All 4 batteries boiled dry on C28

[jswhal]

I haven't been able to use my boat for 2 months, and left it on shore power with the battery charger on. I found the engine battery dead when I tried to start it. All 4 batteries had no water, and the strap holding the engine battery down had its plastic buckle charred, indicating a lot of heat in that battery. I added water to them and after 8 hours, none showed much charge on a hygrometer. When I changed the house bank out, I turned the charger on and it showed "Charging 2.1 volts 10 amps". It doesn't tell you what battery is on 2.1V. I measured them and it was the engine battery. I think the 5 cells must have shorted and only one was putting out the 2.1v. My question is why did the other 2 banks lose the water? I have the ProMariner 3 bank charger.

 

[BB marine]

My question is why did the other 2 banks lose the water? I have the ProMariner 3 bank charger.

The unfortunate part of the Fluid motion charging design when using the ProMariner Charger with 3 individual outputs along with the ACR's once one battery reaches 13V for 90 seconds or 13.6V for 30 seconds the batteries combine and charge as one bank. When Fluid motion installed the ProMariner 3 bank charger they never installed a way of disabling the ACR's. The ACR's are needed when charging from a single output charger Engine Alternator or the Promariner Charger/inverter because there is one output and the isolation is done through the ACR. The Promariner 3 bank charger has the isolation built into the charger. It will charge each bank according to need. When the batteries are connected to ACR and not disable when one bank is at or above 13V and does not go below 12.7 the batteries are all connected in parallel. Your charger kept charging all the batteries based on the needs of one of the batteries and "cooked them" The system works if all batteries are equal. If one bank is bad and the batteries are not monitored. The results is what you experienced. It is a poor design that has been discussed many times on TugNuts. It works ok but many have stated that it decreases the life expectancy of the batteries. I tend to agree with this theory.