Are Can Gen3 Prius Battery Modules be used in a Gen2 HEV Battery rebuild?

Are you changing the battery ECU too? The one in your car was designed for NiMH. Perhaps get one from a PiP?

 

Yes. The ECU knows the specifics about how to handle the battery chemistry. The rest of the car only knows that there is a source of ~200 volts that can be used and has to be fed. Lead acid batteries would work as far as the rest of the car is concerned.

 

The battery ECU is inside the battery box. I suspect that you could even exchange a Gen4 Lithium with a Gen4 NiMH. What I don't know is whether a Gen4 Lithium ECU can talk properly with earlier generation Prius.

 

The inverter is meant to charge NiMH though, isn't it? That should likely be witched too, if compatible with the rest of the car/

 

The inverter (or maybe it's the engine ECU) knows how to talk to the battery ECU. Where the battery ECU gets its information about the storage device is hidden from the inverter/engine ECU. Could be a bunch of hamster wheels...

 

Hi TMR-JWAP, I am new to the forum. A search for "mixing Prius G2 and G3 battery modules" brought me here. I am facing the same problem: I am rebuilding my HV battery pack for my 2007 Piurs touring, and the order from Amazon seller who claims selling G2 module arrived in mixed of G2s and G3s, most of them (9 out of 12) are G3s. I wonder what was the result of your G3 mixed with G2 test? Is the general advise of "Do not mix G3 in G2" still a good practice? Or it doesn't matter? Thank you for your advice!

 

I have the same car as you. This is my 3rd time removing that big battery. Most all of my modules are 2007. I have 4 that are 2006 and 1 that is 2011. I‘ve identified the bad module reading 6.2v but I have 4 modules on the way so I’m load testing them with a 12v 37watt fog light. I’m recording the time it takes each to go from 8.0v down to 7.5v. Most of them are between 14-16 minutes, but the 2011 module was taking forever and went 30 minutes. For as old as the gen 2 cars are I’d say you can in fact mix gen 2 and gen 3 modules. This isn’t rocket science. If anyone says you can’t mix them, ask them if they personally have tried it and if they have not ask them to provide you the math behind why this will not work. Likely they do not have a degree in electrical engineering. We should get that Enginnering Explained guy to do a video.

 

Do you? @2k1Toaster here works with rechargeable batteries for his day job and sells an excellent lit of new cylindrical cells that have given people a like-new battery pack for less cost than a new pack. I would like to hear his professional, trained opinion on mixing generations. I know Toyotas said they used a higher grade Nickel in the Gen 4 NiMH cells so there are likely some differences.

 

Wondering whether this experiment was done or whether anyone has more feedback on the idea of putting Gen 3 cells in a Gen 2 pack. My Gen 2 pack has mostly questionable or completely non-functional modules. And, I recently got a complete battery out of a crashed Gen 3 at the junkyard so am thinking of directly swapping the modules into my old Gen 2 pack.

 

I know Todd from Tampa Hybrids put Gen 4 Ni-MH modules into a Gen 2 with no issues.

 

Likely if Gen 4 modules work, then Gen 3 would as well. I was thinking of moving the middle modules toward the ends on the theory that they've been exposed to more heat so far.

 

Gen 4 Ni-MH modules will work. Many Gen 4 are Li-Ion and those will not work. My Trim 2 is Ni-MH. I think the Trim 1 was too. All others were Li-Ion.

 

Yes, there is no question that you can put all of the Gen 3/4 (NiMH) modules into a Gen 2 case.

As for mixing Gen 3/4 in with Gen 2, my punt would be it will work as long as the Gen 3/4 modules match the rest of the existing Gen 2 modules. The problem I see, getting that match will be harder the greater the gap between manufacture dates of the modules.

At the end of the day, matching the replacement modules to the existing is where the work is. The better this is, the better the end product.

For myself, if I wasn't going to put in a new set of modules (for whatever reason), I would be looking for the newest Gen 3/4 (NiMH) pack I could find and transplant all of the modules into my Gen 2 pack and be done with it for another 4-5 years (or more).

 

What about moving the end modules to the middle and the middle ones to the ends due to prior heat buildup?

 

I don't really have an opinion on that. I haven't really seen in practice where the middle modules fail more vs the end modules.

 

Just to shed some light on this...gen 2 gen 3 comparison is only relevant when we are talking about comparing IR. Obviously the firmware in the GEN 3 cars..camry...prius...lexus stuff, even the new highlanders ive found act the same...middle of the packs are burnt, and the end of the packs (maybe modules 1-3 and 26-28) are nearly new a lot of the time.

2 years ago I matched a pack of gen 2 and gen 3 to nearly 6.0 ah across the board and the customer has reported that in 2 years they have the same MPG and on Dr Prius everything looks balanced and nice still.

I think it’s safe to say that if at all possible mixing gen 2 and gen 3 should be avoided, but if you have the capability of observing IR, voltage, and of course AH capacity, and you can be sure everything is as balanced as possible, you can get away with it. I am very picky with my packs that I put into customer cars. I have done just about every one of the weird cars under the sun, and as weird as some of the packs are, for the most part, the stuff is apples to apples.

 

So has anyone actually tried this experiment yet on a random module? It's been almost 4 years since the OP asked. Ok, theory, blah blah blah. But has anyone dropped a G3 module into a G2 pack and ran tests? Measured voltages as it drove with Dr. Prius? Seen if any warning flags get thrown? Does it continue to work for many more miles? Just generally see what it does if you threw in some random G3 pack into the G2 bundle.

 

ok, I'll try to make this perfectly clear. The gen 2 and Gen 3 modules are effectively identical. The difference is in the serial number date code stamped on the top.