Battery being drained overnight + substandard voltage when running.

cgguy09

1971 CB350 K3
Wizards of the Black Art of Electricity,
My battery (now batteries at this point) are being drained overnight by some unseen force. During my testing I also noticed my voltage while the battery was running was not sufficient. I’ve gone through about a dozen threads on this issue. Here are all the facts:
Current conditions:
1.) Two Brand new batteries
2.) When hooked up to the tender overnight, the tender thinks the battery is bad and stops charging.
3.) New 50V 25amp Radioshack rectifier.

When Testing the voltage:
1. Key off: ~12.6 ((whatever I charged it to)
2. Key on, lights off: ~12.6 ((little draw))
3. engine on at idle?: ~11.6 (( should be at about 13v+)
4. engine on at 3500 rpm? ~11.8, with small fluxuations (should be at about 14v, but no higher than 14.4v)
My intended action:
1. Test Stator: I’m supposed to look for roughly 50 VAC between the yellow and the stink…I mean pink.
2. Briefly drop the regulator to see if that allows the voltage to increase.
3. Begin dropping things in the system and see if that solves any of the problems.
My Questions:
1. What witch doctor cursed this poor little Honda?
2. I’ve been testing the voltage through the system. When I touch the meter to the main fuse and ground it. I get my standing voltage. Should I be getting this or is this a symptom of the problem?
3. Are my battery drainage and my lack of voltage during operations related? I know it is easy to conflate problems…especially electrical ones. And want to know if I’m battling two demons or just one.
 
Make sure everything is turned off and then pull the ground strap wire from the battery. Use a multimeter to read voltage between the (now disconnected) ground strap wire and the negative terminal of the battery.
 
Sonreir said:
Make sure everything is turned off and then pull the ground strap wire from the battery. Use a multimeter to read voltage between the (now disconnected) ground strap wire and the negative terminal of the battery.


I conducted the test and there was no current flowing between the the battery's negative terminal and the ground wire. For kicks I also grounded it to the frame in a few locations. Again, no current flow.

Thanks.
 
Dead battery and/or non-functional charging system. If you're not getting voltage when the bike is turned off, then you don't have a drain.

Also... this is sort of a side thing, but don't run without a regulator for "testing" purposes. You might fry something.
 
Updates:
First things first: my trickle charger shit the bed. I bought a cheap Schumacher 1.5 Amp trickle charging ($15). I believe this was the cause of the battery drainage overnight.

When Testing the voltage:
1. Key off: ~12.6
2. Key on, lights off: ~12.6 ((little draw))
3. engine on at idle?: ~12.5(( should be at about 13v+)
4. engine on at 4k+ rpm? ~12.5, with small fluxuations (should be at about 14v, but no higher than 14.4v)
5. engine on with HID headlight on 12.2
6. engine w/ HID on at 4k+ rpm 12.4

Actions Taken
1. Test Stator: Between 15 V (AC) at idle and 48 V (AC) when rev'd to about 4k rpms
2. Briefly drop the regulator: :No Change
3. Begin dropping things in the system and see if that solves any of the problems...begining this now.
My Questions:
1. What witch doctor cursed this poor little Honda?
2. I’ve been testing the voltage through the system. When I touch the meter to the main fuse and ground it. I get my standing voltage. Should I be getting this or is this a symptom of the problem?

What else am I missing in the changing system? Stator appears good. New Rectifier. Removing the regulator seems to have no impact.

Thanks gents, I appreciate any help.
 
The AC voltage on the stator sounds about right. Your assumptions about the regulator are not, however. The regulator regulates the DC portion of your electrics, not the AC. If you were measuring voltage across the terminals of your battery when you pulled the regulator, you'd see the voltage go up quite a bit. I don't recommend this.
 
Sonreir said:
Dead battery and/or non-functional charging system. If you're not getting voltage when the bike is turned off, then you don't have a drain.

Also... this is sort of a side thing, but don't run without a regulator for "testing" purposes. You might fry something.

Whoops....dropped the regulator. but nothing happened. Guess I got lucky. I saw other people say to drop it for a brief second. But, I'll skip it from here on out.

Thanks, man.
 
Sonreir said:
The AC voltage on the stator sounds about right. Your assumptions about the regulator are not, however. The regulator regulates the DC portion of your electrics, not the AC. If you were measuring voltage across the terminals of your battery when you pulled the regulator, you'd see the voltage go up quite a bit. I don't recommend this.

So had I been measuring AC (not DC) at my battery terminals I would have seen a jump?
 
Not sure what happens when you measure AC on a DC circuit. You should probably measure DC again, though.
 
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