Strange thing with my battery

[mleach72]

So I go out to take the pitbull out for one last ride before cold weather sets in. I hit the start button. Engine spins over fine, but won't start. Now I'm worried that I have a problem with the ignition system. Just for shits and giggles, I pull the battery out of my harley and stick it in the pitbull. The engine cranks over and fires right up. Now I'm confused. So I put the pitbull battery in my harley. The same thing happens. Engine spins, but won't fire. I was also getting a bunch of pops and bangs from the exhaust while the engine was spinning. Now I'm really scratching my head. I've never had this happen before. Usually when a battery is shot, it won't crank the engine. It's like this battery has enough juice to turn the engine over, but not enough to create a good spark. Strange! Anybody else ever run into this?

 

[Jersey Big Mike]

So I go out to take the pitbull out for one last ride before cold weather sets in. I hit the start button. Engine spins over fine, but won't start. Now I'm worried that I have a problem with the ignition system. Just for shits and giggles, I pull the battery out of my harley and stick it in the pitbull. The engine cranks over and fires right up. Now I'm confused. So I put the pitbull battery in my harley. The same thing happens. Engine spins, but won't fire. I was also getting a bunch of pops and bangs from the exhaust while the engine was spinning. Now I'm really scratching my head. I've never had this happen before. Usually when a battery is shot, it won't crank the engine. It's like this battery has enough juice to turn the engine over, but not enough to create a good spark. Strange! Anybody else ever run into this?

It's right at that threshold where the voltage dropped low enough that the electronics are stumbling but the AMPS were high enough to turn it over is what it sounds like to me.
How old is the battery?
Was it on a tender?
What was the temp like in the garage recently and when you tried to fire it up?

 

[mleach72]

It's right at that threshold where the voltage dropped low enough that the electronics are stumbling but the AMPS were high enough to turn it over is what it sounds like to me.
How old is the battery?
Was it on a tender?
What was the temp like in the garage recently and when you tried to fire it up?

Mike it's about 4 years old. I realize it's near the end of it's life. I don't have a problem buying a new battery, just never had this happen before. It's been on a tender, but I haven't fired it in about a month because we have been working a lot of OT. My garage is unheated, but it hasn't been extremely cold here yet.

 

[Mikeinjersey]

Mike it's about 4 years old. I realize it's near the end of it's life. I don't have a problem buying a new battery, just never had this happen before. It's been on a tender, but I haven't fired it in about a month because we have been working a lot of OT. My garage is unheated, but it hasn't been extremely cold here yet.

Very strange symptoms but if your battery is 4years old getting a new one is probably your best idea. It can't hurt and it's the most important part on your bike. Age and cold are a batteries enemy . Remember : Big Dogs need totally healthy and strong batteries to operate well. It will be money well spent!!

 

[Jwooky]

That doesn’t make sense at all to me either. It takes 10x the power to start compared to power the coil.

Had many bikes were so dead where it could not turn over, but will fire right up with push start or jump.

 

[mleach72]

That doesn’t make sense at all to me either. It takes 10x the power to start compared to power the coil.

Had many bikes were so dead where it could not turn over, but will fire right up with push start or jump.

Yeah, it's strangest thing I've ever seen. Just to make sure I wasn't going completely insane, I changed the battery back to the harley and it fired right up. I'm not saying the battery in the pitbull produced a strong crank, but it spun it fast enough that it should have started. I've never seen anything like it in 40 years of riding motorcycles.

 

[Sven]

The old battery load check.

Charge battery. Has to read at least 12.7, 12.8v
Volt meter across the battery posts, start engine. The motor is the load test so a good battery drops to 11.1v then climbs back up to 12.8v, then the volt reg kicks in and hit hits 14+v at idle.

So if bad, battery drops under 10v and does not recover back to 12.8v.