Gen II Prius Individual Battery Module Replacement

Up and running with new leads. Results to follow. I bought 14 guage bulk wire. They didnt have the GE banana plugs so I bought what they had at 5 bucks a pair.

 

Much better setup and I'd be surprised if your results don't improve quite a bit.

Also for people making your leads later make sure to use stranded wire not solid core (ie no romex wire).

 

Well, so far its not looking good. 3 out of 4 so far have peaked out in the mid 3000's on the first charge cycle. I guess ill let it finish the cycles and hope for the best

 

Any advice on forcing them to take more charge by running manual charge cycles and keeping track of the mah numbers till I hit 7000?

 

Yes, definitely. I used manual cycles with mine too....just be sure to use a fan.

Go into "save program" and input the manual cycle info:

NiMH, 7.2v, 7000 mAh, 2.0A charge, 1.0A and 6.0v discharge, DCHG>CHG 3

Then at the DCHG>CHG screen hold down "start" until it saves. Then go into "load program" hold down the start button again until it loads the data for the cycle, then scroll to DCHG>CHG and hold down "start" to begin the cycle. When the cycle begins properly it should start with discharge first (blinking "D"), then charge.

Make sure you also had your "user set program" settings done (waste time 5 min, safety timer off, capacity cutoff at 7000 mAh) as I mentioned earlier.

 

Doing this disables delta peak detection? Or is it just a way to more quickly choose different programs?

 

I don't know the answer to that......I may need to run some experiments on my bad module to see how it works. In any case that's why I suggest keeping the charge current way down (1-2 amps) since this will limit the heat given off (P=IxV so around 10-20 watts per battery) when the battery stops accepting charge. You could also lower the capacity cutoff to around 4000 mAh initially for one cycle as a precaution, then if all goes well step it to 5000 then 6000 then 7000 mAh on subsequent cycles to see if there was any improvement. This is also why the fans are important but mine never got hot regardless even when I destroyed one of my test modules by way overcharging it (I didn't start the modules on discharge first so it went way over the capacity limits). If you increase the capacity cutoff and you don't see much improvement on the discharge capacities, chances are you've found the max capacity of your modules and you can make a decision on how to proceed from there.

 

Yeah I've been doing testing on trashed modules too and I wanted a way to disable delta peak so I can run a C/20 charge on one for 24hrs. I agree about the heat thing.. Below about .4a I get no heat or ballooning.
On a side note I put a water balloon (I rolled the air out) over that vent and dumped 5a into it way past capacity and the module ballooned up to scary proportions but nothing seeped or vented into the balloon.. I've also burst modules with no sign of venting (although not proven).. I don't know what their design specs are...but these things don't want to vent!

 

It has long been known that these modules do not like to vent and that the vent release pressure is greater than the pressure it takes to blow the case. Idk why but that's the way it is.

 

The vent is there to release pressure when the module is clamped so it releases at a higher pressure than you created.

Jeffd

 

I've burst them clamped (they pop at the top seam), unclamped (sides) and even frozen (loudly from the sides). The vents don't vent at any pressure I can get them at.. Maybe it's for a short/fire situation, I don't know.. I would love to get one to vent! It's my unicorn.

Edit: I forgot to add, there is a rubber plug inside that vent tube, too big to come out the top.. I thought perhaps it slowly allowed high pressures to seep out slowly rather than a full on pressure release scenario, hence the balloon test..

 

You will not get them to vent. Bob Wilson has also tried everything and the case always failed first.

 

Don't kill my unicorn.

 

Ok im gonna try 1 run on manual mode. But what I meant was, my numbers came up in the 3000's, they just completed the last charge cycle. So I write this down and run subsequent charge cycle till I hit 7000mah. Maybe auto mode is what is doing it though so ill report back. Heres the second set of 4. Just ugly.

 

Hey, at least they're coming up. If you can input 7000mah into them, these modules will be fine. I'm not familiar with the HiTec X4 so I don't know why its auto shutting off at less than 4000mah but you have to put in 7000mah to even come close to getting 6000mah out.

 

Im not sure either. Maybe a defective charger? Who knows. Im running a subsequent charge now, so far they've all taken an additional 1000mah so we'll see where they peak out again. Ill just watch it and shut her down when I get to the magic number. Thanks for the input. Dont know where I'd be without this forum. Probably shelling out $1800 bucks! Haha

 

Good info to know, I suspect this is why most grid chargers aim for around 350 mA (0.35A). Doing a manual program on a Hitec X4 like I did will definitely stop on capacity input but then again my modules came back to nearly full capacity in all cases. Even the replacement module was from a 2006 Highlander Hybrid and it came back to around 6000 mAh too.

Yes, the auto mode is definitely limiting how much capacity is being put into the modules on the charge cycle so I'll be curious to see if the manual cycle did any better after. The critical part is not what you put in, it's what amount of capacity is being returned on the discharge cycle (ie looks like you are getting just slightly less than 50% of your input capacity back on each discharge). If the amount being returned starts to go up (ie you put in 5000 mAh and you now get 3500 back, that's a good sign) then your modules are improving and you want to continue until you don't see any more increase in capacity returned.

Not likely a defective charger from what I can tell, just keep going with your cycling. As a side note I did have one of my Hitec X4 chargers lose a display on one of the channels (other 3 channels worked great) but none of them ever had any issue with cycling modules regardless. I'm going to put it through warranty and see how good Hitec's customer service is on these things.

 

Sounds good. The charger peaked out the second time around at 1200 to 1700mah. So I did my calculations and went for round 3. It peaked out at 600 to 800mah. Getting closer to 7000mah now. Hopefully once I run them up to 7000 and discharge, they wont peak out so low then I can run 2 more cycles without having to go calculate and start more charge cycles. Anyhow, yeah im hoping they come up and ill keep cycling till I see no further result. This is gonna take longer than I thought but oh well, bought it as a project car and dont need it for driving so... thanks for all your help! Ill keep you all updated.

 

Good luck. Hope they just replace it. Some of these electronic mfgrs will keep your product for 2 months before returning it

 

Honestly even if they don't replace it, I more than got my money's worth out of it through rebuilding my pack. Later I'll have 7 channels instead of 8 if I ever need to rebuild again in the future.....no worries either way.