Just a bad battery or my alternator is gone too

[lazyazn]

It seems that my battery just kicked the bucket. It would only hold a charge around 10.5v. I used a buddy's jump starter to jump my bike. It took few tries but finally worked. I had the biking running for 10 mins or so. After shutting the bike, the battery would go back to 10v. To me it sounds like a bad battery. however, here is where my electrical knowledge become insufficient. In order for the bike to keep running, i have to keep the jump starter attached to the battery. If i turn the jump starter off, the bike would just die. In my head, this leads to an alternator problem. thoughts?

also, my battery is so shut now, i can't even start my bike with a jump starter.

[green_bread]

If the bike wont stay running without the "jump starter", then Id suspect a bad alternator.

[Kreylyn]

Step 1, replace battery.

A bad battery can do all kinds of things to make problems. It's not just a matter of it not putting out enough power, but it can actually cause a power drain/short too. This could cuase the bike to die with out the external power source. Change it first.

Then... test the alternator with the new battery. Start the bike, put a volt meter on the battery, and see what it reads. When running at 3500 rpms you should get between 14.5 and 15v aprox in power at the battey. Key off should be around 13.2-4 v on a fully charged battery.

If your not getting any more power running or not, then you should look at the alternator and wiring to/from it. (don't assume it's the alternator, could be wires between and so on..)

krey

[green_bread]

Great points, there, Krey! I often forget that some people out in "internetland" might forget to look at the obvious things like that, first.

[arsenic]

Did you ride the bike while it was running for that 10 minutes? Or was it just idling?

[None2Slow]

Great points, there, Krey! I often forget that some people out in "internetland" might forget to look at the obvious things like that, first.

Not just on the net, but dealerships as well. I've had experiences at auto dealerships where if the computer didn't tell them, they couldn't figure it out. They couldn't figure out that it was a dirty throttle body causing the car to not idle.

As for the OP, just cause you get 12+ volts, doesn't mean the battery is good. You also need the amps to start as well.

[KATANA-BRASIL]

Step 1, replace battery.

A bad battery can do all kinds of things to make problems. It's not just a matter of it not putting out enough power, but it can actually cause a power drain/short too. This could cuase the bike to die with out the external power source. Change it first.

Then... test the alternator with the new battery. Start the bike, put a volt meter on the battery, and see what it reads. When running at 3500 rpms you should get between 14.5 and 15v aprox in power at the battey. Key off should be around 13.2-4 v on a fully charged battery.

If your not getting any more power running or not, then you should look at the alternator and wiring to/from it. (don't assume it's the alternator, could be wires between and so on..)

krey

Just perfect explanation
Battery sometimes gets correct voltage when you just turn off the engine, but lose the power to re-start the engine after some hours, lights start's on normal but when you start there is no power its time to change the battery