I just finished my first Discharge/charge cycles (x3) on my first module and it appears to be bulging slightly. I had my Imax b6ac set to charge at 5.0 Amps and discharge at 0.7. I watched it as the last charging cycle came to an end and it topped out at 8.86 volts, which seems a little high to me. I had it set to max out at 7100 mah, but i figured the 4ma delta v would cut it off before it overcharged. It took the whole 7100. Now it seems to have a small amount of separation from the case and the adjacent module. Is this normal? Will the swelling go down and the module will be fine? I stopped all cycling until I figure out whether I'm doing more harm then good. Here are some pictures. Thanks
In my view, I do think the 5A you were using is much for the charging. Y not use something lower, say, 1-2A? Did you put a fan close to the modules while charging? Even with the 5A you were charging those modules with, if there's a fan blowing air across it, it won't overheat, and bulged. Charging with such a high current, would stress the batteries, and impact on the lifespan. Let's await what other PC members gonna say. Dxta
I scoured these forums for days before I started cycling. 5A seems to be a common charging Amperage, and no one else said anything about bulging. No, I did not have a fan blowing across it, but I felt the module multiple times as it was nearing completion and it never even felt warm. Maybe the plastic on the outside of the module is not a good indicator of the temperature of the cells. Any suggestions are appreciated.
Welcome to Prius chat. How many miles on your 06? Have a failed module? Preventative maintenance? Are you using 5A or 0.5 A wen charging? I have the Prolong setup for our 2010 and it uses a charging rate of 0.375 A. You should have a fan blowing across the pack when charging because it will create heat that needs to be dissipated. What were your plans for this endeavor and how much time were you allowing to the process? Keep us posted .
My 06 has 120,000 miles. Got a P0A80 code last week. Found a module that was resting at 6.6v while all others were 7.9v. I am replacing that module and the other in it's block. I decided to do 3 discharge/charge cycles on all modules while I had the pack out of the car to bring up capacity and balance out the cells. I am charging at 5A per many posts on this site. I have another car I can use for work right now but I was hoping to have things all said and done in less than a month.
I use a 2A charge rate with a cooling system providing air flow through the modules at all times. The delta V charge stop doesn't always work as well as needed. If the module "tops out" and you're still pounding 5 amps through it, you're going to have some heat generation and bulging issues.
Thanks for the advice. It seems as though most of the swelling has gone down. Do you guys think this module is ok? My last discharge to 6v was over 6000mah. Resting voltage right now is 8.26v.
Ok, I have adjusted my setup. I have now moved on to modules 3 and 6. Let me know if this looks right to you guys. Also, am I correct in that the modules are counted from the ecu side? I have seen conflicting information.
Hello bhp110, from my point of view your approach is somehow missing a plan. If you have identified a weak module you should replace that with another one which is as similar to the others as possible. Most probably you won't bring the old one back to the others. Checking for weak modules is better done by performing a load test, e.g. with a head light bulb for 120 sec., and comparing voltage drops between modules. A replacement module having the same/similar voltage drop would be a good fit to the others. Charging with hobby chargers using delta V is from my point of view waste of time. The charging will end too early and you never reach balancing or you end up in over-charging, e.g. see your bulging experience. Btw: your bulged module should still be o.k. If you don't use a grid charger, e.g. from Hybrid Automotive, I would recommend to use the same charging strategies with a hobby charger for a single module as HA recommends for a complete pack. Check their homepage for instructions. Charging in 3 cycles with 0,334A for up to 48 hours with good fan cooling should balance a module. Good luck! Thorsten
To @priusb78 ’s point, if you wanted to “borrow” a Hybrid Automotive Charger for a period of time, I have one . All you would need is a harness and since the battery is out, the install is easy. Let me know.
PM me and @SFO and we’ll see what we can work out. Another thing you’ll need to do is contact (PM) @jeff652 to get a harness. Since you’re local, you might be able to work something out with Jeff to pick up and not wait on delivery. Keep us posted .
Thanks for the advice. I bought 4 modules from ebay. According to the serial numbers, they are from a 2008 prius.
2amp charging seems still to high to me. That will create heat. HA chargers limit charging the entire pack to 375 ma. I would pull those bulging modules out for a real close look for tiny cracks. The plasttic case was not designed for that kind of expansion. Even the smallest electrolyte leak and you will be back in there chasing a ground fault code. Pulling pack out multiple times will really suck. It really helps to have a IR thermometer. They are so helpful around the house and you can get an instant and very accurate reading on the temp of the module. Notate as you go. If you see it getting a little hot lower the charge current. All it takes is time.
Will do. I haven't taken the pack apart yet to replace the bad module. Good thing I bought 4 modules. What if I charge at 5A up to ~8v then bump it down to 350mA? Wouldn't this do the same thing but in much less time?
Is time a factor for you? I understand. Need the car on road but will really hurt if you have to pull the car back out of service. If time is severe Get the IR thermometer and see at what charge level it starts heating up and then stay south of that. Heat is the only factor that will Ruin your day. Every battery has its own current demand depending on health. And remember when the module is completely discharged it has a very low impedance so initIally it will draw as much current as you provide so limit that current at the beginning. If you don’t the heat will increase exponentially. Heat is the enemy and conquering it is the goal. HA chargeres adress that with a very mild charging current. Just takes 15-20 hours and no spike in heat. That is correct. Cute kid.
Thanks Ed. The only thing about the IR thermometer is that the module never felt warm, not even when it maxed out at 8.86v. I was watching it closely as it rose from 8.2. I felt it many times on both sides and on the top and there was virtually no change. I can see where that would be a good idea, though. I'll still pick one up.
Yes the IR IS 100 times more sensitive than your hands. What’s happening was the other batterys were heat soaking it.
Toyota really screwed up not putting a battery temp gauge and engine coolant temp gauge on the dash. The battery gauge could have tracked the hybrid fan levels at least you would know the battery was getting very hot Other than the fan screaming in the back seat which I doubt most people don’t know what that is. It’s the high current demand on the battery over heats the modules and cracks them and they leaked electrolyte and very soon you have a P0AA6 hi volt isolation fault. Nite nite. The no temp gauge for engine coolant is just ridiculous, you lose the pump belt and your done. Rant over.