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HV Battery Drain?

Discussion in 'Gen 2 Prius Main Forum' started by Nick munoz, Sep 3, 2022.

  1. Nick munoz

    Nick munoz New Member

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    Hey everyone first time posting in the Prius chat. I have an 04 base model and just installed and 09 used battery since the main one failed. Purchased from a VERY reputable dealer known as TAMPA HYBRIDS Decided to take it for a joy drive to see MPG and battery charge/ discharge. Mpg seemed pretty good to me for an 09 it averaged 45MPG for 19 miles. What does concern me is I turned it on and charge was at 3 bars dropped to two within minutes. After driving it for 10 minutes or so it went back up to 5 bars and while was on the highway Even went to green for a lil. During the entire 20-30 min drive it didn’t drop below 6/5. When I got off the highway the HV started to kick in and dropped back 5 bars and when I got home and parked to see what would happen it had dropped back to 2 bars within 5-10 minutes of car sitting ready with ac on. I’ve seen some people say it’s normal but then others say it’s “ready” to fail. I know the used battery wasn’t the best option but it’s the best I could afford. So here is the dreaded question is it Failing or normal? Appreciate the help in advance.
     
    #1 Nick munoz, Sep 3, 2022
  2. SFO

    SFO Senior Member

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    Welcome to PriusChat!!
    Normal.

    FYI : you're moderated until you've posted 5 times.
     
    #2 SFO, Sep 4, 2022
  3. bisco

    bisco cookie crumbler

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    normal

    what's the warranty?
     
    #3 bisco, Sep 4, 2022
  4. PriusCamper

    PriusCamper Senior Member

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    Well a brand new battery pack will be very stable on its charge levels and not fluctuate very much at all. On an older pack if it does fluctuate wildly that could be caused by a couple things: 1) is that battery has lost capacity and needs reconditioning, also known as deep cycling to restore capacity, which basically means several deep discharges and recharges. 2) It could be corrosion from the voltage sensing harness working it's way up into the ECU where it creates micro-shorts between blocks and as the corrosion grows it gets worse and worse till it finally shorts out. Tampa Hybrids will likely understand and work with you on these concerns. As it gets worse it will throw a P3000 error code. Here's a photo of what this problem looks like as it starts to grow inside your ECU:

    PXL_20220813_064430386.jpg
     
    #4 PriusCamper, Sep 4, 2022
  5. pasadena_commut

    pasadena_commut Senior Member

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    How strange, just the one pin? It's neighbors are pristine, not a blue spec in sight. What makes that pin special?

    Zoomed up the picture a bit and it looks like that one is not soldered quite like the others. The others look like they were pressed all the way down to the circuit board and then soldered, so that the blob comes up nicely all around the pin. But that one looks like it was not all the way down, almost like it is sitting on top of the solder ball with just its bottom touching, no solder running up the sides. Could be the lighting though.
     
    #5 pasadena_commut, Sep 4, 2022
  6. PriusCamper

    PriusCamper Senior Member

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    I can assure you all those pins are soldered in exact same way and there's no problem with the soldering joints. It's a very common problem, on older Gen2.

    This pin first shows signs of trouble where the corrosion starts at the negative battery module terminals, which seeps out a microscopic bit of NiMH electrolyte that gets the corrosion growing on the bus bars and beyond. If you pull the plug on the other side of this pic you'll first see the corrosion color on that pin in the plug, especially in regions with high humidity. Not cleaning all this up has been a problem for 3 of the 200+ Project Lithium packs sold and They're actually upgrading their voltage balancing controller to ensure this problem doesn't turn into warning lights. But if you have a really old Prius with lots of corrosion and upgrade to Project Lithium you'd be wise to start with a brand new voltage sensing harness and cleaned out or new Battery ECU
     
    #6 PriusCamper, Sep 4, 2022
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