HV Battery Repair, My Epiphany. Is It A Good Idea???

I should have probably replied more generically.

Better to prevent situations where the pack gets out of balance in the first place.

If it is truly an internal resistance issue, then the module will need to be replaced because causal rebalancing cannot fix a shorted module or one with high IR.

 

My prius has a module that needs to be replaced, and I am going to try it soon.. And then I saw this thread..
After I replace the module, will the prius slowly balance the module its self? Or do I absolutely need to buy the grid-charger for it?.. It is expensive, but I don't want to try to make a charger my self.. But will the grid-charger balance the new modules and every thing?.. Or do I need some thing else also?.. I am trying to do this as simply as possible..

 

If you want to do it simply and don't mind doing it more than once, then I'll sell you a pair of modules close in voltage to what you have.
It's definitely not the best solution, and it is not the right way to do it for longevity, but it is simple and will probably work for a least a little while.
I wouldn't do it that way, but to each his own.

Call me if you want to discuss more details.

 

This is quite an interesting idea. Pre-balanced module. Why would it not be the best solution? What is the pricing?

 

Because voltage is not the only measure that makes a good pack. It is helpful that it is the same voltage though.

 

...would it be an improvement in this short cut to wire up all cells in parallel for a couple hours to exactly equalize voltages?

 

If you aren't dealing with the other parameters like capacity and resistance, it seems like a lot of busywork for not much gain. Plus it open up opportunities for accidental errors.

 

So, I ordered the grid-charger from that link (with the discharge option), along with the "simple battery discharger" that it needs to discharge the battery.. So, I will see how that goes when ever it gets here I guess..

I can think of one disadvantage to it though: the price..

I will see if this thing will actually help my car run or not (probably not).. I kind of kept driving the car long after it got the P0A80 error, and just kept driving it even though I shouldn't have.. Battery meter kept filling up and draining back down quickly.. It started studdering some times when I tried to accelerate.. Eventually it just died completely to where it won't even start any more.. So I am sure 1 or 2 modules are probably completely damaged and need to be replaced.. I will still try the grid-charger any way I guess, but I will probably have to end up replacing some modules..

 

One nice thing is that the Hybird Battery Charger/Balancer can be moved to any other Prius.
Will be interested to hear your results.

If anyone ever needs a charger, modules, or battery pack I can always get one. Give me a call or email and I can help out.

 

Okay, so, I got the grid-charger, and spent long time taking prius apart so I could hook it up..
I left it charging for about 1 day, so all of the modules should be full.. Then I tried to start it.. It actually went in to the Ready state (it couldn't before), and had no errors on the HUD (or MFD?) thing.. But, I turned it off and tried to turn it on one more time to test it again, but it didn't go in to Ready any more, and the hybrid error came back up on the MFD/HUD thing..

So, I took the battery out, and tested all of the modules.. Since I ran that car in to the ground even after the hybrid error appeared, I was expecting to have several modules that were bad.. But actually, every single module except one posted at exactly 7.60.. I was amazed that they were all exactly coming up 7.60 each time (except the bad one).. But the bad one was super low, like 3.68 or some thing.. I tested it multiple times just to make sure it was actually that low.. I was shocked at how low that module was/is..

So, in short, I need a new module.. I suppose I might as well order it from ericbecky since I can't think of any where better to get one from..

One question though: After I receive and install the new module, how many times should I charge and discharge the battery to balance every thing?.. The grid-charger that I have allows me to charge/discharge the entire battery, but how many times should I do it? 4 charge and 3 discharge? (In other words: charge, discharge, charge, discharge, charge, discharge, then charge one last time and see if car works fine)?..

I am really looking forward to getting my prius running again.. I have been having to use a crappy 1996 dodge caravan since my prius died, and that stupid vehicle gets 17 mpg!.. So I really want to get prius up and running again.. I have been spending way too much on gas lately..

 

You shouldn't need to do it more than 3 times. Even 2 would probably be fine. I'll help get you on the right track.

Driving a Caravan? Painful!

