What is my battery life

[Jerrypd]

Hi all,
This is probably a dumb question, but I cannot find any documentation.

Just took delivery of a 2021 hybrid x23b with solar on the roof.

I have 2 interstate srm-24 batteries hooked up in front. Solar is attached to them.

I have the gp-pwm-30-sq solar charge controller.

I was in the trailer overnight plugged into shore power (30amp).
Used the lights for about 4 hours and ac running all night.
Right now the controller is reading in sequence of the amp/volt switch press:
13.2 volts / 0.7 amps / 0.7 Ah
The green light is next to the 3/4 battery on the left, and the red solar and blue charger lights are on.
Do any of these indicators tell me how much battery power I actually have?
If I read the battery specs right, I think I have 81 * 2 amp hours?? And what do the numbers on the solar module mean?
A bit confused...
Jerry

[Jagiven]

I'm no solar expert. Sure a few will jump in. The solar charge amps will vary based on the amount of sunlight. You posted your question at 7am, and said "right now the controller...." at 7am, the sun is low in the sky, and the panels are not able to absorb a lot of power, due to the sun's angle. Look again around noon. The amps will be much greater. Cloudy days verses sunny days will have a huge affect too. Unfortunately being in the shade will reduce the power absorption rate.

As for how long the battery's charge will last. Bit hard to say, as it is user dependent. Two batteries and being in a sunny spot, theoretically you can go indefinitely.

We do not have solar, have a single 100 amp hour battery. Needing the furnace, 1 day. If we are not using the heat, and not too careful we can go a couple days. Being ultra conservative 4 to 5 days.

Just remember unless you have an inverter only the 12V system will work off the batteries.

[Jerrypd]

Thank you for the reply!
I understand the solar issue, and the low morning sky... I have had solar on my house for 16 years.
I was trying to understand the numbers from the station.
I get the voltage, and sure enough before I left the trailer at 830 it said FUL.
BUT, the second press read 0.7A and third said 0.7Ah.
I was under the impression that meant I was using 0.7A (which would be quite high since I had turned everything off) and that the 0.7Ah was battery capacity?
Nowhere does it show the 162 amp hrs available to me from the batteries.
Shouldn't I be able to see that reading?

[ARoamer]

Not familiar with your system, but.....

If you want to know your battery's remaining charge level you would need to install a battery monitor with a shunt.
I don't think your solar controller will tell you your battery remaining capacity, but usually it will tell you if it's charged, and how much your solar is producing.
You can estimate your battery's remaining capacity by it's voltage, that depends on battery type, lead acid, lithium.
According to my Victron solar controller, my 5er uses about 24AH per day sitting in my driveway unused, but it has lots of electronics, CO detector, BMPRO system. .7A draw sounds normal.

[67L48]

For your batteries, you have two 12V batteries with 81 AH. Thus, your total is double, but your available power is half (you damage batteries by drawing them down more than 50%). So, you have ~81 AH to play with from your batteries.

Your solar recharge is based on Ohm's Law: P=VI. You didn't specify your solar panel's rated power. That's critical to know.

Let's assume 100W for an example calculation. The equation above tells us that the maximum juice this panel could supply is 7.6 amps per hour (100/13.2). But, there are losses in all of the circuitry and the panel's rating, itself. So, assume 80%. So, you get 6 AH back per hour. How many hours of sun do you see? Multiply that by your value to see your recharge rate.

You'll probably put 30-45 amps back into your batteries every day with a 100W panel. More if you're in the deserts of Moab. Less if you're in a forested campground.

If that reading of "13.2 volts / 0.7 amps / 0.7 Ah" is the capacity of your panel, then you have a (13.2*0.7=) 9 W trickle charge panel that won't do much more than recharge your iphone.

[Jerrypd]

Ok. Got it.
I think that WAS trickle charge since I was full at the time I looked at it.
I think I will get a battery monitoring system so I have all the info on both the battery and the solar.

[Bob K]

If that reading of "13.2 volts / 0.7 amps / 0.7 Ah" is the capacity of your panel, then you have a (13.2*0.7=) 9 W trickle charge panel that won't do much more than recharge your iphone.

Originally Posted by Jerrypd

Ok. Got it.
I think that WAS trickle charge since I was full at the time I looked at it.
I think I will get a battery monitoring system so I have all the info on both the battery and the solar.

If it helps, my Renogy suitcase solar panel indicates what its current condition is. On my solar controller, 13.2v would be the present output voltage to the battery. 0.7a would be the present amperage output to the battery. 0.7Ah would be the amount of juice the solar controller has put into the battery since it was connected and started this particular charge cycle. The numbers you listed indicate to me that the solar charge controller is in the float charge portion of the charging cycle.

I've enjoyed having the Victron SmartShunt so that I have better insight into what the battery bank is doing.
https://www.amazon.com/gp/product/B0856PHNLX