Hi, Steve! As this site is public, I am taking the liberty to forward
this message and my response to mailto:eaa-phev@...
Although your web page didn't show any conversion specifics, all power
to you! For what they are worth, here are my suggestions, which
actually apply to anyone intending to use one or more Prius battery
packs as a PHEV pack.
1) If you plan to use BatteryECU spoofing (instead of replacement), I
recommend adding cells to a gen-2 or removing cells from a gen-1 Prius
pack to create a pack with around 200 cells in series. This should give
you approximately the same voltage differential as the 20 12V PbA
modules I am currently using. You might need to add or subtract a few
cells if, after experimentation, you find the PHEV pack's end
state-of-charge (SOC) is too high or low, respectively.
2) To help keep track of SOC while experimenting, I highly recommend an
Amp-hour meter such as the Trimetric TM-2020 ($140 at
with a 100A, 100mV shunt
3) One 6.5Ah Prius pack, used as a PHEV battery, should provide about 5
miles of EV range. It will take 2 to provide the same 10 mile EV range
as my PbA pack; four should give you 20 miles. However, these cells
were not designed for deep discharge or (especially) to be repeatedly
charged fully, so their lifetime may be shorter than desireable.
4) If more than one Prius pack is put in parallel to form a PHEV pack,
you should do the following:
a) Fuse each pack separately, with a 60A fuse for each of two packs
or a 30A fuse for each of 4 packs.
b) Charge each pack separately, with a charger specifically
designed for an NiMH pack. NiMH cells and packs cannot be charged to
end-of-charge in parallel, as only on string of a parallel set will ever
get fully charged. Also, chargers with algorithms designed for any
other chemistry will not behave properly around end-of-charge, and will
destroy the battery.
5) Tom Driscoll (mechanical) and I (electronics) are working on, and
will soon be publishing documentation for an updated version of the
spoofing-based PbA PRIUS+ conversion that has now been successfully
running on my car for over a month (more info in an upcoming message at
eaa-phev). It will be designed for flexibility, capable of working with
all sorts of battery packs with their own battery management
electronics, and with various types of high-power electronics, e.g.
contactors vs. a DC:DC converter such as Manzanita Micro's PFC-40
charger. Once again, I believe that a wait for this documentation will
be well worth it.
> Hello All, I invite you to visit this website to see my efforts on
> another PHEV Prius. My name is Steve Woodruff and I have been silent
> too long. I welcome constructive critisism and your correspondence.
> http://www.autobeyours.com/PHEV.htm <http://www.autobeyours.com/PHEV.htm>
Ron Gremban, rgremban@...
California Cars Initiative, a nonprofit organization: http://www.CalCars.org
Moderator & Technical Lead
PRIUS+ PHEV Conversion Group: http://groups.yahoo.com/group/priusplus
Do-it-yourself PHEVs: http://www.eaa-phev.org