DIY Gen 2 Prius Upgrade Mod(Planning)

As far as I know, nobody has serialy connected 2 oem nimh cells.
They where always paralleled. That's to say the + pole with the other + pole.
Note that average voltage is not 201v but 220-230v, so you would have 450v.

This would have been a solution in order to bypass the boost converter, which is the main power limitation in EV mode, about 22kW.
But connecting after this boost converter would be a huge chalenge.
Forget it..

All the diy I saw have paralleled there nimh battery packs.

May I suggest you having a look on hybridinterfaces.ca

Please be very carreful. 220v dc (or 450v dc) will kill you.

 

400 volts? series?

mm forget it!

just do what you read that the other guys do

if your unable because of cost then save the money right now because it will be lost.

 

Lithium with BMS+ is the way to go for a complete DIY. There isn't enough energy storage in adding just one extra Prius battery to make it worth the headache. Plus, the cost of used batteries has gone way up in the past 5 years. A few years ago you could get good ones for 200-300, now they are $500 and up. Basically, the cost per kWh of used NiMH is now comparable to the cost of new lithium. The issue with lithium is getting reasonably matched quality cells without paying more than $1.50 per amp hour. The stream of consciousness PHEV conversion thread has a wealth of information...you've probably read some or most of it, but I'd say it is the best source of info for the current DIY PHEV state of the art and the issues involved. http://priuschat.com/forums/prius-p...0-planing-canview-bms-conversion-lithium.html

In the end, I think it would take you weeks if not months of work to get either a lithium system or a NiMH system up and running satisfactorily. If you are going to put that much time into the project, be sure to go all-in and do it right.

 

Lithium will take up much less room. Shop around for prices. Flying White Dutchman, how much did it cost to get your cells? Note also the precautions that were built into the parallel charging process, multiple failsafes, etc.

Some statements from NWPriusPlus that you need to take very seriously:

"It requires significant work and prior knowledge"
"it took me a whole year to figure out a suitable way to install and tie-in the batteries, and I also built 4 versions of my charging system."
"By far the most difficult and risky part of the conversion is the charging operation, as has been proven by several documented battery "expansion" incidents."
" All three batteries are fan cooled, by powerful computer case fans (full 1 amp at 12 volts, Vantec TD9238H 92mm Case Fan, 119 CFM). These are noisy, but powerful, and continue to run even after the charger shuts off, until I check the battery temps before physically unplug."

Do not think for a moment that a single charger will just work. You need cooling, temperature probes, and timers. Even with multiple charging failsafes, people have still had explosions which have resulted in insurance writeoffs.

It is too bad that you and Flying White Dutchman live so far apart, as you could learn a lot just by helping him finish his project.