Getting a merv soon and need to know if two stock batteries on series with 23 tooth pinion running on gravel and grass would be a problem?
yes, series is a really bad idea running any gearing unless you are planning on upgrading the esc
I agree with Jimbo,
The stock ESC cannot handle that voltage for very long.
"grass" is a pretty general term. The merv can run well on very short & sparse grass. If it's "dense" and even a little bit long the merv will be slowed too much from the grass and will heat up the motor/esc.