Part 3- Prius P0A80 Battery Rebuild- Load testing/internal resistance testing

[@Chemike21]

One thing I realized watching these videos, is that internal resistance should be checked after the whole pack has been charged to where the modules are all the SAME voltage, because of the curve of charge discharge. This will insure that the resistance is different not because the module was at a different point in the curve, but because it actually has bad resistance.

[@GaryMarkowski]

"Internal Resistance" in the video title caught my attention. Internal Resistance of the modules is an important attribute, and I find it is extremely difficult to track it. If the Internal Resistance of the module is high, then the voltage drop may be considerably less than other modules. You measured the amps of about 4.74 amps for one module with a known resistance of the headlight bulb. As the bulb heats up, its resistance will change. I find it elusive to calculate the Internal Resistance of the module itself. I do know that as the voltage of the module drops the measured amps will drop as well. When I use a load of about 4.5 amps, some modules drop below 7 volts after about 2 1/2 minutes. A few of the modules will last 12 minutes, and the bad modules will drop below 7 volts after 20 seconds. I am currently using an Arduino and my computer to track the voltage drop and graph these in excel. I ordered a module that will allow me to capture both voltage and amps, which likely will give me an idea of how good the Internal Resistance of the modules are. At this point, I think pairing the modules by internal resistance is a good idea, and also weeding out the batteries that have a big voltage drop when resting is a good idea as well. Thank you for your thoughtful video. It has helped me to further my testing process.

[@wizardmaster6639]

use a battery analyzer that can measure it right off the bat - no calculations needed

[@peglegtoo]

steve, thanks for this video. the only problem I saw with your testing was using the surface voltage in your calculations. instead I believe you should have used the voltage reading with the load applied as soon as it stabilized. it looks like you recorded this in your chart but you didn't mention it.

[@ShenzhenFactories]

nice operation

[@jbesrod]

did you fully charge up the whole pack prior to doing any laod test or internal resistance check. or did you dive right into it in whatever condition the pack was at when purchased?

[@reikisponge]

Can you load test using the charger/discharger to discharge say 10 mins? I think it shows internal resistance info and you get the time.

[@mauriciomanfredini435]

I have been doing some research, it seems like you can use gen 3 cells in gen 2. But can you use gen 2 cells on gen 3. Mine is a gen 3 from 2010. Most of my cells are above 7v I have 4 that are in bad shape in the low 4v those I am going to replace for sure. However would you recommend to change anything below 7v? I have 4 other cells in 6.6. Please help :) and thank you for your video

[@streetrage]

Would you please be able to provide that excel spreadsheet that you are using to record these?

[@priusgame1178]

What's a good capacity tester meter for doing these Toyota packs?

[@gregmeinholz6819]

what are those duplex banana plugs you have plugged into your voltage meter and where do you get them?

[@Chemike21]

you should have matched up the modules to where both the modules in one bank had the same resistance.

[@lakshmanfernando7899]

Hi my charger show over charge capacity than stop what that mean it’s fully charge or what please suggest

[@roscoeb209]

Where did you buy your replacement battery pack

[@metrork1]

Most videos call for 2 minute load test, is there a reason why you went with 1 minute?

[@stevevanpelt4475]

As far as I know, there is no standard time for running a load test (I'd be more than happy to be corrected if I'm wrong). So any time you choose should be fine since it's just used to compare one module to another.

[@kavinda6372]

can i get this xl chart plz

[@panicosvasiliou4914]

Hello and thanks for the video. I have tried some different loads to test the modules on my car like you did. Your method, which i tried only pulls 4 or 5 amps if i can remember. I drove my car and watched how many amps the battery is giving whilst driving. Its pulling about 1 amp just by doing nothing. It pulls about 30 Amps before the engine kicks in and i noticed it going over 90 amps. What i'm trying to say is to use a car LOAD TESTER, the car electricians use it to test the 12volt batteries. This gives the true picture of how a battery will behave in real conditions. Here's a video i watched and it made alot of sense. kzbin.info/www/bejne/e4O3Xmd5hLuhpM0

[@panicosvasiliou4914]

Don't go for 30 seconds though. 10 seconds are enough, because you don't want to discharge them under 6.6v if they are weak they drop very fast

[@hogwash1462]

Yes but 4amps multiplied by 28 is 112amps isn't it?

[@panicosvasiliou4914]

@@hogwash1462 no. You give a load of 4 amps to one battery module which is 7.2v to 8.5v. You test one battery module at a time. In the real world, the battery is asked to give 90 to 110 amps. Even for 10 seconds. I believe it is better to do a 75 ampere test than a 4 ampere test.

[@hogwash1462]

@@panicosvasiliou4914 yep on reflection i see you're right. All cells will be experiencing this current draw as in series.

[@GaryMarkowski]

My experience is if you charge and discharge these modules at 5 amps or less, the batteries stay cool, and you don't need to clamp them. I think load testing at 5 amps for 2 minutes is a good test. Any higher amps than that will cause the battery to discharge in a different manner than what takes place in a car. The video you posted is not a good way to discharge these modules as it generates heat that can cause the battery to expand, which diminishes the life of the battery. At least that is my thought. I think the dude in the video you posted also sells reconditioned packs, and I even see someone selling Prius modules on Ebay where they say they load test the batteries at 70 amps. This is a quick and dirty way to test modules. Guess what modules I am NOT gonna buy.