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  1. #1
    RC Competitor
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    Is it safe to mix lipos?

    Hey guys, I'm getting an x-maxx for x-mas(not funny? Fine &#128553 and its gonna be my first truck that uses 2 batteries. But I don't have 2 of the same batteries. I have a 3s and a 2s 4400 mah. Is it safe to use these two at the same time? Im using the velenion esc.

  2. #2
    RC Qualifier Fuglio's Avatar
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    I wouldnt recommend it. When you series a battery the current rum through each one so capacity and voltage may affect it. But im not an electronic engineer, or very knowledgeable on rc car batts... but with lipos and all batteris typically you want every batt in the certificate to be identicall same brand and everything. Im thrifty but i wpuld still say plan on getting 2 fresh identical batts. Always use them together to get the best results. ... I hope its not the case cause im in the same situation as you, getting x maxx have 2 lipo batts ,but i dont really wanna mix them

  3. #3
    RC Turnbuckle Jr.
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    If they are the same brand and c-rating and mah I don't see the problem in using them as a 5s setup. The main battery experts can chime in with further details though. I don't kno if the VXL-6s in the X-Maxx will read 5 cells though??? If it were a Castle ESC then yea for sure.
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  4. #4
    RC Turnbuckle Jr. Wolfslash16's Avatar
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    Quote Originally Posted by Fuglio View Post
    I wouldnt recommend it. When you series a battery the current rum through each one so capacity and voltage may affect it. But im not an electronic engineer, or very knowledgeable on rc car batts... but with lipos and all batteris typically you want every batt in the certificate to be identicall same brand and everything. Im thrifty but i wpuld still say plan on getting 2 fresh identical batts. Always use them together to get the best results. ... I hope its not the case cause im in the same situation as you, getting x maxx have 2 lipo batts ,but i dont really wanna mix them
    Pretty much nailed it on the head. It is possible to run two different 2s, or 3s, but you can't run a 2s and a 3s at the same time. Even running two identical batteries that are different ages can affect it. I would personal get two brand new batteries at the same time so you know they're the same and even. Hope this helps!
    Last edited by Wolfslash16; 12-11-2015 at 09:08 PM.
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  5. #5
    RC Competitor
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    Quote Originally Posted by G-Rustler View Post
    If they are the same brand and c-rating and mah I don't see the problem in using them as a 5s setup. The main battery experts can chime in with further details though. I don't kno if the VXL-6s in the X-Maxx will read 5 cells though??? If it were a Castle ESC then yea for sure.
    I concur with G-Rustler, as long as the ESC is okay with 5S, it isn't unreasonable to run a 2S and a 3S in series. I'd bet it is just fine with 5S, since it'll do both 4S and 6S. It'll be a little more powerful than a 4S (pair of 2S) and a little less powerful than a 6S (pair of 3S). You would want to take care that they are both of very similar capacity (which you say they are, but maybe use your charger to analyze them both?), because you wouldn't want to accidentally run one of the batteries down below safe levels and it would be easy to do that if say the 3S were much higher capacity than the 2S. I think matching the C rating is less of a concern, but obviously both of them should meet or exceed the recommended value. And of course you'd want to have them start out at the same level of charge, but the same is true of any pair of batteries.

    For the first run, I'd watch out for the low voltage cutoff. That is about the only thing I'd wonder about, did they maybe do detection of voltage for 6S and 4S? Seems like an easy shortcut to take when making the speed controller, but then again... why go to all the work of designing a speed controller and then not supporting all reasonably usable battery voltages?

    Maybe you have your own LiPo voltage monitor you could throw on the first run?

  6. #6
    RC Competitor
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    Thanks guys. I'll keep it safe and just get 2 brand new batteries.

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