Temperatures....

Sorry guy's this might be a bit noobie but...

What are the apsolute max temperatures for motor, Esc and Batteries?

What are the optimum temperatures for each of those components as well?

I'm running a MMM combo (2650kV) and just wondering what kind of temps i should be seeing? so far the max i have seen on it is 40°C on the motor and 35 on esc, batteries never get above ambient...

I know the mmm fan comes on a 65°C, but is that too late?

[suicideneil]

Motor = 180*F, ideally stable at about 130-150*F. It it just keeps climbing during a run then the gearing may be a bit off or load is too much for prolonged use.

ESC = hard to say, but roughly the same as the motor really. I like the esc to stay below about 120-130*F as do alot of other guys. If the fan comes on briefly near the end of a run thats fine, but if it comes on early into the run and stays on, you know its being overworked.

Lipos = I've always believed 120*F was the safe max temp for lipos, but drag racers will tell you that you need to warm them up to get the most current from them. This is true, but just how much to pre-warm them is another question- you shouldnt use them if they are stone cold though as they may struggle to output current until they warm up through use; you can puff a lipo by running it too hard when its been stored somewhere cold like in a garage over winter or a cold night. Store them in doors and warm them to about 90-100*F before running them.

[nativepaul]

They maximums are all different from manufacturer to manufacturer but in general getting a motor above 80degC electronics above 70degC and batteries above 60degC puts them in serious danger of damage or at least reducing their life.

As for optimum temps motors and ESCs would work best at about -10degC the cooler the better but you don't want to freeze the electrolyte in the caps or make anything too brittle and I know epoxy goes brittle in my domestic freezer at -19degC,
batteries are a different kettle of fish, NiCads and NiMh are best used warm of the charger at about 40degC and LiPos are weird giving there best at about 60degC their maximum allowable temperature so it depends on how they get to that temperature, if they start off at an ambient temperature of say 20degC and reach 60degC from the work they do then that is too hot, but if you preheat them to 60degC and they are still the same temp after running that is ideal and you will be getting the highest voltage from your cells that you can get throughout the run Also while no battery likes being used cold LiPos especially don't like it and using a cold LiPo at high current in winter can puff cells before they warm up in use whereas during the summer your more likely to puff on at the end of the run when the've given as much as they can and are getting too hot.