square peg, round hole

September 19, 2008 2:23 PM

i may have injured the electrical system on my motorcycle.

so i left my lights on and killed my battery. I was able to get enough charge in it after jumping it that it was starting on its own

then i did it again... battery wont hold a charge (or my alternator is slowly dying?). I was able to get enough charge to get the lights running, but pressing the starter gets me lots of clicking.

in either case, im too lazy to test the alternator so i just buy a new battery. at the shop they don't have my battery so they call another shop and they're like "no, we don't have it either but if you've got battery X, its the exact same dimensions." cool, the shop actually has battery X in stock. So they charge it over night and i pick it up. Throw it in the bike. The lights turn on in the dash, i hit the starter and no click. the lights just go out.

can't get them back on. put in the old batter (the one with just enough juice to run the lights) and no good either - no lights, no futile clicks.

me thinks i shorted my electrical system using the wrong battery.

so what now? can the shop be liable for giving me the wrong battery?

will i have to replace the electrical system or is there just a fuse some where ill have to replace?

any observations about the original problem (dead battery vs dying alternator would also be welcome).

posted by nihlton to travel & transportation (9 comments total)

First, motorcycles don't have alternators, they have generators, and the odds that yours has failed are slim.

Secondly, a battery is a battery is a battery. Unless you've put a 12V battery in a 6V bike, or have wired the new battery in backwards, you won't have broken anything.

Do you know for a fact that the new battery is charged?
posted by TheNewWazoo at 2:42 PM on September 19, 2008

this says ive got an alternator: http://www.cyclemaintenance.com/elec/electrical.htm

I don't know for a fact that the new battery was fully charged, but it had to have at least something in it for the lights to have turned on right?

the problem is that even the old battery (with a lingering charge) wont bring the dash lights on anymore, while moments prior, it did.

I suppose I am really asking if that would indicate the electrical system is terminal and needs to be gutted replaced, or if there is a simple little fuse that needs to be replaced.
posted by nihlton at 2:47 PM on September 19, 2008

Most likely your battery has so low of a charge that it won't even light up your indicators. You may have gotten a new battery with low charge also, no big deal. Get a trickle charger or ask the shop where you bought the battery to charge it up.
posted by wongcorgi at 4:08 PM on September 19, 2008

It is possible that yorur starter motor is jammed/seized and the lights going out is a sign of the load on the battery. Have you tried (if possible) kick starting it?

Also: As long as you have checked the voltage (6V versus 12V) and that is right, then checked that the battery is indeed charged (voltmeter and/or charge again anyway) it looks like the cause is a high batter drain while starting. This pretty much means the starter, solenoid or wiring from the switch to the starter, I think. They are usually unfused, so it won't be that.
posted by Brockles at 6:09 PM on September 19, 2008

I agree, charge the battery before you do anything else... If you don't have a charge, buy one, they are useful to own...
posted by HuronBob at 6:11 PM on September 19, 2008

Did you check the battery voltage while it was under load? A battery with a low charge can indicate full voltage unloaded. Check if there is a voltage drop when you hit the starter. BTW do not charge the battery with a big charger meant for cars.
posted by Raybun at 6:29 PM on September 19, 2008

First, check that you connected the new battery correctly (+ / - terminals to the correct wires). Reversing this can do bad things.

Second, check that the battery you bought is indeed correct for the bike. Call the manufacturer, ask on a brand- or model-specific forum, or just figure it out with Google.

Third, check to see if you blew any fuses (or breakers, or however your bike is wired; there can also be fusible links, etc; a repair manual will help greatly with this if you are new to this).

Fourth, (assuming the first three things are ok), buy a good battery charger and make sure the battery is fully charged. I like the Deltran Battery Tender, but there are plenty of similar chargers for sale. Just make sure to buy one that is optimized for long-term charging of motorcycle batteries, rather than one that is meant for fast charging of large batteries.
posted by Forktine at 2:30 AM on September 20, 2008

Another bit: make sure your terminal connections are tight.

I once had a very bizarre situation where my lights would come on, but as soon as I tried to turn it over everything would shut off for a seemingly randomly amount of time. What had happened was that the negative terminal had come a bit loose, and the connection wasn't good enough to turn the starter.

Electricity is weird sometimes.

But it's almost certainly a charging issue. Get a battery tender. Bikes don't tend to charge their batteries very well, especially if you're not doing long slab runs at high RPM.
posted by flaterik at 6:04 PM on September 20, 2008

I think you probably put the new battery in the wrong way around. Check that, change the fuse(s) you blew, and get back to riding.
posted by The Monkey at 8:22 PM on September 20, 2008