| Author | Message | ||
     Jaredc01 |
First post here (with a hello thread coming after work)... Here's the situation: I purchased a 2008 1125R last week from ibppjr (who recommended this forum to me and is a member here). The bike is fantastic, and I love everything about it, but I'm noticing after a full charge on a trickle charger and a couple of rides now in ~45 degree weather that the battery voltage while riding / charging is only hitting 13.8v max. Didn't think too much of it initially, but yesterday after parking the bike, I let the fans finish running before turning off the key... After the bike was shut off (key on, and fans on), the battery voltage started at 12.4v and quickly dropped to 12.0v in a matter of 10~15 seconds with the fans running. The fans stopped after the battery dropped to 12.0v, and the battery seemed to level out, but I didn't leave the key on long enough to find out for sure. tl;dr Based on the info here about the 08 stator being rock solid, I'm assuming the battery is going to need to be replaced soon, but I wanted a second opinion due to the charging voltage from the stator. Thanks! | ||
| Reepicheep |
13.8 is perfect for a running bike charging it's battery. If it is draining quickly with the motor off, the battery is just getting old (they do that, some sooner than others). | ||
| Jaredc01 |
I didn't think it would be a stator issue with the praises the 08 gets here, but I have also looked at some stator numbers over 14v while charging (09+ seems like). Just wanted to make sure. It hasn't had any starting issues since I charged it up overnight, but I did have a battery light and a couple of hard starts before the charge (sitting in a garage all winter it's expected). Just steering on the side of caution as I don't want to be stuck somewhere with a dead bike. | ||
| Dktechguy112 |
When the battery is @ 12v, u should go ride the bike to charge it up. The higher the rpms, the more the battery charges. The rotor is on the crank, the mre rpms the more power the stator/rotor will generate. The 1125 likes to ridden hard.  | ||
| Jaredc01 |
The battery almost instantly drops to 12v. Stopped for a bite to eat today after a bit of decent riding, fans on after engine off, volts down to 11.9. Started fine after coming back out from eating, but I'm curious to see how much longer it will continue to do so. Suppose if I notice any hard starts or signs that the battery isn't holding a charge well I'll see about replacing it. | ||
| Timebandit |
There's a significant difference between the voltage output of a functional charging system, and the resting potential of a charged battery. If your bike is turned off, voltages in the range of 12 VDC are normal. There is a good page in the owners manual that covers how resting voltage corresponds with a battery's state of charge. Definitely worth reviewing. | ||
| Reepicheep |
Timebandit, do you believe that chart is reliable for an aged battery? I've wondered about that and never been able to come up with a good answer. I'm reasonably certain that for a new good battery out of the box, that table is a very useful and accurate measure of the state of charge of the battery. However, once the battery starts to "wear", I wonder if it is still generally accurate. So if 12.2 volts corresponds to 80% capacity (a guess, I don't have the chart here to get the real number), I suspect that is a fairly accurate number for a new good battery. But say I have a 4 year old battery, and I measure that 12.2 volts after a 2 hour ride and I have a fully functional charging system. Does that mean that my battery maximum charge is now 80% of what a new battery maximum charge would be? I'm guessing no, and that there would be two different curves measuring two different things, and the first curve is for a new battery state of charge. What we need is an old battery max charge versus days of life left (or something). Something I've always wondered about... | ||
| Baf |
Also note that resting voltage is without load. With ignition on, you have the ecm, lights, possibly fans and/or fuel pump, etc all loading the battery down. Your voltages sound fine to me. Also, the fans will keep running with the key off if the motor is hot enough. No reason to sit around with the ignition on waiting. |
