Prius Early version
I saw on eBay some battery packs for the old style Prius> I guess they are prismatic? Well anyway I was wondering is there some special way to test and charge the 7.2 volt cells. I used the RC hobby charger from ALL Battery. It does so good on my "Made- in - China " RC packs of 4300 mAh and 5500mAh battery packs, Tenergy Brand. I figured for 6500mAh Prius cells or what they called them "modules" it would charge using the same parameters and Rc packs. I haven't been on the VISFORVOLTAGE site for many months so I almost forgot my password. So my question is can a 10 year old module be any good and have any AH left? I would like it for RC and radio control circuits. 56.6 volts.
the modules swelled up and got so hot. On a slow slow charge they quickly got to 8.0 volts and on a light load went down to 4 point something in minutes. They are supposed to do 6 amp for 10 hours or so. I was using the RC packs wired up in series but liked the MODULAR design of the older Prius packs. BTW it is NiMH technology. I don't know the exact charging algorithm of Prius Prismatice cells or modules. But is should accept 1.3 volts per cell? My Vectrix seems to do 151 volts for the 125 volt pack.
So my question is can a 10 year old module be any good and have any AH left? I would like it for RC and radio control circuits. 56.6 volts.
the modules swelled up and got so hot. On a slow slow charge they quickly got to 8.0 volts and on a light load went down to 4 point something in minutes. They are supposed to do 6 amp for 10 hours or so.
yes 10 year old nimh batteries can still be good (the batteries in many of the Vectrix's were manufactured in 2003 for instance).
6.5Ah = 6.5A for 1 hour
The modules that have swelled up have been overcharged, so are probably at least reduced capacity with raised self discharge
I would suggest charging at 0.3A for 25 hours, then immediately discharge the stick at 6A until voltage falls to 5.2V.
record how many Ah
Then charge again at 0.3A for 25 hours, leave to sit for 2-3 days, then discharge to 5.2v and record how many Ah.
That will test capacity, and self discharge rate.
Them match up the cells with the most similar self discharge and capacity
I suggest you search Endless Sphere for Prius batteries, there is much info there.
I looked at the battery modules when I received them. Just dead and not swelled. I had to give enough charge in order to measure the Impedence of them. On the first try only 3 or 4 took any kind of charge. After a day the rest took a small amount. I have a number of ALL battery chargers so I charged them and that is when they swelled up. the 7.2 volt times 4, pack broke one of the terminals on charge. Lots of lateral pressure. Even the 7.2 volt miss matched pack modiles swelled up at 850 mA charge rate. I suppose you are correct using a low low charge rate of 1/4 ampere. Either way I could not get out even 5 amp for a light bulb on discharge. Basically the automatic discharger tries to do 5 amps. The eBay seller said he would send more if I paid shipping cost. I will at least for the learning proccess of prius modules vs age.