Bike won't start. Acts like dead battery but it isn't.

[Gcente]

Hello. I own a 2007 sportster 1200. I ride this bike often, several times a week. Recently I went on vacation and the motorcycle sat for 10 days. At the same time the weather cooled down significantly while we were away. When I came back I put in the key the lights and odometer came on but the motorcycle didn't have enough juice to start. It tried to turn over and ultimately just died. The lights went off, the odometer turned off, no power. I tried to jump start the battery with a portable battery pack but had zero success. When I attached the terminals the lights/odometer/fuel pump would turn on, but it still wouldn't turn over. It tried, almost sounded successful, but in the end - nothing. I went out and bought a battery tender/ trickle charger. I plugged the bike in for a few hours and the bike started right up. I let it run for 20 minutes then hopped on and cruised around. I went to Costco to have them put air in the tires. Turned the bike off and it started right back up for me to get home. I let the bike run for about an hour altogether, then parked it. We had rain for the next 3 days and it stayed parked. The 4th day I jumped on to go to work put in the key and nothing. No lights/odometer/fuel pump - nothing. I plugged the battery back into the tender overnight to get a charge. The next day I jumped on and...nothing. No lights/odometer/fuel pump. I tried to jump the bike again with the portable battery pack, and again when I connected the terminals lights come on, odometer and fuel pump come on. The bike tries to turn over but with no success. So I figured my battery was just way too low. So I got my riding mower out(also 12 volt) and tried to jump it with cables but had the same experience that I did with the portable jumper pack. I went out and bought a better battery tender and tried that, but this time I plugged it in and the charger said the battery was fully charged. So I put the key in and not a thing. No lights/odometer. So I removed the battery to get it tested. The battery is testing great. In fact pep boys was amazed that such a small battery produced so many cold cranking amps. I don't really no where to go from here. I have a fully charged battery that when installed can't even turn on the lights, much less start the bike, but when I put jumper cables on this great battery things start to work but still not enough for the bike to start. Where should I go from here? I have a hard time believing that my bikes electrical system failed over a week and a half, when it had been a daily rider. Where should I go from here. I could trailer it over to HD, but they charge so much. Any help would be greatly appreciated.

[Robby]

If your battery is the one that came with your bike (4YO) replace it. A 4 YO battery is going to strand you at the worst possible time. Clean battery cable connections at both ends. With the bike running at 1200 to 1500 RPM check to see if your charging system is working.

[Gcente]

I appreciate the help. The battery is two years old. However, I received the same loose/clean cables advice elsewhere. Thanks for the guidance.

On a side note. Folks, please forgive the grammar in my post. I was on my phone and in a hurry.

[sawdust]

Sounds like a combination of[possibly]: a bad/faulty ground connection, I would check both ends and check for continuinty. You may also have a blown fuse. It definitely sounds like a connection problem, with the possibility of a fuse being blown. If you have a voltage meter, check the voltage with the battery installed at the battery, then check the voltage at the starter.
Good luck.

[junior]

you said that in the end you had issues with lights and starting. it's easy to start drifting into the exotic stuff, but first start with the real basic stuff...

- just for s&g, grab each of the cables at the battery and try to wiggle them. do the same at the solenoid and the frame ground. good?
- you say the battery is good. agm batteries like yours should have 13.2 volts standing and no less than 10 volts or so during cranking. try hooking a meter between the hot and ground sides of the battery directly (eliminating peripheral connections). is it more than 10 volts even though it won't crank?

if it was just the starter or just the lights, i'd go another direction. but if it's both, i'd start with the stuff above and go from there.

j

[RacingOrangeRoadster]

1. Test the voltage by placing your meter leads directly on each battery post. Should be around 13 volts.
2. Do the same test except place your leads on the cable terminals. Should have the same voltage. If not then you have a bad connection. If the voltage is good then go to test-3.
3. Place the negative lead on the the battery and the positive lead on the starter and hit the start switch. Should have 10-12 volts. If you have 12 volts you have a bad Starter. If you don't have 12 volts at the Starter, then go back and check the voltage on the input to the Starter Solenoid. If 12 volts then move the lead to the output of the solenoid and hit the start button. If no output voltage or there is a large voltage drop then you have a bad Starter Solenoid.