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davelondon
Guest
I'm considering using Hotspot Energy 48V DC mini split air conditioning units in my expedition vehicle... Does anyone have any experience with them? https://www.hotspotenergy.com/DC-air-conditioner/
OffGridInTheCity
Solar Wizard
You know... I looked at these but ultimately went a 120v Senville 9000BTU heat-pump for my 7 x 14 cargo trailer -> camper conversion. https://senville.com/9000-btu-mini-...164704750&mc_cid=5c5cb6b52d&mc_eid=b2e8bcbe9c
I get that you might worry about 15% DC -> AC inverter loss etc. However, I must say that I'm so pleased with this Senville in conjunction with 1" insulation (wall, roof, and floor - tight). It takes about 2kwh / day for 85F/29C weather - and a little less than 4kwh / day for 104F/40C. In winter, it had no problem going down to 25F/-15C and used a little less than 5kwh / day.
Not trying to be discouraging - just sharing that 'mainstream' 120v also work pretty well
FYI... (I'm not pushing Senville - just sharing) Senville also has a model (https://www.sylvane.com/senville-aura-9000-btu-mini-split-heat-pump.html?s_kwcid=TC-2378-2332888796289074-b-81089043850713-Senville Heat Pump extreme cold&mkwid=&crid=81089043850713&mp_kw=mini-split&mp_mt=b&pdv=c&msclkid=5a65d9d8c56813f8c440b91a863ddb15&utm_source=bing&utm_medium=cpc&utm_campaign=Dynamic Search Ads&utm_term=mini-split&utm_content=DSA - Search Partners (DuckDuckGo)) that goes down to -22F/-30C for more $ if extreme cold is an issue.
I get that you might worry about 15% DC -> AC inverter loss etc. However, I must say that I'm so pleased with this Senville in conjunction with 1" insulation (wall, roof, and floor - tight). It takes about 2kwh / day for 85F/29C weather - and a little less than 4kwh / day for 104F/40C. In winter, it had no problem going down to 25F/-15C and used a little less than 5kwh / day.
Not trying to be discouraging - just sharing that 'mainstream' 120v also work pretty well
FYI... (I'm not pushing Senville - just sharing) Senville also has a model (https://www.sylvane.com/senville-aura-9000-btu-mini-split-heat-pump.html?s_kwcid=TC-2378-2332888796289074-b-81089043850713-Senville Heat Pump extreme cold&mkwid=&crid=81089043850713&mp_kw=mini-split&mp_mt=b&pdv=c&msclkid=5a65d9d8c56813f8c440b91a863ddb15&utm_source=bing&utm_medium=cpc&utm_campaign=Dynamic Search Ads&utm_term=mini-split&utm_content=DSA - Search Partners (DuckDuckGo)) that goes down to -22F/-30C for more $ if extreme cold is an issue.
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davelondon
Guest
Yes indeed. Standard 230V air conditioning is definitely an option too, and lots more to choose from. However, all of our other essential loads (fridge etc.) are low voltage DC, so if we use 48V aircon, we can totally turn off the inverter overnight and still leave the aircon on...
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davelondon
Guest
We're going to have 100mm (4") of insulation, so we should be good!
Good morning Dave, I recently finished my diy install using the DC4812VRF. It's only been a week so i have little test data to go on, but from what i've seen so far it's looking promising. I'm going to start a thread soon where i'll do power consumption vs temperature differential. I haven't been able to find anyone that has a 48v dc mini split installed, which left me with almost nothing to go on. bgflyguy started a thread with a few options i failed to find prior to ordering, which may be helpful too.
