Because of the bottom of the trailer being 'tubbed' you'd probably also want to put a plug in the bottom of the trailer, not just the floor.
In theory your idea of a bottom exhaust sounds good, in reality I'm not so sure....
All you have to do is think upside down. Put a deck plate on the bottom. They're waterproof and come in a variety of sizes. One could also be put on the exterior of a side, whatever's the most convenient.
It seems a hatch door would be the simplest location to cut a hole and mount a water-proof deck plate on the outside of the hole - if you can conveniently route the exhaust duct to said hatch door.
you need a FLAT surface the outside diameter of those deck plates for them to seal decently, I dunno how flat the bottom of a 17 is (actually, I'm not even sure how flat the bottom of my 21 is, as its been foamed).
All you have to do is think upside down. Put a deck plate on the bottom. They're waterproof and come in a variety of sizes. One could also be put on the exterior of a side, whatever's the most convenient.
Ron
Those are nice plates Ron but I would feel more comfortable not cutting a hole in my trailer when just exhausting out a window would work very well. Wish I had a picture but at this time don't . We are finally getting winter here now Pat
Ever since I installed the mini-split I’ve been intrigued with the idea of running it off lithium batteries similar to what Kimberley (now closed) did on their beautiful trailers in Australia. Remember the mini-split is only 9,000 BTUH and has inverter technology meaning it only runs as hard as it has to for the conditions. It has an economy mode which should put the power input at about 580W or ~5A at 120V. Cost aside for a moment, Goal Zero agrees that I should be able to run 5-6 hours with their 3000Wh unit with built-in 1500W inverter. I know you can draw much more power from lithium without issue and you can draw them down to almost zero, but I’m not an electrical whiz. Can any of the gurus provide feedback as to the feasibility of this? Anything I’m missing? I may be able to get a refurbished unit cheaper just for proof of concept. This can also take simultaneous solar input for charging, but I’m not considering that as part of my calculation for runtime.
Ever since I installed the mini-split I’ve been intrigued with the idea of running it off lithium batteries similar to what Kimberley (now closed) did on their beautiful trailers in Australia. Remember the mini-split is only 9,000 BTUH and has inverter technology meaning it only runs as hard as it has to for the conditions. It has an economy mode which should put the power input at about 580W or ~5A at 120V. Cost aside for a moment, Goal Zero agrees that I should be able to run 5-6 hours with their 3000Wh unit with built-in 1500W inverter. I know you can draw much more power from lithium without issue and you can draw them down to almost zero, but I’m not an electrical whiz. Can any of the gurus provide feedback as to the feasibility of this? Anything I’m missing? I may be able to get a refurbished unit cheaper just for proof of concept. This can also take simultaneous solar input for charging, but I’m not considering that as part of my calculation for runtime.
Living in Arizona, the biggest drawback (aside from cost) of Lithium batteries is their dislike of heat. Their life goes down in higher temperatures. I have not been able to find anything about high discharge rates in hot conditions, but you (presumably) only want to run the A/C when it is hot out. This MIGHT be a problem.
In Arizona in the summer 5-6 hours of A/C would not cut it, 24 hours is more like it. In a more moderate climate 5-6 hours might let you run long enough to recharge with a generator. And the more moderate temperatures would reduce any possible negative effects of heat on the battery performance.
As long as you stay out of the deep South and Southwest, I would give it a try. Especially if you can get a reduced price. And the much better capacity to weight ratio (than lead acid batteries) is a bonus. And you can put the batteries anywhere (like in the trailer reducing any high temperature concerns and maybe improving the weight distribution) since they are sealed.
Living in Arizona, the biggest drawback (aside from cost) of Lithium batteries is their dislike of heat. Their life goes down in higher temperatures. I have not been able to find anything about high discharge rates in hot conditions, but you (presumably) only want to run the A/C when it is hot out. This MIGHT be a problem.
In Arizona in the summer 5-6 hours of A/C would not cut it, 24 hours is more like it. In a more moderate climate 5-6 hours might let you run long enough to recharge with a generator. And the more moderate temperatures would reduce any possible negative effects of heat on the battery performance.
