[Oeva-list] EV Batteries

Sat Oct 10 16:16:22 PDT 2009

A local-ish source for the Thunder Sky batteries is www.evcomponents.com 
They are in Lacey, WA and you can save money by picking the batteries up at 
their warehouse.  They carry three lines of LiFePO4, and several battery 
management systems.  I bought the batteries and BMS for my conversion from 
them.  It's taken more than two months for them to arrive - I'm supposed to 
pick them up this week.  These folks have the best prices I could find 
anywhere.  Be aware that they charge separately for the ocean shipping from 
China, but it's still a good deal.

I am using the 60AH batteries as I am more concerned with size and weight (I 
need 90 of them for 288V) than range.  If you are doing a 96 Volt 
conversion, you'll only need 30 and could go with the 220AH if you really 
want range.  They make them in a variety of ratings.

The only other source for Thunder Sky that I could find was Jungle Motors in 
San Diego, but their prices were 50% more.

Good luck!
Richard

----- Original Message ----- 
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Sent: Saturday, October 10, 2009 12:00 PM
Subject: Oeva-list Digest, Vol 72, Issue 15

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>   1. Ev Batteries (Rob Russo)
>   2. Re: Ev Batteries (Graunke, Gary)
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> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 9 Oct 2009 18:45:20 -0700 (PDT)
> From: Rob Russo <theboarddoctor at yahoo.com>
> Subject: [Oeva-list] Ev Batteries
> To: oeva-list at oeva.org
> Message-ID: <170760.80443.qm at web57006.mail.re3.yahoo.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Thanks to all who responded.?
> I guess my main concern and?probably the first decision I have to make is 
> the type and voltage of the battery pack.?I want to avoid lead acid 
> batteries because it seems counterintuitive to add all that weight to such 
> a light vehicle.
> Is this battery pack practical for my application?: 
> http://www.lifebatt.com/HPSpacks.asp?. Are there any alternative sources 
> for this type of battery?
>
> Thanks,
> -Rob
>
>
>
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> Message: 2
> Date: Sat, 10 Oct 2009 09:46:37 -0700
> From: "Graunke, Gary" <gary.graunke at intel.com>
> Subject: Re: [Oeva-list] Ev Batteries
> To: Rob Russo <theboarddoctor at yahoo.com>, "oeva-list at oeva.org"
> <oeva-list at oeva.org>
> Cc: "Wallace, Paul" <paul.wallace at intel.com>
> Message-ID:
> <9662F248D13E8C45B097A77F005E97293E00872D at orsmsx503.amr.corp.intel.com>
>
> Content-Type: text/plain; charset="us-ascii"
>
> Looking at the Sandia report, these batteries should be great in an EV. It 
> doesn't answer the question of quality of manufacturing, but covers 
> everything else.
> Our experience with A123's LiFePO4 was that 1-2% have a higher 
> self-discharge rate, but they are otherwise very consistent and meet and 
> exceed specs in every way.
> These also meet or exceed specs in every way, according to the authors.
>
> To deal with these kind of variations, I would suggest the 12V 40AH to 
> 80AH batteries (maybe even the 120AH if you have a pickup truck), so you 
> have 4 to 12 cells in parallel.
> The 26 to 34 lb batteries are easy to life by hand if you need to work on 
> them. The AH depends on your desired range and/or $ you have to invest.
>
> The low temperature performance is better than lead-acid as well, losing 
> only 25% at freezing (about our low in Portland) or 34% if you live in 
> Bend. The high power of the cells helps the low temperature performance, 
> however, compared to lead, and you still can put in battery heaters or an 
> insulated battery box if this is a concern. An insulated battery box would 
> also help if you have a catastrophic cell failure with 160C temperatures. 
> (Always vent the box to the outside (not cabin) for this reason, though it 
> is not critical).
> There is no high temperature concern (life with most other batteries!).
>
> Buying the batteries in this package makes it difficult (if not 
> impractical) to do individual cell group management, but it sure is 
> convenient!  However, it may well be that monitoring the battery voltage 
> at 12V will be good enough (that is what we are forced to do with lead 
> acid batteries in any case). (The issue is that one should slow down/shut 
> off the charger when a cell reaches maximum voltage to avoid overcharging 
> it). The self-discharge rates on a cell mean that you may want to charge 
> individual cells (or cell groups if they are in parallel) to keep them in 
> balance. I do this manually right now every 10 months or so with A123 
> cells, but will eventually put in equalizers to do this continuously.
>
> Bottom line-I would have used batteries like this in my Insight had they 
> been available 3 years ago. Let us know how much they want for them.
>
> Other sources are thunder sky (though they have not met specs in their 
> early offerings), peak battery (K2). I am running K2 batteries in my 
> plug-in Prius from EEtrex-they have less (but still adequate) power than 
> A123's, but 30% more energy per same size and weight cell.
>
> It is important to assess the quality of the batteries. It helps to know 
> someone who has been using them, but this is difficult with new batteries. 
> The Sandia report is very helpful in this regard, but there is always a 
> concern that they "cherry-picked" the cells that they sent for testing 
> (rather than a random sample from their production).
>
> Keep us informed with your progress!
>
> Gary
>
> ________________________________
> From: oeva-list-bounces at oeva.org [mailto:oeva-list-bounces at oeva.org] On 
> Behalf Of Rob Russo
> Sent: Friday, October 09, 2009 6:45 PM
> To: oeva-list at oeva.org
> Subject: [Oeva-list] Ev Batteries
>
> Thanks to all who responded.
> I guess my main concern and probably the first decision I have to make is 
> the type and voltage of the battery pack. I want to avoid lead acid 
> batteries because it seems counterintuitive to add all that weight to such 
> a light vehicle.
> Is this battery pack practical for my application?: 
> http://www.lifebatt.com/HPSpacks.asp . Are there any alternative sources 
> for this type of battery?
>
> Thanks,
> -Rob
>
>
>
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