lithium ion high polymer batteries at 21 amp hours for $794.

http://www.all-battery.com/36vto60vnimhbatterypackseries.aspx

Here is another one. How about 50v 5 amp hour for $165 or 48v and 13 amp hour for 441.55

Just thought you might like these sites, hope it comes in handy.


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## Technologic (Jul 20, 2008)

Jason Lattimer said:


> http://www.batteryspace.com/index.asp?PageAction=VIEWCATS&Category=864
> 
> Here, check out this site. They have 39.6 volt packs at 10 amp hours for $420. They also have 37volt lithium ion high polymer batteries at 21 amp hours for $794.


1 dollar/wh vs 35 cents 

I can get lithium polymers for 50cents/wh in whatever quantity I want. I want something more in the 25 cent range though that ISN'T LA. Weight is a large factor in my build, and range. (shooting for 700lbs and 120 mile range for the completed car)


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## gerd1022 (Jun 9, 2008)

hey that is great!

do we know whether the larger formats are actually larger Ah cells, or are they just more cells in parallel in a case?


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## Technologic (Jul 20, 2008)

gerd1022 said:


> hey that is great!
> 
> do we know whether the larger formats are actually larger Ah cells, or are they just more cells in parallel in a case?


Well in general most larger AH batteries are just more cells in a case 

I assume it's 1 or 2 cells in a larger case based upon pictures of their "packs", but I can't be sure yet. Chinese new year is coming up and going to try and get some samples at least in the mail to test during that.


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## gerd1022 (Jun 9, 2008)

wierd... i was under the impression that there were just bigger cells.

isnt it like the difference in AAA and D cell batteries?


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## Technologic (Jul 20, 2008)

gerd1022 said:


> wierd... i was under the impression that there were just bigger cells.
> 
> isnt it like the difference in AAA and D cell batteries?


Correct. However if you had say a 48vx100AH lithium polymer battery, it's probably about 15-20 cells inside of the case all wired in series.

I believe this battery is a custom made package that they can manufacture in cases... they make F sized NI-MH as well, and also prismatic cells (which is what i assume this is)

Only company I know of that makes prismatic NI-MH batteries.


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## order99 (Sep 8, 2008)

Why...WHY...

...do none of these websites just list pre-made, high Voltage, 90+ Ahr packs in thier Products section? It would be SO much easier for me to estimate costs, and i'd pay a little extra to have some pre-assembled packs-really I would.

Maybe i'm just not looking hard enough.


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## Technologic (Jul 20, 2008)

order99 said:


> Why...WHY...
> 
> ...do none of these websites just list pre-made, high Voltage, 90+ Ahr packs in thier Products section? It would be SO much easier for me to estimate costs, and i'd pay a little extra to have some pre-assembled packs-really I would.
> 
> Maybe i'm just not looking hard enough.


They will preassemble them. They don't list them because I doubt they ever sell any NI-MH batteries over F size. In fact, I'm fairly certain they don't realize they're the only manufacturer I've been able to find that produces high voltage/AH packs at all for this battery type.

You can look at skyenergy.cn for their lists... they have premade polymer packs that large


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## Technologic (Jul 20, 2008)

*Update*:
It appears that 12Vx50AH may be too large to make with Ni-MH using the methods they use. He's sending out price quotes today for 20AH and 40AH... we'll see what comes up

I seriously love how easy the BMS's are for NI-MH... no worries of overcharging, no worries if one or two cells go out of balance... with a "stupid" charger that simply reads pack voltage and keeps pumping charge into the pack past when most batteries are full it will autobalance itself. Ni-MH can be overcharged for up to 20 hours past their fully charged point with no damages to battery life etc. All you need is a pack timer and low voltage cut off and your batteries should always stay perfectly charged and last up to their 1000 cycle life... assuming there isn't manufacturer's defect
Cheers.


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## slurryguy (Dec 16, 2008)

Techno is probably already aware of the points I will be making, but I'll throw it out for the sake of full disclosure to everyone. I do NOT consider myself an expert on the topic. I encourage others to do their own research and not just take my word for things.



