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  1. #1
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    How to charge NiMH with this charger

    I'm brand new to RC and don't know much about batteries. I recently bought a Stampede and a friend of mine recommended this charger:

    Skytoy ST-B6AC Lipo Battery Charger
    https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

    I have the battery that came with my Stampede:
    3000mAh NiMH 8.4V Battery

    I don't quite understand the instructions that came with my charger. I can get the charger into NiMH Mode - Manual and it asks me to set the a value of "A". I assume this is Amps. I set it to 3. I tried to charge the battery with these settings and it seemed to work, but the battery only lasted about 5 minutes when using my Stampede.

    What am I doing wrong?

  2. #2
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    bump - any help?

  3. #3
    RC Qualifier corneileous's Avatar
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    Quote Originally Posted by KidBilly View Post
    I'm brand new to RC and don't know much about batteries. I recently bought a Stampede and a friend of mine recommended this charger:

    Skytoy ST-B6AC Lipo Battery Charger
    https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

    I have the battery that came with my Stampede:
    3000mAh NiMH 8.4V Battery

    I don't quite understand the instructions that came with my charger. I can get the charger into NiMH Mode - Manual and it asks me to set the a value of "A". I assume this is Amps. I set it to 3. I tried to charge the battery with these settings and it seemed to work, but the battery only lasted about 5 minutes when using my Stampede.

    What am I doing wrong?
    Sure, youíd have to buy the AC to DC inverter from Traxxas to use it but why donít you just use the charger that came with your truck? Really, the only thing that charger you bought is good for unless you decide to move up to Lipo, is having the option to charge at different amps and have the ability to manually discharge your batteries but other than that, Iím not familiar with that charger you bought. Have you tried looking for a tutorial on YouTube?


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  4. #4
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    Quote Originally Posted by corneileous View Post
    Sure, you’d have to buy the AC to DC inverter from Traxxas to use it but why don’t you just use the charger that came with your truck? Really, the only thing that charger you bought is good for unless you decide to move up to Lipo, is having the option to charge at different amps and have the ability to manually discharge your batteries but other than that, I’m not familiar with that charger you bought. Have you tried looking for a tutorial on YouTube?


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    I don't use the charger that came with my truck because it's a car charger.

    So as long as I have to buy extra equipment, I might as well buy a charger that can support the upgrade to Lipo, right?

    There are some instructions are similar styles of chargers that I've found on YouTube, but they didn't really solve the problem.


    Edit
    The problem now is more clear.

    My charger is only charging my battery for 5 minutes or so, then the charger thinks it's full and stop charging.

  5. #5
    RC Turnbuckle Jr. olds97_lss's Avatar
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    There's a timer limit in the settings you can adjust. Also a capacity limit. Or there should be. Found this for a similar charger:
    https://www.pololu.com/file/0J525/iMAXB6ACmanual.pdf

    Page 18-19 if scrolling, says page 16-17 on the actual page.
    https://www.youtube.com/c/olds97lss

  6. #6
    RC Qualifier corneileous's Avatar
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    Quote Originally Posted by KidBilly View Post
    I don't use the charger that came with my truck because it's a car charger.

    So as long as I have to buy extra equipment, I might as well buy a charger that can support the upgrade to Lipo, right?
    Well yeah, and I donít blame you. I even asked a Traxxas tech about it a while back and pretty much his answer was so that you could have an all around multi charger for home or auto and I was like, in the last 15 years of having this caliber of RC vehicles, thereís only been like three times that I can honestly count where it wouldíve been nice to be able to plug my charger into the cigarette lighter port but it didnít matter even then that I didnít have the optional cigarette lighter cord with my old charger because I already had a DC to AC converter so I just simply plugged my old charger into the converter but I was like, itís still redundant to have a charger that automatically comes set up to be plugged into a cigarette lighter because a lot of cars these days come with some kind of AC converter built in to them, Itís just better to make a charger that plugs into your wall outlet thatís probably for a lot of people, the majority of the places that theyíre going to be charging the batteries is in their garage or somewhere within their home.

    But letís face it, Traxxas knows this so if all you want to do is charge your batteries with that free charger at your house, you have to spend another $40 on a part that you really shouldnít have to need.

    Edit
    The problem now is more clear.

    My charger is only charging my battery for 5 minutes or so, then the charger thinks itís full and stop charging.
    I am going to go out on a limb here but it kind of sounds to me that maybe you need to raise the maximum voltage to either at or slightly above what your battery is and you may need to also set the MAH to a little higher than what that is on your battery is as well.


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  7. #7
    RC Qualifier corneileous's Avatar
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    What olds97 said. I forgot about the charge timer but then again, I donít know why the default charge timer would be set for five minutes, though.


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  8. #8
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    My charger has a safety timer but that's set to 120 minutes by default.

    I just tried charging my battery again and this time it only charged for a minute or so before being full.

    The battery must be full already, is there something wrong with the ESC? I tried the steps in this video but it didn't seem to change anything.

    Now I put the battery in the car and it's like the battery is completely dead. Yet when I try to charge it, the charger says it's full.

    https://www.youtube.com/watch?v=FCNs...hannel=Traxxas
    Last edited by KidBilly; 03-09-2021 at 02:20 PM.

  9. #9
    RC Champion grizzly03's Avatar
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    Quote Originally Posted by KidBilly View Post
    My charger has a safety timer but that's set to 120 minutes by default.

    I just tried charging my battery again and this time it only charged for a minute or so before being full.

    The battery must be full already, is there something wrong with the ESC? I tried the steps in this video but it didn't seem to change anything.

    Now I put the battery in the car and it's like the battery is completely dead. Yet when I try to charge it, the charger says it's full.

    https://www.youtube.com/watch?v=FCNs...hannel=Traxxas
    Same as in your other thread, when you plug in the battery what color is the Led on the ESC?

  10. #10
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    Quote Originally Posted by grizzly03 View Post
    Same as in your other thread, when you plug in the battery what color is the Led on the ESC?
    Solid red.

  11. #11
    RC Qualifier corneileous's Avatar
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    Have you tried different batteries? How old is the one you got? If your charger supports it, you might try a few cycles of letting the charger drain the battery and seeing how much mah it takes out of it and charging it back up if itís a fairly old and used battery.


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  12. #12
    RC Champion grizzly03's Avatar
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    Do you have a volt meter to see what the voltage is of the battery? That would help point toward the issue, either the battery/charger or truck/esc.

  13. #13
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    Quote Originally Posted by grizzly03 View Post
    Do you have a volt meter to see what the voltage is of the battery? That would help point toward the issue, either the battery/charger or truck/esc.
    Just tested it. 7.85 volts coming from the battery. And the Stampede acts like it's 100% dead.

  14. #14
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    Quote Originally Posted by corneileous View Post
    Have you tried different batteries? How old is the one you got? If your charger supports it, you might try a few cycles of letting the charger drain the battery and seeing how much mah it takes out of it and charging it back up if it’s a fairly old and used battery.


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    I have not tried other batteries as I only have the one. The battery, stampede and charger are all less than a week old.

  15. #15
    RC Champion grizzly03's Avatar
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    Quote Originally Posted by KidBilly View Post
    Just tested it. 7.85 volts coming from the battery. And the Stampede acts like it's 100% dead.
    Is that what it is after charging? What is the voltage when the truck is "dead"?

    That 7.85 voltage does mean it is discharged. A charged NiMh cell is about 1.5v fully charged. So a charged 7 cell NiMh battery should be around 10.5volts.

    If your battery is around 10.5volts after charging and then after running it in your truck your voltage is 7.8 (or around there) and your run time was very short like you are saying points towards a bad battery.

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