This guy is doing some neat stuff. Currently running a 9,000 BTU mini-split off an inverter tied to a bank of Battleborn lithium batteries supplied by a copious amount of solar. He's into some serious money but seeing this gives some insight in to what is possible. His heat pump unit is no longer available. I compared the currently available Pioneer unit to the Fujitsu 9RL2 I installed. Very similar specs. The Pioneer is more efficient, but the outdoor unit is 4" wider and the profile of the indoor unit would be difficult to recess in the overhead cabinet as I have done on a 19 and 21. You will notice he has it surface mounted.
I'm getting word from Jake (Viator36) that his mini-split heat pump we installed performed flawlessly on a 2 month, 8000+ mile trip across the country and up into the Yukon Territories. This was early August to early October so both cooling and heating modes were used. They appreciated the whisper quiet operation, especially at night. I hope he weighs in and tells us about his trip!
Yes Dave, as I told you the mini split system you installed on my 21 performed flawlessly on our 2-month over 8,000 mile trip from early August through the beginning of October. And let me take the chance here to give a big shout (way overdue though) to Dave for the fantastic job he did for my install and he made the whole process a smooth and most enjoyable experience!
For our trip we set off from central NJ going west and got on I75 N across Michigan until we hit US 2. We then followed US 2 west to Minot in ND then crossed into Canada to Moose Jaw. Following Canada 1 we continued west and passed Calgary and stopped by Banff NP and then up to Jasper NP. Continuing on we stopped by Dawson Creek, Fort Nelson, Muncho Lake, Watson Lake and reached Whitehorse YT, the west most point of our trip. We then turned back on our return trip and crossed the US border into Montana. We visited the Glacier NP and then drove east to the Theodore Roosevelt NP and turned down south to the Badlands NP and after that followed I90 and I80 back home.
In terms of the mini split system performance there really isn't a whole lot to say, it just worked. I turned it on and it did its job quietly and unobtrusively. When we started out in August we only turned on ac and enjoyed our cool relief. So I didn't realize the benefit of the mini split's heat pump function until the last third of our trip when the season was getting close to the end and some nights were a bit chilly. At a few places we stayed overnight on Walmart parking lots with no hookups so the furnace would kick up during the night and sometimes I could hear it during the night or early morning, even though I would't say the furnace noise is very load. But when we did have power hookup and used the heat pump I did not hear it at all through the nights.
we have two digital thermometers in our trailer and after giving the mini split time to run the temperatures on the thermometers would usually be within 1 or 2 degrees from the mini split run setting. There were some road sections on our trip that were somewhat rough and bumpy like on US2 going west and elsewhere, and we did hit a few potholes in some parks' parking lot and there was a particularly nasty one in Jasper NP about a foot deep and the size of a manhole cover in a packed parking space we couldn't avoid and had to go over it. I was really afraid it could cause some damage to our mini split but luckily nothing happened.
So the mini split system served us well on our trip and so far it met my expectations on performance and durability. It did cost quite a bit more than the ac unit ETI offers but to me the ac plus the heat pump function and their quiet performance are worth it.
But when we did have power hookup and used the heat pump I did not hear it at all through the nights.
Music to my ears Jake. Whisper quiet A/C and heat is possible! Escape are you listening? I’ve started the R&D for you and have a proof of concept. Work with Mobile Climate Control or maybe Dometic if needed on a quiet factory mini-split solution and you will differentiate your trailers even more. Many of your customers from the US (70% of your sales as I recall) will appreciate it. Especially since you are looking to start a new location in Texas. No brainer!
Hi Dave, I watched the video you linked in your post #422 and it got me thinking a bit. The guy's original power source was 900w of solar with 600 amp hours of AGM batteries, and he said he could run his mini split system 24/7/365. Leaving cost aside for the moment I am trying to do a rough calculation to see if an Escape 21 for example has the space and weight capacity to get to that power specs.
