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Post Info TOPIC: Airconditioners and battery power


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Airconditioners and battery power


Airconditioners and battery power.

Apology for my ignorance but I was just wondering how many members use their caravan airconditioners from purely battery power when off road in terms of practical hours of usage.

I realise the airconditioners draw a huge amount of power and their off road usage needs to be minimised, 

I have a fairly powerful battery, solar, inverter system in my new caravan which I have not used yet.

The specs are:  500A batteries, 1.2kw solar, 3000w inverter and it is all RedArc gear.

It is also a soft start, inverter style airconditioner. 

So is it naive of me to think that I should be  able to get 1 or 2 hours of airconditioning say at lunch time on the side of the road and as long as I keep my eye on the Redarc monitor I can be pretty sure all will be okay? 

I do have 4 kw of generator power but I would prefer to only have to use this when camped permanently with no  240v power available.

Just curious and as I said  I am a newby so please be gentle with me  :)

Regards 

 

'trollin Dave 



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should be OK for a few hours when the sun shines, watch your voltage though, AGMs will suffer a bit with voltage sag during the first half hour or so when the system is going full tilt. If you can get it to idle down a bit with curtains and insulation, etc, then a good inverter splitty only draws a few hundred watts once settled in

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Thanks.

I should have said they were lithium batteries to hopefully they will work better.

Regards and thanks.

David



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Pradokakadudavid wrote:

Thanks.

I should have said they were lithium batteries to hopefully they will work better.

Regards and thanks.

David


 Should be no problem....PM sent.Cheers



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What are the specs of the AC.



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You didn't say how many watts the aircon draws,,, that's the start point. You could have very high dc draw obviously, as you say the inverter to cope.

As an example I have the smallest and most efficient Diaken house reverse cycle fitted to van, draws 500W max @ 230v, which is 40A dc from battery approx.

Soft start helps but wattage in use will give you the answer as to dc load.

You will have high dc charging and output available so should be OK, but trial will tell you.

 



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There is a good series called "Trip in a Van" on YouTube. 3 of the short videos show setting up an off the grid van with a Dometic soft start air conditioning which uses less current at startup. https://youtu.be/lfyVkUTv4ok https://youtu.be/aaL5XdaQ7bM https://youtu.be/19v1aVzTDoQ You would need large capacity Lithium Batteries and quite a few solar panels but it is now possible to run your a/c off grid for quite a few hours per day.

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Your assumption is is not naive at all. Our system with 900w roof mounted and 300w portable with 400ah lithium have run aircon up to 6 hour stints. Simply haven't tried to run it longer. Overnight we  just use a large 240w fan blasting away.

With a couple of assumptions. If you are talking split system inverter aircon. Ours pulls 50-60A on startup for about 10 mins then runs when it is needs to on 25A.

With 1200w roof mounted  solar at this time of year you could easily see 30A going in by 9.30am and 60Aplus by midday.

Plenty of excess solar for other gear (depending on how much power you use) and good battery capacity to cover once the sun goes down.

Your genny probably won't get much use in summer (again depending on what you wan't to run).

If you are using the same system for heating in winter you might struggle with solar input and battery capacity. Diesel heating will soon cover that and your genny might get a 

workout to charge your batteries back up if down south. If that is a well designed system you should never have to be on power if you choose not to.



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Compared to the 1200 watts solar mine is 1/10 the size at 120 watts. At 14.13volts I'm getting 8.5amps going into the batteries with my MPPT. You might need to put thicker wires in &/or get a larger controller to get closer to 85 amps.

At 12.47volts 9.8amps, so 98amps with 1200 watts of solar.

Screenshot_20191113-131053.png

Screenshot_20191113-132638.png



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try looking at 'close comfort' with tent 3500 btu's and 170 watts

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beaul wrote:

try looking at 'close comfort' with tent 3500 btu's and 170 watts


 I have a 3.5kW output Dimplex unit, very highly modified, unless both the condenser air intake & air output are ducted to the outside, this design of air conditioner is useless.



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Given the power an AC will take ensure your 12V wiring and connections are very near perfect.



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It is a Harrier Dometic nominal compressor capacity 3.7 kw, cooling 3.1kw, 6.5A/5.2A  whatever all that means!!!!

If I knew what all this meant I would not have to ask lol!

:)

 



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Thanks. 

