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2001 prius battery problem and pictures

Discussion in 'Generation 1 Prius Discussion' started by statultra, Aug 2, 2009.

  1. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hmm, since the battery modules are wired in series, every module has to have exactly the same charging and discharging current applied at all times. Any resistance caused by corroded busbars should affect all modules equally.

    I hope that you marked the module that measured 6.5V, so that you can see if the same module has failed, the next time your car logs a battery-related DTC. Good luck with your repairs.
     
  2. statultra

    statultra uber-Senior Member

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    maybe it wasnt the busbars causing the module to read such a low voltage, It could be leaking electrolyte, because on that module I used to have a 2.5-3.0 volt reading to the battery case, so my guess is the leak was causing a short or load on the module. We will see when I put it back together, hopefully weather permits.

    also I think the bus bar corossion tricked the battery ECU into thinking there was less voltage then there really was, when the bus bars were on with the corossion i read 275.9 volts from those two plates located next to the battery ECU, but as soon as i checked each individual module after bus bars have been removed I was getting 7.8 volts each, which would mean its 296 volts total, Hopefully the battery ECU will know the true SOC now, before when the vehicle ran, it would always charge the HV battery, to the point where the battery fan would run all the time and the case would be warm to the touch. My idea is the corossion was causing the battery ECU to have false SOC readings.
     
  3. statultra

    statultra uber-Senior Member

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    so i plugged everything in started it up, it worked fine for 20 minutes then the battery dropped down and 10 minutes after that it triggered a DTC, i ordered a battery ECU on ebay for 10 bucks and a module for 33, so hopefully its that 6.5 volt module that is the problem.
     
  4. hobbit

    hobbit Senior Member

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    Where'd you find said "3M electrical sealant"? What is it
    normally used for? Interesting looking stuff, reminds me of the
    sticky goop used to glue in the felt runner pads in older
    clothes dryers that the front of the drum slides on -- after doing
    a dryer rebuild many many years ago I still had lots of the glue
    left and still use it on various projects.
    .
    _H*
     
  5. statultra

    statultra uber-Senior Member

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    its 3m electrical coating, we used it on splices of high voltage cables underground.

    3M 14853 Scotchkote Electrical Coating

    update on the car, i got the module and a battery ECU and all the electronics, im going to replace the faulty module so maybe another week of work left.
     
  6. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Try to get the replacement module voltage as close as possible to the other modules. Remember that NiMH batteries have a significant self-discharge rate. You may want to charge it so it is a little over the other modules, say 0.10-0.15 V over. Then let it sit over night and check the voltage the next day. Your goal is to equalize the charge.

    GOOD LUCK!
    Bob Wilson
     
  7. statultra

    statultra uber-Senior Member

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    can i use a normal DC power supply that supplies 9 volts with 1 amp?
     
  8. bwilson4web

    bwilson4web BMW i3 and Model 3

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    I would recommend a voltage regulator that limits the peak voltage to 8.00-8.25V maximum. If you have an LM317, set it to a maximum of 8.0-8.25V and feed it with say a filtered, 12 VDC source and current limited to 1 A. That should be safe enough if you watch it like a hawk.

    I would not use the 9 V supply unless I had the module, charger, current limiting power resistor, and everything in front of me. Then I would make a log entry every:

    1 - minute
    2 - minute
    5 - minute
    10 - minute
    15 - minute
    20 - minute
    . . .

    When you see the module begin to swell, STOP CHARGING. Perhaps some sort of duct-tape setup to automatically alarm or stop the charger when the sides bulge out would work. In my case, I used a smart charger that had all of safety features built-in:
    [​IMG]

    Plot the values to predict when it should reach ~8 VDC and about 10 minutes before, resume logging. Seriously, [ame="http://en.wikipedia.org/wiki/Nickel_metal_hydride_battery"]read at least the Wiki article on NiMH[/ame] and possibly a couple of datasheets.

    You want to avoid this:
    [​IMG]
    It was done with a sub-amp, solar charger. Over charging NiMH batteries are a bad thing.

    Bob Wilson
     
  9. statultra

    statultra uber-Senior Member

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    well i was thinking of having my tester on it while it charged and get it to float around 8 volts then turn off the charger, then watch the voltage drop, the rest of the modules are at 7.8 so ill find a 8 volt power supply, that delivers less than 1 amp and try that. I have NiMh chargers but they arent powerful enough for the battery.
     
  10. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Time is your friend. If you can 'safely' clamp the voltage at 8 V. and let it sit over night, you'll be in 'high cotton.'

    Bob Wilson