Voltage 50 percent

This explains it all: the 12v side of life

For me being exactly at the required DC voltage has no meaning at all for me.

I use 12.0VDC as my point to start realizing my batteries are around the 50% charge state.

The charts for the wet batteries is like this I think...



Using the 12.0VDC here as the point to recharge back up to the 12.5 VDC point which is around the 90% charge state gives me great performance with my batteries. i.e. they last about the same time period when I am drawing around 23AMPS DC current during the 6PM to 11PM time frame each night doing this... When I do this including my parasitic drains I usually see around the 12.0VDC point at 8Am the next morning. This is when I will run 2KW Honda Generator connected to the trailer shore power cable to recharge my batteries back to the appx 90% charge in about three hours of generator run time. I don't have any solar panels going yet...

Thats all that really matters to me to be able to do the same thing the next day/night run off the batteries.

For me it really doesn't matter if I missed by a couple points...

Roy Ken

Voltage numbers may not be useful unless there is zero charging and zero load on the battery.

For AGM it is important to not exceed the gassing voltage.

Everything Ive ever read about AGMs is they are NOT the best choice for regularly deep discharging- discharge should be more like down to 60%.

Holding charge on battery and discharge percentage in volts, regardless of type, is pretty much the same .



GELs charge at a lot less rate than Flooded or AGM batteries so a GEL setting shouldn't be used for AGM or flooded wet cell.

Not knowing what "sealed" is on your charger, though instruction/manual may show a charge rate chart which would help identify, flooded would be my choice unless 'sealed' closer (higher bulk & less float than gel)

'Depends' is a shrug and dunno-though in fairness no pat answer.
another good articlehttps://www.westmarine.com/

We stay above 12.3 OV with flooded wet cell golf cart batteries. Renogy tech support is a joke.

Exactly what brand is the AGM? They have different specs.

What are the absorption voltages of the three profiles on Renogy?
Still I would avoid anything with automatic equalization charge.

In the mean time safest is probably GEL.

that is what I like about my Bogart Engineering system. you can change every setting in the charge profle incuding turning on and off equalization charging.

My Universal Battery UB12900's (sold by Cabelas) show the following specs:

charge method (constant voltage)
cycle use (repeated use)
initial current 27A or smaller
control voltage 14.6-14.8V
Float use
control voltage 13.6-13.8V

This is my battery. Duracell AGM

I think sealed is the right choice?

One other thing after reading a rather long and boring article looks like the best thing to do is plug my converter/charger in now and then and let it do its thing to keep my battery in the best shape. I have one of those high tech converter chargers from BEST converters. The reason I say this is because if you are using your solar you never really have enough peak solar time to float equalize and all that good stuff. When plugged into the grid you do.

Voltage is a very inaccurate state of charge indicator for batteries. THere's so many variables involved, such as age of batteries, how long that have been at rest, how big the load was that was running on them, and the list goes on.

I'd recommend a Amphour meter for accurate battery monitoring.
Xantrex LinkLite or LinkPro are two that come to mind.

The best of the best for everything but LI chemistries is the smart gauge. It becomes more accurate as it is used where as all the others drift out of calibration. A distant second is the Victron gauge--which is a LOT better than the trimetric and Xantrex