Air Conditioning run off Solar, batteries and Inverter

[ZipTie]

Looks like you can run Air Conditioning off Solar, batteries and Inverter.

1) Li batteries - yes
2) 3000 watt inverter -yes
3) 1000 watts of solar panels - yes

Note: Need a soft start on the AC unit.

https://www.youtube.com/watch?v=B0rZY5uotKI

[exMaggieDrum]

Not rocket science so long as you match your power in to your power out as much as possible as at some point you have to replace the difference. If you could get the full solar output for ten hours (not likely but for discussion) as per the vid, and used the AC during that time, with a net draw rate of 30 amps, that would be a 300Ah deficit you would have to make up at the end of the ten hours. Plus whatever you used beyond the AC. You would need some way to replace that power in a way that you can deal with, e.g. genset or engine = noise and fumes and fuel.

And like they say you have to match your batteries to the net draw for the time. Li batteries are better for this in one respect - they maintain a steady voltage for a wide range of Ah's remaining (SOC).

[Brewgyver]

In reality, I doubt you could get enough solar panels on most sailboats to come close to the capacity required.


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[a64pilot]

To run a very efficient 16 K AC requires 110 amps at 13V, so if you run it for 12 hours that is 1320 AH.
How many watts of Solar does it take to make 1320 AH? I don't know, but I bet it's a lot.
Now make that a 5 K AC and the numbers change significantly, but a 5 K doesn't cool much either.

With enough Solar and a big enough bank, you can run anything, just a matter of scale.
Cost a fortune of course and you may have to tow a barge of Solar panels, and that is one problem, cost.


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[StuM]

> How many watts of Solar does it take to make 1320 AH?

Figure on a max about 70 Amps from 1000W of solar. Or about 350Ah per day.
So your 1320Ah will take nearly 4000W of solar to keep up.

[HKTim]

Here is a little more reference data on the subject. I have a Cruiseair 12,000 BTU reverse cycle air con with a soft start. I recently installed a 3000W Mastervolt combi inverter and 720 Amp hour Mastervolt lithium bank. My experience in the winter here has been that the heater mode of the Cruiseair will consume about 50 amps per hour from the batteries via the inverter to keep cabin temp at 22 C when outside temp is 15 C (I pre-heated the cabin with shore power). In compressor mode, its around 70 amps and in when only the fan in running. it consumes about 7 amps. My batteries have an alarm at 30% SOC and shut off at 20% SOC. So to get to 70% discharge, I have 504 amps to use. Thats over 10 hours of the air con running in this configuration. Obviously more interested in getting some results in air con mode, but that will have to wait to this summer.

[StuM]

Originally Posted by HKTim

Here is a little more reference data on the subject. I have a Cruiseair 12,000 BTU reverse cycle air con with a soft start. I recently installed a 3000W Mastervolt combi inverter and 720 Amp hour Mastervolt lithium bank. My experience in the winter here has been that the heater mode of the Cruiseair will consume about 50 amps per hour from the batteries via the inverter to keep cabin temp at 22 C when outside temp is 15 C (I pre-heated the cabin with shore power). In compressor mode, its around 70 amps and in when only the fan in running. it consumes about 7 amps. My batteries have an alarm at 30% SOC and shut off at 20% SOC. So to get to 70% discharge, I have 504 amps Amp hours to use. Thats over 10 hours of the air con running in this configuration. Obviously more interested in getting some results in air con mode, but that will have to wait to this summer.

Please:
http://www.cruisersforum.com/forums/...ml#post1933764

But more importantly, how do you replace that 504 Amp hrs after 10 hours?

[HKTim]

Sorry for the mistakes on the use of amps etc.

How do I put the 504 amps back in? A 130 amp alternator on each engine (we have a cat) and 150 amp charger on my genset does the job quickly over breakfast the next morning.

I am on a program where we overnight at most for a few days at a time. Everyday we are out the engines are running a least for a few hours. So its not too hard to go to bed with fully charged batteries and to bring them back to full charge shortly after we wake up.

I am not using solar and do not want to suggest that there is no cost for running a night of air con without a genset running. I just prefer to have the option to not have the genset on all night.

[Ribbit]

It seems to be an awful lot of money to lay out, just to run air conditioning?

I know I'm a fine one to talk , as I'm going with a 50 pint a day dehumidifier. But that's a penalty I have to cope with to keep molds and spores under control (they affect me very badly), as is having a 1,500 watt steam cleaner to blast things back under control when necessary. Plus I need the heat, cold is a bit dangerous too.

The water tank with the steam cleaner has enough water for 45 minutes running (using about 95 amps). I can easily do the whole boat interior in less than that, and it should only be needed infrequently, and hopefully once cleared initially, not at all other than during rare connections to shore power.

