My 07 sportster battery keeps dying randomly.

What could be the problem. I charge it it works for a day then dies by the next day. I'm crossing my fingers it doesn't die again, I've already charged like 4-5 times. Same thing keeps happening. Do I need a new battery or is could something else be causing the problem. The alternator? Does my bike have a alternator?

What type of battery brand should I look for is there any to avoid?

 

Best place to start is get a reading at the battery terminals. You will need a volt meter, if you don't have one you can get them cheaply at radio shack etc - $20 or so for a basic one and its a great investment tool that you can use for many many things. Set he meter to volts, start the bike and get a reading at the battery terminals. You should be seeing something around 14v while the bike is running...that would prove your charging system is working and you likely need to replace your battery. If you do not get 14, but something 12 or less well then it gets a bit more complicated. Start with ruling out the battery.

 

It sounds as if your bike's charging system isn't working. For instructions on checking that and finding the culprit, go to the DIY Electrical section, where you will find a couple of helpful stickies. You will need a multimeter.

 

If it's the original battery that's probley the problem have it checked

 

Having the battery checked and testing with a meter is the right way to go,but a quick check is to start the bike and rev it up and see if your headlight gets brighter.

 

However, if your battery voltage is good then it's the voltage regulator, guaranteed; It's located below the horn on the frame of your bike. These bikes have pitiful electronics on them. My battery AND voltage regulator crapped out simultaneously last season. (Voltage regulator fried battery)

At time my bike had about 5,000 miles on it and is an '08. I bought it used with around 2,900 miles. A friend of mine who works at a Harley dealership and his parts manager tried to sell me a factory voltage regulator. I told them if it can't last longer than 5 years/2,900 miles, why in the hell would I want to replace it with a FACTORY unit? I went with Cycle Shack Electric.

While you're at it, remove all your fuses and apply dielectric grease to them. They are located left of your battery when you remove the left side cover. I'm positive this isn't causing your issue but they do corrode because of water intrusion. One of Harley's many crappy designs. Think of it as preventative maintenance.

Our bikes do have an alternator. It's called a "Stator." These do at times go bad but not nearly as often as voltage regulators. The Stator is located in the Primary Case. (bottom left side of the engine)

 

Start simple; check your battery lead connections at the battery for tightness and for corrossion issues, and your ground connection at the engine...these are the most common causes of charging system/battery related issues. If the leads are loose or there is corrossion/cheese present, remove and clean the connection surfaces, reattach them securely [not too tight on the battery side; remember, it's only lead you're tightening that steel bolt into], and apply some anti-corrossion spray or dielectric grease to the uninsulated connectors.

If all is good then go ahead and undertake the battery testing as outlined elsewhere in this thread...at 6 years old it might just be time to change it out...

=8^)

 

an issue that i used to run into all the time with my 09 was the relays getting corrosion and causing a steady draw that would result in a dead battery every morning. check all your fuses and relays for corrosion and while you are at it just replace the relays as it could be that simple. A multimeter will give you a for sure answer on the charging system though. To me it doesnt sound like the charging system as i would expect it to die while riding if the charging system isnt working.

 

`Could be a bad diode too, sending A/C voltage to the battery instead of DC voltage.