FYI, you can usually drop the first question mark and everything after it, to shorten the URL.
https://www.sylvane.com/senville-aura-9000-btu-mini-split-heat-pump.html
https://www.sylvane.com/senville-aura-9000-btu-mini-split-heat-pump.html
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davelondon
Guest
Awesome, yes please I'm very interested so any more information you might have that would be great.
jameshowison
New Member
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Yeah, I was considering something similar and I'd love to hear your experience and schematic with the DC4812VRF.
jameshowison
New Member
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Can we discuss pros/cons for integrating the Hotspot 48v HVAC systems. See specs at: https://www.hotspotenergy.com/DC-air-conditioner/ They are heat pumps that run either directly from 48v batteries with no AC connection needed.
Main advantage as I see it are the same as other mini-splits:
1. Quiet operation when compared to existing RV air-conditioners (including 12v rooftop systems). Like 40db rather than 65 or 70db.
2. VRF and inverter fans mean calm draw on electricity (ie no start up surge)
3. Heat Pump delivers heat as well, so can remove other heating systems. Hotspot appears to have decent low temp operation (claims down to 5°F, which is way colder than I intend to be out!).
Compared to inverter driven mini-split systems:
1. Doesn't require upsizing the inverter to handle the AC in addition to other loads.
2. Doesn't require the inverter to operate, meaning lower noise during operation.
3. Doesn't require 230v or split-phase 240v and still has a COP of over 5 for cooling (~500W draw) and over 3 for heating (~750W draw).
The downsides seem to be:
1. Can be hard to place the indoor unit (same as all wall-mounted mini-splits), and the CFM air blown can be quite high given that it's all in once place.
2. The split-system requires an HVAC contractor for the install.
3. Running all HVAC through the batteries means more cycles, even when plugged into shore power.
3. A 48v system in an RV or Van is a little difficult, due to larger all-in-one inverters, and compatibility with 12v systems (step-down voltage to power lights etc, and the difficulty of charging 48v battery systems from 12v alternators.)
4. This would require a large battery bank, something like 12kwh for 24 hours of cooling, and 18kwh for 24 hours of heating. Therefore also requires large amounts of solar input (although these issues are shared with any off-grid airconditioning and any heat pump heating approach.)
In terms of integrating these systems seems like two options, either an all-in-one inverter/charger running at 48v or a not all-in-one 48v system. Either way requires a step-down approach to integrate with existing 12/24v circuits, and some way to charge from alternator 12v.
I can find the all-in-one 48v systems, but most seem large for an RV, especially in terms of inverter capacity. I also can't find much info on noise for these units (at least not in terms of decibels people do say the Growatt and MPP are loud!). These all seem to have sufficient solar
Growatt SPF 3000TL LVM-ES (48v, 3000W inverter)
MPP PIP 3048LV-MK (48v, 3000W inverter)
Victron EasySolar-II 48/3000/35-32 MPPT 250/70 GX (48v, 3000W inverter)
Are non-all-in-one 48v systems worth considering? ie you'd need an AC charger for 48v, a 48v powered inverter, and a 48v capable MPPT solar charger. Could anyone link to schematics for a system like that?
Step down 48v->12v seems doable with the Victron Orion, and the 12v->48v step up could be handled by a Sterling BB124870?
Seems to me that the real blocker is the battery and solar input requirements for heating ... those seem huge. So maybe the diesel heater has to stay?
But the extra battery cycles when plugged into shore power also seem a problem. Perhaps those can be avoided by using Hotspot's hybrid unit: https://www.hotspotenergy.com/solar-air-conditioner/ That can take direct solar 48v (no battery, but it could come via batteries) and switch to AC power when needed, although it can't use single phase 120v, so to plug in directly would need a 50amp RV connection (which reduces the usefulness, given that there are tons more 30amp sites and 30amp 120v provides more than enough power. I guess an autotransformer could help there, but then might as well power via an inverter or the Victron style pass through AC?
Main advantage as I see it are the same as other mini-splits:
1. Quiet operation when compared to existing RV air-conditioners (including 12v rooftop systems). Like 40db rather than 65 or 70db.
