Battery voltage help

[Geodude]

Reg rec is new Tour Max 717835 best i could afford at mo red wire at battery and live wire at reg rec check done with no difference.

After cleaning all the contacts i could physically find on the entire bike i now have
Engine at idle with lights on 13.70v
Engine rev at 5k with lights on 13.02v
Doesn't seem to go any lower than 12.99v and yoyo's between that and 13.02v @ 5k
Dont know if it makes a difference but rev@5k with lights off puts it up to 14v plus quite easily
So i will have a ride around tomorrow see what happens

[Geodude]

Ignition off battery 12.7
Idle lights on +14v
Rev 5k lights on 12.90 - 13.02v
Ride 10 miles with lights on check battery with engine off 12.90v
Ride ten miles back with lights on check battery with engine off 13.00v
Still drops when rev @ 5k with lights on but takes charge when idle?

Am i just getting hung up on the whole voltage thing?

[mikerj]

Originally Posted by yorkie_chris

The readings look correct, but that's the "rectifier" part of the system. Since you don't have loads of AC frying your bike, or any burnt alternator coils, that's probably not the problem.

The other part of the reg rec is the crap bit, the regulator, it's old school tech which just dumps excess charge as heat, and is fragile. If you get a good new un they use MOSFET power transistors which switch the supply on and off, runs much cooler.

Note that the MOSFET regulators fundamentally work in exactly the same way as the old SCR based ones, i.e. they are shunt regulators. They run cooler because the MOSFETs have a lower voltage drop, even though the same amount of current is being pushed through them. It just means the stator will now get a bit warmer instead.

[Geodude]

Right todays adventure may have sorted it but also showed how daft i maybe at the same time..

Ignition off battery 12.7
Idle lights on +14v
Rev 5k lights on 13.8 to 14v

This was achieved by running a wire from the black wire on reg/rec to the -ve on the battery so it looks like it was a bad earth or wire somewhere Is it safe to keep this wire permanently attached now as it seems to work?

[yorkie_chris]

Yeah just make it neat, do same to +ve, wires from reg-rec to ring terminals on battery. Good idea to put a fuse on +ve.

[Geodude]

Will do yc. Cheers for all the guidance

Geo, resurrecting your thread here, did you splice the wire into the black on the reg/rec or somehow fit it into the connector, also which black as there is two, also 2 positives? I seem to have the same sort of issue reading through your thread, all voltages seem OK except when revved it drops to just below 13v.

I have a new battery and 18 months old reg/rec

[Geodude]

Sorry was away from pc. I spiiced into -ve wire direct from reg/rec then ring connector on other end of wire on to -ve on battery. Before you do any of that though do a loose fit with a bit of wire to see if it makes any difference first. Poke the wire into black on regrec connector then onto battery neg and do rev test to see if it works before you make a 'proper' connection. Just seems to give a better earth? HTH

Would do that anyway, will give it a go.

What size fuse did u use on the +ve?

[Geodude]

Just did the wire trick on my brothers sv the other day as his battery was going flat when riding and its fixed his voltages/charging so fingers crossed Davey. I cracked his seat fairing though when taking it off ssshh dont think hes seen it yet