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  1. #1
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    3s Lipo Parallel in MERV

    I just picked up a MERV VXL and (2) 3s Traxxas 1400mah Lipo batteries. Can I run them in parallel for longer run time with the Traxxas 3064x parallel adapter? It says 2/3A battery packs only, so I assume that means NiMH packs. I've searched the forums and have conflicting info on some running 3s lipo's in parallel in a MERV.

  2. #2
    RC Champion grizzly03's Avatar
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    The new parallel adapter with the ID TRX connector plugs (part #3064x) wont fit the connectors on the Traxxas LiPos. You would need to find an older adapter (part#3064) or make your own.

  3. #3
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    I bought the parallel adapter without realizing it was now nimh only. I asked the guys at the Traxxas retail store what’s the deal and they said that with lipos, there is a higher chance of user error when setting them in parallel, although if the exact same two batteries are used, then it’s all good.

    There is a tab on the battery that sticks out and a corresponding area on the adapter that blocks it.

    You choice is to remove the tab from the battery or cut out the part that blocks it on the adapter. Alternatively, you can buy a third party parallel adapter.

  4. #4
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    In general it's not advised to run LiPo batteries in parallel. Even if you bought two from the same batch and with the same rating, they will still age different. So the ESC will not see if any cell has under voltage.

  5. #5
    RC Champion grizzly03's Avatar
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    Quote Originally Posted by Nighti View Post
    In general it's not advised to run LiPo batteries in parallel. Even if you bought two from the same batch and with the same rating, they will still age different. So the ESC will not see if any cell has under voltage.
    I don't know why it's not advised as the same thing could be said about using LiPo batteries in series. Both ways (parallel and series) are being used without issues.

  6. #6
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    Quote Originally Posted by grizzly03 View Post
    I don't know why it's not advised as the same thing could be said about using LiPo batteries in series. Both ways (parallel and series) are being used without issues.
    In series the voltage sums up. Means if one cell drops the voltage, you will have voltage drop at the output. Under voltage protection will kick in.
    In case of parallel connection if one cell drops voltage, the other will still provide the higher voltage. The output will show the higher voltage and the cell with lower voltage will be still drained risking under voltage for this cell.

    So far the theory. Practically you might be right. There is no bigger harm then shortening a live of one of the batteries. As you charge them separately, you should see any deviations pretty fast.

  7. #7
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    I will say I have noticed that the batteries seem to drain at different rates in mine. It’s not uncommon for me to plug them both into my dual charger and see one lower than the other.

  8. #8
    RC Champion grizzly03's Avatar
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    Quote Originally Posted by Nighti View Post
    In series the voltage sums up. Means if one cell drops the voltage, you will have voltage drop at the output. Under voltage protection will kick in.
    In case of parallel connection if one cell drops voltage, the other will still provide the higher voltage. The output will show the higher voltage and the cell with lower voltage will be still drained risking under voltage for this cell.

    So far the theory. Practically you might be right. There is no bigger harm then shortening a live of one of the batteries. As you charge them separately, you should see any deviations pretty fast.
    Also they are still manufacturing and offering from reputable battery suppliers LiPo batteries in a 2P configuration without anyway to check each individual cell.

    If your getting a significant difference in voltage between batteries either in series or parallel you shouldn't be using them together anyways. Using a parallel or series connection is not going to cause a battery to go bad quicker one way or the other. It is up to the user of the batteries to properly maintain and care for their batteries so an desirable condition doesn't happen.

  9. #9
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    Sure hope it's ok, because I'm gonna do it! Been doing it with 2S LiPos for months, and just got my first set of GensAce 3S LiPos that fit beautifully, and I'm all about run time. Keep in mind that she heats up quite a lot on 3S, so make sure you're monitoring temps.

  10. #10
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    People over think lipo too much. Ive used 3s parallel for years and no issue. Even with LiHV batteries. If one cell drops voltage and low voltage does kick in, so be it. That battery is no good anyways. Lately i've gone back to dual nimh series in my merv cause its faster anyways than 3s

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