Dead Battery?

[chief]

Yeah, I realized it was an 800 after I added the EFI stuff...  still applicable to modern carb'd bikes.

[49Reo]

I let the battery in my '05 Ultra go completely dead, boosted it, as soon as I took the booster cables off, putt. Dead. Had to charge it for awhile, then it would stay running after boosting. It is a carbureted  model, so it was not an EFI issue. Good luck with it; that kind of crap can be frustrating.
Regards and such;
49 Reo

[TripWire]

Put the new battery in her and she was ready to go.  Got her home with no issues and tomorrow I am going to run a few tests on the charging system just to make sure.

[chief]

I'm no expert but this is my understanding.

There's a big difference in modern EFI bikes and the old bikes. My old bikes would run without the battery, but newer EFI bikes have the battery as part of the circuit so its needed for the bike to run. It will run with a low battery, even dead as long as its not shorted and as long as the overall current draw doesn't overwhelm the charging system.

If the battery has shorted that's why the bike won't stay lit.

I'd monitor the battery for a while after its installed to ensure the charging system is maintaining it properly.

[TripWire]

Have 2000 800, had the bike service about a month ago and they indicated the battery was going,  Picked up a new battery but haven't had the time to put it in yet (damn honey do list).  So today I am leaving work go to start her up, get a slight turn over and then nothing.  No lights, idiot lights nothing.  So with my tail between my legs I go get the company jump start kit, connect it up, wait a few minutes and start her up but as soon as I disconnect the jump start battery she dies.  My back ground is scooters and once they start (kick start), even with a dead battery, they will run.  I did give her a quick wash the night before, but she start fine the next morning and got me to work.  So is this:
a) probably dead battery
b) possibly a regulator / rectifier issue
c) got water in something while washing her (when I should have been installing the new battery)
c) not enough information to help my dumb butt
d) other

Have the new battery charging up and I will be installing it tomorrow at work, I figure even if it's a charging system issue I should be able to ride her home 12 miles.