Rooftop Air

Strategery

New member
All,

Looks like I’m putting in a rooftop unit on the new Sprinter here in FL. I’ve got a Honda 2000 generator, and will wire in shore power when in civilization. Would love any recommendations on units. Really intermittent use - 1 or 2 weekends a month. Not sure we will be sleeping in the van vs. using it as a base of operations at regattas.

Seems like there are Dometic units from ~600 to ~1000 and the Quiet units from Oz that are ~2100.

Can they run off the generator? Do I need to use one of the EZ start capacitors that we see a bunch in the marine world?

Thanks!
 

Shawn182

Active member
I have Dometic Penguin II and pulls about 1400 watts at full power. Was the right balance of price, efficiency, and physical size for my needs.

Soft start will definitely prolong the life of the equipment if you are running off inverter or generator. If 2K generator is your primary source of power...then highly recommended on the soft start as the compressor startup surge will overload the generator for just a second.

Best piece of equipment I have on board to support the AC is the 3000w Viltron Hybrid Inverter. Allows you to dial in and limit exactly how much amperage you want to pull from shore power source then pulls the rest from solar and/or battery if needed. Allows you to run AC off of a 30A shore power hookup endlessly down to a random 15A wall outlet somewhere if you have the battery to supplement the rest of the system for a bit. Usually with a 15A outlet and good sun for my 450W of solar I do not see any battery drain. I can run off full battery, 30A shore power hookup...or any other 110v power source I can find and set my draw accordingly.

If money was not object I would have Advanced RV install one of their quiet run systems.

Just as a data point, if you want to run 100% on battery you need about 100AH of LiFePO4 Battery capacity per hour of runtime desired. That is full bore at 95 degree day. Can stretch that out to 1.5 hours on a mid 80's day and the unit cycling to a higher thermostat setting.

Prepare for the onslaught forthcoming of why AC in a van is impossible/impractical.
 
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agreenjacket

New member
I had Advanced RV install one of their Houghton units on my 144. It wasn't cheap but it is super quiet and you can make it a meat locker on the hottest day. Don't forget that insulation in your van will also play a big part. When I am not connected to shore power I run it off of a small very quiet Wen generator without any issue. https://www.amazon.com/dp/B07XZX5FTR/ref=cm_sw_em_r_mt_dp_U_LQXfEb0ZF4B5F
I have noticed a very small hit in my mpg now that it is on my roof. I also have a Max fan up there too.
Say what you want, it keeps my wife happy.
 

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agreenjacket

New member
How many BTU or amps pulls this Houghton? It is made in Australia , I know they make couple of sizes .
I am not sure what the BTU's are, the ARV website may have more info. Not sure where it is made but I am fairly certain it is an Australian company. I have family in Australia that caravans quite a bit and they swear by these things. This past summer I stuck my Kill-a-Watt monitor on it and it was cruising at 900w on an 85degree hot day keeping the van super cool. I could do a more in-depth analysis on what it pulls but I'll be cranking the Espar for a few more months instead. Sorry I don't have more specifications right now....as I said before...Happy wife....
 

ziggyko

New member
I am not sure what the BTU's are, the ARV website may have more info. Not sure where it is made but I am fairly certain it is an Australian company. I have family in Australia that caravans quite a bit and they swear by these things. This past summer I stuck my Kill-a-Watt monitor on it and it was cruising at 900w on an 85degree hot day keeping the van super cool. I could do a more in-depth analysis on what it pulls but I'll be cranking the Espar for a few more months instead. Sorry I don't have more specifications right now....as I said before...Happy wife....
Thank you.
I know they are very quite . 900w that would be great on 800ah battery for 8 or more hours.
Do they ship it? I see on their webside cost about $2749 is that with installation?
 

agreenjacket

New member
Thank you.
I know they are very quite . 900w that would be great on 800ah battery for 8 or more hours.
Do they ship it? I see on their webside cost about $2749 is that with installation?
Sorry, I don't know if they ship. I made an appointment about 2 months in advance and made a roadtrip out of it. Dropped it off on a Monday morning, they installed the AC and the Maxfan, I picked up a rental car to get back home and returned to pick it up on Friday. If you are interested give them a call or email, they were very professional to deal with. I needed a towel to wipe up the drool when they gave me a tour of their shop and facilities.
 

thataway4

New member
I have used several Coleman Mach 8 Cub 9200 BTU AC on 25 foot boats and they work well on the Honda 2000 (now 2200) Inverter generators. If you get a larger unit they will run with the EasyStart by MicroAir. ($299). Just an extra capacitor will not do the trick.

