I recently purchased a new Deep cycle battery for our camper from Orieleys. Sure start brand or something like that. At the time of purchase its labeled with a MFG date of 5/2014 . I assume its been sitting uncharged for 4+ months off the get go. Ive charged this with a 2,4 & 6 amp charge for a couple different 24 hour periods, and it never seems to go above 13.8 volts unlike the usual 14.3 I'll get with bike & car batteries using either the same charger or leaving a bike on a battery tender Jr. Once the surface charge is gone the RV battery drops to 12.7ish. We have yet to use it on a trip but Im thinkin its not a very good battery or is screwed up from sitting so long before being sold. What sayeth the battery gurus?
12.8 is fully charged........so your 12.7 ish is very close. I have two RV batteries and the small low amp charger will take for ever if ever to reach max charge voltage...............they go into float charge mode and never get to the 14.0-14.2 voltage. BUT the batteries end voltage is about 12.8 v. Some of this is determined on how "smart" the charger is........ If charged for longer periods the fully charged light on the charger lights on the trickle charger. I use that all winter and the the batteries are 5 years old. The Schmaucker charger never push water out of the battery evm long term. I have 10-15 amp auto charger it completes the charge cycle in about 24 hours. The on board RV charger is faster but I do not trust it for long term storage to taper and maintain. As for the battery sitting for 4-5 months that should not be a problem. The other factor is you new battery AGM or conventional wet battery? Getting back to how "smart" the charger is.
The battery is wet type. I stuck the tender Jr on it after it was up to 13.5 or so, but the JR gets pretty hot and I didnt wanna damage it. The 2,4,6 amp charger is a automatic type Duracell labeled unit with float,maint and charge much like a tender. Although Ive had good luck with it over the years with other RV & starting type batteries, its probably not the best made.
Sounds normal. Is the battery connected to the RV? Could you have some parasitic loss ie something using power from the battery?
deep cycle batteries usually use a lower SG electrolyte.... it will never read higher than about 12.5v, maybe 12.7 tops as a resting voltage.... its in the chemistry. it's related to how they can do deep discharge & not die
