Battery Reconditioning Using Prolong charger and discharger question

Discussion in 'Gen 2 Prius Main Forum' started by Scrmaverick29, Oct 9, 2020.

  1. Scrmaverick29

    Scrmaverick29 New Member

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    Hello! I recently started the process of reconditioning my Prius hybrid battery with the Prolong Battery Charger and Discharger kit. I performed the charging and the discharging cycles as described in the instructions for reconditioning for 3 cycles each. I have reinstalled the battery back in my Prius, and used the Dr Prius app to check the battery blocks. According to the app, block 2 is bad. According to the app, block 2 is generating a higher voltage than the others. My question is, could I have just overcharged the battery? Also, if that is case, if I tried to do another round of discharging, would that fix it? If I could do that instead of buying any new modules I would prefer that. Thank you!
     

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  2. PriusCamper

    PriusCamper Senior Member

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    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.
     
  3. Scrmaverick29

    Scrmaverick29 New Member

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    That’s actually what had me confused. It shows that block 2 has higher voltages consistently, but then the code for it is that block 2 is weak. Also, it looks like block 14 consistently runs weaker than the other blocks, but I receive no code for that block. I don’t know enough about the hybrid batteries, or electrical issues in general, but I didn’t know if a higher voltage rating could also mean the cell is weak?? Does anyone know if that is the case, or could that code also just mean there is something wrong with the block in general and doesn’t necessarily mean it’s a weak cell??
     
  4. mr_guy_mann

    mr_guy_mann Member

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    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.
     
    #4 mr_guy_mann, Oct 10, 2020
    Last edited: Oct 10, 2020
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  5. Jmack111

    Jmack111 Member

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

    Posted via the PriusChat mobile app.
     
  6. PriusCamper

    PriusCamper Senior Member

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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.
     
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  7. Scrmaverick29

    Scrmaverick29 New Member

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    Thank you! So I tried that and this time it did show block 2 was lower. One thing I did notice that I didn’t the first time was that it looks like the battery is not recharging. On one of the tests in my Dr Prius app, it states that the inverter is too hot to charge the battery? The car had been running for under 10 minutes, and wondered why it would be too hot to charge. There were no diagnostic codes to indicate anything was wrong other than block 2 being weak... any suggestions on this issue would be greatly appreciated!
     

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  8. PriusCamper

    PriusCamper Senior Member

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    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.
     
  9. dolj

    dolj Senior Member

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    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.
     
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