My understanding is that NiMH batteries need thermal monitoring for proper charging. Therefore, just slamming the battery with a typical car battery charger may not be the best way to go. *Some* type of other care must be taken.

Not all NiMH batts are constructed with exactly the same chemistry either. Some have different catylists that create different temperature responses.

The point of my post isn't to correct Techno as it is to make everyone aware that it is possible to damage NiMH batteries with improper charging. In extreme cases, improper charging could even be dangerous. 

In other words... anyone that wants to play with some new toys should read up on those toys so that they can play safe like all good little boys and girls. 

Have fun!


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## Technologic (Jul 20, 2008)

slurryguy said:


> My understanding is that NiMH batteries need thermal monitoring for proper charging. Therefore, just slamming the battery with a typical car battery charger may not be the best way to go. *Some* type of other care must be taken.
> !


Certainly not a good idea... the charger needs to be matched to the setup being used... however as far as overcharging goes, these batteries are significantly less "worrisome" than lithium polymer... Also if misbalancing occurs it's not an amazingly huge issue.

Just for god's sake don't trickle charge them.


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## slurryguy (Dec 16, 2008)

Technologic said:


> Also if misbalancing occurs it's not an amazingly huge issue.


Speak for yourself. I've been unbalanced for years and my friends say it's a BIG issue.


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## Technologic (Jul 20, 2008)

slurryguy said:


> Speak for yourself. I've been unbalanced for years and my friends say it's a BIG issue.



SSDD.....


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## Hondacrzy (Mar 15, 2008)

Tech, Are the 12v Packs listed on the web site?


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## Technologic (Jul 20, 2008)

Hondacrzy said:


> Tech, Are the 12v Packs listed on the web site?


They have 9v prismatics listed, that's all I'm aware of that I can see.

Cheers.


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## david85 (Nov 12, 2007)

Heres another one for me to follow. Nicely done done, Technologic.

Although I think I should mention that it is better to have a smart charger even with NiMH. Ballancing is a none issue, but overcharging will generate heat and believe it or not, they can go into thermal runaway if unchecked.

But compared to lithium, they are much more forgiving. I look forward to any sample testing you can perform. Large NiMH cells was something we had generally given up on.

4:00 AM? thats crazy!


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## Technologic (Jul 20, 2008)

david85 said:


> Heres another one for me to follow. Nicely done done, Technologic.
> 
> Although I think I should mention that it is better to have a smart charger even with NiMH. Ballancing is a none issue, but overcharging will generate heat and believe it or not, they can go into thermal runaway if unchecked.
> 
> ...


haha I'm crazy

I absolutely gave up on them, I wasn't even going to try anymore after I got prices for a few Fsized (14wh) batteries... all in the $7/each range.

But there is something here


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## david85 (Nov 12, 2007)

Technologic said:


> But there is something here


I sure hope so. The more none lead options, the better.


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## order99 (Sep 8, 2008)

Sooo-assuming the prices are reasonable and that the NiMH packs are sturdy enough not to need balancing, and I were (for example) building a 48V, 100Ahr system...

Would 5 48V,20Ahr packs lined in parallel be the order of the day? 6 8V,100Ahr packs in series? 8 6V, 100ahr in series? Or 1 48V, 100ahr pack, period? I'm told the arrangement of the packs(assuming space and weight allow)is critical with LA batteries, but is it equally important with NiMH chemistry, or do I only create multiple packs so I can fast-charge using multiple chargers? 

My knowledge of NiMH is lacking. I'd all but given up, you see...


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## Technologic (Jul 20, 2008)

order99 said:


> Sooo-assuming the prices are reasonable and that the NiMH packs are sturdy enough not to need balancing, and I were (for example) building a 48V, 100Ahr system...
> 
> Would 5 48V,20Ahr packs lined in parallel be the order of the day? 6 8V,100Ahr packs in series? 8 6V, 100ahr in series? Or 1 48V, 100ahr pack, period? I'm told the arrangement of the packs(assuming space and weight allow)is critical with LA batteries, but is it equally important with NiMH chemistry, or do I only create multiple packs so I can fast-charge using multiple chargers?
> 
> My knowledge of NiMH is lacking. I'd all but given up, you see...