Yes I plan to trial all of these gadgets (when I get the caravan back from the dealer!) before we venture out for the first time at Christmas. 

I will sit the van in the driveway and trial all of the appliances and watch the Redarc monitor to see you much current draw there is.

I will also see if I can get away with one 2000kw generator (20kgs) instead of needing to take 2@40kg + fuels and oils. 

The van went back to the dealer as the design specs meant everything was supposed to work off road (albeit a short period of time) but when I received it new, only the fridge, microwave and 240v power points worked off the inverter. 

So they sent back the ibis 3 and replaced it free of charge with the soft start inverter style Dometic Harrier which is what Justin and Bec installed with their Enerdrive battery system on the Trip in a Van YouTube channel. 

His airconditioner seemed to work fine albeit with a less powerful battery and solar system but of course they never actually tell  you for how long. 

All you guys seem to be able to determine the current draw and amperage and all that staff. 

Do you have meters to measure these kinds of outputs and if so, where do you place them to determine the current draw?

Still learning!!!!!

 

:)

 

 



-- Edited by Pradokakadudavid on Saturday 23rd of November 2019 04:39:02 PM

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Well I just bought it new  from Retreat so lets hope all was done properly!



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Senior Member

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Posts: 189
Date:

Airconditioners and battery power.

Apology for my ignorance but I was just wondering how many members use their caravan airconditioners from purely battery power when off road in terms of practical hours of usage.Y

I realise the airconditioners draw a huge amount of power and their off road usage needs to be minimised, 

I have a fairly powerful battery, solar, inverter system in my new caravan which I have not used yet.

The specs are:  500A batteries (lithium) 1.2kw solar, 3000w inverter and it is all RedArc gear.

It is also a soft start, inverter style airconditioner. 

So is it naive of me to think that I should be  able to get 1 or 2 hours of airconditioning say at lunch time on the side of the road and as long as I keep my eye on the Redarc monitor I can be pretty sure all will be okay? 

I do have 4 kw of generator power but I would prefer to only have to use this when camped permanently with no  240v power available.

Just curious and as I said  I am a newby so please be gentle with me  :)

Regards 

 

'trollin Dave 



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What device do you use to show the information you showed me in your post?  I have a Redarc BMS system but you need to scroll through screens to get all the information you have shown on the same meter!



-- Edited by Pradokakadudavid on Sunday 24th of November 2019 12:40:04 PM



-- Edited by Pradokakadudavid on Sunday 24th of November 2019 12:40:21 PM

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Senior Member

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Yes I watch the Trip in a Van YouTube channel with Justin and Bec all the time.  This is what first started me wondering how caravanners run airconditioners off their batteries.  Then I started researching soft start airconditioners (saw them first on Dash Offroad a Nissan Y62 4 wheel drive site that I like.

All good advice.

:)

 



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All sounds great thanks but I find all the amperage stuff confusing.

I have a Truma Gas heater in my caravan which was recommended by someone and had very good reviews. 



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Guru

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Get a AC/DC clamp meter then you can check everything. I have a Kyoritsu 2046r clamp meter & would be lost without it.



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Thanks.

I have seen Dave in Dash Offroad constantly check his volts and ampe using one of those meters but he seems to have to continually pull lounges etc apart to get to the wiring.  Is there some advice/notes/bookets/websites etc that show people how to check these electrical currents?



-- Edited by Pradokakadudavid on Sunday 24th of November 2019 12:44:56 PM

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Newbie

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Hi Dave 

You may not receive too many replies to your queries and with good reason. As no one really knows how your system is set up and too many false assumptions will be made.

As you also have 240vac running and obviously not much knowledge yet on how it all operates it would be prudent to get some one to actually show you how to operate and carry out tests in a safe manner. A lot of power available in that system and knowing what to touch and not to touch is critical.

Regards

Mark



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Thanks Mark.

Yes I most certainly plan to do exactly what you suggest.

I have a 3 hour induction set up with the dealer so when they finally figure out how to solve some of the issues I am having (new caravan ha ha) I will gain some more knowledge.

Like all things, small steps one at a time and I will get there.

Cheers.

'tollindave

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Great idea thanks.



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Insanely jealous of your power setup!

Should be plenty to run the AC (soft start) for a couple of hours at least without an issue.  I note that you mention elswhere that you also run the fridge, microwave and etc off the inverter?  Plenty of scope there to overload the inverter I would think.



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Cheers

 

Gazza

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