U
As long as you stay out of the deep South and Southwest, I would give it a try. Especially if you can get a reduced price. And the much better capacity to weight ratio (than lead acid batteries) is a bonus. And you can put the batteries anywhere (like in the trailer reducing any high temperature concerns and maybe improving the weight distribution) since they are sealed.
Thanks for the feedback. I did notice the maximum operating temperature is 104F for this unit. As you noted it doesn’t typically get that hot in this area and I believe the unit could reside in the trailer in the cooler space. It appears this can be recharged via a generator with their AC wall charger or up to 685W of solar with built in charge controllers. Looks like the recharge is awfully slow (25 hours?) via their wall adaptor which is a bit confusing. Enough solar can get you recharged in roughly 6 hours.
I should have noted that this concept assumed we are out of the trailer most of the day or if in a place that isn’t bothering anyone running the A/C on a quiet inverter generator. The main idea is that this unit could carry A/C operation through most of the night when generator is shut off. The temperatures don’t typically drop much at night depending on the area one is in. Obviously this would be a circumstance where you had no hook-ups and were not remote enough that running a quiet gen at night might be ok.
The battery chemistry is Li-ion NMC which is Lithium Nickel Manganese Cobalt Oxide. How stable is this? Does this have a meltdown risk like the cell phones we hear about?
While this might be technically possible, as Brian B-P said in a previous post, the cost needs to come down on lithium batteries and solar to make this more feasible. Even the reconditioned units are expensive. If they would let me return it I would consider buying one just to test how long I could run the A/C.
I know you can draw much more power from lithium without issue and you can draw them down to almost zero, but I’m not an electrical whiz. Can any of the gurus provide feedback as to the feasibility of this? Anything I’m missing?
It's not good to take a lithium battery to zero, either, and the battery management system of any competently designed equipment with a lithium battery prevents this. Overcharging is also bad. Good management means avoiding the ends of charge/discharge range, and monitoring each cell individually to ensure that none hit the limits (since in a real battery the cells are never quite balanced so they're in somewhat different states).
The usable range compatible with long life is much wider (a greater fraction of the nominal capacity) for any lithium battery than for even a good deep-cycle lead-acid battery... but plan on something like 80% of nominal, not 100%.
I think their value of this system is mostly that they provide a complete package for convenience, rather than that any of the components are particularly valuable. For someone who wants an all-in-on portable power system it probably makes sense, but in a trailer that has much of this equipment anyway I think it makes more sense to integrate the desired battery and suitable other components into the trailer.
The strangest thing about this unit is the voltage. The battery is configured as three cells in series (and some number in parallel); that results in 10.95 V nominal voltage, going higher and lower than that as it is charged and discharged. It will spend most of its operating time at a voltage too low for "12 volt" systems to be happy with it; that doesn't matter if using the built-in inverter or USB (5 volt) power supply, but awkward for those wanting to power - for instance - RV equipment. Lithium battery systems sold to replace lead-acid in 12 volt systems typically use LiFePO4 (a.k.a. LFP) chemistry, which has a lower nominal voltage and so with four cells in series matches "12 volt" lead-acid battery voltage levels well.
Quote:
Originally Posted by jamman
Living in Arizona, the biggest drawback (aside from cost) of Lithium batteries is their dislike of heat. Their life goes down in higher temperatures. I have not been able to find anything about high discharge rates in hot conditions, but you (presumably) only want to run the A/C when it is hot out. This MIGHT be a problem.
Heat is certainly a problem, but manageable. Some electric cars keep the discharge rate down to avoid problems; for instance, an original Nissan Leaf has a 24 kWh battery and limits discharge power to 87 kW, so it can get away with no battery cooling system, even driving in hot climates. Proportionately, this suggests that a 3 kWh battery (the size in that Goal Zero unit) should be able to handle about 10 kW even in hot weather - that's a 3C discharge rate, and pretty moderate by lithium battery standards. Other electric cars run their battery harder, and so they have circulating liquid coolant systems... although that is as much to warm them up in cold weather as to cool them in hot weather or when working hard.