Assuming I can get 12Vx50AH packs, you'd need to series then parallel them together. (or parallel then series)

You could fast charge them... NI-MH actually like being fast charged, doesn't damage their life cycle. You can do just 1 pack to the charger... or have multiple chargers. Multiple chargers won't really give you an advantage on speed however.
As long as NI-MH batteries allow proper venting... the only maintenence you need is a timed charger (that shuts down at a certain time to prevent too much overcharging) and a low voltage cutoff to protect it from memory issues being possible (at about 85% DOD)

The batteries vs. LA can be drained almost fully, similar to lithium. They weigh a tad bit more than lithium polymer does, however, I'm hoping for about half price of lithium when all this is figured out for larger packs.

You don't want to trickle charge NI-MH like you can with lithium batteries... not a good idea. Overcharging/balancing concerns don't exist though, just keep charging them until the pack voltage reaches what you want... batteries should constantly be autobalanced this way.

I'll be testing one of these packs for everyone, and myself, if it turns out to be a good chance this will work. I will PROBABLY make sure the things last a hundred cycles without degrading any measurable amt. If they pass that test, you should be able to see 1000 charging cycles. Their graphs for this show a 70% DOD at 1000 cycles.


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## order99 (Sep 8, 2008)

You mention venting-does that mean the NiMH are wet cells and I can top them up? I didn't see an obvious port on those F type for watering, so I assumed they were dry, and i'd hate to treat them roughly if I couldn't replace the electrolyte.

So multiple chargers on multiple packs does nothing as opposed to LA? Good to know. My original Delta Trike design called for 4 or 5 12V LA in series, with a multiport marine-style charger I saw on the SUNN NEV last month-or failing that, 4-5 single chargers hooked up to a UPS. Sounds like NiMH might save me on extra chargers even as it costs me on batteries.

Alas my Trike is still a purple-crayon schematic due to lack of funds...but when tests are done please let us all know. Between the lower DoD, somewhat higher capacity and lower weight, these NiMHs might double my possible range...

And I say this from the bottom of my heart-my eternal gratitude for your attempts to break the Chevron NiMH Trust!


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## Technologic (Jul 20, 2008)

order99 said:


> You mention venting-does that mean the NiMH are wet cells and I can top them up? I didn't see an obvious port on those F type for watering, so I assumed they were dry, and i'd hate to treat them roughly if I couldn't replace the electrolyte.
> 
> So multiple chargers on multiple packs does nothing as opposed to LA? Good to know. My original Delta Trike design called for 4 or 5 12V LA in series, with a multiport marine-style charger I saw on the SUNN NEV last month-or failing that, 4-5 single chargers hooked up to a UPS. Sounds like NiMH might save me on extra chargers even as it costs me on batteries.
> 
> ...


I'll keep you updated... multiple charges on multiple packs probably wouldn't do a ton of good in this situation, the batteries can regulate/balance themselves in series/parallel just fine

This is how the Toyota EV was and they usually got about 100k miles out of 1 pack (and it had a lot less mileage per charge than I will get)


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## evcars (Mar 15, 2008)

I'm interested in these batteries. My only question is since these are still rather heavy batteries, how much would shipping be to the US??


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## TheSGC (Nov 15, 2007)

I am definitely interested in these!

As for the Rav4 EV, it had a 27 KWh pack, that got 100 miles of range, but the kicker is that is was never drained below 50%. So a 27 KWh pack should yield some sweet results for our EVs!


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## david85 (Nov 12, 2007)

TheSGC said:


> I am definitely interested in these!
> 
> As for the Rav4 EV, it had a 27 KWh pack, that got 100 miles of range, but the kicker is that is was never drained below 50%. So a 27 KWh pack should yield some sweet results for our EVs!


Are you serious? I did not know the battery size was so small. Are you sure about the 50% DOD? I thought that only applied to the prius battery.

My car will have about 29kwh of energy from lithium and will have less than half the aerodynamic drag and lighter weight.....hmm.......


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## Technologic (Jul 20, 2008)

xtreme cartz said:


> I'm interested in these batteries. My only question is since these are still rather heavy batteries, how much would shipping be to the US??


