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Prolong System Smell from Discharger

Discussion in 'Gen 2 Prius Main Forum' started by 2GenPrius, Oct 8, 2020.

  1. 2GenPrius

    2GenPrius Member

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    I finally sourced a used one, and had a quick question because my search of PriusChat didn't find any info.

    Is it normal during the discharging process for the discharger to smell like burnt electronics (or at least the discharged air to smell bad since its essentially trying to cook off the energy)? It seemed to be functioning fine and slowly dropping in voltage and I was only using it for the initial 134 volts mode. Did note that it was getting warm, felt that it should be a put on cool surface and have an AC unit blasting on it.

    Also, I read on here that the third discharge to 17 volts is no longer recommended. Just wanted to see what the consensus was from those with experience.
     
    #1 2GenPrius, Oct 8, 2020
  2. dolj

    dolj Senior Member

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    As the recommendation come from Hybrid Automotive, I'd go with that. Why tempt fate? Just do two (second and third) to 84 V.

    If you were feeling like you had time to spare, you could manually stop the second discharge at 101 V.
     
    #2 dolj, Oct 8, 2020
  3. Albert Barbuto

    Albert Barbuto Member

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    There is a very good reason bringing the pack down to 17v is no longer recommended. When your pack is nearing the 84v cutoff, under load, measure each module with a test meter. You WILL find the weakest modules near zero volts, or even a negative volt reading.

    Once you determine which modules are the weakest, work on them, right in the car with a proper "hobby charger".
     
    #3 Albert Barbuto, Oct 8, 2020
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  4. PriusCamper

    PriusCamper Senior Member

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    However the best way to find weak modules / rebuild a pack is to discharge each module individually and race them against each other during discharge to find the ones that discharge the fastest and replace them. Catch is it's not till the third discharge that you're going to get accurate discharge data. My current rig let's me discharge 7 modules at a time... My friend in Oregon with lab grade electronics gear recently discharged 138 modules at a time.
     
    #4 PriusCamper, Oct 8, 2020
  5. Albert Barbuto

    Albert Barbuto Member

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    138 modules... :eek:
     
    #5 Albert Barbuto, Oct 8, 2020
  6. SFO

    SFO Senior Member

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    Best to ask George the ever friendly CS rep at HA. If I had to offer a WAG, it could the resistor array which may have a limited amount of discharge cycles before burning out. A replacement isn't that expensive, and building a better one should be possible.
     
    #6 SFO, Oct 10, 2020
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  7. 2GenPrius

    2GenPrius Member

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    Oh dammit, that's not good.

    What's the normal discharge readings at different volts? If this thing is defective, I gotta let someone know right away.

    First discharge cycle worked fine, second discharge cycle to 84V only made it to 139V then quit. There was literally no amps left.

    I have a Hitech hobby charger, so going to experiment with that too.
     
    #7 2GenPrius, Oct 10, 2020
  8. SFO

    SFO Senior Member

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    Maybe it reached the preset discharge voltage (84v) then bounced back?
     
    #8 SFO, Oct 10, 2020
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  9. 2GenPrius

    2GenPrius Member

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    Nah, I was watching it over my shoulder. I know the discharger converts the amps to heat so it blows it out.

    I put it back on the charger and going to let it sit for 12+hours at stable voltage and see what happens when I try to dip to 84V again.

    I agree that maybe individual modules is the best way to go but I'll look into what you said about the discharger being on the fritz too. It's quite possible I got sold a bad unit (or used way too many times).
     
    #9 2GenPrius, Oct 10, 2020
  10. 2GenPrius

    2GenPrius Member

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    Ok update: I let the charger soak the battery at 239V (.35X amp rate) for about 14 hours after it hit peaked at 9 hours in (238/239V). I failed to do this during the initial charge, thinking I hit peak so I only let the charger soak at 4 hours additional.

    I hit 134V with 4.5 hours elapsed at an discharge amp rate of .263amps.

    Started at 239V with 1.5XX dc amps load discharge rate
    At 196V, it fluctuated between .738 to 1.17X dc amps discharge rate
    169V-195V, it fluctuated between .493 to .508
    134-151V fluctuated between .263 to .271

    After the load release (discharge cycle over), the voltage climbed back from 132V to 178V over a period of 40 minutes, it hit 170 in the first 20 minutes.

    Assuming I hit it down to 84V, there would be nothing left, right? So I should just quit while I'm ahead after this charge cycle. This is my fourth charge cycle.
     
    #10 2GenPrius, Oct 10, 2020
    Last edited: Oct 10, 2020
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