2. VRF and inverter fans mean calm draw on electricity (ie no start up surge)
3. Heat Pump delivers heat as well, so can remove other heating systems. Hotspot appears to have decent low temp operation (claims down to 5°F, which is way colder than I intend to be out!).
Compared to inverter driven mini-split systems:
1. Doesn't require upsizing the inverter to handle the AC in addition to other loads.
2. Doesn't require the inverter to operate, meaning lower noise during operation.
3. Doesn't require 230v or split-phase 240v and still has a COP of over 5 for cooling (~500W draw) and over 3 for heating (~750W draw).
The downsides seem to be:
1. Can be hard to place the indoor unit (same as all wall-mounted mini-splits), and the CFM air blown can be quite high given that it's all in once place.
2. The split-system requires an HVAC contractor for the install.
3. Running all HVAC through the batteries means more cycles, even when plugged into shore power.
3. A 48v system in an RV or Van is a little difficult, due to larger all-in-one inverters, and compatibility with 12v systems (step-down voltage to power lights etc, and the difficulty of charging 48v battery systems from 12v alternators.)
4. This would require a large battery bank, something like 12kwh for 24 hours of cooling, and 18kwh for 24 hours of heating. Therefore also requires large amounts of solar input (although these issues are shared with any off-grid airconditioning and any heat pump heating approach.)
In terms of integrating these systems seems like two options, either an all-in-one inverter/charger running at 48v or a not all-in-one 48v system. Either way requires a step-down approach to integrate with existing 12/24v circuits, and some way to charge from alternator 12v.
I can find the all-in-one 48v systems, but most seem large for an RV, especially in terms of inverter capacity. I also can't find much info on noise for these units (at least not in terms of decibels people do say the Growatt and MPP are loud!). These all seem to have sufficient solar
Growatt SPF 3000TL LVM-ES (48v, 3000W inverter)
MPP PIP 3048LV-MK (48v, 3000W inverter)
Victron EasySolar-II 48/3000/35-32 MPPT 250/70 GX (48v, 3000W inverter)
Are non-all-in-one 48v systems worth considering? ie you'd need an AC charger for 48v, a 48v powered inverter, and a 48v capable MPPT solar charger. Could anyone link to schematics for a system like that?
Step down 48v->12v seems doable with the Victron Orion, and the 12v->48v step up could be handled by a Sterling BB124870?
Seems to me that the real blocker is the battery and solar input requirements for heating ... those seem huge. So maybe the diesel heater has to stay?
But the extra battery cycles when plugged into shore power also seem a problem. Perhaps those can be avoided by using Hotspot's hybrid unit: https://www.hotspotenergy.com/solar-air-conditioner/ That can take direct solar 48v (no battery, but it could come via batteries) and switch to AC power when needed, although it can't use single phase 120v, so to plug in directly would need a 50amp RV connection (which reduces the usefulness, given that there are tons more 30amp sites and 30amp 120v provides more than enough power. I guess an autotransformer could help there, but then might as well power via an inverter or the Victron style pass through AC?
jameshowison
New Member
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- Jul 30, 2021
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- 184
Hmmmm, I'm realizing that an unspoken requirement here is that I can plug into 30amp 120v TT-30 power to charge (ie campsites), but would also like to be able to plug into 50amp, 240v circuits and benefit from quick charging from those. Is that a problem/possible for the grid connections for the MPP and Growatt? Also I'm realizing that the Victron EasySolar-II outputs 230v, so perhaps most suitable Victron all-in-one would be their Multiplus 48v (although that too seems to only charge from 240v not from 30amp 120v).
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davelondon
Guest
Hey how did the Hotspot AC unit work out?
I see no reply from the OP -did you end up installing a 48V mini split?
I have a 17kxh 48v (60v actually) system with an MPP3048 in my 34' 5th wheel RV so can run the (2!) installed AC but burn through staggering amounts (2Kwh+) of energy. A 12,000btu mini split heat pump seems like a very useful (<1kwh) replacement/addition.
