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Re: Batteries

On Monday, October 10, 2016 at 11:06:50 AM UTC-4, Phil Hobbs wrote:-

> > Torque is proportional to current, no? > - > Yep. But a DC motor dead-stopped is a short circuit. And even a very > nearly crapped-out battery may have enough to blow a fuse if > dead-shorted. Fuse action is not voltage dependent (as long as the fuse > is rated at a higher voltage than the application). > > Peter Wieck > Melrose Park, PA

Hi...i am a new user here. As per my knowledge the bad batteries caused the electronic controller to draw too much current in an attempt to maintain speed.That's just a guess, though. It is hard disagnose something with no information.

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AlfySande
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AlfySande
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I think you left out a step:

a) The batteries ran low. b) The user kept 'upping' control to maintain speed. c) As long as the motor is turning, things are (mostly) OK. d) The motor (brush-type) stops dead, but the speed control is still on MAX. e) Now the full - remaining - battery capacity is going through the fuse. f) *POOF*

But, the batteries are sulphated, the speed controller has been overheated, the motor overheated - or at least those commutator contacts arced. Altogether a mess.

Any properly designed system would have a condition meter and a low-battery cut-off to prevent this. And a thermal breaker in addition to the fuse.

Peter Wieck Melrose Park, PA

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pfjw

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