1. For roof solar ETI can install 2 190w panels one front and one back. Would it have enough room to add two more panels installed lengthwise one on each side of the two roof vents in that general location? Or maybe some other roof configurations can be worked out to fit 4 panels up there. If that's possible the total roof mount solar would be 190 x 4 = 760. Then by adding a portable plug-in panel of the same 190w we will get a total of 950w for solar.
2. For battery total amp hours Jon said in his conversion to lithium that one 12v 100 amp hour rated battery weighs 31 lb, just about half weight of one lead acid type for the same amp hours. So two lithium batteries with 200 amp hour is equal to one lead acid battery in total weight. If we replace the two lead acid batteries with 4 lithium batteries the total amp hours will double to 400 but the total weight will remain the same (31 x 4 = 62 x 2). If we add two more lithium batteries we will get the total amp hours to 600 by adding an additional 62 lbs of weight. I understand the battery total weight distribution is a concern for the trailer proper front/back and left/right weight balance but an additional 62 lbs doesn't seem excessive and impossible to accommodate. And let's not lose sight to the one additional benefit of the lithium battery and this is a big one as Jon mentioned. He said that "while it is rated at 100 amp hours, in most ways it is the equivalent of a 200 amp hour lead acid battery". So with lithium there will be much more juice available in draw down capacity for running the mini split system.
If the above rough estimation is not too far off the mark then getting the 9,000 BTU Fujitsu mini split system to run on combined solar and battery power without relying on shore power sounds achievable. I am not a techie person so I left out all technical details since I don't feel confident enough to talk about them. I would like to hear comments from tech gurus and others on this forum on whether this is feasible to do.
The good news is, you're typically not going to need to run 100% duty cycle on the air conditioner so with some batteries as a buffer you don't actually need enough solar to power it constantly.
Next good news is that there are better solar panels in terms of efficiency. Either big residential panels if there's room, or Hightec 200W panels (which come in electrically-identical square and rectangle formats for easier layout).
The bad news is, you're not going to get 950W of power out of 950W of solar. A general rule of thumb is that you'll get about 5 hours worth of peak power per day (that is, 100W of solar gets you 500Wh per day) on a good day. Shading, clouds, and lack of ideal tilt will drop lower, potentially by a lot. I've seen 1500Wh out of an 800W roof-mounted array in the winter (well, around the shortest day of the year) even on mostly-sunny days.
I think with good roof layout for solar, lithium batteries, commercially-viable multi-junction solar panels, and good insulation solar A/C will be truly viable. Multi-junction panels outside of a lab could be a looong ways away, though.
If the above rough estimation is not too far off the mark then getting the 9,000 BTU Fujitsu mini split system to run on combined solar and battery power without relying on shore power sounds achievable. I am not a techie person so I left out all technical details since I don't feel confident enough to talk about them. I would like to hear comments from tech gurus and others on this forum on whether this is feasible to do.
I would need to consult the electrical engineers I work with to really dial this in but I think the rough numbers are not too far off. The Australian company, Kimberley, is back in business and are known for making some serious off-road caravans with advanced technology. They have used a 2.2kw (~7500 BTU/H) split system air conditioner powered via a 480 Ah lithium battery bank and 720W solar. So with 4 X 100Ah lithium batteries and 4x 190W panels you are in the ballpark. As was said the unit doesn’t need to run 24/7 so the reduced duty cycle and the efficiency of the mini-split unit with inverter compressor that runs only as hard as it needs to should help offset the fact that the solar will not produce at 100% and some inefficiency of the power inverter.
This would take some serious coin but I say let’s try it. I can handle the engineering. All I need is someone with a willingness and money!!
my napkin calculations say, 12V*400AH is 4.8 KWH battery capacity. lets say the A/C unit is running with a 25% duty cycle (on 5 mins, off 15 mins) so 2.2KW/4 is about 0.6 KW, so a full charge of the battery could run the AC for 25% of the time over an 8 hour period, using the whole of your 4.8 KWH battery capacity.
