Battery Reconditioning Using Prolong charger and discharger question

Once the pack is put back together running it on a Prolong charger overnight is a good way to balance the voltages of all modules in pack. OR alternatively you can do a force charging (car in drive, foot on break floor gas pedal) every hour? Before I had a prolong charger I would use a light bulb to slightly discharge modules to make sure they all had the same voltage.

But please clarify... Why does one screen shot say block 2 is too weak and the other screen shot says its too strong? Which is it?

One common problem is people replace both modules in a block when only one module is bad... Problem is replacement modules are often healthier and have stronger voltage than rest of pack and it's twice as bad when you double it up in the same block. Always best to spread replacement modules out into separate blocks so your voltage difference between blocks is less likely to trigger the warning lights.

 

You want to check block voltages while the battery is discharging. Find a clear area, and drive hard in reverse and log the data or have someone else do a capture while the discharge amps are high. Reverse puts all the electrical load on the battery, while drive uses the ICE and generator in addition to the battery. The idea is to stress the battery and see if any block is significantly lower.

What typically happens is that one module has a weak cell, so that block (which is 2 modules or 12 cells total) will go lower voltage under discharge and higher when charging.

If the volts are higher than the other blocks under all conditions then that would indicate that the block has more capacity or a higher State Of Charge than the others and the battery control module is flagging it as "weak" based on the voltage differential.

Posted via the PriusChat mobile app.

 

The a bad cell in that bank just replace both batteries in that bank

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I'd recommend only replacing one bad module per bank/block... Usually a quality replacement module will have higher voltage numbers than the rest of the pack and if you double it up in the same block that block is going to have way higher voltage readings than other blocks and it will periodically throw warning lights and put your car into limp mode. The key is to blend in replacement modules to keep block voltage as balanced as possible.

 

Well if the warning lights point to voltage in block 2 being weak and Dr. Prius app showing it's stronger than the others I'd check for signs of corrosion in the voltage sensing wires, especially where it plugs into the ECU. This part, known as Wire Frame No. 2 only costs $50 and comes with new bus bars for that side of the pack.

 

Check that your inverter coolant pump is functioning well.

To do that, put the car in IG-ON (from off, two presses of the power button with your foot OFF the brake), take the cap off the inverter coolant reservoir, and look in at the coolant (it may help to shine a flashlight from the side). You should see coolant moving from front to back reasonably vigorously.