I am very hesitant to pull the trigger given the dearth of reviews and may settle for a more typical 110v mini split but I can't shake the thought that I would rather have the least items in any particular circuit possible.
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davelondon
Guest
I didn't install one. Project is on hold unfortunately.
jameshowison
New Member
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- Jul 30, 2021
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Sorry for such a long pause in replying. I was flatchat getting the camper ready for the trip
I'm happy to report that I completed the installation of the Hotspot 48v minisplit and that it is working well. Ran it for over a month in the driveway and then used it on the road on a drive from Austin TX to Jackson WY. It arrived and worked fine. Used it overnight boondocking (Harvest hosts) and then an hour or so for lunch on the road (random parking lots etc).
Pic here shows the outside unit mounted on the trailer tongue and the inside unit on the wall You can see that this is a small travel trailer (rpod 171), just three of us onboard. I estimate that the whole thing is ~125 sq feet. We have 10kwh of batteries (2x Jakiper 100ah 48v).
In full sun in the driveway, with the inside temp set to 77°F, the energy consumption over 24 hours was well within my expectations. I have about 1100 watts of solar connected on the roof and on a three panel external array (you can see that things were basically replenishing as long as temps weren't above 100°F, the solar peaks at about 800w production).
On days in the mid-90s with full sun I saw under 4kwh. Here's June 1, which peaked at 96° with passing clouds.
On days when it was about 100°F and full sun I saw usage just under 5kwh. Here is June 6, which was just over 100°F.
On really hot days (109°F!!) that went up to 12kwh, but on those days I was also working and so in and out of the camper a lot. See attached pics (the HVAC is the only load here).
When it is running I usually see about 400-600w power usage, but when it is really hot (ie bringing things down from high temps if hasn't run a while or on the brutally hot afternoons, I have seen 1100w. It is wired and fused for 30amps, using a Midnite breaker. The unit is rated at 12,000 btus and had zero trouble maintaining 77°F air temps.
Biggest pain has been securing the cover for the compressor, just cut a piece of lightweight aluminum diamond tread and have it strapped on, going to tap some holes to secure it properly. Have to take that on and off while on the road.
One big advantage that I hadn't thought much about is that the inverter is not involved in running the HVAC, so I can have the HVAC on and still use 3000W AC from the inverter (e.g. microwave + induction cooktop). With HVAC at max and 3000W that's about 90amps from the batteries, less than half of what they can put out (and are cabled and fused for).
Other details. Mount was a pain on the tongue, a friend welded up a bracket for me. I paid an HVAC guy $300 to vacuum the lines, bend the supplied copper, flare etc. They were super curious about the equipment, so that helped!
I had been worried that the charger powering the unit (ie retifying AC to DC while plugged into shore power) would be noisy but that hasn't been a problem (loads are low enough at night for the charger not to turn it's fan on (Victron 48/3000/35). In any case, easy to run it on the batteries overnight and
Oh, the unit is amazingly quiet. I measured our previous rooftop unit at over 60 db, and the inside unit is down in the mid 40s. The outside compressor can almost not be heard inside. The 12v fans we have (Sirroco II) are way, way, louder than the wall mounted unit.
I know there is at least one other forum member who has this unit up and running, and used it for heat through the winter. Definitely consumption will be much higher for heat, since cooling peak for much less time (and just a little shifted from when solar is available).
I'm happy to report that I completed the installation of the Hotspot 48v minisplit and that it is working well. Ran it for over a month in the driveway and then used it on the road on a drive from Austin TX to Jackson WY. It arrived and worked fine. Used it overnight boondocking (Harvest hosts) and then an hour or so for lunch on the road (random parking lots etc).
Pic here shows the outside unit mounted on the trailer tongue and the inside unit on the wall You can see that this is a small travel trailer (rpod 171), just three of us onboard. I estimate that the whole thing is ~125 sq feet. We have 10kwh of batteries (2x Jakiper 100ah 48v).
