Help with tempermental battery charger

[Rohan]

This makes zero sense to me, so putting this out on the forum. I have a Promariner Protech-4 battery charger, the 12v 30a version. The charger is connected directly to the batteries. It's a little old, from 2006, but been very reliable and haven't had any problems with it until now.

I went through a lot of steps but I'll be as brief as possible.

Got to the boat after being away for a few days, usually solar keeps it topped off, but this time voltage was a little low after some cloudy days so I plugged into shore power and flipped on the battery charger. Normally a second later I would see the voltage jump up significantly. But this time it didn't.


1. Turned the battery bank selector, (I have AGM starter and Lithium house batteries), turned the charger on/off again, checked the fuse and breakers, reset switch, everything. It still wouldn't charge either battery bank. The lights on the battery charger were on, but the little fans weren't, although that doesn't mean much since they don't run all the time.

2. So I randomly flipped some of the float and battery type settings on the charger and flipped them back just to see what would happen. The voltage did jump up and it started charging again. But 10 minutes later just stopped on its own. No reason that I can see. Tried it again several times but this time that wouldn't work. hmmm

3. Then I turned the battery charger off - checked voltage at the terminals, reading 12.5, so just reading the battery voltage. No surprise there.

4. Then turned battery charger on - checked voltage at the terminals, still reading 12.5, so still just reading battery voltage. That's not good.

5. So I unhooked all the batteries. Then turned on the charger and tested again - this time it read 15 volts. So outputting very strong now!

6. Then I turned it off, and hooked the batteries back up. Then turned it back on. No output. Grrrrr.. very frustrating, and feels so random.

I don't think it's a battery problem, they are still charging normally from solar. Before I buy a new charger, and deal with all the hassles of installation, I'm wondering could I be missing anything?

[leecea]

I had that same charger - probably original on my boat from 2004. It failed last year, but in a different way.

I contacted the company and described what happened, and they responded very quickly saying it should be replaced. Perhaps you could contact them?

[dougweibel]

The voltage that a charger, or a battery, shows with no load does not give you a lot of information. When you see 15 volts on the output of the charger when it is not connected to a load does not equate to "outputting very strong." It is not uncommon for a device to be able to supply the proper voltage when there is no load and therefore no current or power being delivered. If you apply a load and the voltage drops radically the device has a problem. If the charger were operating properly you should see more than the resting voltage of the battery when the charger is attached and operating.