***This is simply an account of how I optimized our refrigerator efficiency. It is not technical advice. I am not qualified to give anyone technical advice about RV refrigerators. Don’t go monkeying around with your refrigerator based on this post. Do your homework, call your manufacturer, and/or consult a professional.***
Early in this blogging endeavor, Jessie gave a good overview of the electrical system of our RV (Link to Jessie’s earlier post). We knew from the beginning that we needed to keep our electrical needs at a minimum so that we could avoid having to pay for electrical hookups and so that we could remain generator-free. We’d need several things to make this happen.
First, we’d need to follow the weather to the best of our ability to minimize our need for A/C. We don’t mind being hot and sweaty during the day. We are usually out hiking or doing something active, so this is to be expected. But we do want to be somewhat comfortable at night so that we can sleep well. We are both cranky monsters if we are sleep deprived and/or hungry. You see, to run A/C on most RV’s you need (1) an electrical hookup OR (2) a serious generator which would be: heavy, loud, expensive, and in constant need of gas.
Second, we’d need decent battery capacity. We decided on two 6-volt golf cart batteries wired in series to produce 12-volts with the capacity (215 amp hours) we needed to “get by” for several days of LED light use, inverter use (to charge phones, our laptop, run the blender for smoothies, our small “house fan”, etc), and water pump use in a conservative but comfortable manner.
And finally, we needed a way to recharge our batteries at least to a small degree to slow the rate of discharge of our battery bank (all two of them). A generator will do just that and then some, but for the reasons listed above and our huge desire to keep this endeavor as “green” as possible, we decided to go with a 100w portable solar panel. I’d done the research, crunched the numbers, and devoured every article/blog post I could find on the subject. I purchased all of the necessary equipment and proceeded to very carefully, so as not to electrocute myself or blow anything up, install all of the necessary components Jessie referenced in her “It’s Electric” post many months ago. I had supreme confidence that all would work as planned. And everything did work as planned except we just weren’t able to recharge the batteries using the solar panel at the rate I’d calculated. It became clear in Texas that we had an energy vampire.
Energy vampires are sometimes difficult to ferret out and this one proved particularly elusive. It even got to the point where we began shopping for a (gasp!) generator. But that would be a $1,000 commitment and an admission that I was wrong. Not something I’m good at. So we decided to give it another couple weeks. I’d finally identified our vampire as our refrigerator. All of the literature I’d read said running your RV refrigerator on LP gas mode uses virtually no power except for a tiny bit used by the electronic monitoring hardware that tells the unit what to do and when to do it. But it became increasingly clear that everything I’d read was wrong in our particular case.
I began our investigation of this vampire by isolating variables. This proved tricky because we needed power and time to test the multitude of theories I had. Finally, we arranged for a campsite at Zion NP that had power. So we defrosted the refrigerator (RV refrigerators in most travel trailers are not frost free) and we purchased a small RV refrigerator fan designed to run off two D batteries and circulate air to help prevent frost inside the refrigerator. Both of these things seemed to have helped to a small degree but they weren’t “the” answer we were looking for.
Enter our campground neighbors at Bryce Canyon. A lovely retired couple from New Orleans who ran the generator in their motorhome a lot. More than anyone we’ve encountered by a wide margin. He struck up a conversation with me about our portable solar unit, which turned into a lengthy conversation about boondocking/dry camping/off-the-grid. He knew nothing about his battery bank. Not how many batteries he had, what kind, not the capacity. He’d never so much as opened the battery compartment in his motorhome. I spent a bit of time educating him about batteries and capacity. He seemed interested but he was well into his 3rd-12thcocktail of the evening. Then he mentioned the heater in his refrigerator as being a big energy draw and proceeded to tell me about how he’d installed an on/off switch to disable this heater. To say I was skeptical would be an understatement. He showed me the switch he’d installed and explained the heater to the best of his ability. At the very least I figured it would be something worth reading about so that I could dismiss his information or, in the very unlikely scenario that he had provided us with the magic bullet, I could take action.
Son-of-a-bitch if this guy who knew NOTHING except the exact thing that I didn’t know was right. The RV refrigerator manufacturer of our unit had indeed hardwired a heating coil around part of the door frame to prevent condensation from building up and preventing a tight seal (not a bad idea in very humid climates, but we were in Utah). For a very long time the manufacturer had installed an on/off switch to allow the user to disable this feature. Somebody in their infinite, bean counting wisdom decided to do away with this switch to save a few bucks on each unit. Anything that produces heat uses power at a high rate, especially when you are running on battery power. This was, indeed, the silver bullet we’d been looking for. A couple of hours of cellphone internet research later, I was able to disconnect the cable providing power to this little heater (it also provides power to the refrigerator light, so ours is now dark), wrapped it in approximately 17 feet of electrical tape (perhaps a small exaggeration), and taped it out of the way but in an easily accessible place if we decide we need to reconnect it. I’d considered installing a switch similar to what our campground neighbor had done but I’m reasonably sure that would void our two-year refrigerator warranty. I am happy to report that the next day our TOTAL energy usage for the day was cut in half and we’ve had no problem keeping our batteries charged with our 100w solar panel. We are now as energy efficient as possible and we’ve driven a stake into the heart of our energy vampire.