Current State of the Art in Battery Balancers?

Thanks.

 

It would be interesting to see your start to finish process written out, even if it was a condensed version

Finally got the battery reconditioned and into the Lexus. The Dr Prius full battery test was good. The life expectancy is good but it says 102% life which I'm guessing is inaccurate. It was tested right after install so expect the mAh to go down.

Do you match battery blocks by putting high / low modules in each block for overall balance? What measurement do you use to determine high / low modules?

How many cycles of discharge / charge do you usually do?

 

Do not attempt to charge loose unclamped Prius modules. They will swell up to where they look like a large Subway sandwich. The one exception to this rule is that if you limit charging current to <600mA and make sure the module isn’t getting more than 10 degrees above ambient.

Years ago I bought a pair of the white plastic end plates for the Prius HV pack on eBay. I usually stack 6 modules between the end plates. I clamp them with 4 long bolts and nuts. I never had any modules get bloated with this setup.

 

Lately, I've been starting with a discharge (to save time), then a charge, and so on for 3 cycles. 2 cycles is not enough, the voltage between the modules varies by 0.05 volts. One module is 8.00 volts, and the next one is 8.05 volts, and so on.
It looks like this
8.00
8.05
8.00
8.05

After three cycles, the voltage across modules usually looks like this
8.00
8.01
8.00
8.00
8.01
8.00

Battery packs that just need capacity restored I do 3 cycles and after working on bus bars, I install it back into the car.

Batteries that have trouble codes, I pinpoint bad modules in them, replace them, do bus bar work and then do 3 cycles, after that I put it into the car, discharge it to 40% and after 10 minutes I measure the voltage on the modules, looking so that there are no modules with a voltage lower than the rest by 0.1 volts or more.

If a battery pack has a single P0A80 code, such a battery usually does not have obviously bad modules. I do 3 cycles, then I dothe bus bar work, after that I put it into the car, discharge it to 40% and after 10 minutes I measure the voltage on the modules, looking so that there are no modules with a voltage lower than the others by 0.1 volts or more.

When a battery pack is old or with high mileage, I disassemble it and weigh each module by writing the weight on top of the module. I recently changed a battery pack in a 2012 Lexus ct200h with 195k miles. The battery pack with a single code P0A80. I weighed the modules and their weight was 1031-1034 grams, mostly 1033-1034 grams. Such a battery may still last for a couple of years, but you shouldn't rely on it much anymore.

102% means that the recovery process has worked. This percentage will decrease and on a healthy battery it should stop at 70+% and it will stay that way for several years. The similar thing happens to module voltage. On a healthy battery sitting on a shelf, the voltage does not drop below 7.7 volts, even after a year.

 

Did you not read everything???



The battery overdrew power, accuracy was compromised.
It as an ESTIMATED 102.57% capacity.
So the app is NOT inaccurate.


QUOTE: Finally got the battery reconditioned and into the Lexus. The Dr Prius full battery test was good. The life expectancy is good but it says 102% life which I'm guessing is inaccurate.

 

I forgot to ask... how are things going with the P0A80 code now?

 

It finally cleared. Apparently it's saved in memory because it won't clear even with a small battery disconnect. I think the system has to see a good battery, then it self clears. It took about 30 minutes of driving after the good battery was installed.

I saw that about the overdraw. It's very tricky to keep it in range while testing, I'm still learning how to do it. I knew it was going to be a good test though because it ran the full 10 minutes. The previous 2 tests failed after about 4 minutes.

 

thanks for taking the time to write this post

So when you weigh the modules you're checking for fluid loss?

 

To load the gen 3 prius battery pack with 6.5 amps:
I set emergency brake,
put it into reverse,
turn on the headlights with high beams,
turn on the rear window defroster
and the heater blower. By the blower, I regulate the needed consumption.
Do not use the a/c, its load is not constant. The window defroster turns off automatically after a certain time, you need to monitor this.

2 previous tests failed because the battery pack had weak modules. The discharge starts evenly and then it drops sharply and the test fails.

Yes.

 

Very Interesting: I just looked at the Harbor Freight shopping page. They currently offer 2 different inexpensive Viking battery testers:
Price: $39.99 USD for either model.

• Digital: https://www.harborfreight.com/12v-digital-battery-and-system-tester-58759.html

• Analog: https://www.harborfreight.com/135-amp-6-12v-battery-and-system-load-tester-58944.html

Harbor Freight also has this cheaper ($17.99 USD) analog unit:

https://www.harborfreight.com/automotive/diagnostic-testing-scanning/battery-testing/load-testers/100-amp-612v-battery-load-tester-61747.html

Is the digital Viking model the same one you have been using?

Both analog testers look very much like the Neiko.
As of today my local Harbor Freight store has the 2 analog models in-stock but not the digital one.
I'm tempted to run out to their store and grab the Viking analog unit. It has the highest user rating among all of the Harbor Freight battery testers

 

Yes I have the HF digital. The Neiko is 100 amp, you shouldn't go over 10 seconds, with the 135 amp HF I wouldn't go over 7 seconds

I would get both, they both do different tests. The digital one checks 5 different things. The analog does just a load, but it's very similar to what the car does when you floor the gas. I've tested and condemned modules with both of them. It's best to test with these before you start a grid charge because when you find bad modules after a grid charge you have to start all over.

 

I'm holding the test button just long enough to observe how far the meter needle moves. 1 second is long enough.
I also have a multimeter with "max - min" capability. If I have this connected to the battery under test the difference between the two readings (test button pressed or released) will allow me to calculate the battery series resistance precisely.

The "load" inside the tester is a simple resistor made out of very thick nichrome wire. I will test its actual resistance. It's likely to be in the neighborhood of 0.01 to 0.05 ohms. Aka 10 to 50 milliohms.

Note: when testing a single Prius module (7.2V rather then 12V) the load current will be about 1/2 of the rated 135A. Just about right for a Prius.