 

If I had to balance charge a large string of NiMH cells I would go slow, like C/40. This is basically a low trickle rate which eliminates heat and pressure. Charging the battery at this rate for 60 hours would balance all the cells. You would then have to discharge the battery enough to make the car happy as the Prius never let's the battery get to 100% SOC. Also having the battery assembled (clamped) eliminates any mechanical degradation as the cells swell a little during charge.

Let me mention that this method can kill you. If you don't know exactly what you're doing stick to the hobby charger method.

 

Cooling the pack when charging/discharging is essential as well.

 

Okay, so, I put one of the modules in that I got from ericbecky guy, but I am still having a problem:
I put new module in, then used grid-charger to charge it for 1 whole day..
It started, and it runs fine, it doesn't stutter any more and the battery-meter on the MFD doesn't go up/down wildly now.. So it acts like it is completely fixed....
..but then, after a minute, the triangle of impending doom came on again, with same "hybrid-system" error icon..
It will keep running fine, even with that error on, but as soon as I park some where and turn off car, it remembers the error, and it won't let me turn it back on to Ready mode again.. So what I have to do is disconnect 12-volt battery negative terminal for about 1 minute, so it forgets any errors it has, then put back on negative terminal, and then I can start car again.. But about a minute later, triangle comes back on..

So basically, every time I want to drive some where, I have to unplug 12-volt battery for about 1 minute (if less than 1 minute, it still remembers the error some how, and doesn't let me start car)..

I can't get to a laptop that has techstream until next week (my laptop runs linux, I refuse to put some thing as crappy as windows on my computers), so I am not sure what codes it is still throwing up, but the icon on the MFD still shows that "hybrid system" icon (the one with the "!" sign)..

So, what does any one think the problem could be?.. I charged/balanced the battery up using grid-charger.. Although, I didn't do the discharge cycle on it because the discharge mode on the grid-charger requires different weird types of light-bulbs, like a 5-watt light-bulb etc.. Where am I going to find a 5-watt light-bulb?!?.. I've never even seen such a thing..

I was thinking, if all of the modules are charged up to the same level (like I did), then why would the car still be having a problem?.. All of the modules are showing very close to 7.6 volts of super power..

Any way, tell me what you guys think the problem could be, thanks!..

P.S.: Some times when I would unplug 12-volt battery for long time, then plug it back on, the MFD would show temperature in Celsius!..ｏ＿ｏ I was shocked.. I would love to have temp gauge in ℃...But sadly, when you turn prius off and back on, it reverts back to gay Farenheit scale.. Seems ridiculous that you can put car in to kilometers/hour, but can't put temp in to ℃.. Oh well..

 

Did you check the orange traction battery interlock switch? When installing it, you have to pivot the lever 90 degrees, then slide the lever down to lock in place.

 

Also, did you carefully examine the entire harness on the voltage probe side of the pack? A hairline break can cause intermittent voltage issues.

Edit: Do you know what codes you have? For example a P3009? Or some Vblock voltage code?

 

I suggest that now that the HV battery seems to be working like it should, it would be wise to start looking for other reasons why your car is still not working correctly.
I would start with getting the actual ODB2 codes from the car, as ericbecky has recommended above.

I have a grid charger and have had success re-balancing ( charge / discharge cycling ) my pack. And I also drove my car for 6 months after it threw it's first battery pack deterioration code. But I wanted to know as much about why the car threw the code in the first place, So I spent that 6 months finding out why the car was misbehaving.

These hybrids are pretty complex machines, and there are a lot of different things that can cause them to show problems.
They are so complex that most automotive mechanics will not touch the hybrid systems when working on the cars.
So the amount of knowledge regarding how the hybrid systems work and especially how they integrate with the rest of the cars systems is known by only a few select mechanics with specialized experience.

Don't get me wrong, I know how difficult it is untangle these hybrid systems, and the amount of time it takes to learn even the basics of the one cars hybrid system. But once you start learning, if you're anything like I am, it's hard to stop learning about these systems.

 

I have used this method to rebuild 7 or 8 packs with great results.

I add a few steps though.

