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  1. #1
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    ESC Low Voltage Cut-Off

    Hey,

    My Summit is about 3 weeks old, hence my esc has the low-voltage cut off. It is going into the low voltage mode at about 3.8 volts per cell.... I have searched however can not seem to find what Traxxas sets them at from the factory.

    Does anybody know if this is normal or if it can be changed? I have low voltage alarms so I could run it in NIMH mode, but really do not want to.

    Thanks!

  2. #2
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    After doing a ton of reading and research out here, the consensus is that it is around 3.5V. Somebody please correct me if I'm wrong. I have never found an actual number from Traxxas.

  3. #3
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    Wonder is mine is defective, going off so early?

  4. #4
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    3.8 does seem pretty high. I would give Traxxas support a call. They are very good to deal with.

  5. #5
    RC Turnbuckle Jr. jamann's Avatar
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    Are you testing them after the run.
    as they not under load the voltage comes back up some
    3.8 resting says to me under load they may be dipping under 3.5 v (would like a firm answer out of intrest mostly what is the cut off voltage)triggering
    Lvd.If you desire you could run a alarm that is set table and disable the onboard cut off.


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    Last edited by jamann; 12-21-2012 at 11:49 PM.
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  6. #6
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    Quote Originally Posted by jamann View Post
    Are you testing them after the run.
    as they not under load the voltage comes back up some
    3.8 resting says to me under load they may be dipping under 3.5 v (would like a firm answer out of intrest mostly what is the cut off voltage)triggering
    Lvd.If you desire you could run a alarm that is set table and disable the onboard cut off.


    Sent using lipo power
    I forgot about that. I'm guessing that's what is happening but am curious now as well. I know some people like to run them down more, but I know that when I bought my SPC batteries it says right in the instructions to set the LVA between 3.4 - 3.5V. So I have mine at 3.5. I have yet to run them out down to that amount yet though. Hoping to do that tomorrow. My son has the ESC with LVD and I have the older version with two LVA's.

  7. #7
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    Thanks for the responses. I will give Traxxas a call.

    I just purchased 2 SPC 8000mah's ran them from fully charged until the lvc cut in. Fired them on the charger and they only took 3000mah.... That would suggest that the packs were only 40% drained.

  8. #8
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    Quote Originally Posted by cjhike View Post
    Hey,

    My Summit is about 3 weeks old, hence my esc has the low-voltage cut off. It is going into the low voltage mode at about 3.8 volts per cell.... I have searched however can not seem to find what Traxxas sets them at from the factory.

    Does anybody know if this is normal or if it can be changed? I have low voltage alarms so I could run it in NIMH mode, but really do not want to.

    Thanks!
    Well, I got a chance to try my sons truck out today that has the LVD in his. It's the same as yours. His LVD kicked in and it started to run very slow. I pulled the batteries and tested both of them and they were at 3.8 and 3.9.

    Question for you, when your truck goes into LVD protection mode, are you able to shut the ESC off?? Mine flashes red and they only way to shut it down is to unplug the batteries.......

  9. #9
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    I also have the Summitt with the LVD built in. I like using a separate LVD which I set at 3.4 rather than the built in one.

  10. #10
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    Quote Originally Posted by heggie View Post
    I also have the Summitt with the LVD built in. I like using a separate LVD which I set at 3.4 rather than the built in one.
    Do you just run in NiMh mode and not LiPo mode then???

  11. #11
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    Yes - Once the low voltage protection kicks in the esc will not turn off until the battery on the bec side is disconnected.

    I think my batteries may not be lasting as long as I am running in the snow, just below freezing. From what I can find online it looks like in the cold run times can be cut short by up to half.

    Was still expecting more than 20 minutes out of SPC 8000mah packs - They seem to be providing about the same run time as my Duratrax Onyx 5000mahs....

    Think I will try and run in NIMH mode with a lva attached.

  12. #12
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    Coming from an electric heli background the mortal sin for lipo batteries is to take them below 20%. That equates to 3.6volts/cell.

    My concerns with my Summit are as follows:

    The EVX2 LVC would appear to be around the 3.4volts/cell and this gets you close to zero %. Also, this LVC only seems to work on the battery connected to the BEC side of the ESC and there is usually a 10% difference between the two batteries.

    I have tried a y-cable and bridging the non-BEC side of the ESC connectors to get both batteries to discharge at the same rate, however, my ESC is one that shows an over-voltage message with batteries connected this way and won't initialise. Others I have read about don't have this problem.

    I believe the EVX2 LVC is a tad low for good lipo battery care but having said that, my Summit is nowhere near as hard on batteries as my helis so it may not matter as much in the long run. It would be nice to have the option to change it though. I use Hyperion EOS1420inet3 chargers.

    Now that the Mamba Monster 2 (waterproof) is almost here, I am seriously considering going brushless. The CC ESC does give me the option to change the LVC, BEC voltage, run my batteries in series, etc, etc.

