[jaketurner]

Due to local forest fires, I could not ride my old 1970 CL350 for about three weeks. Yesterday went to start it, battery dead dead dead. Battery just two months old, so odds kinda low that it's the battery. So recharged the battery, attached the positive cable, then put a voltmeter between the ground cable and the battery's negative post. The meter sees 10.3 volts going between the post and cable. Dang. As simple starting places I (1) made sure one of the points were still gapped correctly, and (2) completely disconnected the ignition switch. No joy.
Very strong voltage across the battery terminals... which is not particularly relevant considering the draw.
Anybody know of anything that pulls roughly 10.3 volts sittin' still?

thnx - Jake

 

[J-T]

You'll need to start disconnecting components until you identify which circuit the problem is in. You might check by removing the fuses one at a time.

 

[slofut]

That would be 10.3 amps? :shock: And that's a lot. I'm surprised your meter handled the current without burning up. Should be some warm wires too, with the battery connected.

 

[slofut]

Ok, wait. Your meter is in series with the neg battery cable? That is neg cable off the battery, meter wire to that cable and other meter wire to the neg batt post. In this situation you usually have to move the lead connector on the meter to a different port on the meter to read current (not voltage).

 

[WintrSol]

Just to clarify, you disconnected the cable from the battery negative terminal and connected a Volt meter between it and the battery, measuring 10.3V? Most DVMs are 10megOhm input, so that means it was measuring 10V/10,000,000Ohms, or 1 microAmp, which could be just be moisture in the key switch - basically nothing.

If, however, you set your DVM to Amps, and connected the leads to measure current, you could be measuring Amps or milliAmps, depending on the settings of your meter and which inputs you used. A 10mA load would drain your battery in about 3-5 days, but a 10A load load in about an hour.

 

[J-T]

With the voltmeter connected between a battery terminal and it's respective disconnected cable the meter should read zero when everything is off. If it reads other than zero there is a load on the circuit or, in other words, something is draining the battery. Being an OCD type I would of course have to first determine how long it takes to drain the battery then track down the culprit and eliminate it.

 

[WintrSol]

JT, a 1 microAmp load would take over 1000 years to discharge a 10Ahr battery, so can be safely ignored. If he actually read battery Voltage with a typical DVM, then the load could be of unknown value, which is why you need a current reading in Amps, not Volts.

 

[jaketurner]

volts ~

 

[jaketurner]

Ok.... so I gather that I'm approaching this incorrectly in that I need to measure *current* draw, rather than looking for any sign of voltage from the cable to the negative post. I'll just add here that I also put a simple trouble light between the negative post and the ground cable and it lit up nicely. Bottom line, there's a errant completed circuit that I need to track down. As suggested (which I super appreciate) I will attempt a methodical elimination by component and/or fuse.
Film at 11:00....

 

[WintrSol]

Just to be sure, are you turning the key to OFF or P? P stands for Park, which leaves the tail lamp on, and can kill a battery in no time; it can be hard to see in sunlight, though.

 

[slofut]

Just to be sure, are you turning the key to OFF or P? P stands for Park, which leaves the tail lamp on, and can kill a battery in no time; it can be hard to see in sunlight, though.

...and a front turn signal, on my 360 it's the right one. Never could figure out why everything went dead when I switched the key to the last position. Finally read a factory USER manual!

 

[slofut]

Ok.... so I gather that I'm approaching this incorrectly in that I need to measure *current* draw, rather than looking for any sign of voltage from the cable to the negative post. I'll just add here that I also put a simple trouble light between the negative post and the ground cable and it lit up nicely. Bottom line, there's a errant completed circuit that I need to track down. As suggested (which I super appreciate) I will attempt a methodical elimination by component and/or fuse.
Film at 11:00....

Yes, check your meter too, you'll have to plug the red lead into another hole on the meter to read current. Then connect the meter in series with the battery cable as you described and read current draw. Test light is a good indication you have a short circuit or a completed circuit as you stated. As wintrsol said, be sure the key is in the off position. Unplug one lead off your horn first and check (common short circuit with large current draw), also with the test light connected play around with the handlebar switches (horn button) a bit, they tend to get flaky at this age. Wires don't usually just "go bad" within a run unless someone has been dicking around with it, usually mechanical problems at the ends like connectors or devices like switches.

 

[jaketurner]

Yep, turning the key off... ;-)

So getting back to the amps vs volts setting, with my DVM set to the 200m scale (amps), I see a current of 29.2 between the negative cable and negative post. A friend mentioned that I cycle the electric starter (or even disconnect it). No change.

When y'all mention eliminating circuits at the fuses... I could be a jackass for not knowing this, but I don't have a "fusebox" on this 350 do I? I mean, my impression has been that fuses are spread around the bike.

sigh... I can't even work on the bike due to the forest fire smoke here in western OR... friggin impossible to find time to work on the bike.

 

[slofut]

Jake, did you get this sorted yet?