Weird charging problems

[psyguy]

educate me further please

with the sense wire connected directly to the batt positive:

tested at 2000rpm (charging measured at the battery):
- headlight OFF = 14.30V
- headlight ON = 14.15V



the previous reading with the sense wire on the main switched positive (this spot has 0.7V drop compared to the battery):

tested at 2000rpm (charging measured at the battery):
- headlight OFF = 14.8V
- headlight ON = voltage jumps to 15.6V

so, what should i take from this all??

.

[posplayr]

This is really good advice. While ShirazDrum was here we tested the brake light switch on my bike that the RR sense wire was hooked to and it was about 9v. Not good. That tells the RR to keep charging the battery even if not needed (due to voltage drop over the years on old wire)....will cook your battery

Shiraz suggested wiring RR sense wire directly to battery positive in my case (which effectively "by-passes" sense wire). I will probably wire sense wire into my 'hot to coil' wire from relay after the coil mod as it tested out at 11.9v.

Does this make any sense to you?

That is essentially what I described

Support ShirazDrum if you can

BTW, here we are - well me not in photo taking it and ShirazDrum (Chris Sorbi) in my garage wrenching on our bikes night before last. Please support this guy doing a brave thing for a great cause.

c.) Connect the R/R sense point to a power relay (output) like the coil mod relay is best; if you dont have or want to do that then connect to the oil light switch

This is really good advice. While ShirazDrum was here we tested the brake light switch on my bike that the RR sense wire was hooked to and it was about 9v. Not good. That tells the RR to keep charging the battery even if not needed (due to voltage drop over the years on old wire)....will cook your battery

Shiraz suggested wiring RR sense wire directly to battery positive in my case (which effectively "by-passes" sense wire). I will probably wire sense wire into my 'hot to coil' wire from relay after the coil mod as it tested out at 11.9v.

Does this make any sense to you?

[posplayr]

thanks guys for educating me on this issue.
you understand that after chasing my tail for a long time and spending considerable money i don't want to fry anything

i'll try the following first:

there is not much danger as the worst that could happen is you leave the sense wire disconnected and the R/R provides no regulation so charging voltages go to 17V at high RPM.

Do the test in the garage and sort before doing any road trips.

[psyguy]

thanks guys for educating me on this issue.
you understand that after chasing my tail for a long time and spending considerable money i don't want to fry anything

i'll try the following first:

Yes I agree, just try that sense wire temporary directly to the battery and check the voltage. If it comes down it confirms what Jim has said and you will confirm that your R/R is still healthy as well.

Yes I agree, just try that sense wire temporary directly to the battery and check the voltage. If it comes down it confirms what Jim has said and you will confirm that your R/R is still healthy as well.

[posplayr]

After he drives around for a while maybe the charging voltage will come down a bit. He also might want to look at losses in the various switches and connections.

tested at 2000rpm (charging measured at the battery):
- headlight OFF = 14.8V
- headlight ON = voltage jumped to 15.6V, then after a few seconds the 10A in-line fuse on the RR+ wire burnt out.

Ok I see now he is using a Honda 6 wire regulator and the charging voltage is going up with the light on.

Might I offer a theory as to what is going on?

The voltage sense point is being loaded by the current going to the lights. That cause teh sense point to drop due to resistance between the R/R (+) and that sense point. The R/R increase it's output voltage to compensate.

My new recommendation is to

a.) Hook the R/R sense directly to the battery to confirm the light operation does not affect the charging voltages 14.8.

b.) See if the contacts cant be improved so that voltage drops between R/R and battery are lower.

c.) Connect the R/R sense point to a power relay (output) like the coil mod relay is best; if you dont have or want to do that then connect to the oil light switch

This should get you back to 14.5V nominal and you wont have to do the science experiment I previously described.

[duaneage]

After he drives around for a while maybe the charging voltage will come down a bit. He also might want to look at losses in the various switches and connections.

[posplayr]

The R/R is going to charge it at whatever the stator is putting out, minus what the bike is not using, there is no real regulation on just how much current goes to the battery.
.