The Coleman is a low profile and well suited to the Sprinter Vans. I would not try to run it off LiFePO4 batteries--I have 200 amps and it would not be enough for more than a couple of hours use.
 

mikecol

Member
How many BTU or amps pulls this Houghton? It is made in Australia , I know they make couple of sizes .
I have the Adv RV A3401 AC which is 13500BTU. Draws about 80-85A running.. see about 850-1050 Watts from Xantrex 3000W inverter.

My insulation is only about 50% complete, but attached is a typical hot FL day...takes 15-20 min to cool down, then cycles maybe 50%..more running as day gets hotter.. Mostly use for time shifting power during day...but have used it for 3 days of AC in FL with my 1100AH LifePO4 bank (10 X Trojan Trillium).

AC is excellent; I would buy again. Mine was shipped to FL. Unit is a monster so had to change original layout plans....mainly becuz of the 2019 XMradio antenna location.
 

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ziggyko

New member
mikecol
That is nice setup 1100 ah. How did you place those 10 battery in 144 sprinter, any pictures?
That is 300lbs that need to be installed with correct weight distribution.

Thank you
 

mikecol

Member
mikecol
That is nice setup 1100 ah. How did you place those 10 battery in 144 sprinter, any pictures?
That is 300lbs that need to be installed with correct weight distribution.

Thank you
Placed mine in 2 rows of 5 on drivers side...pass side has water system to balance (25G +7G hot).

Have required spacing between batteries for airflow. Also offset one row to shift the positive terms to be approx centered for my individual battery switches on center copper buss bar. Final Class-T fuse at end of Positive buss bar to manual SW then GX14 contactor (controlled by BMV712 FET buffered).

Two Neg buss bars from each row feed on opposite side (from pos) to balance drop between batteries.

Mech clamped and Fiberglass L straps holding to floor/wall rails. Have polycarb cover over entire area so I can throw tinsel at it...
 

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Strategery

New member
I have the Adv RV A3401 AC which is 13500BTU. Draws about 80-85A running.. see about 850-1050 Watts from Xantrex 3000W inverter.

My insulation is only about 50% complete, but attached is a typical hot FL day...takes 15-20 min to cool down, then cycles maybe 50%..more running as day gets hotter.. Mostly use for time shifting power during day...but have used it for 3 days of AC in FL with my 1100AH LifePO4 bank (10 X Trojan Trillium).

AC is excellent; I would buy again. Mine was shipped to FL. Unit is a monster so had to change original layout plans....mainly becuz of the 2019 XMradio antenna location.
Sorry, are you running this entirely off battery? 10 100AH Trilliums? Shore power to recharge or will your charger sustain when car is running?
 

Strategery

New member
OK... so 1100 AH is roughly $11k, plus $2,100 for SuperQuiet AC and $1,500 for inverter/charger, plus assoc wiring, etc for top of the line all battery solution. That’s ~15k DIY price.

Or lower end: Dometic Penguin 2 ~$700, plus inverter Charger $1,500, 100AH Lithium Battery $1,000, and box for generator on stern of van ~$400. That’s ~$4K

Or quiet AC for another $1,400 - so ~$5,400 all in. Does that sound right to you all?
 

Shawn182

Active member
Or lower end: Dometic Penguin 2 ~$700, plus inverter Charger $1,500, 100AH Lithium Battery $1,000, and box for generator on stern of van ~$400. That’s ~$4K
You will be closer to $5-6$K at least in my experience for that configuration. There are a zillion electrical and fabrication odds and ends that add up quickly if you are starting from ground zero.

For example on the Penguin II alone you need not only the AC unit but control box, thermostat, soft start, rooftop adapter, 120V AC wiring and breakers, shore power inlet, 30A cable...and so on.

Beyond nicer AC Units the rest of cost is battery capacity. 100AH will only give you only about 1 hour of rooftop AC run time not taking into account any other in van power needs. Add 100AH of capacity for each hour of run time desired.

I have a 200AH 24V battery (equivalent watt hours to 400AH @ 12v) and I see 4 hours continuous run time. I am adding a second battery soon.

On my sterling B2B 12>24v battery charger off of stock alternator I see about 30% capacity recharge per hour of driving. I may add second charging alternator when I add second battery.

Regardless of which brand/model AC, you'll want to use our patent pending adapters and internal framing strips to mount and seal it to the roof.
Can't recommend Hein's Fan and AC adapters enough. AC units and Fans are made to sit on flat surfaces, not the ribs of Sprinter roofs and the adapter solve that sealing problem between the unit and van brilliantly.
 
