Voltage leak

[nitroman]

Hello again gasser people. My 2002 FSE400 is testing my love (again) My latest problem is my battery is going flat all the time . At first i thought my original battery had done it's time so I replaced it, and now the new one is dead too. It charges 13.5 volts which i think is ok, but I did a battery leakage test with the ignition off, negative cable off the battery and multimeter (set on volts) between the negative terminal and cable, and it seems to be leaking though the circuit that has the 3 amp fuse. I can't find a wiring diagram anywhere to tell me what this circuit supports. Can anybody tell me what fuses power what so i can find the culprit stealing my electricity?

[blitz11]

Voltage won't tell you anything about a battery being drained. Two things to check.

1. insert an ammeter between the negative battery post and the ground wire(s). With ignition off, you should read zero (or single milli-amps). That will tell you if you have some sort of parasitic drain. if it is 100's of milli-amps, then you have a parasitic loss.

If that is the case, then you need to start opening circuits to try and find the circuit which is causing the loss. once you open the circuit and the drain drops, you've found the bad loop. now you just have to find the issue with that loop.

2. if you read zero or single milliamps, then you probably aren't charging. you should also use an ammeter to see if you're putting current back into the battery. If you are, then you need to see that you have a voltage rise at the battery terminal when the bike is running (probably over 3K rpm).

You have to look at both voltage and current to get a good handle on the charging system.

blitz

[bergerhag]

I measure 14.4 V over the battery on my '05 with engine running.

[anathema]

As Blitz said Nitroman, you are almost doing it right, but you need to make sure the multimeter is on the AMPS setting, not volts. Also make sure if the cable needs to be changed position on the multimeter (plugged into the amps hole, not volts) you do it, or else the test wont show much

[nitroman]

Thanks guys, I hate diagnosing electrical problems so every tip helps heaps.
One question. Should I be using a lead acid type battery that the bike came with or the gel type that was supplied by the local bike shop?
I'll do a current draw test this weekend and see if I really do have a voltage leak. Does it work both ways? Should I have a certain current (amps) input into the battery when it runs? How can I perform this test? Maybe this is my problem all along . I think it's charging with sufficient voltage but it's not getting the current input.
Thanks again everybody!

[blitz11]

Thanks guys, I hate diagnosing electrical problems so every tip helps heaps.
One question. Should I be using a lead acid type battery that the bike came with or the gel type that was supplied by the local bike shop?

I would use the newer battery, but start with it in in full or mostly charged state. Assuming that battery is good, it removes one variable from the analysis.

I'll do a current draw test this weekend and see if I really do have a voltage leak. Does it work both ways?

Not sure what "both ways" means. Voltage and current? If that is what you meant, then "yes."

Should I have a certain current (amps) input into the battery when it runs?

I am not too hip to the battery, but what is the Amp Hour rating of the battery? My guess is that you should see 3-5 amps flowing INTO the battery at a reasonable engine speed (say 4000 rpm) at start up. As the battery charges, the voltage regulator voltage and the battery voltage differential reduces, and the current flow will be reduced. But, 3-5 amps initially is probably reasonable.

You also want to make sure you have a Voltage rise to about 14.4 volts while the system is charging. (Thanks, Bergerhag)

How can I perform this test? Maybe this is my problem all along . I think it's charging with sufficient voltage but it's not getting the current input.

Connect an ammeter between the negative post of the battery and ALL of the leads which are connected to the negative terminal of the battery. Activate the ignition, and look at the SIGN of the current draw (i.e., either positive or negative). KICKSTART the bike (if you E-start it, you will draw enough current to blow the fuse or destroy your ammeter). When the bike is running, watch the ammeter. as you rev the engine, you should see the Ammeter switch current polarity (i.e., current in, not out) and move to 3-5 amps. If you see that, then check to see you're getting a voltage rise across the battery terminals. (If you have only one multimeter, you'll have to connect the negative leads to the negative post, and then restart the bike and check voltage.) you should see 14.4 volts as Bergerhag reported.

Also, I would suggest that you do these tests with both the lights ON and the Lights OFF. You should still see current flowing into the battery with the lights ON, but perhaps a diminished amount as some of the current output is going to run the lights. (but maybe not 'cause the lighting might be on a different circuit/winding in the generator/alternator).


If both of these tests pass, and a charged battery goes dead, then you have a parasitic loss somewhere. If it doesn't pass the test, it means you have a charging issue. We can help you with that, too.

Do you have a wiring diagram you can post? Looking at that would help me be more specific. Thanks.


Best wishes.

blitz

[nitroman]

Thanks for the information Blitz. What I meant was ( what you in fact anwered) can you have a positive and negative current draw and charge. It seems like a silly question now you have explained it thankyou.

[nitroman]

I found it! It wasn't a current draw as i suspected (after doing a draw test properly thanks Blitz)
The thick red wire that goes to the charging thing up the front near the headset had nearly broken through completely, with only one strand of the wire still connected. I soldered it back together and straight away I'm getting 14.5 volts instead of 13.5 . It all makes sense now why I thought it was charging and really was only just giving me slightly more than battery voltage because the cable was severed.
Thanks again for all your information and support guys, it really helped me a lot.

[blitz11]

Terrific! Congratulations. Being methodical really helps with electrical problems.

blitz