[Oeva-list] Ev Batteries

[gfifield at onlinenw.com]

Hi,
I visited the website for LifeBatt.com
They don't sell individual cells but sell in multiples of 12V packs.
The RFQ page has the following statement:
" NOTE:  LiFeBATT does not sell individual Cells or sub-components! 
Please only fill out this RFQ for complete Plug & Play XPS Packs with
On-Board Diagnostics, Battery Management Systems, Over & Under Voltage
protection circuits and overall Battery Protection Modules."

They provide the on-board diagnostics and BMS, etc.
I suppose they will supply the protocol, or is it a closed system?
Anyone know?

Gene
> I'm just about to pick up a set of 96 100ah Sky Energy Li Ion cells from
> EV Components.  I am also getting the BMS that they offer, which allows
> them to extend a 2 year warranty on the cells.  The total package cost
> is just under $15k.  The people at EV Components and their customers are
> seem to be having good results now with both the Sky Energy and the
> Thundersky cells.  With the 2 year warranty, I feel that I should be
> covered for any infancy failures.
>
> I wasn't able to get IE to open the web page you sent this morning.
> I'll try again later with my Mac.
>
> Paul Wallace
>
> Graunke, Gary wrote:
>> 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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