Charging system underperforming at idle.

[Dave20046]

I know there's a lot of threads on charging systems, I've looked through a load but can't find anything similar to this.

I have a second generation sv650s with a datatool system 3 alarm and hotgrips fitted (but not on during testing) and led indicators (not on while testing voltage)

Aware there's a problem with my power as tail light and headlight flicker a lot and are dim on tick over (very obvious when parked next to other SVs) and both get a lot brighter and stabilise when I rev. Hot grips also turn off after sat at the lights for a minute or so.

A couple of days ago I went to check the readings after not using the bike since the 6th of december (not on trickle and yes I was being a puff in the car)
standing battery 12.4v
5k revs ~14.5v (forgot to get tick over readings )

Today after being on charge :
standing battery 12.9v
idle 14.6v
...
after a few mins I rev'd it to 5k and it was only reading 14.5v
...
then when it dropped to idle it was reading 12.6v
after another few minutes idle settled at 12.4v and didn't go down any further.

Could anyone clever give me their thoughts?

I can't see it being the infamous reg/rec or alternator for that matter as the output is good when revved (14.5v is better than I ever got on my curvy and that had no alarm and a brand new r/r, and it all worked fine)

Battery - I'm not sure, not clued up on how they behave when they're old/have a dead cell. It's possibly the original battery - the terminals are clean.

I'm starting to worry it's drain from the alarm or a crap connection but wouldn't know where to go from there... Although if it was alarm drain, loads of other people would have the same issue and in theory the system should be able to handle it.

Would appreciate some help - ta.

[yorkie_chris]

Check the voltage across the wires from RR to battery. Maybe you have a high resistance.

[Dave20046]

cheers...is it dc across there?

[yorkie_chris]

Yes DC, if there is loss it will be a volt or so not much

[Dave20046]

just gotta work out how to get to the poointy rigrac now - think it's a tank up job

[Dave20046]

how awkward.

Anyway, afraid my multimeter didn't come with instructions. But hoping I was on the right mode. Negative measure 0.2v and positive measures 2v/1.9v (flicked between them but near enough 2.0v)

There were four pins coming away from the regrec 2 negative 2 positive I just put the m.m between one positive pin and the positive battery terminal and vice versa.

[yorkie_chris]

Did you disconnect it while you did this? It should be a test while it is in use.

2V sounds like a big voltage drop but if that was disconnected then it would make sense.

[Dave20046]

Erm I left everything connected bar the 4 pin output from the reg rec, I then measured between the pins on the reg/rec's side and the battery terminals.

Did you mean bare a bit of the wire and leave it connected or something?

[Dave20046]

...ahh I now see why there wouldn't me much voltage between the battery and the pins when disconnected doh

[yorkie_chris]

Put the pin of multimeter in the back of the connector with it still connected, put the other one on the battery terminal. That will tell you if there is a difference in potential across the wire. I.E a voltage drop indicating a high resistance