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Post Info TOPIC: Looking at rev cycle air con on solar


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Looking at rev cycle air con on solar


Hi,

I saw a post about requiring 1.4KW of solar to run a split system reverse cycle air con.

After collecting my bus (1988 Hino Rainbow R145A), and driving home through a Victorian heat wave (only mid 30s) I KNOW i need an aircon.

There is no existing roof vent, as I first thought. However there is existing motor compressor etc, but is 7 years unconnected and probably defunct. The problem being I do not just want it to drive but also when generally really hot.

This is a need for me, not a want, the heat drastically affected by driving capacity.

I need a unit that can run on a hot day, whether driving or stationery. The post I am referring to (but cannot find again) referred to a split system, rear mounted running off 1.4Kwh Solar system.

My questions are, will they operate moving or only stationery? I can achieve the panels on roof, (looking at the existing 400W - -5yr old, and an additional 1300W Teksolar roof mounted panels form Dubai).

I have two new 170AH Gel batteries for the solar system. What kind of set up will I need to support the larger system, with a view to running the air con. I'm asking here, because I am absolutely stumped on the best way forward, A roof mount with generator will not work whilst mobile. 

Anyone who can help, without an overwhelming amount of technical jargon would be most appreciated. Obviously I will get done professionally, but I do not know whether this is even feasible.

Thanks in advance

Susie

 



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S Burke


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Sounds like the bus already has an airconditioner that will run while you are driving. It will be powered by the motor and will blow cold air out of the vents on the dash. Get it checked out and serviced by a service guy - your local mechanic will direct you to one. If the hardware is all OK, you should be up and running for a hundred bucks or so. If the compressor is stuffed, then maybe $300 or more?

Running aircon while stationary will cost lots more.
First the solar that you know about, plus an inverter to provide 240V power, plus the aircon itself and installation and then some significant battery power to run it when the sun does not shine. How much battery depends on how long you want to run it and they is a big question.
Could be done from any type of battery, depending on what weight you can tolerate.
Cheers,
Peter

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OKA196, 4x4 'C' Class, DIY, self contained motorhome. 960W of solar, 400Ah of AGMs, 310L water, 280L fuel. https://www.oka4wd.com/forum/members-vehicles-public/569-oka196-xt-motorhome
 

 



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A quick look at 2.5kW split systems. Cooling at rated output 518 watts, 5.6amps cooling, 673 watts, 7.1amps heating.

So it's going to use more when starting but while it's actually running at it's rated output you are looking at about 500 watts. Allowing for inefficiencies in your inverter etc. Let's say 600 watts. So it's drawing about 50amps.

So just work out how long you are likely to run it In a typical 24 hour period. Add spare capacity in your batteries.

Enough solar to run the AC during the day, say about 800 watts if solar. Plus additional solar to charge the batteries while the AC is running. Let's say another 800 watts minimum.

& capacity for everything else you want to run at the same time.



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Thank you gentlemen. I'll go to an installer.

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S Burke


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Thing is, any aircon that is going to be useful when stationary is going to be useless when on the road because of air infiltration and all that glass around you. Maybe if you mount the aircon right behind the driver's seat and blow cold air on you it will keep you cool while driving but won't be well placed to cool the living area when stationary. 

My Hino is 35 foot long and has three working roof airconditioners and the 280Ah 24 volt lithium battery, 1500 watt inverter, 1000 watts roof mounted and 600watt ground deployed panels allow me to run one aircon indefinitely when the sun is shining.

It also has a dash unit on steroids that probably doesn't work but I haven't bothered to check it out. As Peter said, the dash fan and condenser fans probably work anyway so a new filter dryer and recharge and maybe a compressor and it will be good as new. One day..

We have heavy curtains across behind the passenger seat so the dash air should be very effective. There is one roof air forward of the curtain so guess I should give it a try one day.the 15 amps from the alternator should make up for the lack of ground deployed panels

 

Here in Tasmania we tend to drive no longer than an hour between camping spots so aircon really isn't a priority while driving.



-- Edited by Tony LEE on Saturday 23rd of January 2021 03:46:48 PM



-- Edited by Tony LEE on Saturday 23rd of January 2021 03:53:33 PM

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Susie, have a look at this thread on acoustic insulation. The best thing about foam acoustic insulation is its thermal properties.

What I would do is pull off all the panels & stuff everywhere with polybatts. Also make thermal barriers for the windows.

If you then you decide to still have air conditioning then the system will be far more efficient.

 

https://thegreynomads.activeboard.com/t65443581/car-acoustic-insulation/



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Procrastination, mankind's greatest labour saving device!

50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.



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An excellent article here on acoustic insulation.

 

https://www.megasorber.com/soundproofing-case-studies/4wd-coach



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Procrastination, mankind's greatest labour saving device!

50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.



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Susie Burke wrote:

Hi,

I saw a post about requiring 1.4KW of solar to run a split system reverse cycle air con. After collecting my bus (1988 Hino Rainbow R145A), and driving home through a Victorian heat wave (only mid 30s) I KNOW i need an aircon.

There is no existing roof vent, as I first thought. However there is existing motor compressor etc, but is 7 years unconnected and probably defunct. The problem being I do not just want it to drive but also when generally really hot. This is a need for me, not a want, the heat drastically affected by driving capacity.

I need a unit that can run on a hot day, whether driving or stationery. The post I am referring to (but cannot find again) referred to a split system, rear mounted running off 1.4Kwh Solar system. My questions are, will they operate moving or only stationery? I can achieve the panels on roof, (looking at the existing 400W - -5yr old, and an additional 1300W Teksolar roof mounted panels form Dubai).

