Great explanation that most non-technical people will understand. I recommend that anyone who's considering a second A/C for off grid use not to add a rooftop unit, but to install a high efficiency mini split heat pump instead. My 12k 28.5 Seer-2, EG-4 heat pump only draws about 1/3 of the power as my front rooftop 14.5k Furrion, and cools just as well. Plus, it doesn't take up any valuable roof space of cast any shadows on a rooftop array. It's cheaper (and saves weight) to consume less power than to add more solar, more batteries, a bigger inverter, heavier wiring, etc. A couple added benefits is that it makes efficient electric heat, sparing propane use, and it is whisper quiet too, unlike our noisy rooftop A/C unit. If I had more money, I would have removed both rooftop A/Cs, replacing them both with heat pumps, not just my rear unit.
@@mytsolar I used the EG-4 28.5 Seer-2 unit. I paid $1,500 for mine, but they have dropped to $1,350 now. Mine is the non-hybrid model that just uses AC, not DC voltage. It was a plug and play unit that was a piece of cake to install. I had no prior HVAC experience, so I just followed the instructions. I mounted the indoor unit in my rear bedroom. It is huge - much larger than their SEER-22 unit, but I guess that's what it takes to produce the added efficiency. I mounted the outside unit on the upper rear of my motorhome, opposite the ladder. I welded up some angle brackets out of 2" rectangular steel tubing and bolted them to my roof to carry the weight. I then bolted the bottom of the bracket through the wall to stabilize it. By mounting it high rather than low like other RVs I've seen, the coils stay much cleaner as there's less dust kicked up the higher you go. I think I sent you a couple pics of the install in August. Take care, Chip
Great explanations, Tom. I am sure many people don't understand how much power 2 legs of 50A is vs 1 leg of 30A. This is also important when plugging a 50A rig into a 30A pedestal with the typical adapter. One comment when you were showing the Touch 70 with the AC running is that the AC Load is a little misleading. If you look at the DC power consumption it is much higher than just for the typical DC loads in a trailer. I assume this is due to the (in)efficiency of the inverter being less than 100% of the battery draw. I noticed this right away in our rig when running the AC of solar/battery. Also the AC load does start out lower and climbs up for quite a while. Is this due to the soft start or just the nature of the Air Conditioner load?
Thanks for watching Wayne. Hope you guys are traveling safely. Just curious what comment was misleading? I think my comment at the Touch 70 screen was that we were running the AC and still charging the batteries. If you look at the battery section there was net positive amps meaning the AC was running and the batteries were charging. The Multilplus efficiency we usually see is about 70-80%. As the AC runs and the refrigerant changes temperature it also changes the pressure at which the compressor works against so the compressor runs harder over time and draws more power.
@@mytsolar Thanks for the explanation about the Air Conditioner changes as it runs. I didn't mean you made a misleading comment. I was commenting that if you only look at the AC Load on the touch screen, it doesn't show the whole picture because of the efficiency. So one needs to look at the actual current in (or out) of the battery as you did point out in the video. Also, if I am correct the touch screen display for DC Loads is not actually measured, but is calculated from the other numbers as the "remainder".
Expectations vs Reality vs budget vs education. I'm sure some customers "want it all." But, as you say, all parts of the equation have to balance out. Great explanation. Are there "hybrid" systems that would support the 50Amp/30Amp (120V system) with an added 48V second Air Conditioner? Does that make sense?
It sounds like in that case the solution would be a 48v battery bank to power the 48V DC Air Conditioner directly and a 48v suited inverter to run the 120V as usual.
For most people they only need a Multiplus 3000. The Multplus II 2x120 if they are a 50AMP. The Quattro is a nice 5000W unit but only has a single leg of 120v out, so can be used for a 30AMP rig -or 2 of them can be stacked for a 50AMP rig. But that would be 10000W output which if used will drain a battery bank in no time.
Thanks for running through that! Super helpful. Beautiful work by the way. I'm deciding to dumb my 50 amp rig down to 30 amps as it only has a 12000btu mini-split as the main consumer. I am looking at your setup there and have a question. I hear a fair amount mentioned about making the positive and negative wire legs (leading from the batteries to the system) the same length and not being an electrician, can only guess it has something to do with added resistance on the longer leg. Considering my batteries (5 Victron 200ah Smart LiFePo) will be lined up and oriented away from my system, one of my legs will be about 3' longer than the other. Should I just make the wires the same length and coil the extra material of the closer leg to one side? Or is it such a small amount that the resistance wouldn't amount to much? Thanks!
