Problem with new batteries keeping the charge
Recently had two new house batteries installed by the yard as part of bigger maintenance project. Engine battery is a relatively new one (about a year old). All batteries are wet-cell. In the process, also changed my old switches from "ALL/1/2/OFF" to just "ON/OFF."
Nonetheless, it seems that the new system is not keeping the charge. I will leave the batteries fully charged by running a charger (shore plugged in) for at least 3-4 hours without any load on the batteries. All three batteries will show a charge of 13.2-13.4V upon completing the charge and then slowly settle to around 12.8V. When leaving the boat for the week, I usually turn off all the switches at the [breaker] panel as well as turning both battery switches to "OFF" position. (The bilge pump is wired directly.) I will also empty the bilge with the hand-held bilge pump.
However, when I come back to the boat a week later, I usually find both of my house batteries down to 12.5V and the engine battery around 12.6V. The bilge is still empty and nothing else is on. I have observed this on several consecutive weeks and it is driving me crazy. The yard mechanic appears to be stumped as well.
Any suggestions ? Thanks in advance.
The sea, once it casts its spell, holds one in its net of wonder forever.
Jacques Yves Cousteau