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Has anyone charged a Prius Gen 1 HV battery pack with solar?

Discussion in 'Generation 1 Prius Discussion' started by GreenTechFusion, Dec 27, 2015.

  1. GreenTechFusion

    GreenTechFusion New Member

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    This is a question for the die hard engineers of the group that have repaired or replaced any hybrid HV packs in the past.
    I have two 2002 Gen Prius, one with over 260K original miles and recently had to replace the HV battery last year since it sat for over a month without starting. That was to much of a drain on the HV battery and basically would not start. I replaced that battery pack with a "reconditioned" one that had 40K miles on it. Working great.
    My other 2002 Prius just had the same issue only after 198K miles and I parked it at the airport for 6 weeks. Would not start and the 12v battery was fine. I got the error codes and found that the problem was the HV battery pack. Took out the HV battery and tested each cell to find that 3 where bad or way under 7.2v. This project has been on the back burner for over a year now and I just got back to it and bought replacement cells and putting it all back together.
    Now for the main question to you all. Because it has been sitting for such a long time without a charge, I am afraid to install completely to find it not start due to low state of charge on the pack. I know Gen 1s are very finicky and the ICE engine will not start if the battery pack is to low. I do not want to buy a $600+ 200-400v DC charger for a one off charge. Since I do solar, I have plenty of high voltage DC to work with and was wondering if anyone has tried using a Series string of solar totaling in the 200-212v DV range to charge a HV battery pack? I have 6 solar panels that put out about 38v open voltage and 28v under load at 8Amps each. My total voltage connecting them in series gives me 228v DC at 8amps open circuit and should be around 168v DC under load. I basically just want to "top up" the pack in order for the car itself to start OK and take over the proper charging of the pack.
    Thanks in advance.

    John
     
  2. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Consider paralleling the modules. Lowers voltage and ensures balanced as automatic.

    There was one unfortunate solar charge of an NHW20 pack that ended badly. You really can not charge without a limit protection circuit.

    Bob Wilson
     
  3. bisco

    bisco cookie crumbler

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    could you trickle charge in some way just to keep it from getting too low when sitting?
     
  4. S Keith

    S Keith Senior Member

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  5. GreenTechFusion

    GreenTechFusion New Member

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    Thanks Bob for the comments. I was originally thinking about setting up all the cells in parallel in pairs of two, so that each pair would be 14.4v. So a typical 12v charger can be used to charge evenly. The charger typically starts out at a high 14v charge and then levels off.
    This just takes a lot of wiring and no mistakes.
    I liked Steves answer as well with the LPC-100 trickle charger at the high voltage needed and low Amps. That is my worry about using my solar with the 8Amps, may be way to high and make the pack too hot. However, what is the Amps being push by the cars regen braking and ICE charging as it is in motion anyway? I dont have that info. This device looks like it would be good for "trickle charging" the pack if the car has to sit for long periods. That, in my experience is the biggest issue with hybrids is you must keep driving them and if you let them sit to long, be ready to replace or rejuvenate the HV pack.
    Cheers

    PS: I already added a 12v battery kill switch to all 3 of my Prius which solved the battery going dead issue I have had several times.
     
    #5 GreenTechFusion, Dec 27, 2015
    Last edited: Dec 27, 2015
  6. bisco

    bisco cookie crumbler

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    not with newer ones, but you're dealing with classics. but even the newer ones can't sit forever.