Tractor Battery on charging

[Willsk]

I have a vaaljapie tractor with battery bought 2 months ago, when i start the tractor the alternator must charge the battery but looks like the voltage goes down instead of rising. There are 2 wires going to the alternator not so sure if these are enough or they must be three. Anyone with an idea why battery is not charging?

 

[dodge man]

Is the alternator bad?

 

[LS Tractor Owner]

Bad battery, bad cables (wires), bad alternator, ??? Could be a bunch of different things.

 

[WranglerX]

Typically on new alternator systems they have three wires, one is a B+ that goes to battery, one is a source of 12 volts to initialize charge sequence at start up and one is for ALT indicator light on dashboard.... IF wiring us all plug&play its pretty hard to get it wired wrong.... Could possibly be blown fuse in either initialization or ALT lamp circuit causing alternator to not charge battery....

IF alternator is functioning properly you should see about 14 volts DC at battery with engine running (slightly above idle) ...

Have you checked all you battery cables for clean connections and no corrosions?

 

[Roadworthy]

If you want to know how many wires should go to your specific alternator you need a schematic diagram as it can vary pretty widely. The minimum is obviously one but there can be a whole lot more. You really need a voltmeter to check the battery voltage before and after starting. A resting twelve volt battery should be about 12.6 volts. That will drop when starting but the alternator should put out about fourteen volts when the tractor is running at a fast idle.