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Need help with battery drainage

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Hey all. The battery in my 78' 750 is being drained overnight. I'm trying to get some clarification on how to hunt down the problem. I am expecting to find an open circuit somewhere (I think that's what a broken, fried or non working switch is called). I can read an wiring diagram but am not always so confident with diagnosing stuff. So...I 'think' I start with my multimetre set to 200 ohms, put the negative wire to a good ground and the positive to a point of the wire. If the metre reads 1 (meaning infinite) then current is flowing fine but if it reads any other number, most likely 0.00, then I have a problem. I move down the wire section by section, testing, to find where the break is. Is that any where near correct? I'm not blowing any fuses with the bike, the battery is just being drained overnight and when I take out the main 15A fuse from the main fuse box I no longer have any drainage. I guess I will just follow the wiring diagram from that main fuse until I find a problem??? any help is as always appreciated.
 
Is your battery in good condition, is it being charged correctly when the bike is running.
 
Yes, is it charging right ? I would do the charging tests and even if they turned out reasonable , disconnect the R/R and see what happens overnight. If that doesn't fix it then next isolate the ignition switch to eliminate a short to ground in the main supply wire to the switch.
You are looking for a short, not an open cct. If the ignition switch is still doing it's job and removing the main fuse stops the leak the only ways I can think of off hand are an internal fault in the R/R or a short ( frayed insulation) in the red supply to the ign switch.
 
Draining overnight is a pretty high current that should be easily measurable. You want to put a amp meter in series with the negative ground to the battery. That means:

  1. disconnect the large ground wire to the starter
  2. put amp meter between Battery (-) and Ground wire
  3. If there are other wires to the battery(-) put them all together at the same side away from the battery.
  4. DO NOT CRANK THE ENGINE and
  5. DO NOT TURN ON THE IGNITION

You should see something like 100-500 mA so the 10 amp range on the amp meter will probably have enough resolution. This is the amount causing the battery to drain overnight. Confirm that the load current is there by disconnecting the amp meter and reconnect. You can even reverse the leads and confirm it changes direction. Yes it is there. Phase 2 tests:
Start removing fuses from the fuse box panel. For example:
  1. Any accessories you have added (either to the ACC fuse or direct to the battery)
  2. Ignition
  3. Headlamp
  4. Signal
  5. Main
When you see the current drop off you know which circuit has the drain.
If you don't see any drop then it is most likely the R/R. Remove it. Look for the drop in the amp meter to zero.

If that still doesn't get the amp meter to drop then you are probably looking for a cut or abraded wire. At what ever step above you do see a drop in the current, you that as a guide to figure out what component in the circuit it might be that is leaking current. Remove the components one at a time from the suspected circuit (after you have restored all of the fuses).


You
 
azr, no offense but you have it all backwards. :)

A battery getting drained overnight either means a bad battery, a charging system that isn't up to snuff, or something pulling a load from the battery when it shouldn't be. (When the bike is off.)

In the latter case, you're not looking for an open circuit, you're looking for a closed (or partially closed) circuit. A circuit is a loop, with current flowing from one end of the battery to the other. With a break in the circuit (an "open"), current can't flow. It helps to imagine an electrical circuit as a plumbing system. Your battery is a pump, the wires are pipes. Voltage is pressure, current is volume. (Someone will point out that this is not an exact analogy, but it's good enough for a very basic understanding.)

If you're testing things with a multimeter set to the Ohms function, a reading of zero indicates a closed circuit. Infinite resistance (an open) is represented differently on different meters, but it's usually not a number. When you have the meter set to ohms (any value) and the leads are not connected to anything (even each other), then that's your "infinite" resistance.

If I were in your shoes, I'd spend an afternoon or evening watching YouTube videos with titles like "electricity basics" or "how to use a multimeter". Then some of what posplayr said will make sense. :)
 
Yes, the battery is fine. All the stator tests come out just fine and I've already tested the stator independently and it is fine. I'm actually able to measure the load loss by simply connecting the battery, I can see slowly see voltage loss. I've already confirmed the the loss is coming from the main as the drainage stopped when removing the main fuse, I even left it overnight with the main fuse out and no drainage from the battery, this was not the case if I removed other fuses and left the main in. I'll play around with your method though, thanks. And just so I know my terms correctly, I thought a wiring open circuit meant that there is no current flowing from one point to another, ie; break in the wire, burnt wire, broken switch and a short is when a wire or switch is grounding somewhere it's not supposed to, and I also thought that if I had a short a fuse would blow.
 
eil said:
azr, no offense but you have it all backwards. :)

A battery getting drained overnight either means a bad battery, a charging system that isn't up to snuff, or something pulling a load from the battery when it shouldn't be. (When the bike is off.)

In the latter case, you're not looking for an open circuit, you're looking for a closed (or partially closed) circuit. A circuit is a loop, with current flowing from one end of the battery to the other. With a break in the circuit (an "open"), current can't flow. It helps to imagine an electrical circuit as a plumbing system. Your battery is a pump, the wires are pipes. Voltage is pressure, current is volume. (Someone will point out that this is not an exact analogy, but it's good enough for a very basic understanding.)