I have two new 170AH Gel batteries for the solar system. What kind of set up will I need to support the larger system, with a view to running the air con. I'm asking here, because I am absolutely stumped on the best way forward, A roof mount with generator will not work whilst mobile. 

Anyone who can help, without an overwhelming amount of technical jargon would be most appreciated. Obviously I will get done professionally, but I d not know whether this is even feasible. Thanks in advance Susie

 


 Hi Susie smile

Ahh you have your bus, good show !! Now to the problems hmm

To address the questions in no particular order. Why buy some unknown big panel from Dubai ?? Big panels are not recommended on mobile bus roofs for various reasons AND who knows anything about that panel !! Just get more matching spec panels to put on beside the existing ones. As many as you can fit there and get a new bigger solar controller also, all from reputable local suppliers. biggrin Generally if it is hot there is plenty of solar available. If you were sensible you would rig the panels on a frame to shade the roof of the bus also.

People have used a small split system air con unit with an inverter compressor. These inverter compressor types do start up easily with low current and can be turned down very efficiently to run with lower current needs and do not switch the compressor on and off which is the problem with normal units running on batteries. i believe Peter has that style. There is no reason why you could not use that while driving but the cool air might not be close to the driver no as pointed out. I believe you should not be looking at the maximum capacity of the A/C unit, like the sales people do, but looking at the lowest setting, as that will be what you will want to use overnight. That is what I would do.      

You will need more batteries to be safe from excessive low voltages. Your bus will carry them I am sure. Another thing to look at is the voltage to run your "house"  system at. The bus is most likely 24Volt so having the "house" batteries as 24V also is a good idea. Then you can charge then from the alternator on the motor. A powerful way to get them charged when driving and also for bad solar(rainy) days. So you just put two 12V batteries connected in series for 24V total, no mystery there.  All the solar systems, controllers, inverters etc are available to suit 24V. wink

You will need a good inverter also but they are easy to find, get a pure sine wave only, and decide on the size after the air con unit is decided, as the start up current is the important spec. It is vital to have the inverter close to the batteries and wired in with heavy cables to minimise losses. A 24V system will help there also.   

I might send you a PM again also.

Jaahn        



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The bus's own air conditioning will be too large for you as the cooling capacity would have factored in about 300 watts per passenger on top of the base load.

 

If you can cover windows you will reduce heat/cool loss by 6 watts per degree difference per square metre.



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Procrastination, mankind's greatest labour saving device!

50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.



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"What I would do is pull off all the panels & stuff everywhere with polybatts. Also make thermal barriers for the windows"

Would you really?

Man hours and material estimate would be interesting.

 

Would bd some point if you get rid of nearly all the windows, but otherwise... 



-- Edited by Tony LEE on Sunday 24th of January 2021 03:55:18 PM

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About 120 hours on my car but I have pulled the ceiling down 4 times which means I have to start with the boot threshold trim panel first. But now can have it all out & in in 2 hours.

About $1500 of various tyres of acoustic insulation of which 2 sheets of very expensive engine bay material at $230 a piece, & 1 piece of aluminium shield at $130.

If I replace the car this will be the first thing I will do to a new car. Couldn't be happier.

 

By comparison polybatts cost nothing.



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Procrastination, mankind's greatest labour saving device!

50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.



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2 layers of insulation inside the windscreen & ice on the car.

_MG_2678-ice.jpg



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Procrastination, mankind's greatest labour saving device!

50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.



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Aren't we talking about a bus?

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Just a bigger piece of metal.



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Procrastination, mankind's greatest labour saving device!

50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.



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I tinted all the coach windows in my coaster, dropped the inside temp by about 5 degrees when in full sun
cheers
blaze

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Suzie, just to give you some hope about your rig's dash aircon. My Hino is 32 years old so I never bothered to even try the dash/passenger compartment aircon unit because I figured it was hadit 20 years ago. Few days ago I checked it out. All the fans worked so booked it in for a regas and new aircon if required. Suck down and regas and it is good as new. 170 dollars. Guess that is the end of summer for this year

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I had the same bus and had a reverse cycle air conditioner mounted on a frame level with the back window and the inside unit was on a panel inside near the roof over the bed pointing to the front.and it ran of my batteries. Wont go into details as many believe it cant be done even when they see it working. It is a case of the right batteries and the right amount of soar and setup properly. PM me if you want to know more.
A lot depends on how you want to travel, eg caravan parks of push camping and what you want to finish up with. I even ran my water heater using excess solar and my bus was full 240v. the only 24v was the radios and a small fan.
If you bypass Mannum I could organise you to look at my setup.

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Thanks for your replies. Tony Lee, in going that's the case here, and am booked in for pressure testing and gassing next week. Here's hoping. Looking forward to hitting the road. Not long now
Susie

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S Burke


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Beiffe,
Thanks for that. Big difference in roof top solar panel capacity, but thank you. I recognise I don't have space. I've bought a generator for my portal air con.
Susie

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S Burke


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Look into a standard room box  airconditioners. I fitted one for my Millard 13 footer, when I had it. It was 1.2 kw cool and 1.7 kw hot. I ran it off a genni, if was very, very effective. Portable airconds, were not around then, but I would not have fitted one anyway. All the exhaust went out the back outside, as well as the humidity water excess. I am sure you would  be able to run it off solar panels just with the amount of room you have on your bus now. If you could afford lithiums as well, it would work exactly as you want it to.



-- Edited by Bicyclecamper on Saturday 13th of February 2021 05:44:43 PM



-- Edited by Bicyclecamper on Saturday 13th of February 2021 05:49:59 PM

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