float voltage for deep cycle marine battery

[stevehull]

Recently installed a "deep cycle" marine battery (type 24M) for one of my automated pasture gates (to open/close gate with automatic opener). The battery label says it has a capacity of 1000 cold cranking amps (CCA) at 32F.

Use a 25 watt PV panel (17 V open voltage; 1.25 A) and have been looking at battery voltage every day. Assuming 5 hours of full PV panel output, then I get about 100 watt hours of charge each day.

This battery has not risen above 13.1 V and I have had it on the PV panel for almost two weeks (very sunny days). Have I gotten to the float voltage?

This voltage measurement is done with the PV panel disconnected and the measurement is onto the actual battery terminals.

The battery is a sealed type (NAPA) so I don't know if it is a gel or what inside there. Yes, it is a Pb-acid 6 cell, but I can't find V-I charging curves on the web.

Only open the gate 1-2 times a day. At basal (not opening the gate) the control box system constantly draws about 40 mA (16 watt-hours/day). During the 12 second open cycle, the current draw is about 2.3 A; same for close cycle.

A remote opening gate is a very necessary thing so you can scoot out of the pasture (through gate) while keeping livestock in timing the gate opening with a remote "clicker" as you drive in and out.

Steers may look dumb, but they know that if you are out of the car opening the gate, that this is the moment to dash out on the road!

May look funny with me driving about pasture honking horn, then a dash out the gate, but it SURE beats "running of the bulls" out on the main road.

Thanks for the information on float voltage. 13.1 seems low, but I am rather ignorant on this stuff and know there are people here with lots more experience/knowledge than I have.

Steve