Converter not charging batteries

facalton wrote:
Converter: Parallax Power Supply. Electronic 7100 Series.

Parallex 7100 has two versions 71xx and 71xxt The T is two stage and might get you to "Full" Either live with it (Finishing with an external Smart Charger) or upgrade the "Guts" of the unit with a Progressive Dynamics 4600 series (Match the last 2 digits as close as possible)

The 7100 is a single stage (Float) Charger. it does not do bulk or ansorption the 4600 does. The 7100 T has a "Timed" Bulk phase when you first plug it in.. I'm guessing if you unplug wait a few minutes and re-plug that "Boost" mode will finish the charge (may take a couple replugs)

Also how accurate is your method of measuring charge?
A temperature compensated hydrometer is accurate.
Other methods (Unless lab calibrated) not so much.

Start with the basics & check all connections between converter & battery bank.

If you determine that the converter is at fault you might consider upgrading to a multi stage programable charger & get all of your 12V needs from the battery bank, just like boats are set up.

While you are in there get a pure sinewave inverter. Do not get a inverter charger. If one part goes bad the whole thing needs to be replaced. Separate units means just the faulty unit gets replaced.