I have noticed at very low speeds on almost flat batteries my mobility scooter seems to get a regular reverse pulse, abt every 0.5sec. I'm unsure what to make of it, unless it's some sort of speed regulation??? the machine is abt 12yo. The jerks are quite distinct and power wasting when I'm struggling to get home [due to now poor battery performance?] They're 5 mths old and fast dying, or so it appears. They just aren't big enough for my needs, so some surgery will be done to fit larger batts into the footwell, and so reduce the proportion of charge used on a normal journey. That will increase battery life dramatically. a normal journey uses 80% charge, and I need to at least halve that.

 

Does your scooter have a forward/reverse switch separate from the speed control, or is a single potentiometer (paddle/lever) used to control both speed and forward/reverse selection? If the latter, I seem to recall some controllers use a voltage comparator to sense the pot position and hence determine if forward or reverse is commanded. An error in the comparator output as a consequence of low battery voltage could result in misinterpretation of the command.

 

Does your scooter have a forward/reverse switch separate from the speed control, or is a single potentiometer (paddle/lever) used to control both speed and forward/reverse selection? If the latter, I seem to recall some controllers use a voltage comparator to sense the pot position and hence determine if forward or reverse is commanded. An error in the comparator output as a consequence of low battery voltage could result in misinterpretation of the command.

Pot and paddle, but you could be right. also there's occasional brief power losses, as if wear or poor contact in the wig-wag paddle.

 

If the pot is showing signs of wear, I'd consider replacing it.

 

If the pot is showing signs of wear, I'd consider replacing it.

I will do that, ebay says >=$40ea sounds ridiculously high for a pot.... Seller claims dual track 3 terminal pot with 75mm shaft. need my glasses to read what's on the back of it. I doubt element14/Farnell would be that expensive.

 

Product ID is : rvq24ys08 b502 $17 in Taiwan with free shipping. a 5K pot.