[Oeva-list] Ev Batteries

Mon Oct 12 19:04:37 PDT 2009

Hi Paul,
Why not just fill out their quote form with your particular desired
configuration and see what they come back with? I'd be curious to know if
they will deal with individuals.
Gene

> Too bad they aren't offering the 12v modules in a 100ah version.  to get
> same total energy I'm going to have would requires 32 of the 80ah
> modules, pushing the nominal pack voltage too high for most DC
> controllers available today.  Even my Zilla 1kehv limits out at about
> 375vdc.  AC controllers may go a bit higher, but the one I'll be using
> limits at a voltage similar to the Zilla.  Using the 120ah modules puts
> the nominal pack voltage too low, making the current too high under
> cruising conditions for standard chemistry Li Ion.  I wasn't able to
> find any technical data on max and sustained discharge currents on the
> site.  If they are similar to the A123 cells, then they will be able to
> withstand higher sustained and max currents than the Sky Energy cells
> I'll be using, making a lower voltage equivalent total energy pack
> possible.  The weight of the batteries is also interesting.  The cells
> I'm getting will be about 675lbs, while an equivalent pack of these
> LifeBatts will be around 1300lbs.
>
> Paul
>
> gfifield at onlinenw.com wrote:
>> 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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>>
>>
>