Ammeter not showing charge | Scotts Owners Club

This topic has 6 replies, 3 voices, and was last updated 6 years, 7 months ago by Adriangv.

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3rd July 2016 at 3:19 pm #4391

Adriangv
Participant

Hi Guys I have a wiring problem I hope you can help me with.
I recently bought a Birmingham Scott. I didn’t like the idea of riding a bike without a voltage regulator so I bought one and fitted it as per the instructions. My problem is that now the ammeter does not show charge, it shows discharge very well. When the headlamp is on it shows about 6 amps of discharge and when the ignition is on and the engine is not running it shows about 2 amps of discharge so I know I haven’t wired the ammeter backwards. I know the battery is charging otherwise I would have broken down on the A259 with a flat bat and my multimeter shows there is charge with the engine running.
Does anyone have any suggestions what I might be doing wrong?
Adrian Vandyk

3rd July 2016 at 3:25 pm #14669

BRIAN MARSHALL
Participant

Hi, does the bike have a Miller alternator or a Lucas MC45 dynamo ?

4th July 2016 at 8:56 am #14670

Adriangv
Participant

It’a a Miller alternator

4th July 2016 at 9:37 am #14671

BRIAN MARSHALL
Participant

Hi again,
It shouldn’t need a regulator with an alternator. Has it got a rectifier with heat sink fitted ?
Brian

5th July 2016 at 10:06 am #14672

Adriangv
Participant

My bike came as standard with just a selenium rectifier. The battery I guess, was meant to be the regulator. The problem for me with this system is if the bike is taken for a long run, then at best the battery will overcharge and at worst the battery may boil. This overcharging will shorten the life of a battery and spread acid fumes on to the paintwork. I am no electrician so I may be wrong but that is what I think happens. I have junked the selenium rectifier a design that has been about since the 1880’s and replaced it with 6v Alternator Regulator/ Rectifier, this comes wit a heatsink. This rectifies the current to DC and also regulates the current so that the battery does not overcharge.
I was just surprised that after fitting it, the ammeter ceased to work properly only showing discharge. The battery itself is charging fine which has me even more perplexed. I wondered if anyone has a solution.

5th July 2016 at 3:25 pm #14673

Tman
Participant

If you’re sure the wiring is still correct for the ammeter to work properly, then try swapping the ammeter leads over to see if it can be made to swing in the other (charge) direction.

6th July 2016 at 10:00 pm #14674

Adriangv
Participant

Thanks, I will try swapping the leads over.
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