holding charge problem - Harley Davidson Forums: Harley Davidson Motorcycle Forum

Rockerbox1 · 08-10-2009, 08:35 AM

Ok, I have an old sportster, and lately, if it sits more than a day or two without being started/ridden, I have to jump the battery to get the thing to start. I was starting to think it may be the generator, but it can't be, cause I can take it out (after getting it started) ride for a while, then the rest of the day, I can start it just fine, but let it sit for a while and the batt doesn't seem to have enough juice to kick it over. I checked the fluid levels int he battery, everything is fine there. I had a problem for a while where the brake light would stay on, but after changing BL switch, that problem is resolved. but now, it is having this problem. I don't have a volt meter, so I can't test the battery. I can't find any place where there might be a short causeing a power drain. I will say also, that battery sat all winter without losing charge, adn fired the bike right up this spring.

I have to be missing something, I can't see the battery going bad, overnight. is there anything I can check? voltage regulator? anything?

thanks for any adice

SCHMIDTYS · 08-10-2009, 08:41 AM

Could be the regulator . If you had the battery or generator disconnected for any reason then you need to reflash the regulator . Touch a short piece of wire between the A and B+ connects on the regulator briefly . Better check the book on which connects to jump though , my brain is a bit foggy this a.m.

Rockerbox1 · 08-10-2009, 08:42 AM

hmmmm, but nothing has been unhooked...not since putting th bike together this spring

Badassbrutus · 08-10-2009, 08:45 AM

Polarity should be good to go.never completley died out right?
Battery tender you should have one to maintain your battery speacialy from sitting for long periods of time good way to kill it.
you have to test the chargin system and the battery to know fo sure..

Badassbrutus · 08-10-2009, 08:45 AM

And when you put it together did you polorize it???

Rockerbox1 · 08-10-2009, 10:11 AM

Quote:

Originally Posted by Badassbrutus

And when you put it together did you polorize it???

my own ignorance coming out here..................polorize it? brief explanation please

Smokin Sam · 08-10-2009, 12:53 PM

It sounds like it is charging. It won't do that if it is not polarized. Scoop a cheap dc volt meter, it will help. If it charges the battery to 12.5-14.7 you are good. To polarize the generator on the bike and connected to the regulator, "connect one end of a jumper wire to the generator armature terminal. Momentarily touch the other end of the jumper wire to the battery positive." (I had an old manual handy.)
When your battery is charged, try disconnecting the neg cable. Strike it against its terminal a couple of times. If there is a spark there is a draw. You may have to polarize after doing this test. Sam.

Rockerbox1 · 08-10-2009, 02:20 PM

I never thought of the neg post test for current draw, I use to do that when working with car electronics, thanks for refreshing my memory