Looking to buy a used battery pack from a private party in the Chicago area. When looking at a battery pack is there any labeling on the cover or the modules themselves to determine manufacturing date/location etc. If a battery is being passed off as "untouched" would like to be able to verify that it's not just a collection of left over bad modules from various other packs. Is there any way to easily & quickly determine if a module is bad?
Prius battery modules have a date code. Just google to see the codes for the year of the pack. If the date codes don't match the model year or there are mixed date codes form multiple years, you'll pretty much know it's not an unmolested pack. If they all match you might get lucky. It might still be a bad or marginal pack, but if the codes match the model year you'll at least be able to judge if it's original or not.
Thanks. Agreed, even if they all match - could still be bad, but I at least want a chance at getting something that has a chance of working. Will see if Google can tell me where to look and what codes mean.
Just paste this for a google search "prius battery module date code". If you can't find the codes let me know and I'll link.
It's best to look at the module date codes. The first 4 digits are the date code. First 2 are day of the month (1-31) Third digit is the month (1-9, x, y, z) . The fourth digit is the year. I=2007, J=2008, K=2009, L=2010 you can see the pattern. The sticker on the outside can be two different styles. The older style uses a similar pattern, but the year code is two years earlier, ie...L=2008 on a cover sticker. The second style label is quite a bit longer serial number and barcode. I've described somewhere else in the forum on how to decode it, but don't recall the exact digit sequence right now. I would have to look in my notes in the shop. A voltage test of each module would be a quick indicator of whether a module has self-discharged, but it's not an accurate indicator of the health or capacity of the module. A good module can hold a charge for quite a long time. Just this evening, I pulled a rack of modules out of a stack that had been cycle tested in January 2019. 18 of the 28 modules were still over 7.4 volts. Only one module was at 6.3 volts, and that module was the original reason the pack was bad, as I had put a red ziptie on it. The remaining were 6.9-7.3 volts. That pack of 28 modules had been sitting untouched, at the bottom of a stack of 5 packs, for over 3 years. Date code 102H, which is....2/10/2006.
Well that complicates things, but good to know. I will use this to make sure I have the best chance of getting something I have a chance of making work. Thanks.
Even if it's an original, if it's gen 2 it's going to be mighty old. Do you know that the modules from a gen 3 (and even a NiMH Gen 4) can be transplanted to a Gen 2 battery housing?
Just for clarity, verifying the date codes only tells you if the pack has been worked on or if the modules are original. You can't draw any inference as to the condition of the pack regardless of if it's the original modules or not. But if the seller says it's original and you can clearly see it's not then you can make a judgement on the veracity of the seller and be extra cautious about the sale.
I'm probably going to buy the pack tomorrow morning. Supposedly it's been sitting idle for one year. I have not yet bought the chargers to do the testing, balancing, and conditioning. Was thinking of just switching out the battery and if the car actually starts up OK, driving the car to charge up the pack. Anything wrong with that idea? Would taking a meter to read the overall pack voltage be of any use? And it if so, what numbers would be either good or bad to see?
Ended up buying it. Went there with my printed handy decoder for the pack case code & right off the bat it didn't make sense. Supposedly it came out of a 2007 Prius, so the code should have started with an F & not an H. But also supposedly the battery had been dealer replaced. So maybe dealer replaced Prius batteries start with an H??? Forgot the sockets and the seller said he didn't have any handy, so didn't even open it to check the module codes. Rolled the dice and bought it anyway. Been fluctuating between thinking I threw away money to thinking I hit the jackpot. Right now feeling pretty good. All the modules seem to be between 7.47 & 7.55 or module pairs between 14.94 & 15.10. Which for a 1 year idle battery seems good to me. Still thinking of just replacing it as is to see if the car likes it as is.
Don't worry too much about the F or H. I think the decode data sheet is a bit off on that, as F is typically on Gen 1 batteries and H is Gen 2.
That data looks very reasonable to give it try. Put it in and take it easy and watch the cell voltages and battery bars. Maybe after you put it in try foot on the brake, put in D, and give it a little gas and see what effect easy charging does for a few minutes before trying on the road. Who knows, it might be a good pack looking for a home.
Maybe next weekend I will do that. Start early in case it goes badly so I have time to recover before the work week starts. My main concern right now is that I've very simply tested module pair voltages, and even though they look good, I have no idea about the condition of the ECU. Nor do I have any idea about how to test it. Looking for opinions based on the what I've shared here. Replace the entire pack as is or go through the longer process of replacing the individual modules one by one in the car's current battery case? I know there are no right or wrong answers, just looking for opinions from those with more experience.
I think as long as you do a good visual inspection of bus bars, wires, and especially the big connector going to the battery computer looking for corrosion you will do fine throwing in the new pack. It would be a good time to verify the cooling fan operation and clean if needed too. Doing it on a weekend is a good idea. You will have time to inspect, install, do a static test, clean the bus bars if needed and if everything looks good take it on the road. As long as you use common sense and are thorough with your inspection you should be able to easily do that in a few hours and be safe about it. I hope it goes well for you.
I bought battery modules from eBay and they were still holding 7 volt charge after 2 years. So I would test the modules before replacing them all. You have to chech the connectors on yhe ecu. The plug you disconnected when you pulled the battery. Check for corrosion in the pins. Check visually. Thanks for that info. I was wondering if gen 3 modules would work on gen 2.
Yes, but mixing them isn't a good idea since there will be such a large difference in age. Several years ago, I got a gen 2 battery that had a full set of modules from a 2015 (two years old) that had been transplanted and then balanced. That was the hot setup. That happened before Toyota started making new batteries more reasonably priced.
