BFL13 wrote:
Nothing new. For years we have been telling folks on here to not use one battery and then use the second one. Instead use both together and get more than twice the AH running the same load.
I don't disagree in the theory but it's all too easy to recommend 2 batts when you're not the one paying for them. :R I'm in this situation myself - I have no choice but to replace my 10 yr old G27 Interstate battery this spring, it's gone to battery heaven, no amount of resuscitation helped. :( We normally camp on electric sites and based on that alone a simple G24 sitting on the tongue would serve the purpose.
However, because we lose campsite power for one reason or another at least 2 or 3 times each season I installed a 1000w PSW inverter in the front pass through storage compartment so we can still use a couple of 120 vac fans and make coffee & toast the same way we always do. Although the 6' run to the tongue mounted battery with 4 gauge cable met specifications for the max 60 amp load I would ever draw voltage drop was still problematic with just one G27 as the source. Obviously the solution was to invest in 2 new batteries but I wasn't about to do that until my existing G27 announced it's entry through the pearly gates. In the meantime I found that if on the few occasions I actually needed to run my toaster or coffee maker using the inverter that load supporting the trailer battery with the truck solved the problem of excessive inverter voltage drop nicely. That was then, this is now, and I need a new battery. I had considered inexpensive flooded dual GC-2s on the tongue but even those would be problematic with the space I have available and no way would dual G31s fit. My solution is to instead go with a single G31 AGM battery that can sit in the front pass through storage compartment, which in turn means I can connect the battery to the inverter with short 18" 1 gauge starter cable that will measurably reduce voltage drop due to cable length & gauge. So - why not 2 batteries in parallel? ... COST. Here in Canada a G31 AGM can easily run well north of $400 Cdn, $800 for a pair, even much more for premium brands. Then there's the issue of recharging them ... my WFCO won't do a proper 14.4 volt bulk charge, the CTEK I have will but it's not really the appropriate choice for recharging dual G31 Deka AGMs I'm considering that
require temperature compensation. Third, because we'd only be running on battery power just a few times each season having 2 would be a total waste the rest of the time. Bottom line - it's easy to
say go with dual batteries but not a universally applicable recommendation for everyone. ;)
