Big Rock Big Rock battery issues

[Tracgain]

Newbie here. Just started enjoying my Big Rock and with an Admiral 2S 5000mah battery running through my lawn I get 15 min runtime. I purchased 2 Povway 3S 5200mah batteries and I only get 7 minutes. So I returned them, and bought Goldbat 3S 5200mah batteries and I got 10 minutes before they quit. When I put them on my charger, it said they were at 4.16v per cell. Why are they cutting out early? I have only balanced charged them. I have discharged and recharged them and still the same issue. I am using a Dynamte passport ultra P2 Charger. Any input would be appreciated. Could there be an issue with the esc?

 

[jondilly1974]

If they still have 4.16v per cell after cutoff then you likely have a bad ESC. It’s common recently. They have a new firmware version that fixes the issue but they don’t allow the public access to it.

 

[Sludog]

Sounds like there in storage mode. I run Spektrum 3s 5000mah 50c packs on my son's Big Rock and we get around 30 minutes easy. Maybe its a charger issue? Do you have access to another Lipo charger?

 

[Tracgain]

I have another charger and I get the same from it. If it’s a firmware issue and it’s not available to the public how do you get it?

 

[jondilly1974]

I have another charger and I get the same from it. If it’s a firmware issue and it’s not available to the public how do you get it?

They generally have you ship it in or they just mail you a new one. Depends on if they have some in stock.

 

[alelys]

Sure it's not only overheating?

 

[Tracgain]

Sure it's not only overheating?

I would understand overheating if it only happens after several passes. But completely cold and 7 to 14 minutes later it’s cutting out doesn’t seem right. If it is then what is causing my overheating?

 

[alelys]

So if you let it sit for a while. And try to use the same battery, it's still setting of a warning?
Is the low voltage cut off set correctly?

 

[Tracgain]

So if you let it sit for a while. And try to use the same battery, it's still setting of a warning?
Is the low voltage cut off set correctly?

If I shut it off and restart it, it takes off like a full charge but only lasts about 30 seconds. Even if I walk away for 20 minutes or so and really let it cool off I get the same thing. It is my understanding that with this esc I don’t have control over the low voltage cutoff setting.

 

[jondilly1974]

If I shut it off and restart it, it takes off like a full charge but only lasts about 30 seconds. Even if I walk away for 20 minutes or so and really let it cool off I get the same thing. It is my understanding that with this esc I don’t have control over the low voltage cutoff setting.

On the BLX100 you can disable LVC by putting it into NiMH mode, but you don’t want to do this without a proper lipo alarm and the understanding of when to stop running. You can run into danger very easily.

 

[West]

I have a arrma big rock and I just got it when I plug the battery in only the fans turn on does anyone know what is going on

 

[razorrc]

I would understand overheating if it only happens after several passes. But completely cold and 7 to 14 minutes later it’s cutting out doesn’t seem right. If it is then what is causing my overheating?

Grass, stuck bearings, too big tires, overgeared, lots of things...

 

[GraniteFox]

Quick way to check is to pull the power module off and spin the front and rear separate. If it all spins with no issue you are good. then check the bearings on the slipper If good then it has to be electronics or motor related.