I remove the pack and completely disassemble it.
Then put the modules in parallel for testing.
First I test with a simple volt meter to find the bad module. It is usually just one but sometimes two. Then I test each remaining module with this load teaster:
6V 12V 500 Amp Carbon Pile Battery Load Tester Alternator Starter 1000A Testing | eBay

I crank it up to 120A and the timer goes off after 15 seconds. Healthy modules hold about 6-6.1V (they are lower toward the center of the pack). Sometimes a module that tested good with the volt meter will drop to 4V or 5V when loaded.
I get rid of those too.
I replace the modules with similar modules (similar year and miles).
Before re-assembling the pack I clean the bus bars by taking the copper inserts out and soaking them overnight in vinegar and then brush with a wire brush or sand paper until shiny and new looking.

Once re-assembled and in the car I charge overnight. Then run 4 cycles of discharge, then charge.

When discharging it is important to keep an eye on the volt meter and switch the bulbs out as close to the chart as possible.
I start with 200W from 237-200, then switch to 90W to about 180V-185V, then 60W to 170ishV.

On my first discharge cycle I go down to about 168V (1V per cell)
2nd discharge 160V
3rd-150V
4th-140V

I'm sure it can be adjusted somewhat but this has worked well and I'm sticking with it for now.

When I am finished I drive the car with scanner hooked up to see how balanced it is as resistance increases. If there is a block or two that is rising significantly faster than the rest it has to be balanced more or modules have to be re-paired or switched. So far(since I started using the load tester) each pack has come out incredibly balanced.

As a side note:
Any time the back is disassembled it would be a shame not to inspect and clean the hybrid cooling fan and ducts.

and

After finishing successfully......


It is a great tool and will help extend the life of the battery but I am sure there would be a market for a used grid charger if money is tight and you need to recover some of the investment.

 

PRIUS WORKS!!!....... I finally found out what the problem was.. I finally got to a laptop that I could hook-up to my giant prius, and I got the error code "P0AA6".. Which is like "high-voltage isolation fault" or some thing.. Doing a little research, I found out that this might mean that the hybrid battery is some how making contact with the body of the car..

When you install this grid-charger, you hook up a cord running from battery terminals to the grid-charger PSU thingy.. I thought you were usually supposed to leave that cord attached to the grid-charger all the time, and just plug a normal power cord from wall power outlet in to the grid-charger PSU when ever you want to balance-up your battery every few months..

So, what I tried to do was just unplug the cord from the grid-charger (although the other end of the cord is still connected to battery of course).. That fixed the error!!.. I have never seen the error since!.. So, I think some how, the grid-charger was giving a path from the battery terminals to the body of the car some how (kind of scary).. I will say though that the grid-charger was sitting straight on the metal of the car body in the back (because I didn't want to put back in the upholstery until I was sure that every thing worked properly)..

Maybe with the upholstery in, the grid-charger would not be making a connection between the battery terminals and the car body.. But shouldn't that not be happening any way?!?.. Why the heck is the grid-charger letting the connection from the cord go through its self (the PSU thing)?!?.. That seems almost like if you touch the grid-charger you could be electrocuted or some thing, although I never was when I touched it.. Any way, this is just my theory of what was happening.. But some how, cord plugged in = P0AA6 error; cord unplugged = works fine and no errors..

That bad module by the way, it looks horrible.. It has a big black opening/hole where it must have burned open to death or some thing.. Although I literally kept driving on it until the prius finally couldn't start any longer..

Any way, so now I finally have a working 2005 prius! Wow.. Very nice upgrade from my previous 1996 dodge caravan that gets like LITERALLY 13 MPG.. I was constantly throwing so much gas money at that stupid thing all the time.. Oh, by the way, that van literally died on the same day I fixed my prius.. Van won't start any more at all.. I hate that van so much I just want to have it hauled off to the junk yard and have it crushed to death for ever.. I got this prius at a decent price ($4500) because it had that one bad module and dealership guy didn't want to try to find out how to fix it..

Any way, thanks every one for helping me out.. Our global atmosphere will be just a little bit better now that I don't have to drive that evil van around any longer.. I think that thing was probably developed by the oil companies them selves..

 

I'd read the manual that came with the grid charger and are also probably posted on the manufactures web site, again at least once.
It's a simple charger, but....
And the voltages the grid charger puts out and the voltages in the pack can kill when not handled properly.

A similar warning should be in big Letters on the first page of the grid chargers manual.