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Testing new agm batteries

I've unplugged my shore power and will let the coach sit for 12 hours. What should the battery voltage be after this time frame with a couple lights on with healthy batteries and a full charge
Thanks
1996 U295-36, Cummins 300hp, 8.3. Build number 4864. Vin number 1F97D536XTNO54271. Purchased October 31, 2019.

Re: Testing new agm batteries

Reply #1 –
You cannot use the vague draw of a couple of lights and get a good answer. You would need an expensive tester. If you completely charge the batteries and unhook them for over 3 days the voltage will tell you somewhat how good they are. My good ones will be 12.8 after sitting 4 days.
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: Testing new agm batteries

Reply #2 –
Mine are usually between 12.80-12.60 after sitting with no load. But to check them you will need to unhook the ground cable so on draw.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Testing new agm batteries

Reply #3 –
Ok. I'll remember that. Thanks
1996 U295-36, Cummins 300hp, 8.3. Build number 4864. Vin number 1F97D536XTNO54271. Purchased October 31, 2019.

Re: Testing new agm batteries

Reply #4 –
Quote from: dans96u295ft –
I've unplugged my shore power and will let the coach sit for 12 hours. What should the battery voltage be after this time frame with a couple lights on with healthy batteries and a full charge
Thanks
Regarding the above information you have provided, with "a couple lights on", no starting voltage at rest, etc., their is no right answer.  I thought you had a Victron BMV-712 or similar device, that would moniter your batteries, to give you your state of charge, amps in or out and ah used, voltage at rest,  etc.?  If not, you will need one to establish your own normal, or what your "what should the voltage be".
https://youtu.be/tV055vmZgvY
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: Testing new agm batteries

Reply #5 –
I bought 3 of these to test three batteries at the same time.  Two would match your setup.

250W DC 12V Discharge Battery Capacity Tester Module With DC Electronic Load...

You will need 12 volt power supplies that put out 12 volt exactly

Plus cabling. 

Real lab grade testing equipment.

"Riding and rejoicing"
Bob & Susan
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