I have a 2007 Prius that the battery gave up about 4 weeks ago when it sat outside without use while we were on vacation. When my wife and us got back, we drove it about 50 miles to the next city and then all the lights on the dash came on. Maybe some of you more knowledgeable folks in here can clear something up for me. I have arranged to go buy a really good condition 2010 prius HV battery with only 42k miles on the odo when it got totaled, and the seller is willing to let it go for $700. Are the two batteries interchangeable as is without any other modifications? Or would i have to take all the 28 modules off the 3rd gen pack, and put them on my 2nd gen pack? Straight swap over with nothing else to do? Maybe if i sell some of the modules off my gen 2 battery pack i can recoup some of my money back from buying the 3rd gen pack. Thanks for any thoughts and opinions.
You should remove all 28 modules from the Gen3 pack and put it in your Gen2 case. You can then sell the individual modules from the Gen2 battery pack.
The batteries are not compatible, but the 28 battery modules are. You will need to disassemble bot batteries and swap the 28 modules from the 2010 battery into the 2007 battery. I would suggest also following the re-balancing. load testing and equalization steps outlined in many HV battery discussions here on PC while you have the 2010 battery intact and out of the car. You can probably use your Prius with its old battery for a while while you get the 2010 modules ready for installation. If you then go through the same steps on your 2007 modules and document their performance, the better ones can be sold to others to fix their batteries. JeffD
Yeah, i really was trying to get out of the whole balancing process. Reading through other threads it seems like having to buy the equipment to do this task would already set someone back around $400-500 in cost and time. Seems like some guys say the newer battery modules from the Gen 3 are better all around. Has anyone out there done this swap and can post real world info if the Gen 2 prius openly accepted the new modules without throwing any idiotic codes afterwards without balancing? Thanks for the replies so far
I follow nearly every battery replacement thread on here and I've never seen someone try that. You could be the first though.
Lol, yeah maybe i'll be the guinea pig try it out and see how it goes (maybe lol), i'll leave all my panels off and if anything goes wrong i can take the battery back off. If i have to buy those Hitec X4 chargers on top of the Gen 3 battery pack this would really suck, or maybe i should just get this local guy here to come trade out my bad Gen 2 battery with his good/rebalanced Gen 2 battery for $600? Which option do you guys think is best? The reason i didn't already do the $600 trade was because the guy trading said the rebalanced battery was from a 2004 with more than 200k miles. Ouch.
I'm no expert at this but I think it would ok to just swap the new Gen3 modules over to the Gen2 case. If the modules haven't sat around for a long period of time, it shouldn't need to be re-balanced if you are swapping the entire pack over. If you have the equipment, balance it, but if you don't have the equipment, you can just swap the modules in and give it a go. The modules should all read a similar voltage, check them all before you install. Last time I read the ones in my Gen2, they were mostly at 7.6 volts, except for the 2 end modules that read 7.5 volts.
As long as the battery modules are reasonably balanced and you at least put the set in parallel to equalize (get them all to the same voltage) them, there should be no immediate codes. JeffD
Thanks for the replies, i guess i'll just go ahead and give this Gen 3 module swap a try and see if all goes good.
I thought I saw someone on ebay that would rebuild gen 2 batteries with gen 3. Do a search. I thought I saw someone here do this with great detail.
Just wanted to update this thread that after i swapped in the newer gen3 modules into my gen2 casing the car is back on the road and going strong. At first there was a check engine light, but after driving the car around town for 20 or so miles the check engine light went away and everything is good now. Thanks for those who commented and thanks to PriusChat for all the info. Heres to another 200k miles. lol
Would you please check back periodically with how things are going? Maybe near 1st of year and 4th of July, just to confirm this is still working for you. Thanks!
I was going to mention, no need for all the re-balancing equipment, if you are swapping with known good modules, just put them in and drive the car, to charge cycle them a few times. Drive it uphill (discharge) then down hill with brakes on to regen charge them. The system will balance them out and any cells that are NG will show rather quickly. One thing I would add is if you're going to do all this work and have the pack out, move the temp sensors (3 of them) to the top side of the modules. Heat rises! Never understood why they mounted one of them on the bottom, and it wasn't even touching the module! Move all temp sensors to the top side of the pack!
Allow me to help you understand. On a Gen 2 HV battery: One temp sensor is mounted on top of the battery, near where the cooling air flow enters the battery pack. This one clips into a small metal tab located on the clamping bars and is suspended in the airstream. It's job is to monitor the incoming cooling air temperature. There are three temperature sensors located on the bottom of the pack, each one clipped to the bottom of a module. One at each end and one in the middle of the pack. These are physically inserted into recesses in the module body and monitor the actual temperature of the modules, not the air. Cooling air from the fan enters the top of the battery case, flows downward between each module and into the lower plenum. It then exits through the plastic duct and leaves the car via the penetration by the 12v battery. Moving the lower temperature sensors to the top of the battery would put them directly into the path of the incoming airflow prior to it actually removing any heat from the modules. Heat rises because hot air rises. Hot air only rises if it's not part of forced circulation. The fan runs all the time, usually on speed 1 or 2, always maintaining flow direction from top of battery to the bottom. So in this case, warm air actually always flows downward.
Although most cases seem to be replacing gen 2 modules by gen 3 modules, I believe this post proves that they are actually really interchangeable. So, the other way around would also work? My situation is that I accumulated a bunch of modules from differences which could be gen 2 and/or gen 3, and now I'm contemplating to install them into a gen 3 Prius.
