Newbie. Cabin solar charging while not there.

**Mike90250** · 09-08-2020, 12:31 PM

Do not leave the inverter on

Can you set your controller to float only ?

**wine_guyu_3** · 09-08-2020, 12:44 PM

Wouldn't float cause more charge, higher voltage on the batteries?

**sdold** · 09-08-2020, 02:21 PM

Originally posted by wine_guyu_3

Wouldn't float cause more charge, higher voltage on the batteries?

If they are lead-acid, either wet AKA "flooded" or sealed AKA "AGM" types, they will benefit by being kept on a float charge so they will stay fully charged. Are they something else, like one of the lithium types?

**wine_guyu_3** · 09-08-2020, 03:47 PM

They are flooded, lead acid, deep cycle.
Won't leaving them on a float charge for a few months put more strain on them?

**chrisski** · 09-08-2020, 05:04 PM

How do you feel about not checking the battery fluids for months?

I am doing something similar with my RV, and I decided I'm going to try and remove them and bring them to the house when not in use. System should be done building in a couple weeks. Those batteries are heavy, so I don't know how long that will last.

I am new at this, but in AZ I lost a battery a year at the RV from being stored in the sun. Actually every 13 months, so 1 month past warranty. The first one was low fluids, my fault, I never checked it the entire year, the second was my fault also, I did not know about DC loss and extended a small gauge 5 watt trickle charge panel by 25 feet, and it did not deliver enough juice to charge it.

**SunEagle** · 09-08-2020, 07:13 PM

Originally posted by chrisski

How do you feel about not checking the battery fluids for months?

I am doing something similar with my RV, and I decided I'm going to try and remove them and bring them to the house when not in use. System should be done building in a couple weeks. Those batteries are heavy, so I don't know how long that will last.

I am new at this, but in AZ I lost a battery a year at the RV from being stored in the sun. Actually every 13 months, so 1 month past warranty. The first one was low fluids, my fault, I never checked it the entire year, the second was my fault also, I did not know about DC loss and extended a small gauge 5 watt trickle charge panel by 25 feet, and it did not deliver enough juice to charge it.

Most RV's have a way to disconnect the battery system from all of the vampire DC loads in the coach while it is being stored. Check to see if your RV has one of those and then a small wattage panel should be able to keep the batteries at float.

**Mike90250** · 09-08-2020, 07:24 PM

A battery being on a true "Float" charge, won't be harmed. Happens all the time for emergency EXIT sign lights. But the float voltage must be properly set for the battery. Often batteries have 2 voltages for float:
Cycle Duty
and
Standby Duty.

And while you are away, you don't want the battery blasted with a 3 hour absorb cycle daily, when it's not been used, so set the controller to Float.

**sdold** · 09-09-2020, 12:08 AM

Originally posted by wine_guyu_3

They are flooded, lead acid, deep cycle.
Won't leaving them on a float charge for a few months put more strain on them?

We have hundreds of radio sites with batteries sitting on float charge 24/7, and we see many years of service. As Mike said the manufactures typically give a constant voltage value for float service and another for cycle service. The batteries we use the most are about 13.6V for float and I think they recommend 14.5-15V for constant-voltage in cycled service. But your manufacturer should have specific numbers and probably a graph or formula to compensate for temperature.

Newbie. Cabin solar charging while not there.

Newbie. Cabin solar charging while not there.

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