Quote:
Originally Posted by rubicon327
It appears this can be recharged via a generator with their AC wall charger or up to 685W of solar with built in charge controllers. Looks like the recharge is awfully slow (25 hours?) via their wall adaptor which is a bit confusing.
Although they allow up to 30 amps while charging through the PowerPole port, they only provide a 10 amp charger. The problem appears to be just the small included charger.
Quote:
Originally Posted by rubicon327
The battery chemistry is Li-ion NMC which is Lithium Nickel Manganese Cobalt Oxide. How stable is this? Does this have a meltdown risk like the cell phones we hear about?
NMC is common in electric cars. That's only the electrode material, and there are other factors relevant to stability in lithium ion battery design. An automotive NMC battery certainly runs a risk of dramatic failure, but the risk is low if it is properly managed and not mechanically damaged. Small mobile devices often have poor management (the BMS or battery management system), and many of the alarming little fires have been due to small physical defects, possibly made more problematic by mechanical damage in their nearly unprotected enclosures. Electric cars have sophisticated BMS and substantial battery housings; most large portable power packs have some form of BMS and a reasonable case.
The Goal Zero Yeti doesn't look like it has much of a BMS: under "Management system" it lists just "PWM charge controller, low battery protection". Perhaps that's why they only claim a life of 500 cycles.
Ignore proper system design and any battery can be hazardous. Some pretty dramatic fires have resulted from ignorant, incompetent, or careless people playing with battery packs salvaged from electric cars (usually Teslas), typically while charging them, although the cars themselves never have these problems unless they are severely crashed.
I think their value of this system is mostly that they provide a complete package for convenience, rather than that any of the components are particularly valuable. For someone who wants an all-in-on portable power system it probably makes sense, but in a trailer that has much of this equipment anyway I think it makes more sense to integrate the desired battery and suitable other components into the trailer.
Brian: Thank you for the great information as always. I understand what you are saying, but I don’t currently have any of this on the trailer. Can I piece this together for anything close to the price of the Goal Zero? Lithium batts, inverter and solar controller and then I’ll have my labor, but let’s not count that for sake of conversation. I agree if done right it would be better overall. The lithium batteries would be charged from the converter/charger when plugged in. My upgraded Progressive Dynamics WildKat charger supposedly can be set with a jumper for lithium.
Jake (viator36) was courageous enough to drop off his brand new 21 for some surgery...a Fujitsu 9RL2 mini-split heat pump recessed over the rear dinette. Having the experience from the 19 has certainly helped but there are a lot of details. Pictures show some of the cabinet rough-in work. The key is that Escape customized the cabinet to our desired width. This meant vertical supports are untouched and the cabinet remains rock solid. Cutting the lower lip off the cabinet was required to make a flat supporting surface and then the upper sandwich of crosspieces were removed. The only piece remaining is glassed into the shell and conveniently pins the upper part of the indoor unit to help with mounting. More pictures to follow...
Work down the corners needs to be meticulous. Cut away vinyl and foam to lay refrigerant lines down the passenger side with condensate drain and power down the driver’s side. I even notched the wood blocks that hold the corner pad so the lines would lay perfectly without bulging. Need to be very careful not to cut any wires. There are some obvious ones in the seam, but others are under the foam in the gooey adhesive against the shell. If you do it right it looks perfectly stock in the end.
A new Eaton 15A breaker was installed to match existing. 120V power, control line and refrigerant lines will exit near the rear. The condensate line is inboard on driver’s side and along the frame so dripping is not right at edge of trailer. The upper condensate piping design incorporates a 90 degree so it pitches from the unit, lays perfectly and makes the turn down the wall without any kinking. Useable under bench area is virtually unchanged.
Mocking up the indoor unit. It recesses 5” so the air delivery vane lines up perfectly with the front edge of the shelf. Top has adequate clearance for return air circulation. Happy with this so far. This will be the only 21 in the world with whisper quiet A/C!
Mocking up the indoor unit. It recesses 5” so the air delivery vane lines up perfectly with the front edge of the shelf. Top has adequate clearance for return air circulation. Happy with this so far. This will be the only 21 in the world with whisper quiet A/C!
