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Ni-Cd Vs. Li-Po

1K views 4 replies 4 participants last post by  crusey_aus 
#1 ·
Hello Everyone,
As you can probably guess I’m a newbie to this thing so please be kind. The problem I have is that I replaced a 7.2V 1800 mAh Ni-Cd with a 7.4 V 2 cell 5000mAh Li-Po Battery in my son’s NQD px -16 Storm to try and improve the longevity and performance of the boat. This had a subsequently fantastic effect on both. Unfortunately the left hand side (390 type) motor burnt out. They use two motors for steering.
1/. Can someone please explain why this happened if the voltages are more or less the same????
2/. Moreover, could someone please recommend an exchange motor (as cheap as possible) that might be able to handle the setup??? It has a 15 amp dual esc built onto the circuit board/ receiver.

Many thanks.
 
#2 ·
I don't really know much about boats but I am gonna throw a couple of ideas out.

1800mah NiCd vs 5000mah LiPo...
The 5000mah LiPo would last much longer than a 1800mah NiCd and so it would have a lot more time to heat up.
The solution here would be to either gear it down or put a bigger motor in.

If it has water cooling (I doubt it), could be blocked up and letting the motor overheat?

Brushes on the motor worn out?


There are a few boating fellas on here who might be able to help you out.
 
#4 ·
Now lets see
5000 lip is it 7.4 volt how many c discharge rate does it have
a nicad battery can only throw out so much power at any one time it cant force any more out like a 4 cylinder car
a lipo battery of 25 to 35 c can discharge a lot quicker therefore pushing more power to your model like a v8
keep in mind dont use a 11.1 volt on a 7.2 system it will blow up
lots of differences in batteries these days
 
#5 · (Edited)
To run lipos safely you need an ESC that is lipo capable

I would guess that the added weight of the larger pack put strain on the motor and caused it to fail

Should be plenty of motor replacement options, best bet would probably be an upgrade esc / motor combo

Cheers
 
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