I agree there is no specific or active current control. However the R/R voltage setpoint will control the amount of charging current to the extent that a higher setpoint will produce a higher charging current than a lower voltage setpoint. (i.e. 15.5V will have a higher/faster charging current than 14.0V ). For the same stator output at 14.0V the R/R is shorting more current back to the stator so less is going to the battery than what woudl happen at 15.5V.

So my suggestion was really to look at the charging current in comparision to the battery capacity to determine if the 15.5V was really too high. If at 5000 RPM the battery continues to receive C/5 or 2.6amps for a 13 amp-hr battery it will probably cook the battery and reduce it's life.

I was offering a way to evaluate the significance of the 15.5V charging voltage using steady state charging current as a guide (C/10 being closer to the desired level).

If you were to regulate that to C/10, you would have a very hard time keeping the battery charged if you only did short rides in town. The battery would never get charged.

.

As mentioned above, not advocating constant current charging at C/10 (there is no means of doing that short of designing a new R/R), but rather looking at the steady state charging of a fully charged battery being not much more than C/10. If you exceed that significantly the battery will just get hot and boil. If C/10 is being exceeded I would suggest getting an R/R that regulates closer to 14.5V which is the nominal set point of most of the later model FET based R/R's.

Acutally my first recommendation would be to just replace the R/R has Psyguys' seems to be regulating too high (assuming all his connections and everything else is good). But if he wants to determine if 15.5V charging is really ok the above will help to answer that question.

[Steve]

IIRC charging should be about C/10 so 30 amp-hour battery should charge at 3 amps (help me out here Matchless).

For long-term charging, it's best to maintain that C/10 rate ("C" is the capacity of the battery in amp-hours), but the fact of the matter is that, after starting the bike, the battery is more than just slightly discharged. The R/R is going to charge it at whatever the stator is putting out, minus what the bike is not using, there is no real regulation on just how much current goes to the battery. That is why, on the earlier bikes that had operating headlight switches, the third leg of the stator was switched off when the headlight was turned off. If you were to regulate that to C/10, you would have a very hard time keeping the battery charged if you only did short rides in town. The battery would never get charged.

By the way, most of our batteries are 12- or 14 amp-hour batteries.
A 30 amp-hour battery is just a bit larger than a garden tractor battery.

.

[posplayr]

The Suzuki manual gives 15.5V as the maximum voltage. Yours is a bit on the high side, if your meter is 100% correct, but not a real train smash if everything else is correct, wiring, voltage drops etc. You will just need to check the battery water slightly more regularly.

Well congrats looks like your charging system is now keeping up with the load and then some.


I know the Suzuki manual says 15.5v and it is probably because of the poor regulation and tolerances that that is all they could achieve, not that it is a good idea to cook the battery at 15.5v . The early OEM SCR R/R just don't do a good job of regulation.

Psyguy: What R/R are you using? And as a quick double check what are your regulator voltage drops after the stator install (same low less than 0.2v at 5000 rpm?).

Just so we understand; you are using a clamp on style amp meter or one is series? Depending upon your harness you should be able to measure charging current to the battery by clamping the red wire to the battery only (this is typically less than 2-3 amps). IIRC charging should be about C/10 so 30 amp-hour battery should charge at 3 amps (help me out here Matchless).

Also clamping at the red wire directly off the R/R you should see 8-10 amps.

The point of all this is that a Honda or a later model FET regulator should be regulating much better ; What R/R are you using now?

[duaneage]

Use a 15 amp fuse, 10 is too small.

yes, that's what i meant. i'll fit a 20A fuse. thanks

but, is the 15.6V all right?

The Suzuki manual gives 15.5V as the maximum voltage. Yours is a bit on the high side, if your meter is 100% correct, but not a real train smash if everything else is correct, wiring, voltage drops etc. You will just need to check the battery water slightly more regularly.

I think, try riding it with lights on, check the voltages and feel the R/R for excessive heat and see if it goes higher or stabilises a bit lower. Also do a test with your sensing wire directly to the battery if you have one.

[psyguy]

Psyguy,
Do you mean the seperate inline fuse you fitted and carries all the current from the Regulator directly to the battery?

yes, that's what i meant. i'll fit a 20A fuse. thanks

but, is the 15.6V all right?