Revs are up - output voltage is up or down?

Motorcycling
1

so on idle output voltage is steady at 14.5 when reving to 5k rpm should voltage go up or down?

2

It should go up I believe

3

hmm mine goes down:

idle: 14.5
5k rpm: 13.6

I measured output from the battery terminals… need to check that the ouput is correct but haynes only mentiones range it should be in… not if voltage goes up or down

4

Being a Honda I’d look at getting a new reg rec

5

guy on hornets nest gets the same with a new reg/rec :ermm:

6

Volts across the battery go up with revs and the regulator’s job is to level them out at about 14.5v so that high revs doesn’t boil the battery.

Exactly what revs is right for idling etc depends on the bike, but as a rule if volts fall with revs it means there is a generator or battery fault as high revs needs loads of electricity for the hundreds of sparks a second at 5000+ revs and either the bike isn’t generating enough electricity to support this, or the battery is faulty and is stopping the electricity flowing through properly. Bulbs may dim.

If volts rise with revs above 14.5v then the regulator is faulty, and the battery has probably been damaged by heat. Bulbs may also blow.

If revs start at battery voltage (usually between 12 and 13.5v) then fall below battery voltage with the engine running, the rectifier is toast and the AC from the generator isn’t being converted to DC. This will drain a battery flat very quickly.

7

Thanks G. :ermm: the volt at 5k is within normal - what haynes says- and i havebt had any probs,its just im not sure if the voltage is dropping should i worry?

8

I was going to say, Is there need to worry? Whats happened for you to check the volts?

I believe the volts will stabalise but may briefly go up or down and around, if you know what I mea.

9

13.6v is not enough to charge the battery properly. 14.2v to 14.5v is optimum for most lead acid batteries which is why the regulator is set to that voltage. It probably won’t go flat with 13.6v being pushed through the battery, but it won’t charge it much either.

The next step is probably to test the output from the generator rather than the volts across the battery.