In full sun in the driveway, with the inside temp set to 77°F, the energy consumption over 24 hours was well within my expectations. I have about 1100 watts of solar connected on the roof and on a three panel external array (you can see that things were basically replenishing as long as temps weren't above 100°F, the solar peaks at about 800w production).
On days in the mid-90s with full sun I saw under 4kwh. Here's June 1, which peaked at 96° with passing clouds.
On days when it was about 100°F and full sun I saw usage just under 5kwh. Here is June 6, which was just over 100°F.
On really hot days (109°F!!) that went up to 12kwh, but on those days I was also working and so in and out of the camper a lot. See attached pics (the HVAC is the only load here).
When it is running I usually see about 400-600w power usage, but when it is really hot (ie bringing things down from high temps if hasn't run a while or on the brutally hot afternoons, I have seen 1100w. It is wired and fused for 30amps, using a Midnite breaker. The unit is rated at 12,000 btus and had zero trouble maintaining 77°F air temps.
Biggest pain has been securing the cover for the compressor, just cut a piece of lightweight aluminum diamond tread and have it strapped on, going to tap some holes to secure it properly. Have to take that on and off while on the road.
One big advantage that I hadn't thought much about is that the inverter is not involved in running the HVAC, so I can have the HVAC on and still use 3000W AC from the inverter (e.g. microwave + induction cooktop). With HVAC at max and 3000W that's about 90amps from the batteries, less than half of what they can put out (and are cabled and fused for).
Other details. Mount was a pain on the tongue, a friend welded up a bracket for me. I paid an HVAC guy $300 to vacuum the lines, bend the supplied copper, flare etc. They were super curious about the equipment, so that helped!
I had been worried that the charger powering the unit (ie retifying AC to DC while plugged into shore power) would be noisy but that hasn't been a problem (loads are low enough at night for the charger not to turn it's fan on (Victron 48/3000/35). In any case, easy to run it on the batteries overnight and
Oh, the unit is amazingly quiet. I measured our previous rooftop unit at over 60 db, and the inside unit is down in the mid 40s. The outside compressor can almost not be heard inside. The 12v fans we have (Sirroco II) are way, way, louder than the wall mounted unit.
I know there is at least one other forum member who has this unit up and running, and used it for heat through the winter. Definitely consumption will be much higher for heat, since cooling peak for much less time (and just a little shifted from when solar is available).
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davelondon
Guest
Great info, thanks!
Anybody ever think about mounting on trailer tongue longways/perpendicular with hookups near trailer hitch end? Doing this would minimize air intake or exhaust restriction. Would possibly reduce likely hood of rock damage to fins. Mini-split could be used while underway.
jameshowison
New Member
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- Jul 30, 2021
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I did think about that, also diagonal, as we were figuring out the mounting. Not enough room on our tongue between the jack and the trailer. Also there are side fins on this model that are meant to have 6 inches on their side.
We also had to raise ours to keep access to the weight distribution hitch hook ups. See pic.
Working while rolling would be cool, though. Lots of side wind, but guessing that’s no worse than the units experience when stationary.
OffGridInTheCity
Solar Wizard
We mounted on the tonque and tow with an SUV which seems to block any rocks etc. No problems with it or running it while driving etc.
Mounted with u-bolts and short pieces of Universal Strut
missingegg
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- Nov 6, 2022
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I'm seriously considering going this route as well. For me, the main consideration is overall energy efficiency, as I'm looking at a completely off grid application mounted on a 26' cargo trailer without generator backup. Secondary consideration is price of electrical components, and I haven't been too happy with what a well engineered split-phase power system is likely to cost me. The major alternative I'm looking at is the Cruise N Comfort systems, but the entry level price for one of their DC air conditioners is more than $4K. That's enough money that I'd probably spring for a split-phase inverter system and get a high efficiency 240v mini split instead.
Think we could get a follow up?
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