B2910 Battery Light

dullpain · Dec 24, 2014

Been a long time since I last posted , so if this belongs in another forum just let me know.

Battery was shot so I replaced it. Immediately got a battery warning lite on the dash with new battery. Checked with Digital Volt meter and am getting 14 V. at the battery so the alternator is putting out. Warning lite brightness decreases as RPM's increase. Lite will go out at about 2,200 RPM's . No problems with the battery charging , battery has been in 6 months now.

???? Any body got any ideas. Merry Christmas to all TBN'ers !

sandyc · Dec 26, 2014

I am no expert but it sounds like a short. I would trace the wiring and make sure everything is tight and right.

deminin · Dec 26, 2014

I checked my B2910 WSM, and it gives three possibilities. 1. Wiring Harness improperly connected. 2. Alternator/dynamo bad. 3. Voltage regulator bad.

If all you did was replace the battery, I wouldn't suspect any wiring harness troubles...you shouldn't have disturbed anything but the battery cables.

If your tractor is equipped with an Alternator, the voltage regulator is contained inside the alternator...PN 66436-64600

If your 2910 has a Dynamo, which most do, the dynamo may not be putting out sufficient Current to shut off the light, until you reach higher RPM's. I didn't find any reference to a voltage regulator on a Dynamo equipped tractor, but there is a "regulator" located under the main panel...under the fuel gauge area. The manual/parts list doesn't say what this regulator does.

If you have had this condition for 6 months, and no problems keeping the battery charged up, the mystery deepens. You might pull the dynamo (or alternator), and take it to a dealer, and see if they can check it out.

BobRip · Dec 26, 2014

If the battery stays charged for six months then the system is good for your purpose. Use a clamp on amp meter, DC of course, and see if it will put out rated current. If not you may have some open diodes in the alternator. It may work fine for many years as is.