Battery packs interchangeable?

First question no. Voltages are different for one thing. With modification? That I don't know, but if it could be done, hobbit would be the first one I'd ask for advice.

 

Classic has 38 modules while 2G has 28 modules. The physical form factor of the modules is slightly different but in both cases the modules have a 7.2V nominal rating.

I don't believe that anyone has yet tried installing 38 modules salvaged from 2G battery packs into a Classic battery case. If you try that and are successful, you'll be adding to the collective knowledge base.

No point in trying to install Classic modules into a 2G battery case since the Classic modules are more scarce and have a poorer design (only one internal interconnection bus vs. two with 2G).

 

DO NOT TRY THIS AT HOME!!! Unless you are VERY experienced with high voltage DC systems. The voltages in the Prius traction battery pack, first gen OR second gen are LETHAL!

You might think as it's only around 200 - 270V it's no problem. YOU'D BE WRONG! If you get yourself across the DC you will not be able to let go, and will cook in your own juices! NOT PLEASANT.

 

What Patrick and David said.
.
I would be interested to someday see how a Classic would do with
a set of '04+ modules, or vice versa, just as an exercise, but
it would basically require building a whole new battery box either
way. The module voltages are the same, but the amp-hour capacities
are slightly different and of course the Classic modules have
a couple of other inherent problems here and there as well --
the positive-terminal leak, only good for 50 amps, etc. So such
a project would have to be babied pretty closely.
.
_H*

 

the old prius battery is 273 volts DC , vs new one which is like 201?

so you would need two 2004-2009 prius batteries, to make one 2001 prius battery?

 

Yes, two 2G Prius batteries contain 56 modules. After assembling one Classic battery (requiring 38 modules) you would be left with 18 extra modules.

 

Current Gen Prius HV pack has lower internal resistance and higher power density. I am guessing the BMS in the Classic may not work correctly with them. Here is a piece from THS II tech link:

Here is a pic of module comparison along with a cig box:

 

Seems likely that the new modules kept the same shape to limit re-tooling costs. As a consequence, it is possible at least to consider this conversion. It also seems likely that the old BMS would not take full advantage of the new cells' characteristics, but they should work at least as well as the previous version in the car?

 

IF you did your homework when you "built" your new pack, and IF you interfaced all required sensors (voltage and temperature), the 2004 to 2009 modules should last -longer- than they would in a 2004 model car, as in the 1st gen they would be used even less than the current model uses them.

I suspect the car would work better, though it may be difficult to tell. It's remotely possible you could overheat the motors or overdrive the electronics, as the battery can output more current, but I suspect the electronics would control that. This is not from "wrong voltage", I already -assume- you would build the pack to the correct voltage (using the correct number of modules). It's from the higher current delivery capability of the newer modules (lower internal resistance).

However, once again, you really MUST know what you are doing. You will have to "adapt" the gen 1 battery protection circuitry to the gen 2 modules. For example, where are you going to put the temp sensors? How about the disconnect switches? The voltage sensor wiring?

Interesting project. Perhaps you could convince Bob to help you? He's an engineer with experience on the 1 gen Prius battery.

 

im considering doing this when my 01 battery goes bad. If the module voltage is the same ill just get two 04-09 prius batteries and use the extra modules as a 12 volt battery

 

So you're good with sheet metalwork? You WILL have to make a new box for the battery. Ditto for the 12V one, but that's a neat idea - a 12V battery that will last! That won't be damaged by full discharge. I've used a NiCd 12V battery in a motorcycle with good results. But like the Prius, it didn't use it to crank the engine - kickstart.