New Brushless System ?'s

[giftacrylic]

Recently installed 9920/7XL into E-maxx w/ UBEC, geared 18/66.

What are some runtimes should I expect?

Also, my GP 3300's are measuring at 130 degrees. What are safe temps for the batts, controller and 9920?


P.S. - Love the system, thanks for all of your posts that helped me decide.

[starscream]

How many cells are you running with that gearing?

[giftacrylic]

As of now, 12-14 cells

[starscream]

With that gearing and 14 cells you will be looking at around 10 minute racing run times and 20+ minute bashing.

130F sounds hot for the GP's,
The motor should not exceed 180F
I'm not positive about the controller temps but I wouldn't go much above 120F

[coolhandcountry]

I think it is about 160 f for the esc. The cooler the better though.

[giftacrylic]

But why would the batts get hot? They have only been used about 10-12 runs.

The motor temp is 135 and controller at 95. Both have fans on them.

Could it be binding in the drivetrain?

[coolhandcountry]

The faster the discharge the hotter the batteries get. The 7xl will take some power. I had warm running batteries as well with the 7xl. Have you figured the run time. I didn't get a great deal with mine. Every one is different.

[MetalMan]

The controller can take about 180 deg. The batteries should be okay for up to 150 deg.

[giftacrylic]

Have not timed the runs, but seem to be about 8-10 minutes of WOT. I stopped early on the last 2 runs because the batts were hot. I tested them and they had plenty of voltage to keep running.

[Serum]

You used a tempgun to measure the temp? your hands feel like burning at 50 degree C allready..

[giftacrylic]

New system = extra cautious. Tempgun is good insurance, not wanting to fry anything the first few days...

[Serum]

i just thought you might find it interesting and valuable knowledge that 50 degree celsius allready feels like burning....

[giftacrylic]

Thanks, now I know.....if 130F is too hot for batts?

[Serum]

130F is pretty much the limit for nimh's.

[giftacrylic]

Any causes/preventions? Or, should I change batts more often?