Yes. This charger works 3 batteries. For my setup, I have for my boat a marine cranking battery. Then I have 2 full deep cycle batteries for a 24 volt trolling motor system. I used to charge them one at a time which was a major pain. Plus I never realized that with the primary cranking battery, running the battery off the alternator once running will not fully charge the battery. It will only get to about 70 percent full. However with this battery charger, it has an internal computer which will properly charge and maintain the battery. The other good thing about this charger is that if you only have 2 batteries, you can still use it. Just pair the other free connections to one of the batteries. I contacted ProMariner customer support directly and they confirmed this is possible and safe. Overall happy with the product!
You have probably tried all the following, but. Turn unit totally off including all connection to and from. Walk away for an hour. I'm not sure, but go through the "reset" procedures and reconnect one line at a time. I've never had any problems to date. I hope yours just hasn't reached the end of the line. Be safe, remember or military and Marines, and enjoy Memorial Day. kmm
Judy, the unit is actually 11inches wide x 6inches tall x 2 3/4inches deep, however you will need a larger area. The wires are stiff and need a couple of inches of room to come out and turn, so you really need 13 inches instead of 11 for the wideth. The unit puts off a lot of heat and I discovered this later, then had to remount it. I take my boat to the lake for the entire weekend and the built in ice coolers would keep ice for the entire trip. After I installed this unit, just a few hours of charging would melt all my ice. I first tried to fix this by just leaving the compartment door open where I had placed the charger while I was charging but this had little if any effect. I ended up mounting a metal plate, then placed 1/2inch spacers between the device and the plate. This solved the problem by reflecting the heat out of the compartment and brought the unit out from under the fiberglass lip that I felt was trapping and channeling the heat. The mounting modification made it 3 1/4inches deep. I also allowed for a inche of air on each of the other sides. My suggestion then is to consider needing 13inches x 8inches x 3 1/4 inches when looking for a location.
Another insite I can share is in regard to the wire lengths. Mine were 52 inches which greatly limited mounting options, they offer a cable extender which I think would be well worth the additional cost.
The last suggestion is battery maintance, this charger does a great job and I would buy one just like it again but the process it goes through to charge the batteries also boils off the water fast. You will need to check the water level in the batteries at least monthly and in warmer weather more often.
Over all I am extremely pleased with this charger, I can tell the engine spins faster on start up and runs better. The trolling motor runs at least 50% longer. Then probably even more importantly the other electronics attached to the batteries have had fewer glitches.(fish finder,DVD player, Laptop etc) I hope this helps, Jared
If you have a question, you really need to call the ProMariner tech service. ProMariner has a reputation for standing behind their equipment. From a previous boat I sent a defective charger back to them that was out of warranty, and they still replaced it without any charge to me. They are a great company and I learned about them from internet chats.