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Topic: Battery charge, need opinions-How does this look to you guys (Read 549 times) previous topic - next topic

Battery charge, need opinions-How does this look to you guys

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?



2000 GV320 4010 build #5712  2019-?
1999 Bounder 2000-2008
Bardstown, KY
🥃The Bourbon Capital of the World🥃

Re: Battery charge, need opinions-How does this look to you guys

Reply #1 –
No need for the inverter for the AH, draw looks normal to me.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Battery charge, need opinions-How does this look to you guys

Reply #2 –
Turning off your inverter will save power.
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport

Re: Battery charge, need opinions-How does this look to you guys

Reply #3 –
Quote from: oldguy –
Turning off your inverter will save power.

Yup, they take power even if nothing is running on them/on "stand-by".
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Battery charge, need opinions-How does this look to you guys

Reply #4 –
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
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Battery charge, need opinions-How does this look to you guys

Reply #5 –
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
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Battery charge, need opinions-How does this look to you guys

Reply #6 –
Quote from: Tommy D –

Total 750AH for house batteries-----3-Oreilly 250AH AGM8D T904

Battery state at 9:15am after turning off inverter, salesman switch, and aqua hot (see Picture #4)
12.52V

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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...
1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Charlie, the Dog was broken out of jail 24 Oct 2023
N1RPN
AA1OH (H)e who must be obeyed.

Re: Battery charge, need opinions-How does this look to you guys

Reply #7 –
Quote from: Old Toolmaker –
You can safely run your battery resting voltage down to 12.2V which translates to 50% state of charge.......

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
97 U295 40, Build #5040, 6C8.3 325 HP
Oregon Continuous Traveler
Samsung Residential #RF20HFENBSR,
Xantrex SW2012, (3)AGM8D Hse, (2)AGM Grp24 Eng, Victron BMV-712, 1800w Solar 4 LG & 2 Sunpower
Extreme Full Body Pt w/hdlmps, new furn/floor, 4 down Lexus 2004 GX470 AWD curb weight 4,740 lbs
Prev: 1990 Barth, 10L 300 2 yrs; 91&92 Monaco Signature, 10 yrs, 10L C 300 &  6C8.3 300; 1997 ForeT 6C8.3 325 since May 2017.  Employed by Guaranty RV 14+ yrs.  Former VW New Car Dlr/Service Dlr, Sales Mgr, Rv Sales, and Service Adviser from 1968-2017
"Don't criticize what you can't understand" Bob Dylan

Re: Battery charge, need opinions-How does this look to you guys

Reply #8 –
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.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Battery charge, need opinions-How does this look to you guys

Reply #9 –
Generic batteries at rest, no charge, surface charge removed:

Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Battery charge, need opinions-How does this look to you guys

Reply #10 –
Different batteries/chemistry, different voltage/SOC

Best answer is to follow your battery manufacturer's chart!
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020
 

Re: Battery charge, need opinions-How does this look to you guys

Reply #11 –
Quote from: Jack L –
Old Toolmaker info is correct, his voltages are not.  See following chart from mfg of Oriellys AGM8D.  100% is 12.8, not 12.6, 75 % is 12.6, 50% is 12.3, not 12.2.


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
1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Charlie, the Dog was broken out of jail 24 Oct 2023
N1RPN
AA1OH (H)e who must be obeyed.