Please help! Hybird battery

You will need Mini VCI or some other Toyota hybrid capable scanner. You can only replace one module but its not very easy and results might not be so good. Gen II Prius Individual Battery Module Replacement | PriusChat

 

Module replacement is best done in pairs. The HV Battery consists of 28 modules, grouped into 14pairs.

If you are a glutton for punishment, just swap out the bad module or module pair, only to revisit the process in hours/days/weeks.

Rebuilding a pack will give you better longevity, so follow the thread Valde3 posted above. That being said, a NEW HV pack will give you the best longevity and trouble free operation vs any rebuilt pack; NEW cells vs old cells (6-11 years old; 2004-2009 model year donor).

If you can DIY, a NEW HV pack can be purchased for $2100+ from a Toyota dealer who sells online. Camelback Toyota (Phoenix, AZ), sells online. You just need to make sure the online dealer will indeed sell the pack to you, as some PC members have experienced online dealers refusing to sell to the public.

 

Thanks for all the info. You guys were right about the all the lights coming on. They came on this morning. I found a place in vegas that sells and installs remanufactured batteries at different price points and different warranties You know 6 mos warranty 700, 1 yr 1000, etc. Called dealer about 3000 installed. I read the info on how to change the cells but that sounds like to much for me. Thanks a bunch.

 

I've been reading alot of the posts on this issue and found one about the goodwill warranty. I'm going to ask the dealer about it since i would rather get it from there. Thanks for all the great info.

 

I disagree. The HV battery is one series string of 28 modules. The modules are not grouped in to pairs. They do not work together as pairs. They work together as one series string. The voltages of the modules are monitored in pairs. This voltage monitoring does mean that a failed module will effect its monitoring pair. It can be argued that a failed module can overheat its neighbors. But with that logic you should then replace both neighboring modules. So now we have " Module replacement is best done in sets of three."

For a good battery rebuild each individual module needs to be tested.

Brad

 

Yes, well aware that the 28 modules are wired in series, and the ECU monitors them in PAIRS. Thanks for clarifying, as some readers may not be familiar enough with the specifics of the HV Battery.

Yes, I agree w/ you that each module should be tested. And I will assume that testing consists of a load test, and putting each module through three discharge/charge cycles.

Pair replacement recommendation is based on Priuschat member "Ericbecky," who appears to have extensive experience and knowledge about HV Batteries, as he does this for work. In addition to Ericbecky, there are also useful insights I have learned from the many threads about HV Battery rebuilding, that has shaped my view.

POST #4, http://priuschat.com/threads/p3019.144832/#post-2064292
Granted, this was for a Gen1 Prius.

Post #14, Page1
Battery Dilemma on my 2010 Prius vs my 2008 Prius | PriusChat

Post #347, Page 18
Gen II Prius Individual Battery Module Replacement | Page 18 | PriusChat

Replacing the pair makes sense to me, based on everything I have read and come to understand. This is what I would do.
You will do otherwise, and that's fine; it is your car, money, and time.

 

I think you have misunderstood the message. None of these quotes say you must change modules in pairs.

Eric's point to me is that you will never just need one module in his experience, and where one module is failing another is not far behind. Therefore he supplies two similar modules at a time.

The issue of internal resistance matching is a totally different kettle of fish. The emphasis here is, when rebuilding your battery to minimise issues down the road, ensure that each block within the pack has a similar series resistance.

That's how I interpret the data. If I'm wrong on point one, Eric will correct me.

 

What are the codes? The red triangle doesn't tell anybody what the trouble is. Doesn't tell you, doesn't tell us. All the red triangle does is indicate that there is trouble, and somebody has to read the codes to know what the trouble is. Maybe the other battery you tried had different problems than this one, and possibly one or the other would be easier/cheaper to fix ... if we had any clue what the problems were with each one. Have you thought about reading the codes yet?

-Chap

 

In addition to what Chap has said, this statement is not correct:

You cannot determine a module to good or bad just on voltage measurement. In addition to measuring voltage you need to test each module under load. Bad modules will discharge faster and also charge faster, when compared to a good module.

To load test, use a 12 V headlight with 65w high and 55w low (120w combined) and wire both on at once and hold it for at least a minute. Measure the voltage before and again at the 1 minute mark, while still under load. Make a note of the difference for each module.

But I come back to Chap's point above, one with which I am in agreement, you do not know what the problem is until you read the codes.

You did buy a Mini VCI cable, as advised back in post #14, didn't you?

 

Not a terrible video, but maybe not a mic drop either. The way a module ends up bursting was given kind of a new explanation here:



And there's a stretch around 25 minutes in suggesting that a module can be "working overtime" because of the condition of the one it happens to be next to for voltage monitoring purposes, which was already discussed upthread here in #25.



The point strawbrad was making in #25 was that the voltage sense wires are only that. They sense voltage, but are not used to carry any balancing currents the way you might see in a full BMS for a lithium pack. There is just one series current through the whole pack; how much 'overtime' a module works depends just as much on a module ten slots away as it does on the module that happens to be next to it.

(Now, if the module next to it is making extra heat, that is an effect that's bigger than heat ten slots away.)

 

The unfortunate part about this old post is that it was likely never a hybrid battery problem @Letha was experiencing. More likely a poorly running engine that wasn't making enough power, causing the battery to drain.