2002 Toyota Prius every other sell half charged

First cell 9.5 volts second cell 4.5 volts right on down the line , have no idea whats wrong .

 

Help

 

I removed all bus bars and measured using a multi meter . First single cell is 9.5 volts next cell is 4.5 volts next is 9.5 volts and next is 4.5 volts right on down the line . All I did was drive to town and back code is reading uneven voltages . I moved it to the garage twenty minutes later and then the time to pull it apart to check the voltages with bus bars off .

 

Removed bus bars and checked each cell separately 9.5 then 4.5 then 9.5 right on down the line . Keep in mind I'm just putting even voltages it was like 9.2 4.3 and so on . I had driven to town twenty minutes there twenty minutes back . It sat for twenty minutes at a guess then moved it into the garage and then the time to pull it apart . I've pulled the thing four times in learning how to charge and discharge the batteries . No more than to a six volt discharge and a top charge of 8 volts three time to each cell . Pulling it again to change a eBay bought cell that went bad and again for the same thing and again to put the batteries in sequence according to charge . Code came up for uneven voltages and that it what I found . It's new to me . If I remember right it's 38 cells charged by the bus bars 24 and 24 so I have one side over charging and one side under charging . I would guess the computer in the battery pack that controls the charging might be bad as all wiring bus bars etc are good and are clean .

 

It did happen removed bus bars to check voltages I put as 9.5 4.5 just as an even number it was more like 9.2 4.1 etc down the line high low high low high low . 38 cells 19 and 19 controlled by the computer in the battery pack ? So half are being overcharged and half are being undercharged

Did happen bus bars off every other battery 9.3 4.2 9.1 etc right down the line . I've been learning on this car replaced bad cells with good , bad meaning cells that lost voltage just by sitting over night causing a code then lastly by putting all cells in order according to voltage . 38 cells 19 and 19 controlled by computer in the pack ? So half are over charged and half are over charged . I'm learning as I go but there is no doubt this is the reading per multi meter . Car was driven to town say 20 to 25 minutes there and then back sat in yard for like twenty minutes and then moved to the garage and taken apart . Say that took me half an hour or so then I took voltage reading .

 

I rebuilt the battery with cells I bought used , had to pull it and replace cells a couple time because of the person I bought the cells from lied about them being good . On top of that I bought a few of the IMAX chargers and did a discharge / charge at a cycle of three . All cells were reading good after I pulled it again to put the cells in place according to charge of the cells . Car was running great no problems then this happened with the code unusual battery fluctuations / voltages . I'm guessing the computer in the battery pack ? What else would cause half the batteries at a charge of 4. Something and the other half at an over charge of 9. Something ? It reads as high low high low all the way down the line

 

Sorry was half asleep when I posted 11:30 pm , yes 19 and 19 . I stacked the batteries by voltage Highest to lowest according to the charge they held after sitting for a few days . I charged and discharged all the batteries three times using IMAX chargers going no lower then six volts on discharge and no higher then nine on charge . Batteries are obviously not put in positive on the same side I don't think that would have been a pretty picture or that the car would have been running fine for the last couple months , its negative positive negative positive down the line with positive started off on the correct side starting at the front of the case . The batteries have very little seepage from the positive side of each some none at all . Buss bars and wiring are all in near perfect condition as I also replaced them when I first started this project . The old ones could have been cleaned but I wanted to start off with new . When I got the car knowing it had a problem with the pack , in taking it apart it had three bad cells . My question was why half were over charging and half under , obviously there is charge going to all of them or the half that are undercharged would have no charge at all . And why 9 volts on half and four on the other half , high low high low makes no since . There has to be something that controls this or it would have happened from day one after reinstall . Thanks for getting back to me , I will do some more research and see if I can figure it out

 

Hate to admit it but also very thankful for your post . I tried I different multi meter and I have right at eight volts all the way across with the last two cells reading 7.5 and 7.6 . I'm guessing this is a difference in voltage enough to cause it to throw the code . Time to pull it apart again lol , again thanks for the help . Side note I love that voltmeter I've had it for years and it's never let me down till now .

 

Lol that's funny I'm the same way ,the multi meter I just go down the line not crossing over and always the same meter and never had this happen . It would just show a negative voltage , no big deal right ? And the cutting the voltage in half every other time I have no idea . I grabbed my sons and it read perfect no problem and I still was not crossing over each time , go figure . I have a 2006 Prius also that I bought from my sister in really nice condition . She let her son drive it and he treated it like a race car till the engine started nocking . She had just had the hybrid battery replaced and new tires put on it . She had also bought the charger and discharger for it , over a $1000 . She let me have it all for $500 . I bought a 100,000 mile engine and transmission for it and just replaced it all . Nice little car now , been letting my mom use it while I fixed up a 2006 Dodge ram 1500 mega cab for her . Rebuilt the engine and now just adding things like black grill blacked out head light and black gas cap cover . 72 years old and she wants a eye catcher truck lol . Anyway good luck with your Prius , again thanks for the advice .