If my experience with china is anything, this will be sent via ship for whatever we order.

On average a 40' trailer full (30,000 lbs) of goods costs about 2200USD shipped. When I've done smaller orders of things in the 1000lb range, it's usually 500 dollars or so (which in this case would be about 30kwh of batteries)

Cheers.


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## Technologic (Jul 20, 2008)

david85 said:


> Are you serious? I did not know the battery size was so small. Are you sure about the 50% DOD? I thought that only applied to the prius battery.
> 
> My car will have about 29kwh of energy from lithium and will have less than half the aerodynamic drag and lighter weight.....hmm.......


It makes sense... the 1900 lb aptera gets 110 miles of range on 10kwh.

Seems very probable that a 27kwh NIMH pack could get a rav4 100 miles.

I personally never worry about shipping too immediately from china, it's usually a non-issue towards the price.

I'm shooting for a similar 10kwh, and hoping for about 200mile-250 mile range (car will weigh around 700lbs I hope).


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## david85 (Nov 12, 2007)

....but, if the battery was only discharged to about 50%, wouldn't that imply that it could drive 100 miles on only ~15kwh? that seems a little too good to be true. What am I missing here?

LOL, I don't suppose anyone on the forum owns an OEM electric rav?


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## Technologic (Jul 20, 2008)

david85 said:


> ....but, if the battery was only discharged to about 50%, wouldn't that imply that it could drive 100 miles on only ~15kwh? that seems a little too good to be true. What am I missing here?
> 
> LOL, I don't suppose anyone on the forum owns an OEM electric rav?


Assuming it didn't have regen braking as well?

It's possible that it could be regenned and add an additional 10-20% mileage per charge seemingly.

It's really not too good to be true if the Rav4 EV had like 3000lb curb weight etc.

Though I don't know if the rav4 really was at 50% or not.


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## david85 (Nov 12, 2007)

The range has been confirmed by the EPA, toyota, and most importantly, the owners of the cars themselves. The battery capacity I can believe, but I'm still wondering about the 50% thing.

Yes, it did have regen.


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## TheSGC (Nov 15, 2007)

I am trying to find the source on the 50% Rav4 thing. I know the Prius is never dropped below 50%, but I swear the Rav4 wasn't dropped below 50% either to allow the battery to last 100,000 miles before wearing down.


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## TheSGC (Nov 15, 2007)

Well I have found that the Panasonic EV95 battery is not 95 Ah, but instead a 100 Ah battery limited to 95 Ah for maximum safety. That's part of the management built into the battery from the factory, not just the Rav4 EV's management computer.

Source: http://avt.inl.gov/pdf/fsev/sce_rpt/rav4_ind_report.pdf

I still can't find the thing about the Rav4 EV. It might have been a show I watched about Ovonics, the EV95, some sweet solar panels and a new hydrogen powered Prius on Discovery that I might be thinking of.


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## Technologic (Jul 20, 2008)

TheSGC said:


> I am trying to find the source on the 50% Rav4 thing. I know the Prius is never dropped below 50%, but I swear the Rav4 wasn't dropped below 50% either to allow the battery to last 100,000 miles before wearing down.


cycle life shouldn't be harmed by 80% discharge, my guess is they were doing that (if they did) to not push any cells into overdischarge. Ie. they didn't want to employ a "hard stop" where the car would be "dead in the water" and wanted some safety net to remain.

Cycle life at 80% DOD continuous should last 700-1000 cycles.


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## Technologic (Jul 20, 2008)

Well the largest "cell size" they can go is 12v x 10AH without upping the price per wh.

The engineer is at festival already 
I intend to order one of these 12vx10AH since it would merely require paralleling them into sets (which is how MOST Ni-MH batteries work just inside larger cases... paralleling first is far more stable).

I'm going to manually charge this with a simple car charger watching the voltage and what happens.

I'm trying to figure out where the "trouble spots" lay in a large pack of NI-MH mostly in parallel, and the reality is, as long as I have 8 under voltage cut off circuits (for each large pack that's paralleled) there's almost nothing to worry about. The packs will autobalance during charging cycles and the normal delta-V charging system will work flawlessly on the entire pack at once.