    BTW, don't use a 14/62 combo with the stock 775 motor. Smoked mine the other day. I love this buggy. So much cheaper to operate than helis. I can't believe how inexpensive things like motors and drive shafts etc are.

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  13. #13
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    Quote Originally Posted by cjhike View Post
    Yes - Once the low voltage protection kicks in the esc will not turn off until the battery on the bec side is disconnected.

    I think my batteries may not be lasting as long as I am running in the snow, just below freezing. From what I can find online it looks like in the cold run times can be cut short by up to half.

    Was still expecting more than 20 minutes out of SPC 8000mah packs - They seem to be providing about the same run time as my Duratrax Onyx 5000mahs....

    Think I will try and run in NIMH mode with a lva attached.
    Sounds like really short run times. I ran today for about 30 minutes with the stock 3000mAh Nimhs in -17C. 60% high gear / 40% low gear, all the time on fresh snow (not packed or crusty). I would hope that 8000mAh packs would give you way more run time than that.

  14. #14
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    Quote Originally Posted by Piranha-z View Post
    Well, I got a chance to try my sons truck out today that has the LVD in his. It's the same as yours. His LVD kicked in and it started to run very slow. I pulled the batteries and tested both of them and they were at 3.8 and 3.9.

    Question for you, when your truck goes into LVD protection mode, are you able to shut the ESC off?? Mine flashes red and they only way to shut it down is to unplug the batteries.......
    Mine did the exact same thing today, my 8000mah spcs came out at 3.85 per cell

    What the heck's going on here?
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  15. #15
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    Quote Originally Posted by TQi View Post
    Mine did the exact same thing today, my 8000mah spcs came out at 3.85 per cell

    What the heck's going on here?
    Did you just get them? SPC's newest pack?

  16. #16
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    Yeah the 50c
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  17. #17
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    Quote Originally Posted by TQi View Post
    Yeah the 50c
    Charged mine from the cut off point and put 5200mah into them. If I used a separate LVA and ran them down to 3.4 volts should increase the run times. Although the snow I am running through is 5-6 inches deep - probably sucking a lot of power.

  18. #18
    RC Turnbuckle Jr. jamann's Avatar
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    Lipo don't like the cold,well no batts like the cold really


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  19. #19
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    So it must just be the cold messing with it
    What's a coffee if it aint Irish

  20. #20
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    Even so, the main issue here is why the LVD is kicking in so early??? Yeah, the batteries are burning down faster because of the cold, but I would have thought they would have a cut-off of 3.5-3.6V, but that is not the case. And it appeaers I am not the only one with this issue?

  21. #21
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    Yeah, I hope its just the cold though.. maybe the cold weather is making the readings spike up and down so it triggers the lvc

    No idea though, we should be getting twice as much runtime
    What's a coffee if it aint Irish

  22. #22
    RC Turnbuckle Jr.
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    Cold ambient temperatures can DRAMATICALLY reduce LiPo runtimes! Also, when running in cold temps and the LVD kicks in, the rebounded LiPo pack voltages can be significantly higher than the LVD point, especially if the stabilized voltages are being read at indoor room temperatures. LiPo voltages and IR's can fluctuate just by being holding the pack in your hand for a few minutes, so imagine the affect below freezing temps will have?

  23. #23
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    Quote Originally Posted by Piranha-z View Post
    Well, I got a chance to try my sons truck out today that has the LVD in his. It's the same as yours. His LVD kicked in and it started to run very slow. I pulled the batteries and tested both of them and they were at 3.8 and 3.9.

    Question for you, when your truck goes into LVD protection mode, are you able to shut the ESC off?? Mine flashes red and they only way to shut it down is to unplug the batteries.......
    Thats what mine did as well. Is it supposed to alarm? Mine didnt, it just got real slow and finally stopped. The esc light was blinking red, i hooked them up to the charger and they read 6.8 and 6.9.

    Sent from my DROID RAZR using Tapatalk 2

  24. #24
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    Quote Originally Posted by his grace View Post
    Thats what mine did as well. Is it supposed to alarm? Mine didnt, it just got real slow and finally stopped. The esc light was blinking red, i hooked them up to the charger and they read 6.8 and 6.9.

    Sent from my DROID RAZR using Tapatalk 2
    No, there is no alarm on it. Just goes to 50% power I think and then eventually shuts off.

  25. #25
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    Quote Originally Posted by Piranha-z View Post
    No, there is no alarm on it. Just goes to 50% power I think and then eventually shuts off.
    Okay that makes sense. I will say, with these spc 8000 lipos, i ran them on high for about an hour and a half and it was awesome. All the other nitro trucks were having to gas back up or were having to fix something on their trucks lol

    Sent from my DROID RAZR using Tapatalk 2

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