4 190W panels is 760 watts. but realistically you'll see 50-70% of that during most of the day, you only see 100% if the panels are facing the sun square on and tracking, and its summer high sun and its 100% clear. Typcailly 4-6 hours of peak equivalent daily output number is thrown around a lot for solar real world output, so lets say 6 * 760 watt*hours == 4.5 KWH a day.
so, on a good sunny day, you could run your AC at 25% duty cycle for 8 hours/day and almost break even. the good thing is, the sunniest part of the day is the hottest part where you'll need it the most... but if its a inland kinda scenario, it can stay hot until after midnight.
my napkin calculations say, 12V*400AH is 4.8 KWH battery capacity. lets say the A/C unit is running with a 25% duty cycle (on 5 mins, off 15 mins) so 2.2KW/4 is about 0.6 KW, so a full charge of the battery could run the AC for 25% of the time over an 8 hour period, using the whole of your 4.8 KWH battery capacity.
4 190W panels is 760 watts. but realistically you'll see 50-70% of that during most of the day, you only see 100% if the panels are facing the sun square on and tracking, and its summer high sun and its 100% clear. Typcailly 4-6 hours of peak equivalent daily output number is thrown around a lot for solar real world output, so lets say 6 * 760 watt*hours == 4.5 KWH a day.
so, on a good sunny day, you could run your AC at 25% duty cycle for 8 hours/day and almost break even. the good thing is, the sunniest part of the day is the hottest part where you'll need it the most... but if its a inland kinda scenario, it can stay hot until after midnight.
John: Thanks for these numbers. The 2.2KW is for the unit that Kimberley was using. The specs for the Fujitsu 9RL2 that Jake and I both have are attached. It states the max for cooling is 1.44KW. With 25% duty cycle I calculated over 13 hours of run time with just a fully charged 4.8 KWH battery bank (unrealistically drained to zero and not running anything else) and ignoring any solar input. A bit more realistically using the rated input power of 0.83KW and running constantly I get almost 6 hours. I am ignoring solar because as you stated it can stay hot well into the night which is primarily when I would want the A/C running. Of course you need to recharge the next day anyway. I see the real-world solar output as a big limiting factor especially here in the east with less solar resource (NREL show 4.5-5.0 KWH/M^2/day for us versus >6.5 for the southwest). Especially if you are trying to purposely park in the shade to keep the trailer cooler. Just brainstorming but possibly solar on the tow vehicle roof or bridged across the top of a pickup bed might be better as you can possibly park it in the sun while the trailer is shaded. Supplemented with some ground mount portable. Obviously if one were to leave the campsite with their tow vehicle then they would only have partial charging.
For anyone interested, I can give some user data on a combination of 480 watts of solar & a pair of 100 amp hour Battleborn lithium batteries here at Quartzsite, AZ. The data was collected by the Victron bluetooth readouts for both the solar controller & the battery monitor. While it is obviously conditioned on the solar conditions, which, of course, are variable, it might give users some "real world" idea of what they can expect from a system. I consider myself a "heavy" user of power - typically 50 amp hours per day. I usually make a pot of coffee, often microwave breakfast or dinner, use an electric toaster, and set the furnace at 60°F (it has been cooler than usual this winter)
I have 2 160 watt rooftop panels tilted for the correct angle for Phoenix, AZ for mid January. The trailer is aimed a bit west of due south. I also have a 160 watt portable panel that I shift 2-3 times a day to "follow" the sun. Batteries are charged through a Victron 100/30 MPPT solar controller. Since lithium batteries stay in the bulk mode until 95% filled, and only spend a few minutes in the absorption mode, unlike lead acid batteries, the full output of the panels is available at the batteries until they are filled.
While so far this winter I have not depleted the batteries to the point where I had to run a generator, after a 3 day stretch without enough sun to put the controller into the float mode, and being down 54 amp hours, I ran a small propane generator for 4 hours to bring the batteries back to full (and do a monthly generator run). This was probably not necessary, although the prediction was for another 3 days of heavy clouds. The lithium batteries can be safely drawn down to 10%, so I could have gone without the generator, but I needed to run it anyway, and I tend to be a bit conservative.
