So I have a 2009 bobcat S250 skid steer with 2200 hours and the battery light came on. I looked at the display which said it was charging 15.8 volts. I didnt think this was correct so I got my multimeter and it showed the same thing. I then checked the battery and it showed 12.3 volts. I did a load test on the battery and showed the battery to be good. So now I am a little confused. Did the regulator in the alternator quit on me? Is it the controller for the machine? Anyone know more tests that I could run to confirm what it would be? I did check the alternator fuse in the cab which was good. Thanks for the help.
How are the cables and the grounds ?
Someone has installed a new ground cable along with new cables going to the alternator. The funny hing is there are no codes on the machine at all.
What your serial number so we can look at the correct schematic plus your email to send it ?
Tool_ king I sent you a pm. Thank you.
They didn't do it right. The alternator has more than one wire, the sense wire is seeing the battery voltage and trying to get it up, and can't raise the battery voltage because there's too much voltage drop in the cable/connections/somewhere. Find where the voltage drops and fix it.
Thanks for the information Delmer. There is a positive, negative and a connector with two wires. Now the positive and negative are fine. The other two in the connector I’m assuming go to the controller? Can anyone verify this? Thanks
If I understood you, there was 15.8V at the alternator, and 12.3V at the battery. If that's the case, then the cables are not fine. There is ZERO current going to the battery or it would be 13V minimum with even 1amp charging current. Fix that voltage drop, should be easy to find with a drop like that, then see what it does.
When the skid i running and I take a measurement with the alternator, I get 15.8V at the battery. With the machine off I am getting 12.3V at the battery. Even the display is saying the same readings in the machine. I just took a multimeter to confirm it. Can someone tell me what an acceptable voltage drop would be? Thanks for the information.
Sorry, I misunderstood. Those readings aren't telling me the voltage drop I was talking about, that would be the voltage at the alternator hot to alternator body, and then battery pos to neg terminals. That should be less than .1V difference with engine running an no big loads on the electrical system. The battery going to 12.3V after been charging at almost 16V is not good, I'd expect 12.7V or more after sitting overnight, and a surface charge of close to 13 for a while after it's shut off. Does this battery start the machine OK still? If the battery is fine, then the next step it to see what the small wires on the alternator have for voltage when it's running with 15V, there may be one that's AC for the tachometer-ignore that one. Then determine if it's an internal regulated alternator, most likely. Can't think of anything besides a ford that would be externally regulated.
Just figured I would add an update. So I changed the alternator and it is now charging 14.3 volts. The old alternator was overcharging. Thanks for all the help
That great you are back up and running .