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Strategery

New member
OK... so - tell me why I wouldn’t go with the following please:

Yeti 3000 Plus Generator, Sterling B2B charger and Genset with shore power hookup for the Yeti...

Portable - handle any load - simplifies systems...

“Popping corn now...”
 

Shawn182

Active member
Outputs: 110 VAC 60 Hz Pure Sine Wave, 12.5 A (1500 W, 3000 W Surge)...that is right at the upper limits of power needs

OK... so - tell me why I wouldn’t go with the following please:

Yeti 3000 Plus Generator, Sterling B2B charger and Genset with shore power hookup for the Yeti...

Portable - handle any load - simplifies systems...
Outputs: 110 VAC 60 Hz Pure Sine Wave, 12.5 A (1500 W, 3000 W Surge)...barely enough to handle Rooftop AC loads. maxing out unit continuously is gonna make a series dent in lifespan. Dometic reccomdens a 30A breaker...12.5A rating is woefully underrated.

Battery Life: 500 Cycles to 80% Capacity (1 C Discharge Rate, 25C Full Charge/Discharge Temp)...that is an awful cycle rate lifespan for LiFepo4 and only 80% discharge...will be significantly less for 100% discharge which would be common with AC use. Battelborn I believe claimes 3000 cycles @ 100%

Expandability...none. Can't add additional batteries for additional capacity if ever desired.

I like that unit as an all in one option...but not for running an AC with the 120v draw required.
 

Strategery

New member
Outputs: 110 VAC 60 Hz Pure Sine Wave, 12.5 A (1500 W, 3000 W Surge)...that is right at the upper limits of power needs



Outputs: 110 VAC 60 Hz Pure Sine Wave, 12.5 A (1500 W, 3000 W Surge)...barely enough to handle Rooftop AC loads. maxing out unit continuously is gonna make a series dent in lifespan. Dometic reccomdens a 30A breaker...12.5A rating is woefully underrated.

Battery Life: 500 Cycles to 80% Capacity (1 C Discharge Rate, 25C Full Charge/Discharge Temp)...that is an awful cycle rate lifespan for LiFepo4 and only 80% discharge...will be significantly less for 100% discharge which would be common with AC use. Battelborn I believe claimes 3000 cycles @ 100%

Expandability...none. Can't add additional batteries for additional capacity if ever desired.

I like that unit as an all in one option...but not for running an AC with the 120v draw required.
Even with a soft start? You can add modules but they are AGM, and it has replaceable cells.
 

Zundfolge

1-2-4-5-3
OK... so - tell me why I wouldn’t go with the following please:

Yeti 3000 Plus Generator, Sterling B2B charger and Genset with shore power hookup for the Yeti...
Battery Life: 500 Cycles to 80% Capacity (1 C Discharge Rate, 25C Full Charge/Discharge Temp)...that is an awful cycle rate lifespan for LiFepo4 and only 80% discharge...will be significantly less for 100% discharge which would be common with AC use. Battelborn I believe claimes 3000 cycles @ 100%
~500 cycles just to be liberal (though in reality yes, 100% discharge will lessen that lifespan). $3000 price tag for basically a glorified disposable 280AH battery with a fancy name (because of your intended use).

$3k in battle borns will get you 300AH of battery that will last purportedly 6x longer than the Yeti setup. Throw in another $1k for inverter, cables, disconnect, fuses, etc.

You'd be buying 3-4 of those yetis for the price and functionality of one well built custom electrical system (that really is not that hard to build, especially with the help of those here who so generously share their knowledge).

Using the Yeti for the purpose of running an a/c unit is, well, crazy sounding to me. For the price of those things you can get SO MUCH more bang for your buck. Maybe it won't look as cool and sexy and have the brand name but at least it will work and work well.

Run the a/c from a good Honda genny and if you really want the Yeti use it for the lower 12V power draws like fridges and heaters and charging (which, as I understand things, isn't possible without some special transformer cable as they don't put out over 12V?) and smaller AC loads...
 
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Strategery

New member
Thanks - I’m sorry this thread has devolved a bit. For frame of reference, I’ve owned and maintained over 40 boats, most with offshore systems including generators, water makers, diesel heaters, AC’s inverter chargers on solar, multiple air conditioning units, washer dryers, and up to 4 independent AC units . I’ve had several RV’s an now have a 40’ diesel pusher with every system you can think of.

I’m not looking to run the AC off the system overnight. Maybe an hour or two while I crash nap on the way to a regatta at a rest area. I’ll have the Honda on the stern of the van in a generator box for any extended AC run. I’m just trying to see if the YETI system can do what I want without a ton of investment on my part. Sounds like it may be a miss though.
 

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