Any overcharging will be worked out from the paralleling and the cool way NI-MH just vent out the additional charges.... obviously you wouldn't be overcharging them chronically, the batteries would stabalize each other in every pack as the voltage of the charger is "winding down"


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## order99 (Sep 8, 2008)

So how's the testing going? Or have your Batteries shipped yet?


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## Technologic (Jul 20, 2008)

order99 said:


> So how's the testing going? Or have your Batteries shipped yet?


I've given up on the NI-MH because I found a LiFePO4 factory that is priced for less per watt hour (around 32 cents)...

cheers


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## order99 (Sep 8, 2008)

Too bad-cheap Lithium sounds great but NiMH sounds really rugged and reliable...but at least I know where to get them now thanks to you. Maybe i'll end up doing the tests myself before the end of this year!


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## ravlegend (Feb 6, 2009)

thanks to technologic for bringing back lifepo4 vs NI-MH battery

question: why is everyone jumping on the lifepo4 bandwagon when ni-mh technology is more forgiving in term of overcharging etc.


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## ClintK (Apr 27, 2008)

ravlegend said:


> thanks to technologic for bringing back lifepo4 vs NI-MH battery
> 
> question: why is everyone jumping on the lifepo4 bandwagon when ni-mh technology is more forgiving in term of overcharging etc.


NiMH life cycle about 500, LiFePO4 2000-3000 estimated cycles


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## david85 (Nov 12, 2007)

The real answer is that NiMH is so hard to find. LiFePO4 batteries are being marketed in china and other parts of asia spesifically for EVs. NiMH batteries were effectively killed by a court rulling against toyota and panasonic for use in EVs.

Small consumer cells have cycle life typically less than 1000, however, you have to remember that development on the technology effectively stopped when that court passed that desision. Its possible that NiMH has more potential to be unlocked, but for now LiFePO4 is the most affordable and accessable non lead performance battery.

Not perfect, but its what we have to work with.


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## order99 (Sep 8, 2008)

Yep, 'what we have to work with' is right.

What the heck-if I can't get anything else i'll use 'effin Edison NiFe's and build a vehicle so light that the reduced Amp draw won't be a problem! I plan on using NiFe in the future (for my Off-grid House renovations) so it isn't like I couldn't play around on a proof-of-concept EV with a few extra Batts...if it doesn't work I just get more power reserves for the house!  Despite the reduced Amp draws and the extra charging required, i'm in love with the idea that those batteries will probably outlive me...and if you don't believe me, Jay Leno's got a Baker Electric with an original Edison NiFe pack!


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## david85 (Nov 12, 2007)

NiFe are probably the longest lived batteries on the planet. They are one of those technologies that no one really knows how long they can last. Best guess so far is about 50 years or more. I heard that they were no longer produced in the USA as of the 1970s, and that their efficiency can be as low as 50%.

The energy density is a little better than lead, but the long life span isn't very palletable for most durable goods (like cars) that only have to live 10-15 years before being scrapped.

The only present day source I found for them so far was the same chinese supplier that I sourced my lithium ion battery from. Never asked about them though.


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## Technologic (Jul 20, 2008)

david85 said:


> NiFe are probably the longest lived batteries on the planet. They are one of those technologies that no one really knows how long they can last. Best guess so far is about 50 years or more. I heard that they were no longer produced in the USA as of the 1970s, and that their efficiency can be as low as 50%.
> 
> The energy density is a little better than lead, but the long life span isn't very palletable for most durable goods (like cars) that only have to live 10-15 years before being scrapped.
> 
> The only present day source I found for them so far was the same chinese supplier that I sourced my lithium ion battery from. Never asked about them though.


Plenty of places make large format Ni-Fe batteries

http://www.alibaba.com/product-gs/200532012/Ni_Fe_Battery.html


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## Zemmo (Sep 13, 2007)

I sure hope that NiFe batteries last as long as everyone says. The van I just purchased has them as their battery pack. The batteries were completely flat. They are up to 215 volts but there isn't any storage yet. I am hoping that they revive to full use again.


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