[ausev] LiFePO4 battery system suitable for DIY EV's

[JohnFM]

Just about every LIfePO4 source for an EV conversion is coming by way
of China. Free trade is great but, there is so little accountability
and support from most of these Chinese companies. I've seen reports of
cells melting, becoming imbalanced even with a BMS with no
compensation. Has anybody got word on what's going on with EEstor and
their supercapacitor? Surely there has to be a better way.

John

On Thu, Dec 11, 2008 at 8:42 AM, Marc Kohler <mkohler at austin.rr.com> wrote:
> Hi Kevin,
>
> I think it's a very interesting idea, one that many would like to see
> happen.
>
> Whose LiFePO4 modules are you planning on using as the basis of the pack?
>
> Have they provided any test data to verify claims?
>
> Best regards,
>
> Marc Kohler
>
>
>
> From: ausev-bounces at austinev.org [mailto:ausev-bounces at austinev.org] On
> Behalf Of Kevin Douglass
> Sent: Wednesday, December 10, 2008 10:05 PM
> To: AusEV at austinev.org
> Subject: [ausev] LiFePO4 battery system suitable for DIY EV's
>
>
>
> Hello to all,
>
> My name is Kevin Douglass.
>
> I'm a member of HEAA (Houston Electric Auto Association).
>
> We have a couple of EE's with experience in this sort of thing in the club
> who are starting on a project to make a LiFePO4 battery system suitable for
> EV's.  Tentatively these modules are expected to be about 4.5KWhr, 75VDC,
> 300Amps max continuous, 600Amps peak, with 22.5Kwatts (29 hp) continuous
> power. Modules can be series or parallel connected just like commercial
> batteries.  DC motor EV's would probably take two modules in series for
> 150VDC, 9KWhr capacity (@ 250W/mi ? 36 miles).  A higher voltage AC system
> could use three or four in series.  A more powerful DC system, or if you
> want twice the range, could use four (150VDC, 18KWhr.) in series/parallel.
> Each module will be fully enclosed and protected; yet individual cells can
> be easily replaced.  Full BMS will be built-in, with remote SOC/SOH
> display.  The system may also have a built-in battery charger and possibly a
> DC-DC converter (for 12V battery) depending on what everyone agrees on.
>
> This is a big project expected to take most of 2009.  The predicted price of
> the modules is currently $6,000 but subject to change as things are further
> defined.  Our desire is to be less expensive than other LiFePO4 systems
> available to DIY EV builders, but of high commercial quality with safety as
> first priority.  To participate in the project, a contract, NDA, and earnest
> money will be required.  There will be a schedule for payments throughout
> the year as major milestones are accomplished.
>
> Is there interest in this from members of the Austin EV list in particular
> but not limited to those that are close to the Houston area.  The cells are
> being bought in quantity and building more modules lowers the cost of cells
> and the proportional costs of getting the electronics made.
>
> Please contact me at 713-927-6997 or  k.douglass at earthlink.net
>
> Thank you,
>
> Kevin Douglass
>
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