This has been the coolest & most cloud covered winter I've stayed at the Q over the last 4 years so the results would probably be better under more usual conditions. This is for December 9 - December 31. (21 days). Today (the 31st) is obviously not finished, but as of 11:00 AM I'm putting 91 watts into the trailer, had a peak of 195 watts, and collected a total of 250 watt hours (it is cloudy). Still down 49 amp hours for the day (I did not reach float yesterday).
Peak solar wattage - 423 watts. Minimum solar wattage - 42 watts. Peak KW hours collected - 1.49KWh. Lowest watt hours collected - 140 watt hours. # of days the controller never received enough sun to get out of the bulk mode - 7.
# of days the batteries reached full - 15. Largest discharge - -72 amp hours.
The image below is the December solar output. White = Bulk, Gray = Absorption & Light Blue = Float.
Jon, thanks very much for your detailed real world data and summary. I wish I had the know-how to take the projected 25% duty cycle usage in Dave's post #432 above and plug in Jon's solar charge data and battery charge stats but scaled up to the projected solar capacity of 4 190w panels with 4 12v 100 amp hour lithium batteries scenario discussed a couple of posts back. I would like to see how much power gap exists and if the gap is bridgeable or not by tweaking a couple of variables. I hope some of you with expertise will weigh in on this.
While I am doing an "educated guess", I suspect that you are going to need to at least double the 4 190 watt panels & 400 amps of battery to comfortably run the AC as wanted.
I have a neighbor that runs his 40' motorhome on solar, including a small, window mounted chosen for efficiency AC/Heat Pump. He rarely burns propane here at Quartzsite, while I'm going through a 20 pound tank every days.
The way he does it is to haul a trailer larger than my Escape 21 with 5000 watts of solar between the trailer & motorhome, and 12KW of lithium batteries in the trailer. Scale wise, the motorhome is larger than any Escape, but I suspect better insulated. In any case, I suspect any system that fits on a small trailer is going to really be pressed to keep the batteries charged. For the most part, it is no longer a battery problem in that lithium batteries store large amounts of power in small, light packages, but getting the power back that you take out is the limitation.
While I am doing an "educated guess", I suspect that you are going to need to at least double the 4 190 watt panels & 400 amps of battery to comfortably run the AC as wanted.
I have a neighbor that runs his 40' motorhome on solar, including a small, window mounted chosen for efficiency AC/Heat Pump. He rarely burns propane here at Quartzsite, while I'm going through a 20 pound tank every days.
The way he does it is to haul a trailer larger than my Escape 21 with 5000 watts of solar between the trailer & motorhome, and 12KW of lithium batteries in the trailer. Scale wise, the motorhome is larger than any Escape, but I suspect better insulated. In any case, I suspect any system that fits on a small trailer is going to really be pressed to keep the batteries charged. For the most part, it is no longer a battery problem in that lithium batteries store large amounts of power in small, light packages, but getting the power back that you take out is the limitation.
That’s insane! If that is a 12V system and my math is right he has at least ten 100AH batteries at ~$1,000 each! Not to mention the cost of 5,000W of solar! Wow.
Spacewise-- I have two BattleBorn batteries under the passenger side dinette seat and could mount two or maybe three more in that space. The inverter would have to be relocated. But my 2014 Escape 21 has different dimensions in that space than the newer trailers like Jon's.
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Mike Lewis
She don't lie, she don't lie, she don't lie-- propane
Photos and travelogues here: mikelewisimages.com
That’s insane! If that is a 12V system and my math is right he has at least ten 100AH batteries at ~$1,000 each! Not to mention the cost of 5,000W of solar! Wow.
like someone posts with their Escape forum avatar- Camping, where you spend a lot of money to appear homeless
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Jim
Sometime life gets in the way of living.......
Jon: Going through a tank of propane every how many days?
Oops, left that out. So far 11 days & 9 days. A colder & cloudier than usual Quartzsite winter. I usually get 2 weeks on a tank here during the winter. Thermostat is set at 60°F.
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