Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club. Today he discusses batteries for boondocking.
We are purchasing a new travel trailer that comes with a 12V DC fridge. No propane option for fridge. Dealer has recommended installing a pair of GC15 6V batteries instead of the normal 12V deep cycle batteries, because we intend to use the camper mostly for boondocking/remote camping. I am concerned about running out of power overnight.
We will have a gasoline generator, but I am concerned about how long we will have to run the generator to recharge the batteries every day. Do I need to install solar panels to keep the batteries charged up during the day? Or will the GC15 batteries and generator work well for us? Other power draws on the 12V system will be lights, furnace fan, water heater ignition.
Thanks for your help! —Phillip
Thanks for joining us on our new forum and the opportunity to provide some assistance with your batteries and boondocking!
RVers switching to 12V DC refrigerator
We have seen a wave of RVers switching to the 12V DC refrigerator and getting away from propane. I’m not sure we have had a long enough trial period to see if it’s working out. I’m still a fan of the old absorption refrigerator – but then, I was a fan of the rotary dial telephone and VHS, as well!
I looked up your GC15 6V description and it looks to be a Deka-brand 6-volt deep cycle battery with a 230 AH capacity. Connecting two of these in series (positive to negative) will give you the 12-volt capacity you need for your rig, but does not double the amp hours and it will stay at 230 AH. So I called my “go to” power and electrical guru, Mike Sokol, to get the skinny on not only the batteries but the 12-volt refrigerator and estimated run time duration. He has tested a couple of versions with Lithium batteries at 100 AH and found he could get 36-40 hours on one model and about 24 hours on a 10-cubic-foot model.
Here is what you need to consider
If your GC15 batteries are lead acid, as the models I found, you will only be able to use about 50 percent of the available amp hours, which means at about 115 ah. So you will be very close to what Mike tested as he used Lithium Ion batteries that can be drained down to almost 100 percent. Also, what other 12-volt appliances and operations will be drawing from the batteries such as lights, vent fans, water pump and any appliance running on LP. Especially a furnace that will take a lot of 12-volt power with the blower fan.
The recommendation for the two 6-volt batteries versus the traditional 12-volt was a good suggestion/ A typical 12-volt deep cycle battery will only provide about 100 amp hours. So even two connected in parallel will only provide 200 amp hours, which is less than your 6-volt. Plus, 6-volt batteries are superior in materials and performance. However, your concern about recharging is legitimate as it will take 6-9 hours to recharge your batteries depending on the type of charger you have.
So, yes, I would suggest a solar panel array from someone like Zamp Solar or Go Power, both of which have a good charge controller. I would recommend the portable models, as you can park your rig in the shade to cool the interior down 20+ degrees and put the portables out in the sun. I would also suggest reviewing this chart to understand the power draw from the various 12-volt features.
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