Total 750AH for house batteries-----3-Oreilly 250AH AGM8D T904 New 6/2019
200w of solar keeping batteries charged while in storage, no 120v plug in at storage
Temp at 4:20 50F and raining.
Got down to 28F last night so decided to run Aqua hot set at 50F to keep anything from freezing.
Auto Gen Set switch was on but the generator never started overnight
Keep in mind the solar was still hooked up overnight so the Friday and Saturday readings had some solar input.
Battery state when I arrived at 4:20 pm (see picture #1) 12.76V
still had some charge going in from solar until about 7:30 that night--a little sun but mostly cloudy
Turned on Inverter.
Turned on Salesman switch
set 3 thermostats to 50F
Turned on Aqua Hot diesel only
Battery state after turning on above at 4:26PM with Aqua Hot and blower fans running (see picture #2)
12.48V
Battery state at 9:09am next morning (see picture #3)
12.38V
Battery state at 9:15am after turning off inverter, salesman switch, and aqua hot (see Picture #4)
12.52V
Questions????
1--Does the inverter need to be on for the aqua hot to work? Or just salesman switch?
2--Does this seem like a normal draw down on the batteries to run the aqua hot overnight?
No need for the inverter for the AH, draw looks normal to me.
Turning off your inverter will save power.
Yup, they take power even if nothing is running on them/on "stand-by".
All inverters use juice even at idle with veteran models having big appetites. Keep it off unless you need it. We turn ours off when not using 110V, always when we leave the coach and during the night.
Pierce
Some models have search modes which turns off the inverter then restarts periodically to check for loads. Those may have user adjustable lower load limits they need to turn on. You may be able to set the lower draw needed to idle to eliminate "instant on" appliances hooked up in the coach. Remember reading the manual about this ability
This is the only important number, that is to say the resting battery voltage, and it's saying that your batteries are at 85% State of Charge. Or, in this case, you are doing well.
You can safely run your battery resting voltage down to 12.2V which translates to 50% state of charge.
IF you had rechecked your battery resting voltage after another hour it may have been even higher than 12.52V. Remember the difference between 85% and 90% SOC is only another 0.06V or 12.58V, lead acid batteries are sluggish and show considerable recovery after resting.
Narrowboat Leisure Battery Recharging & Discharging | Importance Of Narrow... (https://www.thefitoutpontoon.co.uk/batteries/recharging-discharging/)
Tommy D, regarding your Oriellys mfg by East Penn AGM8D batteries, Old Toolmaker info is correct, his voltages are not. The link he posted however is correct. See following chart from mfg of Oriellys AGM8D. 100% is 12.8, not 12.6 as he stated, for your batteris, 75 % is 12.6, 50% is 12.3, not 12.2 for your Orielly AGM8D batteries.
Sorry to Old Toolmaker for not opening your link, I had only 2G here from Sprint, and it would not open your link. After finally seeing, yes, the link has good information, my only disagreement was the voltages you posted for the original posters batteries.
From East Penn Maintence Manual
Proper voltages for Flooded, Gel, or AGM batteries
And, the critical thing is that these voltages are for BATTERIES AT REST (no charging and no discharging for at least an hour).
I suspect everyone who has monitored battery voltage has noticed that after turning off a big load that voltage "bounces back" to a higher reading. So, it is not the voltage under load that is important in determining the 50% discharge, but the "at rest" reading.
Generic batteries at rest, no charge, surface charge removed:
Different batteries/chemistry, different voltage/SOC
Best answer is to follow your battery manufacturer's chart!
You didn't click on the link Jack L. Just as it is with the Red Queen, my numbers are correct for me. The web site I linked to has the correct numbers for all three flavors of lead acid batteries.
As Foretravel friends, I guess I should elaborate: I try to teach, and unless I'm being paid money by the barrow, I don't do the thinking for others. I gave the original poster all of the information he needs, and a link to accurate numbers. If he can't be bothered to check, well, not my problem.
In my day we had to write to the manufacturer for information and walk to the mailbox, in the snow, uphill both ways.
Art Joly