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  1. #1
    RC Racer
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    Apr 2015
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    Run Time and Lipo cut off

    team questions

    I have q Leopard 5123 V2 1090 motor with a Max 5 ESC on Proline badlands

    Ruinning 37T pinion and 50T spur

    Today I took it out for a run.

    Only got 15min run time on 5000Mah lipos? Is this right?

    Additionally the Xmaxx then stopped. The App showed the lipo voltage at 25v, I had it set on the traxxas app for 24V to shut down. Thats 3v per cell.

    However the Lipos themselves had only 2% left in them and had run to far down.

    The stock set up on there Max 5 is 3.2v per cell which is 25.6 before the ESC shuts down.

    Should I increase this to the max setting of 3.4v poor cell which is 27.2V and change the app setting to alarm at 27.2v also?
    Is so what 5 would this leave in my lipos? Hopefully more than 2%

    Anyway I only managed to hit 50mph as it was so powerful and fast I couldn't squeeze the throttle fully. Im happy with the gearing. Its awesome.

    Any ideas and advice please

    Thanks

  2. #2
    RC Racer
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    Apr 2011
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    196
    Depends on how you drive, but sounds the same as I get out of 5000mah. Put lipo cutoff at about 3.2-3.4v. 3.0v sounds very low.

  3. #3
    RC Qualifier
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    Jan 2018
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    3v/cell is lipo abuse....lol.

    You will strain and puff your lipos in no time. As a personal preference, I cut off no lower than 3.7.....3.6 would be rock bottom.

    To be honest...I pick my truck up at 3.8. (Storage charge)

    OF course if you set your lipo cut off at 3.4. That's at the sag level and lipo will probably bounce back up when it sits.

  4. #4
    RC Champion
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    Feb 2013
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    same here - unless I am racing the LVC on any of my brushless cars is set to 3.8v. Yes it's less run time but it's also helps extend the battery life.
    I have an RC problem...

  5. #5
    RC Qualifier
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    Jan 2018
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    Nice to hear the same minded. I think if you want to run longer...bring 2 batteries....lol.

  6. #6
    RC Racer
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    top advice as always team...cheers

  7. #7
    RC Qualifier
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    Jun 2017
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    MA
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    does any one know what the cutoff V is for the stock vxl-8s?

  8. #8
    RC Turnbuckle Jr. ReglarGuy's Avatar
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    It's always best to look at the paperwork that comes with your batteries and chargers to see what they say. Some battery companies want you to put your LVC up higher than 3.2vdc, and some don't. Also, generally speaking, the more you baby your stuff the better off you should be with your stuff lasting longer.

    With that all said, (IMO) I expect a litter bit more out of my stuff than that. I want batteries that have warranties that don't mind a 3.2vdc LVC. I have the Kershaw mod in my truck with the Castle XLX-2/Leopard 5892/1340kv motor, and I run two Vant 6600mah 70c 3s batteries with my 29/54 gearing. I get between 20 to 30 minutes of running time using my stated batteries along with a 3.2vdc LVC.

    So far (over the 9 years I've been using Lipo's), I've only had a couple of batteries go bad on me. Usually what happens is, I use them for about 5ish years (and if they're still good) then I give them away to my other RC friends to finish them off. From what I see, it seems like bigger, better, and cheaper batteries come along about every 3 or 5 years, so I try to upgrade to them when ever I can.

    As time has gone by, my battery needs have changed from when I first started with my Emaxx (which was one of the first brushless editions to come out). Now, along with my Emaxx, I have other trucks, boats, cars, and helicopters to which all use Lipo batteries.

    Through the years, I have standardize my battery stock in support to only need a few different sizes for all my RC vehicle's power needs. Presently, I have 6 sets of Vant 6600mah 70c 3s batteries (2 years old), 6 sets Vant 5400mah 70c 3s batteries (2 years old), and 6 sets Traxxas 5000mah 25c 3s batteries (6 years old). I use my 6600's with my Xmaxx, my 5400's with all my boats (a Spartan being one of them), and my Traxxas 5000's with my Emaxx, Summit, and XO-1.

    My Traxxas batteries are 6 years old, and when I upgrade them I'll probably go with either Vant or SMC. They (as of now) have the best stuff for the best money. Now, I know, I know that SMC is one of the guys who want 3.4 and 3.5 LVC cutoffs for their warranty, but I'm not too worried about their warranty at this point in time.

    I bought a set of SMC's to test them with a 3.2 LVC cutoff. If they work well for me for a good amount of time, then I'll consider more down the road. If they don't, I'll just toss them, and that will be the end of it. I'd go with all Vants, but sometimes they're hard to get due to back orders. I'd like SMC to be by backup brand.

    Anyway, one thing I did start, and I am doing differently this year. Instead of leaving my batteries stored with full charges on them (that's what my LHS told me to do when I first got my Emaxx all those many years ago) I'm doing the ol' storage charge on them, and (when you didn't think things could get better) I'm deep cycling them every other month when not used. Anyhow like I said above....it's best to go by the book when ever possible, and it even doesn't hurt to baby your stuff. But, keep in mind that you don't want to baby your stuff too much either, or you won't have any fun. For the record though, I'm definitely a 3.2vdc LVC kind of a guy.

    P.S. Ooops, sorry I didn't know I wrote that much.
    Last edited by ReglarGuy; 02-26-2018 at 10:44 AM.
    Life's to short to be a sour puss.

  9. #9
    RC Racer
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    So to re-cap. The Traxxas App should I set to 29.6 (3.7v per cell 8 cell). Which before I had it on 24 (3v per cell 8 cell).
    I thought the xmaxx only has 30V so there isn't much room for voltage drop? 0.4V.

    Not sure if im understanding this right. Please tell me in basic terms what my alarm should activate at.

    The Max 5 only has a max voltage of 3.4V per cell which is 27.2V

    If i want to do the dame as you guys and be safer and not run the lipo down then i don't seem to be able to set it to 29.6 which is 3.7v per cell.


    AHHHHHH im confused.

    Please spell it out for me in layman's terms

  10. #10
    RC Qualifier
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    Jan 2018
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    Quote Originally Posted by RVJ007 View Post
    So to re-cap. The Traxxas App should I set to 29.6 (3.7v per cell 8 cell). Which before I had it on 24 (3v per cell 8 cell).
    I thought the xmaxx only has 30V so there isn't much room for voltage drop? 0.4V.

    Not sure if im understanding this right. Please tell me in basic terms what my alarm should activate at.

    The Max 5 only has a max voltage of 3.4V per cell which is 27.2V

    If i want to do the dame as you guys and be safer and not run the lipo down then i don't seem to be able to set it to 29.6 which is 3.7v per cell.


    AHHHHHH im confused.

    Please spell it out for me in layman's terms
    There's two workarounds:
    1) Get a $4 lipo checker/low voltage alarm. They are cheap and can even get 4 packs for like $10. You are UK, so I don't know your sources....maybe direct from China off ebay? You can set your LV alarm to any voltage between 2.7-3.8/cell

    2) Use any lipo checker and run your truck for 10 minutes....take a lipo reading....estimate how much longer you would have until you hit 3.8 or 3.7...whatever your preference. Once you have ran your truck until lipos is at the voltage you want, take note of your run time and how hard you ran it. Next time out, run your truck for a set time that you estimated to be within your range of discharge.

    The LV alarms are more convenient, but be aware, under hard running you'll get a false low reading as the lipo sags under strain. You could pull the lipo at 3.7 and a few minutes later as the lipo rests, it could bounce back up to 3.8.

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