1997 EV1 Traction Battery t-pack

EV1 Panasonic EV-95 NiMH - Retrofit


With the EV1's original battery modules
now obsolete and unobtainable, and the BPCM programing
hard-coded to those old modules, operating an EV1 on
original OEM programing is a difficult task to say the least. The
programming has to 'see' twenty-six (26) modules, with
appropriate voltages and resistances to operate correctly.
Fortunately, these older EV1 era traction packs did
not include overly complex BMSs, but were instead rather basic
when it came to the data that the programing needs to see.
Therefore, to keep the EV1s running on original programming the
challenge is to mirror the original battery modules. The next
level of difficulty is the original OEM battery footprints, quite unusual,
and not used in any other applications these days. Space is
also an issue. To get around these challenges, we have utalized
another older battery module, the Panasonic EV-95, a
quality manufactured long-life module originating from the same era. The
EV-95s, although no longer manufactured, remain in-service in
a number of Rav4-EVs of the era, including other vehicles
in the Beata collection.

Pictured below is an EV1 traction pack fitted with EV-95s for the
purpose of operating on the EV1's original programing,
with its original Magne-Charge paddle charging system, and continuing
to be able to monitor those systems via the
original Tech2 OBD scan tool.

Another challenge in this sequence is module cooling. Where the
original modules, the Delco PbA, the Panasonic 1260u PbA, and the
Ovonic NiMH, were all designed for exterior cooling, the
EV-95 is primarily cooled with air flow between the module's 10 cells,
and from that perspective requires greater care and monitoring
to insure proper temperatures are not exceed.

An interesting piece of EV1 history is displayed in the last picture
below. Check-out this battery pack's serial number.


---> Additional pictures below <---