matthewh

i have a losi xcelorin esc with a 7400kv motor...i thought up a idea i wanted to try but am uncertain about it..so...in the manual it says that the brushless system will hold up to "2-3 cell lipo or 4-12 cell nimh". what would happen if i took 2 fully charged 6 cells,7.2, sub c, 1400mah, batteries made them into a 12cell 7.2v battey pack....? below is a pic of the batteries i will be using...(they are for a propulse 4-2 setup...)

geeunit1014

iTrader: (14)

depending on how you wire the pack, it will either go crazy fast or last for a long time. if you wire them in series it will make a 14.4v 1400 mah pack. if you wire in parallel it will make a 7.2v 2800 mah pack.

series wiring is connecting the positive of the 1st pack and connecting it to the negative of the second pack, and using the negative of the 1st pack and the positive of the second to the connector.

parallel is connecting the (+) and the (-) of both packs together, and then the connector

matthewh

i first wired them to gether as parrallel not knowing the outcome...i only ran it for 2 min. then had to do something...when i got home to day i learned about series....would it be safe for the esc and motor? i don't want to burn up my 109$ investment......

geeunit1014

iTrader: (14)

If the manual says its okay then do it. I suspect the esc will be fine, I would keep an eye on the motor temp. though. high kv motors like yours and high voltage can wear on the motor faster. just keep an eye on your temp and you should be fine, dont let it get above 180*F or so should keep you running strong. You might want to go down a couple teeth on the pinion gear to be safe at first

pinoyboy

iTrader: (2)

http://www.youtube.com/watch?v=Wphcm8Xx_bs
I ran 4S(14.8v) on the 9400Kv and it's fine. Just keep run times and full throttle runs low with breaks.

This motor should be fine though as I've ran a mamba 8000Kv on 4s petty hard.

rschoi_75

iTrader: (30)

You should disable the internal bec on the losi system since its only rated for 3s. Use an external one or a small rx pack. It will prevent your esc from burning up.

matthewh

so there i was ....before i got the previous 2 messages....i went a head and hooked up the 2 batteries in series...making a 14.4v and pulled the trigger...it wound out so fast ....i was amazed and excited...30 seconds later...it stoped...no response.??? i turned it off checked for heat...nothing.
i turned it back on and still no response.... about then smoke started dumping out of the esc...the little fets on the esc...are now crispy...black and burnt....$109.99 gone just like that.....

so tonight i ordered the 9400kv esc combo...i think this time i will just buy a lipo....i want the speed to be around 40-50...i have now a 1500mah 7.2, 15/55 gears, and now the 9400 on the way...any more suggestions....to help me get to where i want to be?....thanx

pinoyboy

iTrader: (2)

That stinks. Get a 3s lipo(11.1V). You'll probably get the same amount of speed as those 2 nimh battery packs in series since you'll be carrying a lot less weight.

rschoi_75

iTrader: (30)

well.... that's why you need to disable the internal bec. I've burnt up old mamba's before doing the same thing. lesson learned I guess.

As for your new set up, it should be able to hit the speeds you want with no problems. It will probably be faster than 50mph with 15/55 gearing. You'll need to watch your motor though because its going to get real hot with that gearing. Your motor will probably be a lot happier on 12/60 (or something near that ratio).