Great question. You are absolutely correct about the reason for the battery to battery cables needing to be the same length. The concept is if one of them has more resistance there may be issues with that battery getting the same cell balancing as the other. Victron does a good job of active cell balancing so you may get away with it if it is only 3 inches. But course there is the correct way and the way that "should work". Making them all 3 inches longer would probably be preferred. What size cable are you using and is it 12v system?
@@mytsolar Thanks for your reply! You mentioned 3 inches but just for clarity... my battery setup would have the far end of the batteries 5 FEET away and the close end about 2 feet away from the Lynx Distributor, so a difference of 3 FEET. As for cable size, I'm thinking 3/0 for a Multiplus II 12/3000/120.
If you need two ac units then a 50 amp system is required? The challenge with a two ac trailer off grid how to power them or can you live with only running one at a time? I have an off road trailer but it has only one 12 volt ac unit. If the sun is out and not excessively hot the 1080 amp battery bank and 1200 watts solar work just fine. One thing people tend to forget is every time you convert power from 12 volt to 120 volt or 120 volt to 12 volt energy is lost,. If a person can run more items at one voltage then you can be more efficient in use of your limited energy. One example is my wife uses a CPAP. It comes as a 120 volt unit which required me to run the inverter all night. I was able to find a 12 volt adapter and now I no longer need to run the inverter all night saving a fair amount of energy.
Absolutely! I think a great solution is a 48v bank with the inverter for 120v items. But then using that 48v bank to power a 48v AC unit directly. What model 12v AC do you use? Does it keep up/cool well?
Great explanation that most non-technical people will understand. I recommend that anyone who's considering a second A/C for off grid use not to add a rooftop unit, but to install a high efficiency mini split heat pump instead. My 12k 28.5 Seer-2, EG-4 heat pump only draws about 1/3 of the power as my front rooftop 14.5k Furrion, and cools just as well. Plus, it doesn't take up any valuable roof space of cast any shadows on a rooftop array. It's cheaper (and saves weight) to consume less power than to add more solar, more batteries, a bigger inverter, heavier wiring, etc. A couple added benefits is that it makes efficient electric heat, sparing propane use, and it is whisper quiet too, unlike our noisy rooftop A/C unit. If I had more money, I would have removed both rooftop A/Cs, replacing them both with heat pumps, not just my rear unit.
Cheers!b What brand Mini-split did you install? Any challenges on the install? Where did you mount the indoor and outdoor units?
@@mytsolar I used the EG-4 28.5 Seer-2 unit. I paid $1,500 for mine, but they have dropped to $1,350 now. Mine is the non-hybrid model that just uses AC, not DC voltage. It was a plug and play unit that was a piece of cake to install. I had no prior HVAC experience, so I just followed the instructions. I mounted the indoor unit in my rear bedroom. It is huge - much larger than their SEER-22 unit, but I guess that's what it takes to produce the added efficiency. I mounted the outside unit on the upper rear of my motorhome, opposite the ladder. I welded up some angle brackets out of 2" rectangular steel tubing and bolted them to my roof to carry the weight. I then bolted the bottom of the bracket through the wall to stabilize it. By mounting it high rather than low like other RVs I've seen, the coils stay much cleaner as there's less dust kicked up the higher you go. I think I sent you a couple pics of the install in August.
Take care, Chip
Thanks for sharing your knowledge Tom, enjoy your weekly shows.
Thanks Matt. A little Sunday entertainment. Hope you're having a good weekend. Thanks for watching, we appreciate the comment.
Thanks Again Tom.. another very good Solar Video! 🙂
Enjoy your Sunday! Thanks for watching
👍
Thanks for checking MYT's videos out!
Great explanations, Tom. I am sure many people don't understand how much power 2 legs of 50A is vs 1 leg of 30A. This is also important when plugging a 50A rig into a 30A pedestal with the typical adapter. One comment when you were showing the Touch 70 with the AC running is that the AC Load is a little misleading. If you look at the DC power consumption it is much higher than just for the typical DC loads in a trailer. I assume this is due to the (in)efficiency of the inverter being less than 100% of the battery draw. I noticed this right away in our rig when running the AC of solar/battery. Also the AC load does start out lower and climbs up for quite a while. Is this due to the soft start or just the nature of the Air Conditioner load?
