By Mike Sokol
Here’s a quick update on my residential refrigerator test and what it takes to boondock on solar power without a 3-way fridge. No, I haven’t forgotten you. It’s just that talking manufacturers out of gear to test and designing a valid experiment takes time. But I’m happy to report that I’m on track to begin gathering data in mid-January.
Now, while many of you couldn’t care less about what’s under the hood, there’s a small segment of readers here who are groupies/geeks and want to know how it all works. And I welcome them for peer review. You see, I don’t do anything in a vacuum. Every hypothesis I postulate, every experiment I devise, all empirical data I collect, and every conclusion I reach is subject to peer review by some of the most intelligent people I know. That is, I have a number of really smart colleagues around the planet that review my work and tell me if I’m doing valid science or not. And these guys are specialists in their own fields of nuclear power, marine power, utility power, pro-sound and lighting power, as well as others that are just plain smart about everything. And our own RVtravel.com staff includes a “persnickety” (her term) copy editor who makes sure everything I write is grammatically correct and makes sense. So you can be sure that before I release any data to the public it’s been vetted for content and clarity by a lot of different people.
That doesn’t mean we (or, more specifically, I) can’t make a mistake, so your job is to keep us (me) honest. If something doesn’t seem right or a conclusion doesn’t seem to fit the data, then by all means, speak out. That’s the same rule I have in my university classroom where I teach as an adjunct professor. If you see something, say something – politely, of course. And then we’ll dig in and find out what went wrong. Sometimes it’s as simple as the arithmetic, and other times it’s a silly premise that just happens to match the data set. But just know that I’m here for you, and doing everything I can to educate everyone from the RV manufacturers to the customers on how this electricity stuff works.
So let me show you what I’ve collected for the fridge experiment. It’s going to be really cool. (Get it…?)
Here’s what I’m assembling for Phase I of the residential refrigerator boondocking test.
Vitrifrigo has sent me an 8 cu. ft. marine-grade refrigerator with a 12-volt Danfoss-style swing compressor. While this isn’t as large as many of your residential refrigerators, it’s a good beginning to get a baseline of energy requirements using the most efficient refrigerator technology available.
VMAX USA has sent me a VMAXTANKS 100-amp/hour AGM battery with built-in solar charger system. This will be another baseline for battery storage. I’m also promised a 100-amp/hour Lithium battery from another manufacturer I met at the RVillage Rally One earlier this year. That battery should arrive the middle of January.
Thornwave Labs has sent me their Bluetooth Smart DC Power Meter which will track the incoming and outgoing current charging voltages, etc. This will link to the next cool monitoring gadget to catalog the data every 5 minutes.
RV Whisper LLC has sent me their RV Whisper WiFi Monitor Station, which will gather the charging data supplied to it via a Bluetooth link, and send it to the cloud, which I’ll be able to view on my computer in my office, or even my smartphone no matter where I happen to be. And I can then export this data and turn it into a number of graphs to help visualize what’s happening.
Xantrex Technology has sent me their Freedom XC-2000 pure sine inverter/charger, which I’ll eventually use to power a standard 120-volt AC residential refrigerator (as soon as I can talk a manufacturer out of one). But for now this will be a 12-volt DC test.
The only things missing from this test are the solar panels, but they’re promised to arrive in a few weeks. In the meantime I can get the rest of the test setup configured and metered up. Once the solar panels are in place I’ll be able to directly compare 100-amp/hr. Lithium vs AGM batteries on a refrigerator with a Danfoss-type swing compressor. And once I swap in a full-size 120-volt AC residential refrigerator, that data will become available as well.
I want to know just how many solar panels and how many batteries (both AGM and Lithium) are needed to run a residential refrigerator on an extended boondocking trip, and if there’s enough power left over for the other basics such as water pumps and maybe a furnace blower. Yes, I know those furnace blowers can be real energy hogs, but just how much of an appetite do they really have? And are there other technologies available that will improve the efficiency of an RV furnace blower? (Think, brushless DC motors.) I’ll also consider LED lighting and anything else that will reduce the electric load in boondocking mode.
Yes, there are lots of moving pieces, but it’s all coming together. I should have an update for you by my next RVelectricity newsletter.
Mike Sokol is an electrical and professional sound expert with 40+ years in the industry. Visit NoShockZone.org for more electrical safety tips. His excellent book RV Electrical Safety is available at Amazon.com. For more info on Mike’s qualifications as an electrical expert, click here.