Regulator/Rectifier?

[Biker Biggles]

Been having a bit of battery trouble for the last couple of weeks with the bike sluggish to start,and the lights getting brighter as I rev the engine.I expected it to be a shagged battery,as it is seven years old,but I dug out the multimeter and checked a few things anyway.And the winner is-------

Reading across battery terminals engine off and cold--13.3 V
Reading across battery terminals at idle--15.5 V
Reading across battery terminals at 5000 RPM lights on--19.8 V
Battery noticeably warm after five minutes.
Readings across alternator output wires all at around 85 V

Now 19 volts isn't vastly higher than the 15 odd in the spec,but it suggests to me the regulator is up the spout rather than the old battery.I tried the same test with a spare battery from an R1 in the bike and still got 19 volts at 5000 rpm so anyone got a reg/rec for a curvy going spare?One that works please.

Before getting "gung-ho" and replacing the reg/rect, make sure your generator is kicking out the required voltage too. Note that this will be AC naturally.

18-19v doesn't sound that wrong to me. Are you getting any specific things going wrong (like flat battery every so often)?

Mines a K6, and my lights get brighter when I rev the bike. Quite noticably too at night.

EDIT: Scratch what I wrote, you've tested the generator (alternator) output. 85V sounds a little low, but nothing major (I think I remember around 90V AC).

Nothing there sounds really wrong to me.

[Biker Biggles]

I'll do the same test on my son's SV when he's around and check that 19 V figure against what his puts out.I think it's too high,and the battery was quite warm after five minutes with the engine running.A sign of overcharging I thought?

To my knolwedge, the output on the battery side of the reg/rect should be around 18v.

Limited knowledge though, but I think that's what I got. I'll try searching for my old post that has the voltages for almost everything under the sun on my K6.

EDIT: how typical is that... it's now 404'd after the move to the new software on the org.

19Volts sounds way too high, you also run the risk of popping lamps etc because of the higher voltage. (Remember there supposed to be 12V items with a certain degree of tolerance. 19 Volts is is asking for a 58% tolerance). Meter reading really shouldn't be more than 15Vdc, maybe 16 if your meter's a bit wonky.

It does sound like the regulator, and no I don't have one!

Good Luck!

[Biker Biggles]

That's what I thought.I checked the output on a ZX9R and it was about 14 V at 5000 RPM.
Doing a search,it seems you can fit a Honda reg/rec but you have to rewire it a bit.Anyone know what this entails and would a Blackbird one do the trick?

Sorry mate, a bit too specific for my knowledge!!!

[Sid Squid]

19V! Way, way too much, as said above, any more than 15V on an averagely accurate meter is too high. It's unlikely to pop bulbs, but it will boil your battery - which is likely goosed by the gross overcharging it's been receiving.

Search my posts on charging system checks - plenty of them here.

Blackbird reg/rec will be fine, some wiring tweaks will be needed with reg/recs from most other bikes, but they're simple changes.

Blew up an NC30 battery at 17.5......


mmmm Sulphur

Originally Posted by Sid Squid

19V! Way, way too much, as said above, any more than 15V on an averagely accurate meter is too high. It's unlikely to pop bulbs, but it will boil your battery - which is likely goosed by the gross overcharging it's been receiving.

Search my posts on charging system checks - plenty of them here.

Blackbird reg/rec will be fine, some wiring tweaks will be needed with reg/recs from most other bikes, but they're simple changes.

There ya go, definitive answer

I really can't remember what I got when playing with a DMM on my bike, and my original post (now lost forever - must get around to playing again) probably reflected the comments of others in this thread.

Sid, I was wondering what reg/rect's would fit, but didn't like to comment as it's a curvy. I know a couple that fit pointies, but again, need minor tweaks.