Battery issue 99 Interstate

[RazorRay]

Hello,
Installed a new battery about 6 months ago and have not been riding much and the battery wont stay charge over night. I disconnected all the accessories thinking it may be a bad relay in the horns or fog lights leaving only the mains to the battey. All connections seem clean and when cranking with a full charge the voltage barely drops so I dont think its a bad battery. I just charge the battery to 100% and disconnected all leads to see if it will stay charge on its own over night to rule a bad battery. I have read in a search I did about some having a promblems with bad relays? I did find the starter relay its clean but I dont have a clue as how to test it and what to put the VM on etc. Any one that can lead me in the right direction and what else I may can check would be awesome. Thanks  Ray

[gordonv]

Know this is from reading, and I might have some of the values wrong.

A new battery needs to first be charged properly with a battery charger. Something like a 2 amp charger. After charged, it should be something like 12.8-13.2 volts. Let it sit, and it should drop no lower than high 12V after 24 hours. If you don't have that, then your new battery might work if charged with a proper charger/reconditioner. A trickle charger is not what you want.

With a meter, check your battery voltage. Start the bike and see what volt you are at. Rev the rpm and see and to what it goes up to. Battery should show a charge. At idle, it might be the same or higher. Rev and it should be up around 14V. If you don't get the 14v, then you have a charging problem.

It sounds to me like you go out on a full battery, but it's not being charged, so after over night, you don't have enough power left to start the bike.

[Ramie]

You don't mention what battery or what type you have but new batteries sometimes go bad.  If you charge most autoparts stores will load test it for free.  As Gordon suggested you need a meter to check if your charging the battery and what type of voltage you have.

[desertrefugee]

A fully charged 12V battery measured with a good digital meter should read at least 12.5 volts.  If it reads as low as 12.0 volts, there is a serious problem.  

If you have a good digital meter, to do a quick check to see if there's a current drain, you'll need to put the meter in current measuring mode (A).  This requires placing the test leads in the correct jacks (not the same as for measuring voltage or resistance).  Usually, only the positive lead needs to be moved.

Then:

1) Put the range selector in a low setting - you'll be measuring values in the milliamps (hopefully).

2) Disconnect either battery connection (NEG or POS) and place the meter in series between the disconnected lead and the battery terminal.

3) Observe the reading with the main key switch off.  Unless you have a digital clock, a radio or an alarm system, there should be virtually no (zero) current flowing -  or read by the meter.   If you don't,  the the battery is definitely rotten.

A clock might draw 20mA, alarms and radios maybe a bit more.  Either of these would take a while to draw the battery down.  If you have 50 - 100mA, start pulling fuses until it disappears.  Pay attention to which fuse affects the reading.  That's the circuit you'll need to investigate.   If no fuses make a difference, that's a whole 'nother story.   We can get to that if need be.  I'm betting on the battery.

[RazorRay]

Thanks for the advice looks like a bad battery