I have a Micro Aire soft start on my front A/C and it ramps up power draw like yours does.
Thanks for watching Wayne. Hope you guys are traveling safely. Just curious what comment was misleading? I think my comment at the Touch 70 screen was that we were running the AC and still charging the batteries. If you look at the battery section there was net positive amps meaning the AC was running and the batteries were charging. The Multilplus efficiency we usually see is about 70-80%. As the AC runs and the refrigerant changes temperature it also changes the pressure at which the compressor works against so the compressor runs harder over time and draws more power.
@@mytsolar Thanks for the explanation about the Air Conditioner changes as it runs. I didn't mean you made a misleading comment. I was commenting that if you only look at the AC Load on the touch screen, it doesn't show the whole picture because of the efficiency. So one needs to look at the actual current in (or out) of the battery as you did point out in the video. Also, if I am correct the touch screen display for DC Loads is not actually measured, but is calculated from the other numbers as the "remainder".
Expectations vs Reality vs budget vs education. I'm sure some customers "want it all." But, as you say, all parts of the equation have to balance out. Great explanation. Are there "hybrid" systems that would support the 50Amp/30Amp (120V system) with an added 48V second Air Conditioner? Does that make sense?
It sounds like in that case the solution would be a 48v battery bank to power the 48V DC Air Conditioner directly and a 48v suited inverter to run the 120V as usual.
do you recomand a Victron Energy - Quattro 12/5000/200-100 instead?
For most people they only need a Multiplus 3000. The Multplus II 2x120 if they are a 50AMP. The Quattro is a nice 5000W unit but only has a single leg of 120v out, so can be used for a 30AMP rig -or 2 of them can be stacked for a 50AMP rig. But that would be 10000W output which if used will drain a battery bank in no time.
Thanks for running through that! Super helpful. Beautiful work by the way.
I'm deciding to dumb my 50 amp rig down to 30 amps as it only has a 12000btu mini-split as the main consumer.
I am looking at your setup there and have a question. I hear a fair amount mentioned about making the positive and negative wire legs (leading from the batteries to the system) the same length and not being an electrician, can only guess it has something to do with added resistance on the longer leg. Considering my batteries (5 Victron 200ah Smart LiFePo) will be lined up and oriented away from my system, one of my legs will be about 3' longer than the other. Should I just make the wires the same length and coil the extra material of the closer leg to one side? Or is it such a small amount that the resistance wouldn't amount to much? Thanks!
Great question. You are absolutely correct about the reason for the battery to battery cables needing to be the same length. The concept is if one of them has more resistance there may be issues with that battery getting the same cell balancing as the other. Victron does a good job of active cell balancing so you may get away with it if it is only 3 inches. But course there is the correct way and the way that "should work". Making them all 3 inches longer would probably be preferred. What size cable are you using and is it 12v system?
@@mytsolar Thanks for your reply! You mentioned 3 inches but just for clarity... my battery setup would have the far end of the batteries 5 FEET away and the close end about 2 feet away from the Lynx Distributor, so a difference of 3 FEET. As for cable size, I'm thinking 3/0 for a Multiplus II 12/3000/120.
I have not seen a video from you about a class c with 30 amp service
Hey there! We’ve definitely done a few videos on 30AMP Class C motorhomes you can search for.
If you need two ac units then a 50 amp system is required? The challenge with a two ac trailer off grid how to power them or can you live with only running one at a time? I have an off road trailer but it has only one 12 volt ac unit. If the sun is out and not excessively hot the 1080 amp battery bank and 1200 watts solar work just fine. One thing people tend to forget is every time you convert power from 12 volt to 120 volt or 120 volt to 12 volt energy is lost,. If a person can run more items at one voltage then you can be more efficient in use of your limited energy. One example is my wife uses a CPAP. It comes as a 120 volt unit which required me to run the inverter all night. I was able to find a 12 volt adapter and now I no longer need to run the inverter all night saving a fair amount of energy.
Absolutely! I think a great solution is a 48v bank with the inverter for 120v items. But then using that 48v bank to power a 48v AC unit directly. What model 12v AC do you use? Does it keep up/cool well?