Flat battery - why?

[psyguy]

ok, thanks, will check the headlight circuit next

[posplayr]

• connected the rr sense wire directly to the batt +. that made NO difference to the charging readings.
• measured rr positive lead voltage drop : 0.13V
• measured rr negative lead voltage drop : 0.10V

Were these voltages at 5000 RPM? If it is they are very good. If not you have not tested at load.

Is your voltage dropping as you previously indicated?

You need to setup the fault condition so we can monitor the voltage in that condition to see what the source of the problem is.

JC actually at this point it would be best to not upset what is causing the problem (what ever it is) so the source can be identified. Psyguy you need to get to the state where you are seeing 13 volts a RPM and check the voltages. Knowing the battery voltage and those R/R drops really tell you everything you need to know about the charging system.

[psyguy]

Were these voltages at 5000 RPM? If it is they are very good. If not you have not tested at load.

Is your voltage dropping as you previously indicated?

yes, tested at 5000rpm. all the connectors are NEW on all the rr leads so i thought the readings should be good.

with the headlight ON (and only then), yes, there is a continuous voltage drop at the battery, to under 13V in a few secconds (and it continues dropping further. with the headlight OFF charging is at 14.8V and stable.

Psyguy you need to get to the state where you are seeing 13 volts a RPM and check the voltages. Knowing the battery voltage and those R/R drops really tell you everything you need to know about the charging system.

i don't understand what you mean here

the battery voltage is 13.4V

[posplayr]

Sorry to not be clear, when you say "no change" you mean the discharge continues with lights on at 5000 RPM (I guess?).

Well if with lights on you are getting the voltage to drop as you say, and you previously checked the stator at 80 VAC, then it seems to indicate that your load is more than the R/R can supply.

Did you swap higher power bulbs in the headlights or add other accessories. If not maybe you have a short some where.

You can check for a short easily by turning off all systems and then remove the positive side of the battery. In a dim light tap it lightly against the positive terminal. If there is a short, you will see little sparkly sparks. You could use an amp meter is you have one, but its sounds like it is a 2-5 amps of shorting current if you did not add any other loads.

If no shorts then perhaps a new FHA012A with higher power rating would be in order. Alternately if you have an old R/R swap it back in to see if the problem still exists. Could be a bad Honda unit???

[psyguy]

thanks guys, i'll do both tests, the headlight circuit voltage drop and the battery + lead sparky thingy (for a lack of a proper term, lol).

btw, no extra load on the system, just a standard H4 bulb 55/60W

[KiwiGS]

Psyguy, I would start with GS110GK's tests they are quick, simple and eliminate a potential problem area.
If the lighting circuit is not the problem then you can get into the charging circuit.
Sometimes with electrics the KISS method is the best.
Its not "rocket surgery" but it's close.
Cheers

[posplayr]

The fact that the battery voltage was dropping and your cable drops are low, directly indicates the charging system is running out of capacity. This could be excess loads or a short.

btw, no extra load on the system, just a standard H4 bulb 55/60W

Since you have a standard configuration, then either the R/R has given up the ghost or you have a short adding to the load.

If you had an amp meter you could confirm, but the sparky test will be a good confirmation.


The fact that you had a

[psyguy]

If you had an amp meter you could confirm, but the sparky test will be a good confirmation.

did the first test:
no sparks in the dark from the + lead to the + batt terminal.
posplayr, i think i may have a suitable amp meter (V / Ohm / A meter). what would i do?

Psyguy, I would start with GS110GK's tests they are quick, simple and eliminate a potential problem area.

will do the lighting circuit test tomorrow.

[psyguy]

will do the lighting circuit test tomorrow.

so, i tested the headlight circuit:

• voltage at the battery terminals: 13.1V
• neg at the bat, pos at the headlight bulb socket: 11.6V

what do you guys think?

.

[KiwiGS]

The volt drop is caused by a high resistance in the circuit.
Check all the connections and the wires thenmselves if you can.
What I would do is run a couple of tempory wires to the light and and then see what happens when you are charging.
Cheers

[psyguy]

What I would do is run a couple of tempory wires to the light and and then see what happens when you are charging.

yup, sounds practical enough for me to understand the concept, lol

will do that next.

[posplayr]

so, i tested the headlight circuit:

• voltage at the battery terminals: 13.1V
• neg at the bat, pos at the headlight bulb socket: 11.6V

what do you guys think?

.

From what I have been reading you are having an issue providing the required power to the system. It could be partially due to a short somewhere. The fact that you did not have sparks does not mean that a switch power wire might not be shorting. Unfortunately the test I gave you would only test for unswitched shorts, not a switched short.

There is no easy way to chase down a short although there are a few things that would help.

If you have done a visual inspection looking for any wires that might have gotten cut and grounded, then the next easiest tact is to replace the R/R and see if that doesn't fix the problem.

If you had a clamp on amp meter I would say to measure the charging current and see if you are trying to deliver more that 10 amps I have previously measured.

This might be a tricky set of measurements to make if you are not familiar, so i would probably just go and get the FET based R/R and see if that doesn't cure your problems. At this point you either have a short or a faulty R/R. It is easier to swap out an R/R than to find a short.

BTW, the low voltage to the lights is a symptom not a problem. The lower the voltage the less power is being drawn from the system. Running direct wires will just make it worse if resistance is the issue.

[posplayr]

(This should check your grounds, at least in this part of the circuit, which can lead to r/r and charging issues, too )

- JC

His R/R is well connected as per his prior measurements of about 0.15V drop at 5000 RPM. The connections to the lights might be bad, but that will not cause charging issues.

[posplayr]

I know you made it clear that you think checking the headlight circuit is stupid, but I don't agree and only want to get this fellow up and running with a solution. I'm not looking to nitpick and try to discredit anyone and I hope that is mutual.

JC

I made the unequivocal statement that the R/R connections were good, based on Psyguy's voltage drop measurements. You made an incorrect assessment when you suggest that the low voltage to the lights might possibly be linked to poor R/R grounding. That statement is clearly false as it dos not take into account the relevance of the voltage measurements that were reported.

That is my dispassionate technical assessment of your comments.

Pos

[posplayr]

Corrections above. Now come on...this kind of sniping is why some folks are afraid to offer suggestions or ask advice. It's not helpful to the OP or the board in general.

So how about you continue with your best advice to the OP and everyone else will do the same.

- JC

sniping???

I'm sorry for not always being able to follow your logic, but this one is truly befuddling. I was simple trying to point out to you , the thread and more importantly Psyguy that he should not have any concern for R/R connectons despite your comments because the Step #2 and Step #3 measurements he had already made confirmed there was no R/R connection issues.

As should be obvious if he would have taken your words as having any relevance in view of the measurements already taken, he might have been enclined to check him R/R grounds (as a waste of effort) once again or continue looking at headlamp grounds which if anything minimize the problem he is having which is demand in excess of supply current.

Electronics seems to be a mystery to most, so I thought I would at least set the above point straight. Perhaps you should be less free with your technical assessment of electronics if you are so sensitive to any comment that might contradict your own.