having trouble charging\using house batteries

First; note what Mexicowanderer said. He is THE MAN when it comes to the care and feeding of batteries.

Once you get the batteries tested and probably replaced do what has been advised above, including upgrading the controller. Controllers of that era, if left on continuously, will kill the battery through overcharging.

If you store it somewhere with no 120V AC power available then you need a small solar panel and solar controller. At a guess, 10 to 20 watts would do IF ALL loads are disconnected from the battery and the battery is at full charge when stored.

If you want to use the solar for more than just battery maintenance, ie off the grid camping, a pair of 6V golf carts would work well with 110 to 350 watts of solar panel and the appropriate controller.

X 2 on your ruining exellent batteries in one year.

The batteries need to be disconnect when stored. Waiting a year before charging does not cut it. Also your old charger should be upgraded. Poor TLC ruined batteries.

Isn't there a boilerplate How-To guide somewhere that would explain all the basic battery stuff in layman's terms.

Unless you are mechanically inclined start off by yellow pages. Find a real, authentic battery shop. Some automotive electrical rebuilders sell batteries and understand them. You need to get those batteries to their shop and have them professionally charged and tested. Load tested AND hydrometer tested after charging.

Yes, you can destroy batteries in a year. You need to learn why and how to prevent it. My first question above is for fellow forum contributors to direct you to a developed site to put you on a basic learning curve.

Moved from Forum Technical Support

Batteries tend to sulfate and permanently lose capacity if they sit for a year and discharge.

Converter terminals putting out? Yes... voltage over 13 Volts, almost 14. What is at the battery? 14 should be. 12 or less? One or the other wire from the converter is not tight and connected. Best option, use a jumper cable and connect to the positive battery, and to the positive converter. Did it fix it? Yes.. find the loose positive wire. No.. use the same jumper cable and connect from the negative battery to the converter negative. Did that fix it? Yes.. check the negative wire to the battery. No.. other things. Try that first and see what happens, then call me back.