A Confounding Problem

[KStepman]

What is going on here?

I am having a confounding battery problem: I have a 2005 Hunter 36, with a ProTech4, model 1230, "Advanced, Four-Step, Battery Charger/Power Supply," output 12V, 30amp; a Yanmar 3YM30 diesel with factory alternator; and a Honda 2000i Companion portable generator (to plug into one of my two, 30amp shore power inputs).

I recently added one Deka 8D AGM, to use as my House battery bank, and ganged my existing two Group 27 lead acid batteries to be my Starter/Emergency bank.

When I am running my engine, all batteries become fully charged. However, when I am plugged into shore power, or my portable generator, only my Starter/Emergency (2-group 27 Lead Acid) bank is being fully charged. My House 8D AGM, is not. What is happening here, and how can I fix the problem?

I have spoken to ProTech, and they say I should not be having this problem.

Here is one more piece of information: When I SELECT the 8D AGM to use as my House battery, while plugged into shore, or generator, the voltage will eventually drop precipitously down to ~ 0, at a point of use, while the DESELECTED 2-Group 27 lead acid batteries are being fully charged. However, when I SELECT the 2-Group 27 lead acid batteries are SELECTED as my House, the voltage in my DESELECTED Deka 8D AGM battery appears to be charged back to ~11 Volts, but not fully to 12 Volts.

What is wrong here? Thanks!

[SailFastTri]

You aren't providing enough info for troubleshooting, but it sounds like you have something connected wrong in your wiring. I recommend you get someone local who can troubleshoot by tracing all your connections and confirming things are connected properly. Also your new battery might be dead, based on the voltages you wrote. Perhaps due to being mis-wired.

[Tellie]

Your house battery is charged by the alternator but not the not the shore powered charger. I'd check to make sure there is a charging lead to the house bank and if there is I'd check to see if it is working when the charger is on. Also when you select to use the starting batteries on your battery switch your two starting batteries sound like they are trying to bring up the weaker house battery. I'd say it's either a bad charger or more likely bad wiring. It's probably a good time to bring in a marine electrician.

[KStepman]

I brought in a Marine Electrictian when I arrived at St. Augustine. He found the problem, but it was confounding him as well. The two leads on my selector switch from the battery charger to each of the battery banks were wired to the same terminal in error. So, only one bank was getting charged.