I have an excavator that wil not charge it's batteries. I put on a brand new alternator but that didn't help. For some time ago someonoe had connected an extra alternator warning lamp from D+ to -, so I tried that and it started to charge, about 28v. This worked for about a week, but not anymore, and now I can't get it to work again. There are som indicators on the panel that are lit, but not always, just from time to time. Anyone's got any idea where to look?
Hi, Welcome to the HEF. Makesure when you post to mention the serial number of the machine. You can find the attached images to clarify the monitor indications. If it comes on time to time there may be a wiring issue some where. But need to check further more. Did you check whether batteries are good ? What is the out put voltage of the alternator at B+ terminal ? It should be 27-29volts. And check the availability of the key switch voltage at the alternator.
I would check the voltage at the big terminal, B+, it should be within .1V of the battery voltage, running or not. Check both. D+ should have battery voltage with the key on, and the engine not running. If the wiring is broken, or the lamp is loose, then that voltage won't be supplied, and the alternator won't charge, and the warning lamp won't light either. If you have battery voltage at D+ running and the alternator is not charging, then it's internal to the alternator. I'm curious about the extra warning lamp, could you post a picture of the wiring for that? All of this is based on a typical alternator, no idea if this Cat has special relays, computers controlling the alternator circuit.
Your D+ wire is maybe shunting to ground or there is an opening circuit. Post your machine serial number for more help.