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Plan of action for no start issue (battery related)

Discussion in 'Generation 1 Prius Discussion' started by beefive, Sep 18, 2012.

  1. beefive

    beefive New Member

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    Good evening,

    Some of you may remember me from my previous thread in which I bought a '01 Prius with a bad battery. I ended up buying a used battery (which resulted being bad) and made a good battery out of both battery's cells. The car has been running great after the transplant and has not given any problems.
    A few weeks ago, I jumped on the chance to get another '01 Prius that was also a non-starter. A second Prius was a great idea considering how well my car has treated me. My wife also loved the gas mileage of my car.

    Upon picking the car up, it was different than my first Prius. This one tried to start, but gave up and presented me the red triangle. This made me think the battery was in worse shape than what I thought.
    Today, I took out the battery and tested each individual cell. About thirty of the cells were between two and three volts. About five of the cells were between four and five volts. The remaining three measured around six volts.

    My question for this community -
    - Is there any way for me to "charge" the battery pack to confirm that the packs are indeed bad? Keep in mind the car does not start for me to force charge.
    - If I can't charge to double check, I am leaning into getting one of those Re-Involt batteries.

    Thanks!
     
    #1 beefive, Sep 18, 2012
  2. John H

    John H Senior Member

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    you might want to also test the resistance of each cell, but wait for one of the battery gurus to chime in.
     
    #2 John H, Sep 18, 2012
  3. John H

    John H Senior Member

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    #3 John H, Sep 18, 2012
  4. bwilson4web

    bwilson4web BMW i3 and Model 3

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    There are two parts to the problem:
    1. Capacity of the individual modules - the bad pack I bought several years ago only had 1.8-2.2 Ahr each. IMOH, these are simply too low and old and should go to the recycler.
    2. Bringing the pack up to service voltage - this is a real challenge because the modules measure so low. It is likely they may not come up at all.
    If you have time to fiddle with the old modules, I would recommend the following:
    1. Number each module from the ECU side from 1-38 and remove buss bars . . . carefully. Do not break the voltage sense wires.
    2. Inspect the terminals and look for a black 'ring' of melted "O" ring seal . . . flag as suspect.
    3. Wire them all in parallel (not series!) - this will rapidly bring them all to the same voltage and relative SOC.
    4. Put a charger on them, no more than 40A to a maximum of 7.8 V . . . monitor them hourly.
      • Any that show signs of swelling . . . flag as potentially bad and take out of the parallel configuration
      • Use an IR thermometer and any that show 'heat' +90F . . . take out of the parallel configuration and flag as bad
      • Reduce amp rate by 0.025A for each module removed (you want a 1/6.5 A charge rate)
    5. Count your inventory of 'good modules' . . .
      • Find replacement modules
    6. Using a 5-10 ohm, 5-10W resistor, add the new modules to the parallel set and get them all to 7.8-8.0 V
    7. Let them sit over night at a constant voltage, trickle charge and thermally reach the same room temperature
    8. Reassemble pack and try to start car
    Now this is only going to give you what is likely going to be a marginal pack. But it 'kicks the can down the road.' You may find other issues but at least you'll be able to crank the engine (if inverter is still OK), check the DC-to-DC converter for 12V supply, and; possibly do a drive test to check the transmission. Then comes the fun stuff . . . finding and fixing everything else. <grins>

    Now testing module capacity is best done with something like an MRC 989 or other automated, battery charger. There are several and new ones show up in the RC world from time-to-time.

    Bob Wilson
     
    #4 bwilson4web, Sep 18, 2012
    usnavystgc and John Hatchett like this.
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