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Mobilty scooter power chair will not move.

Mobility Elite scooter power chair will not power the motors with the control knobs. No sound, nothing. The chairs will go up and down via a second control knob that is not connected to the electronic control unit. Switching the power on will show the LED power meter blinking (not sure what that means.) Charged for 4 hours, the power meter level is at orange, between red and green. Both 12V batteries read 11.9V with the meter indicator at orange.

The control unit is insulated inside what appears to be a heavy duty cast iron housing. Looking around for the model number I find only "Made in England." If this may help, see a glimpse of this $2000 similar scooter here.

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What part of the circuit is best place to start looking for the problem?

Thanks

Reply to
B Squareman
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Could be the battery itself or the charger or both, or even the controller (check out the first two before suspecting the controller). You need to have it checked by a competent repair tech if you are unable to carry out the necessary testing yourself.

Reply to
Ross Herbert

"B Squareman" wrote in news:xzSQe.451$ snipped-for-privacy@newssvr24.news.prodigy.net:

11.9V is too low for charged Lead-acid batteries.It should be around 13.6V. Have you tried a different set of batteries? Any idea of the age of the original batteries? They could be sulfated and will not accept a charge.And they need to be load-tested,their voltage could drop under load.

--
Jim Yanik
jyanik
at
kua.net
Reply to
Jim Yanik

The mobility's deep cycle batteries (two) are probably 5-7 years old. I tried adding one 12.5V car battery. The motor takes 24V. When powering the chair lifters (5-6-amp motor) consecutively for 10 seconds the voltage would drop from 12.5V to 12.4V and stay there. The original battery will drop from 11.9V to 11.8V and stay there until switched off. If this is a reliable battery test, the control unit LED is still blinking. If I had a manual I'd like to know what the blinking indicates. The circuit board used to control the wheel is as complex as an automobile main computer.

If the circuit board wants 12 or 24V and hundreds of amps, it has got it but still refuses to engage the wheels.

Reply to
B Squareman

On Wed, 31 Aug 2005 09:44:31 GMT, "B Squareman" put finger to keyboard and composed:

It probably won't help, but could you post a photo on your web space?

I'd still be blaming the batteries. Otherwise, the typical fault in these types of devices is shorted MOSFETs in the H-bridge(s) that drive(s) the motor(s). If your scooter has two drive wheels, then I would expect to find two sets of four MOSFETs on a heatsink. It would be unusual for both circuits to be faulty, however.

One other remote possibility could be that the charging socket is open, leading the scooter's microprocessor to believe that the scooter is being charged, in which case it will refuse to move.

- Franc Zabkar

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Please remove one 's' from my address when replying by email.
Reply to
Franc Zabkar

Probably getting to the point of needing replacing ...

All sorts of things ...

  • Throttle not in neutral (i.e. the thing will drive off on its own) Could be caused by a duff/erratic throttle pot. Or a wiring problem.

  • Low battery voltage detected

  • Electromechanical stop-brake won't come on/won't come off (both have serious implications!)

  • Motor fault (short/open).

  • Internal fault in the H-bridge (MOSFETS) that do the driving/PWM control.

  • Chair-lift/lower sensor, if any, isn't indicating that the chair is safely locked.

  • Controller *thinks* that you are charging the unit -- it won't drive off if you are charging!

You need the model number and manufacturer's name of the speed controller block. They can be a PITA when they decide they don't want to play. The blink codes aren't standard across every controller. Is it just a flashing LED or is there a pattern of long-short flashes that are repeated?

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--------------------------------------+------------------------------------
Mike Brown: mjb[at]pootle.demon.co.uk | http://www.pootle.demon.co.uk/
Reply to
Mike

"Franc Zabkar" wrote

Good idea, here it is.

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I found 11 transistors on the heatsink. I got the power chair working. Thanks.

Reply to
Burt Squareman

Thanks, it turned out to be loose connections. I disconnected the motors harness and find no resistance (* Motor fault (short/open.) I found resistance from the motors but no resistance from the control unit. Further investigation with a special wrench I found four loose connections. Shown on this webspace.

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The LEDs had no blinking pattern but actually had indicated a code. The code is the number of LED(s). The battery seems to be ok (since it shows 9-leds) after driving it around for 30 minutes straight.

Thanks.:~)

Reply to
Burt Squareman

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