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Discussion Starter · #1 ·
Hi all,
I've run into a problem that's got me baffled. '07 Wee keeps coming up with a dead battery. It's fine if I'm riding it, but anytime I have to take the car for a day or two, the battery won't have enough charge left to start the bike. As far as I can tell, the alternator is fine (using a multimeter across the battery terminals, voltage increases as I rev the engine). At first I thought it might be the battery itself, but I've replaced it with no change. If I put the low battery on a trickle charger for a few hours, everything will be fine again until it sits for a day. I checked voltage, with the ignition switched off, on each port in the fuse box. The only one that pulls voltage with the bike off is the one labeled "fuel", between 12 and 13 volts, same as the battery. Is this normal? I also noticed, just by accident, that the same voltage will read from the positive terminal of the battery to parts of the triple clamp. Is it possible that some wire has frayed and is causing a short through the handlebars?

In case you can't tell, the electrical system is well outside of my expertise. I've been trying to troubleshoot this one for a couple weeks now and am still left scratching my head. Any and all help from those of you who actually know what you're doing (or at least know more than me) would be much appreciated.
 

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Hi, You need to learn to use the Ammeter feature of your multi meter starting at the fuse box to see which circuit is active with the bike switched off. If you have any after market wiring check it out.
You will get a reading of battery voltage if you have the positive probe on the positive terminal of the battery and the negative on any good earth point on the bike so don't be concerned with your Triple tree observation.
You could pull the suspect fuel system fuse out for the night if you wish to eliminate that circuit.
Steve
 

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FORUM GODFATHER.....R.I.P. PAT
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You aren't putting the ignition switch in Park are you? Are there any non stock electrical items?
 

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Discussion Starter · #4 · (Edited)
I'm definitely not putting the ignition in park. I've made that mistake once or twice though. The multimeter I'm using only has a 500mA fused circuit for testing amperage, and I can't seem to get any reading other than zero on it, so I'm not sure I'm doing that bit right. However, a test light will light momentarily on the fuel circuit with the ignition switched to off, but only for a second. If I pull the probes and then reinsert them into the fuse port, it will light again and go off after a second. Am I losing my mind, or does this make no sense at all?

Edit: Greywolf; yes, there are two 12v outlets wired directly to the battery, not switched. They don't seem to be pulling anything, as far as I can tell, as long as there's nothing plugged into them.
 

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FORUM GODFATHER.....R.I.P. PAT
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Make sure those outlets are clean. Dust conducts some electricity. An ammeter is inserted in a break in the circuit. Disconnect anything attached to the negative terminal on the battery. Put the ammeter between the bare negative terminal and the wire(s) disconnected from that terminal. The current should be less than 2mA. It takes a little to run the clock.

Get you battery load tested.
 

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Discussion Starter · #6 ·
The battery has been load tested. It seems to be ok. I'm thinking the multimeter I'm using might have an issue with the terminal for testing amperage (it's borrowed as mine seems to have disappeared). It reads zero across the negative terminal and the wire that connects to it, which I know isn't right. I'm going to run out and pick up an extra one right now. Any ideas on the weird intermittent test light on the fuel circuit?
 

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FORUM GODFATHER.....R.I.P. PAT
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There should be no power to the fuel circuit with the ignition off.
 

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Discussion Starter · #8 ·
Ok, with the new multimeter, there's an 8mA draw on the circuit with the two outlets. Everything else seems to work the way it should. The wiring on that circuit was done mostly by the previous owner, and is messier than I'd like anyway, so for now I've just disconnected it from the negative terminal, and instead of going through piece by piece, I'll rewire it all from scratch when I've got a free day to run everything the way I want it. Thanks for the help!
 

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FORUM GODFATHER.....R.I.P. PAT
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I hope that fixes it for you. Running auxiliary electrical equipment is best done off a relay that goes off with the ignition.
 

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Do you have a GPS fitted which could be drawing current all the time?
 

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I've left my Garmin and Tomtom on a few times and they haven't drained the battery. GPS usually pull a very small load compared to the size of the battery.
A pinched wire can expose a bit of wire and be a parasitic drain and not blow a fuse. We got that all the time on the equipment I used to work on. Just short enough to drive the electronics bonkers and give us t-shooting headaches. Our machines were 80 feet long.
 

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Ok, with the new multimeter, there's an 8mA draw on the circuit with the two outlets. Everything else seems to work the way it should. The wiring on that circuit was done mostly by the previous owner, and is messier than I'd like anyway, so for now I've just disconnected it from the negative terminal, and instead of going through piece by piece, I'll rewire it all from scratch when I've got a free day to run everything the way I want it. Thanks for the help!
The battery is rated at about 10Ah. So, if you have a 8mA drain, it should theoretically take 1,250 hours to drain the battery. That's about 52 days. I'm guessing that your problem may lie elsewhere.

Ron
 

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FORUM GODFATHER.....R.I.P. PAT
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The battery doesn't have to be completely drained to prevent a start but 8mA isn't a lot. It is more than the specified 2mA though.
 

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Discussion Starter · #14 ·
I disconnected the questionable circuit last night, and it started right up this morning. The battery voltage looks good too. There's no GPS left on the bike. I use my iPhone, which does charge when I'm riding, but doesn't stay connected. Whatever the cause of the problem is, it's something that has gone wrong without me making any changes. I'm guessing there's a frayed or pinched wire or some water got into a junction and caused rust or something similar, causing a very minor short, just enough to draw on the battery. It's never been completely dead, just low enough to not turn over and start, especially on colder mornings.
 

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circuit

the questionable circuit may be setting up an unintended circuit through a couple of things including one light circuit - with current too low to cause a light bulb to glow and reveal the problem

a test probe with a LOW wattage bulb (or LED) might diagnose this

on a bike this shoudl be easy - you can access everything - its a nightmare on a car
 
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