Since you stipulated 5 batteries I assume they are 12 volts each hence each will have 6 cells for a total of 30 cells. A liter of water is about 33 ounces or slightly over a quart indicating that each cell is requiring slightly more than an ounce of water every two months. Frankly, considerig the environmental conditions--Mexico/Summer--that does not seem like an unusual amout of water at all. Depending upon how long you will be gone, however, it might have been wiser to simply turn everything off, including the master switch to the batteries, which would loose only roughly 1-1/2% to 2% of their charge per month which could be restored with only a few hours of charging once a month.
07-27-2010 12:03 PM
Hmm another possibilty is that you have a battery with a dead cell this will cause the charger to "see" that the bank needs more charge and ALL the cells get overcharged. I replaced the 2 house batteries in my RV with marine deep cycle batteries from Wamart and in 2 years had 3 maybe 4 go bad. It is an easy check - separate the batteries and check the voltage under load.
07-27-2010 10:54 AM
Keeping wet cell batteries on float forever is not good for them. They will dry up. The two best things you can do for them: either leave them fully charged and disconnected, or get a small solar panel to offset the small amount of self discharge of wet cells.
Yes, excessive water use usually indicates over-charging.
Why would your charger be doing that? There could be a dozen different reasons. I would try to get down to the boat with an accurate digital volt meter and see exactly what the float voltage is.
07-27-2010 02:47 AM
Batteries drinking a liter of water each / Xantrex
First of all I am pretty new to boat ownership and 12 volt systems so please bear with me. I recently acquired my fathers crealock 37 after it had experienced a few years of neglect, unattended in mexico. In December I went down to mexico and after a couple of months, got the boat back cruising. The LifeLine AGM batteries seemed toasted so I replaced them with 5 marine flooded deepcycle batteries from walmart and headed on out for 5 months. Great times were had! I left the boat in Puerto Vallarta in a slip plugged in with the charger set to float. The charger is a Xantrex Trucharge 40 and it is set on the flooded setting with the temperature set to hot. I have been gone from the boat now for 4 months but I have an inexperienced friend who has been kind enough to add water to the batteries every 2 months. It seems that the batteries are taking a liter of water to get back up to full. Does this indicate that the batteries are being over charged and if so, why would my charger be doing that? Thanks for any insight. grant