Tamiya hilux high lift short runtime

[makinao]

My Hilux High Lift is only getting 10 minutes continuous on a fully charged 6800mah nimh battery. Is this normal? My CC02 GWagon averages 20 minutes with the same battery, and AFAIK the same motor. 

[urban warrior]

There are a few things to mention on this.

First. From the weight point of view, considering that a High Lift with PS body shell may weigh nearly twice a much as a CC02 with Lexan shell the ratio from 10 to 20 minutes seem logical ... but ...

Second. With my Traxxas TRX-4 Bronco I have far more than 20 minutes running time out of a 6.000mAh (!) battery (Turnigy 2S LiPo, stock electronics, no added brass). And the TRX may weight as much as a High Lift (estimated). Which leads me to ...

Third. What type of battery are you using (manufacturer)? Or how old is it? Are you sure that the 6.800mAh you stated are realistic? I mean, have you seen the input on your charger or is it just printed on the battery? Some manufacturers seem to get their specs on their batteries by rolling a dice ... I mean the "cheapos". and ...

Fourth. Is your drivetrain of the chassis running freely when no motor is installed? Several other mechanical "issues" can add some resistance in the drivetrain which leads to decreased runtime with batteries.

Just my two cents. Maybe the one or other member has some other ideas here.

Cheers

Martin

[makinao]

1 hour ago, urban warrior said:

Third. What type of battery are you using (manufacturer)? Or how old is it? Are you sure that the 6.800mAh you stated are realistic? I mean, have you seen the input on your charger or is it just printed on the battery? Some manufacturers seem to get their specs on their batteries by rolling a dice ... I mean the "cheapos". and ...

Fourth. Is your drivetrain of the chassis running freely when no motor is installed? Several other mechanical "issues" can add some resistance in the drivetrain which leads to decreased runtime with batteries.

[Mokei Kagaku]

If we consider that a battery has a lower than nominal capacity (in your case 6800mAh) with high discharge current, a rough estimate is that 5000mAh are available before the voltage drops too low for running. With a 10 minutes runtime, that would mean an average discharge current at about 30A, and average wattage of roughly 200W.  That's not a realistic average wattage for the High Lift (with its low gear ratios and original motor) even if you should run your High Lift very hard.

So most likely, either there is excessive drag in the drivetrain, the motor is defective (e.g. one burnt pole), the nominal (and thus actual) capacity of the battery is significantly lower than 6800mAh or the battery doesn't get fully charged. Unless the motor and/or any part of the drivetrain gets excessively hot, the short runtime is probably related to capacity or inadequate charging.