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Hybrid Battery Reconditioning/Replacement Options?

Discussion in 'Gen 3 Prius Main Forum' started by stokesey, Nov 12, 2024 at 6:02 PM.

  1. stokesey

    stokesey Junior Member

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    So I've read up on grid chargers, refurbished hybrid batteries, and the hybrid battery replacement process. Also watched several great YouTube vids on battery reconditioning and cell replacement. It seems that not all of the cells fail, but the system can't charge cells individually. Therefore the charging system can only charge the hybrid battery until the good cells are at full capacity (~7.2Ah if I gather correctly). This means that the worn cells lag behind and pull charge from the neighboring cells, diminishing the total battery capacity.

    Full charging and discharging cycles seem to have a rejuvenating effect on the worn cells, as long as heat is contained. But several pros recommend replacing cells that can't sustain around 5Ah since batteries can be fickle.

    I've got a Prius that sat for 2 years and I'm wondering what my best course of action will be. A grid charger could be an easy fix, but should I go into the battery pack and balance all of the cells? Of course I can do some voltage measurements and maybe run Dr Prius once I get the car running.

    Also, several of the balance chargers used on YouTube say expressly "NOT for use with hybrid battery packs, will cause damage". So can anyone recommend a balance charger that is suitable for the task? Or, should I just buy a refurb battery and drop it in?

    Thanks
     
  2. ASRDogman

    ASRDogman Senior Member

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    Get the Prolong system. It has the PROPER charger and discharger and is the safest way to do it.
    You may be able to revive it. If you can't, there is no sense in playig wack a mole with trying to swope
    out blocks... Unless you have days and days to play with them.
    But if you want it "fixed", try the Prolong system, or replace it with the Sodium Pack...
     
  3. bisco

    bisco cookie crumbler

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    it's a big expense to gamble on vs putting the money into a new battery.
    what year and how many miles?
     
  4. stokesey

    stokesey Junior Member

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    Its 2010 w 120k, low miles so I feel like its worth saving. I'm familiar with the head gasket issues but I'm confident that I'm out in front of the problem and can mitigate it.

    Refurb battery is about $1200 from what I've seen so probably worthwhile if I do the labor. Looks like no coding, just plug n pray?

    On the other hand, I won't mind having the grid charger around. If it can help condition the battery for longer life its probably worth it.
     
    bisco likes this.
  5. stokesey

    stokesey Junior Member

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    Thanks for the advice. If the Prolong can bring the battery back from the dead I'll try it. Just wasn't sure that it would revive a totally dead hybrid battery.
     
  6. james wang 20

    james wang 20 Junior Member

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    The grid charger charges with a low current for a long time. It takes advantage of the charging characteristics of nickel-metal hydride batteries to overcharge with a low current, which can help your battery restore balance. However, if the capacity of the cells itself is lost too much, this kind of charging cannot solve the problem. The problem is, you can find a cell with a capacity lower than 2ah and replace it. I don’t know the threshold value for Prius to detect battery capacity. I can only tell you that battery cells higher than 2ah seem to work very well in the car. The larger the capacity, the better. good.
     
  7. stokesey

    stokesey Junior Member

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    That makes sense. Can the grid charger also cycle charge with discharge, cool down, and recharge, or do I need to do that manually? I've seen a few people saying if the car is in neutral it'll drain down the hybrid battery slowly. Or maybe just driving slowly in EV Mode will also accomplish that result?

    Thanks
     
  8. james wang 20

    james wang 20 Junior Member

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    I have never owned a power grid charger, and I don’t know if it can automatically discharge. I only have a regulated power supply and a homemade discharger, and it needs to be done manually, which is very time-consuming. If you don't like this, you can also buy a charger for model aircraft, which can charge and discharge. The end of charging and discharging is automatically detected, and you can also get capacity information.
     
  9. bisco

    bisco cookie crumbler

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    check hybrid automotives website. should have all the info you need
     
    Brian1954 likes this.
  10. james wang 20

    james wang 20 Junior Member

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    When the hv battery is in the car, you can turn it on and it will slowly discharge. Turning on the air conditioner will accelerate the discharge, or slow EV driving will consume power. Due to Toyota's charging and discharging strategy, it cannot drain the battery. If your hv When a battery has damaged cells and you must open it, you have the opportunity to drain it through a slow discharge, which may help alleviate the memory effect of NiMH batteries.
     
  11. stokesey

    stokesey Junior Member

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    That makes sense, Toyota doesn't want the battery dropping too low, as it could brick the car. It looks like any procedures done to the battery in the car will be approximate, and won't allow servicing of individual cells in the hybrid pack. It remains to be seen just how important it is to service them individually.

    I'm familiar with batteries of each chemical compositions having memory. If I recall, NiMH behave differently from Lithium and Lead-acid batteries. Operating temperature also has an impact on this, colder weather means lower capacity and shorter memory.
     
  12. vvillovv

    vvillovv Senior Member

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    You'll find out more about the pack once you get it open and start taking voltage readings. 7.4 volts is a modules nominal rating and they charge a few volts higher somewhere around 8.5 to 9 volts.

    There are 6 ( 1,2 volt (nominal)) cells per module and 28 modules in the Gen 2 and 3 Prius hybrid battery pack.

    You have to be careful when choosing a charger to make sure it will charge NiMH batteries, since many newer chargers will only charge lithium. The charger must also be rated for at least 6 NiMH cell packs, but most that come with NiNH settings already support more than 6 NiHN cell packs, still it's in your best interest to make sure.

    Since reading above it looks to me like you might have an interest in working on modules individually.
    Here is a link to a charger / discharger that is used fairly widely by priuschat members and has some decent youtubes on how to use it too.

    EV-Peak CQ3 100W x4 AC/DC Quad Balance Charger

    With this charger you can cycle 4 modules at a time. Some even have several of these chargers.