If you're testing things with a multimeter set to the Ohms function, a reading of zero indicates a closed circuit. Infinite resistance (an open) is represented differently on different meters, but it's usually not a number. When you have the meter set to ohms (any value) and the leads are not connected to anything (even each other), then that's your "infinite" resistance.

If I were in your shoes, I'd spend an afternoon or evening watching YouTube videos with titles like "electricity basics" or "how to use a multimeter". Then some of what posplayr said will make sense. :)
Click to expand...


Thanks for the explanation, and I've been watching, reading some videos/web pages but I was getting more confused to a degree :rolleyes: and starting to feel like a simpleton. Your explanation makes sense, sort of, although I don't understand how a bad charging system can pull power from a battery over night. I can understand how a bad battery will lose a charger to to bad cells and something pulling a load when the bike is off but not the other. And don't worry about me taking offense to anything, that's why I'm here asking.
 
azr said:
I don't understand how a bad charging system can pull power from a battery over night..
Click to expand...

If the R/R has failed by allowing current to go backwards through it , it might show up as incorrect voltages when you do the charging tests. Disconnecting the R/R removes this path.
Unless you've modified the stock wiring ,with the ign switch off the only hot things are the R/R, the supply to the starter relay and the live supply to the ign switch. The main fuse eliminates the supply to the starter relay leaving only the R/R or a short to ground on the ign supply wire. This, I would expect to be a fuse blower so on balance my money is on the R/R.
 
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eil said:
It helps to imagine an electrical circuit as a plumbing system. Your battery is a pump, the wires are pipes. Voltage is pressure, current is volume. (Someone will point out that this is not an exact analogy, but it's good enough for a very basic understanding.)
Click to expand...

You are very, very close on that analogy. :clap: :clap:

The battery is more of a reservoir, the charging system (stator, rotor, R/R) is the pump.

Just like a water system, when the "pump" is not pumping hard enough, the "reservoir" takes up the slack.

.
 
Well the issue appears to be of my own doing, how typical :rolleyes:, I installed a relay for the coils as the voltage to the coils was 10V or so. I tested the amp draw and it is isolated to the independent fuse for the coil relay that I put in. The relay makes a click noise every time I connect the power to it, I'm not sure if that is indicative of a failed relay or not but I'll swap it out for new one to be sure but really I'm guessing I did something wrong with the wiring install. I followed the mod instructions from here on the site just as I have with my other bikes so I'm not sure what I'm doing wrong, other than on this bike I have points and on my other bikes I have dyna ignitions, so maybe something is wrong in the way I set it up. Here's what I did. I've taken the feeds from the each points pick up and connected them directly to their coils. I took the wire coming from each coil, attached them together and then connected that to the relay. I took the shortest ground wire and connected that to the relay and then took full 12V power from the starter relay with an inline fuse. The switched power to took from one of the orange/white wires that originally connected to the coil. I'm sure something is wrong in that scenario, possibly from the fact this bike has points??
 
If you hear a click when you put the fuse in and the ignition is off, then the relay is being energized all the time. It's not a relay issue then. You need to verify the wiring on the relay coil side. Sounds like tapped power from a non-switched power source.
 
JTGS850GL said:
If you hear a click when you put the fuse in and the ignition is off, then the relay is being energized all the time. It's not a relay issue then. You need to verify the wiring on the relay coil side. Sounds like tapped power from a non-switched power source.
Click to expand...

I did check the power coming from the orange/white wire, that is supposed to be the switched power source, and it only gets power once I turn the ignition on but I'm going to go back out and test some more things, maybe try a different switched power source.
 
Something is wrong with the wiring because the relay should not energize with the ignition off no matter what condition the relay is in.

Good luck finding the problem. Shouldn't be too hard to narrow down. Make sure you have the correct wires going to the correct pins on the relay. It's easy to get them wrong and accidentally have the hot wire on the coil and the switched wire going to the contact.
 
Problem fixed. Sometimes I think I'm a bit simple. I was getting mixed up with the diagram on the relay mod, I kept thinking "switched input supply to #30" meant the wire coming from the orange/white, not what it was actually supposed to be, direct 12V from the the fuse panel or battery with an inline fuse.....duhhh. Thanks everyone for the help and best thing is I've now learned how to properly test for parasitic battery draw :)
 
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Nice to hear it got resolved, good job troubleshooting!

Don't feel bad about getting mixed up with the diagram. I'm fairly experienced with electricity (repaired avionics in the military and now hack at home for fun) but I still managed to screw up my coil relay mod. After I had it all wired up, everything tested as expected and seemed to work properly. The next time I took it for a ride, however, the engine stalled as soon as I hit the left turn signal. The first time I thought it might have been a fluke. The second time, I knew I had done something wrong. I don't remember exactly what it was now, something to do with choosing the wrong ground point. Once I fixed that amusing little issue it had been working great ever since.
 
azr said:
Problem fixed. Sometimes I think I'm a bit simple. I was getting mixed up with the diagram on the relay mod, I kept thinking "switched input supply to #30" meant the wire coming from the orange/white, not what it was actually supposed to be, direct 12V from the the fuse panel or battery with an inline fuse.....duhhh. Thanks everyone for the help and best thing is I've now learned how to properly test for parasitic battery draw :)
Click to expand...

Well done sir.
 
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