Continuing the custom work on Viator’s 21. Dropped it off to one of the best welders anywhere. He cut off the rear bumper and extended the frame rails rearward to allow for cross bracing to hold the outdoor A/C unit. This keeps full protection across the rear and keeps the receiver functional. The welding is so clean this looks factory stock. The unit is mounted on rubber isolators to dampen vibration. Since the rear of the trailer sees more movement going down the road than my tongue mounted condenser on the 19 I have also decided to use flexible refrigerant line sections at the outdoor unit. This will allow some movement of the unit relative to the lines without putting stress on the connections. The refrigerant lines and power are only roughed in right now. With the unit set the final connections will be made inside and out, system pressure tested with nitrogen, evacuated under vacuum and then refrigerant released into the system from the outdoor unit (pre-charged with R-410A). Unit will be finished off eventually by the owner with a custom blue cover to match graphics. Spare tire that is displaced off the back is getting located underneath towards the front on a winch that can be lowered with the same drill and socket used for the stabilizers. More to come...
If any car gurus are interested in what the welder, Nick Weber, has built over the years check out these links. I’d put him up against any custom builder anywhere. http://www.superchevy.com/features/1...rvette-project
Continuing the custom work on Viator’s 21. Dropped it off to one of the best welders anywhere. He cut off the rear bumper and extended the frame rails rearward to allow for cross bracing to hold the outdoor A/C unit. This keeps full protection across the rear and keeps the receiver functional.
That's nicely fabricated, but radical Why not just add a loop of steel tubing from frame rail to frame rail, extending rearward (beyond the bumper) far enough to support and protect the unit? Since the receiver is just for a bike rack, this loop could carry the receiver.
I wouldn't want the rear corners to be extended rearward like that, from a clearance point of view in close-quarters manoeuvering. With the bumper extended, I would at least want the ends to be bent forward, or to have 90-degree extensions added... as they are they look like great tree-hooks.
Quote:
Originally Posted by rubicon327
The unit is mounted on rubber isolators to dampen vibration.
After the original discussion of isolation, I was thinking that an improvement to isolation would be to rigidly bolt the base of the unit to side frames which would be attached by isolation mounts at more widely spread points, such as (in this rear-of-trailer scenario) at the bottom rear corners and upper front corners (which would require a vertical extension to the base structure). Ideally, the plane between the mounts would pass near the centre of mass of the unit.
That's nicely fabricated, but radical Why not just add a loop of steel tubing from frame rail to frame rail, extending rearward (beyond the bumper) far enough to support and protect the unit? Since the receiver is just for a bike rack, this loop could carry the receiver.
I wouldn't want the rear corners to be extended rearward like that, from a clearance point of view in close-quarters manoeuvering. With the bumper extended, I would at least want the ends to be bent forward, or to have 90-degree extensions added... as they are they look like great tree-hooks.
After the original discussion of isolation, I was thinking that an improvement to isolation would be to rigidly bolt the base of the unit to side frames which would be attached by isolation mounts at more widely spread points, such as (in this rear-of-trailer scenario) at the bottom rear corners and upper front corners (which would require a vertical extension to the base structure). Ideally, the plane between the mounts would pass near the centre of mass of the unit.
Brian I appreciate the input. Different ways to skin the cat and I’m learning a little more on each install. In the end it doesn’t appear we are much further back with the bumper than a 17 with batteries on the rear. I do see that they angle the corners which is a nice touch. With a busy life I had to delegate the task and gave the welder creative freedom to solve the problem. We’ll also see how the isolation works. Going vertical with structure could get clunky. I think movement is restrained enough and with the flexible refrigerant line ends that the stress on the connections will be minimized. If we happen to have trouble with long term reliability of the compressor or other components due to vibration we are going to have to get more creative.
Pat
Why not just add a loop of steel tubing from frame rail to frame rail, extending rearward (beyond the bumper) far enough to support and protect the unit? Since the receiver is just for a bike rack, this loop could carry the receiver.
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