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Balancing Cells - RC Charger or connect in parrallel?

Discussion in 'Gen 2 Prius Technical Discussion' started by Tony Lucas, Aug 2, 2016.

  1. Tony Lucas

    Tony Lucas Junior Member

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    Thank you for all your forums. This website has been very helpful. I have a 2006 Prius with 130K. They all have similar voltages, but I think one or more are bad. I plan to do a load test (hook a high beam light bulb to the battery for 2 minutes). I'm hoping that will tell me which one is bad.
    Then, I think I'm supposed to re-balance them. I've heard you can purchase a RC Charger for NIMH, which I did, but I've also read that you can connect the cells in parallel and let them sit.
    1. I don't know what it means to hook in parallel - how do you do that?
    2. Which way is better?
    3. If I were to charge each one with an RC Charger, would I just charge the low cells to the charge of the other cells?
     
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  2. jeff652

    jeff652 Senior Member

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    The fastest and easiest way is with a Prolong Battery Charger. There is a one time car harness installation and then the battery can be easily reconditioning (and cells rebalanced) at home as often as needed for the rest of the life of the vehicle:
    Prolong Battery Systems - Hybrid Automotive

    Also, in case it helps, here is a good how to on load testing the modules:
    Prolong Battery Module Load Tester - Hybrid Automotive

    :)
     
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  3. Kevin_Denver

    Kevin_Denver Active Member

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    Keep in mind that reconditioning and re-balancing is a major undertaking and one should have good understanding of the batteries and their operation before attempting! Read up on all of the threads on Priuschat about reconditioning before attempting! This is a good one to start: Prius Battery rebalance thread | PriusChat

    To answer your questions:
    1. Series and parallel circuits - Wikipedia, the free encyclopedia However hooking cells in parallel will only balance their output voltages, it will not balance the state of charge which is what is desired to be balanced. It's a huge misconception that the battery voltage indicates how much charge a battery has left (this will only provide one a rough estimate). In general there's no need to hook the cells of the Prius' batteries in parallel during reconditioning.
    2. Re-balancing usually involves doing near full discharge and recharge of all the 28 batteries at least 3 times, and recording the capacity of discharge on each cycle. Batteries that do not recover a certain capacity are then replaced, and those that show improvement but are still below average can often be cycled another 2-3 times to get back capacity. Cells that are replaced must be very close in capacity to the other cells, otherwise imbalancing will occur with normal Prius operation and the car will throw an error code within a short amount of time afterwards.
    3. No, you would fully cycle all of the cells to determine the capacity of each individual battery per my comment in #2. What I've written here is just a general overview. See other PC threads for a full procedure.

    Using a charger like Jeff mentioned can help re-balance your battery before it throws a code. If you're already getting a code, it's probably too late and you'll need to do full battery reconditioning at a minimum. If you're not getting a code, I wouldn't recommend messing with individual cells unless you really know what you're doing.
     
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  4. jeff652

    jeff652 Senior Member

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    You are correct that the most benefit from our products will be obtained if they are used BEFORE the battery fails. This is true 100% of the time.

    However, around 75% of the time people wait until they encounter the 'red triangle of death' before purchasing our products. In about 60% of these cases, reconditioning the pack by charging/balancing and deep discharging three times is enough to restore it to serviceable condition and extend the life of the battery. Around 40% of the time, reconditioning alone is not enough and a module or two needs to be replaced. We are happy to help our customers locate good quality tested used modules to complete their rebuilds. Rebuilding one's own pack takes a bit of work and is not for everyone, but it is much less expensive than a new battery replacement and much lower risk than buying an unknown history rebuilt pack from a local craigslist seller. I agree with Kevin that unless a module has failed and must be replaced, changing/rearranging the cells (modules) is not recommended. :)
     
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  5. Chba

    Chba Junior Member

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    i have diagnosed my cell block with Hybrid-Assistant. I know the faulty cells and I ordered 8 refurbished cells from eBay.
    Now I only want to take the block apart from the car and then replace the weakest cells.

    I don't want reconditioning the pack of cells with charge-discharge cycles.
    I just want to dismantle-replace-assemble and finally start the vehicle.

    Tell me if this procedure will work knowing that the voltage levels of old cells is different from new ones?

    Someone advised me to balance the voltage, but how do I do it?

    I am also very interested in your products, especially the "Prolong Value Reconditioning Package". But I don't live in the USA. Do you ship to other continents?
    i have diagnosed my cell block with Hybrid-Assistant. I know the faulty cells and I ordered 8 refurbished cells from eBay.
    Now I only want to take the block apart from the car and then replace the weakest cells.

    I don't want reconditioning the pack of cells with charge-discharge cycles.
    I just want to dismantle-replace-assemble and finally start the vehicle.

    Tell me if this procedure will work knowing that the voltage levels of old cells is different from new ones?

    Someone advised me to balance the voltage, but how do I do it?

    I am also very interested in your products, especially the "Prolong Value Reconditioning Package". But I don't live in the USA. Do you ship to other continents?

    Posted via the PriusChat mobile app.
     
  6. dolj

    dolj Senior Member

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    Regardless of what the eBay ad says, you have no guarantee that the modules will be compatible with your existing ones
    You may get lucky and it might work, but more likely chances are this will not work.
    If this post is directed to Hybrid Automotive, you would be better off emailing them directly (see their website for details) and chatting with their customer support as Jeff does not get on these forums much these days.

    You say you are off-shore but show New York as your location (in your profile). You also (say you) have a Gen 3 (in your profile) but are posting in a Gen 2 forum.
     
  7. mr_guy_mann

    mr_guy_mann Senior Member

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    You want Fast, Inexpensive, and Functional. Good luck with that. Judging by all of the posts that I have read in this forum, you can usually only get two out of three of those things.

    Yes, it has happened that someone "just" replaced a couple modules and it worked, but there are lots of posts where the red triangle came back quickly. Without cycling you can't know what the capacities of any of the modules are- if they are too different it will set a code again. Those who used RC chargers to recondition did it but that takes weeks. Or you get the Prolong system ($$)- less than a week, or for that matter just get a new pack ($$$$)- quick and functional.