We are having issues with the charging system on a 721b Case loader. We have put 2 Alternators on it, and new batteries, but every 2-3 weeks have to charge the batteries up, and then it's good for a couple more weeks. After changed the 1st Alternator out, we sent it back to the manufacturer, and they said that there were no issue's with the Alternator, so I have it back. It is a 24 volt system, and my tester will not work on it. There is a box under the left side hood, near the Alternator and Starter that has a couple of Relays, or Solenoids. I was wondering if either of those being bad would have anything to do with the charging system. The local Case dealer that works on it, is not very forthcoming with information, they want to work on it themselves I suppose. Any help would be appreciated. Mike
Is it a built in regulator or an external one if so start there.
Built in
Are you installing the proper alternator? (same amp rating?) Have you installed extra electrical loads, such as extra lights? Have you inspected your wiring? Do a voltage drop test. Turn on all electrical loads that you have. Then put one end of your multi-meter on the + of the battery, and put the other end on the alternator + , then record the voltage reading. Are you using the battery disconnect switch at the end of the day?
Yes the alternator is a direct replacement, No equipment has been added. Yes the wiring has been checked. Not sure on the voltage drop. I have told them to try shutting off the main disconnect, but it is at a different location than I am. But they will use it, and an hour or so later go to use it, and it will not start until the batteries are charged somewhat. 95% of our work is during daylight hours, so there is no need to run the lights. The loader is used to fill bins, or push up material, or load dump trucks on occasion, so there should be very little drain. The only thing that it runs is the shut off solenoid and the trans shift solenoids, the throttle and bucket controls are all manually controlled. Again, there is a box on the left side of the engine bay, near the starter, and alternator that has a couple of either solenoids, or relay's, second hand info, is it possible that one or both could be not functioning, or occasionally working, that may be causing this problem. I do not have a manual on this machine, they are very expensive.
Put a test light between one of the battery cables and the post with everything off, if the light comes on , something is drawing current , if it's 24 vt , may have to use a meter
Yes it is a 24 volt system. I know on some older machines and trucks that are 24 volt that they have switches in the system to send 24 volts to part of the system and 12 volts to other parts of the system. I'm not sure if that is the case with this loader. It is a 96 model, I also have a 98 model 721B. The 96 has no volt gauge, the 98 does.
Use a mulitimeter to see if it's charging or not when it's running, then you can divide the potential problems in half at least. No point at all in speculating without even THAT much info.
What he is saying, with the loader off, key off, put a meter on the battery or batteries so you get your 24vdc reading. Make a note of exactly what the voltage is. Then start the loader. While it's running, take another reading at the same point as before. If it's charging, it should be higher. I am not sure what a 24v system would run, but I suspect it would be at least 25 or 26v depending on the charge of the batteries. If you get the same voltage reading as you did with the loader not running, or a lower voltage reading, then the alternator is not charging and you can troubleshoot that, there would be a couple of possibilities causing that. If it is charging but you can't park it for very long before the batteries go dead, then there must be a drain, that can be verified and you can do some troubleshooting for that as well.
Exactly, the resting voltage should be double a 12V so at least 25 V resting. Charging should be 26-28V or maybe a little above 28. If you don't have more than 26 at the batteries when it's running, then take voltage measurements on the back of the alternator running. There should be one big wire and more than one little wires, record all the voltages and the lables of the terminals, or better yet, post a pic of the back of the alternator with the voltages. That's ONLY if the you don't get 26 V running.