I am budgeting at the moment with a 100 amp hours per day allowance for the dehumidifier (perhaps the easiest approach to go about things). A short period after lunch to mildly keep on top of cooking steam - say a half hour - and a long period after the evening meal - say 2 hours to see how it goes - to really get on top of things before I get to sleep.

If the average power budget from 500 watts of solar allows more, then I'll probably add an early session as soon as I get up. Depends how the battery bank (minimum 690 amp hours of FLA Golf Cart batteries, and I am hoping to squeeze in 920 amp hours) voltages look first thing.

The use of the windlass (the only other large demand while being used for me) to raise the anchor, shouldn't impact the power budget too badly. Then I have the unknown quantity at present, that is the compressor cooler fitted in the icebox.

If you did things similarly, by jiggling usage patterns and power budgets around a bit, would you be able to get away with having 'a bit' of a/c when you really would like it, and not have to spend what will be (to me anyway) an outrageous amount of money to have something that on day 2, 3 etc, you are going to have to jiggle around usage patterns with anyway?

The first rule of off grid living (and I say this having lived off grid a long time), is to cut your energy demands to the maximum, then fine tune from there.

Unless money, and the space to do it, is no object (even then, I think unless careful, it can be an appallingly poor investment).

[a64pilot]

The issue that keeps coming up is, can I run AC off of Solar.
The answer is of course, yes you can, but it's gonna be one big Solar Array to pull it off.
I can run my little 5K AC off of my battery bank pretty easily through the inverter myself, and if you assume a 50% duty cycle, and an eight hour run time, it's only 200 AH, but put that 200 on top of the 100 I use for everything else, and my 750W of panels are not going to be able to replenish what was used, so like you, I'm burning Diesel to put it back.
My 5K uses almost exactly half the current of my 16K, so it is obviously not as efficient

[a64pilot]

A dehumidifier, is a vapor cycle system, in short it is an airconditioner, but as it has the output air blowing over both the evaporator first, then the condenser, the net effect is it adds a little heat.
So unless your in a cool environment and want a little heat, your better off dehumidifying with a small airconditioner and get some cooling to go along with dehumidification.

My dehumidifier that I run while connected to shore power in winter while I am away is I think a 50 pt one too, and if memory serves, draws 530W ?
If so then that is about 40 amps from a battery ignoring the losses of conversion, my 5K AC draws about 50 amps, but being a Marine AC, it ain't inexpensive.

However a 5,000 BTU window unit AC draws about 550 W from what I find on the internet and is inexpensive, so it would cool and dehumidify for the same current draw of the dehumidifier

[Ribbit]

Any idea what your average gain per day is, off those 750 watts of panels a64?

Your info for me in a few areas has been first class, and panned out really well with my planning (you have saved me a fortune and resulted in some worthwhile extra spending as a result - e.g. with my anchoring plans - and I owe you a drink).

PS Is it you that is using one of those Tracer MPPT charge controllers? I'm going to try one of those (a genuine one rather then stumble into a fake).

[Ribbit]

Originally Posted by a64pilot

A dehumidifier, is a vapor cycle system, in short it is an airconditioner, but as it has the output air blowing over both the evaporator first, then the condenser, the net effect is it adds a little heat.
So unless your in a cool environment and want a little heat, your better off dehumidifying with a small airconditioner and get some cooling to go along with dehumidification.

My dehumidifier that I run while connected to shore power in winter while I am away is I think a 50 pt one too, and if memory serves, draws 530W ?
If so then that is about 40 amps from a battery ignoring the losses of conversion, my 5K AC draws about 50 amps, but being a Marine AC, it ain't inexpensive.

However a 5,000 BTU window unit AC draws about 550 W from what I find on the internet and is inexpensive, so it would cool and dehumidify for the same current draw of the dehumidifier

Yeah it may sound odd (even to me ) but I am actively avoiding cooling as much as possible, for at least 12 months, until I get on top of things health wise. Acclimatising isn't going to be any sort of a joke for me, I do concede, but it has to be done.

I did look at the portable a/c units and the window ones and your numbers are right.

Some of the 5k ones do seem to be much more effective than others (I have waded through a huge number of customer reviews). The 50 pint a day dehumidifier I am after, is the one you are using (I was pondering going for a 70 pint a day one, but with your boat being a fair bit bigger volume than mine, the 50 pint one should be fine for me).

PS People do seem to refer to threads on anchors as always degenerating into all sorts of infighting, but I must admit, that one I started - not knowing what I might have let myself in for - to help me get to the bottom of things, worked out really well, and the amount of solid info that turned up that allowed me to come to a sensible design, was truly impressive.

[a64pilot]

This is the one I got
http://www.amazon.com/gp/product/B00...ilpage_o06_s00

The trick would be to find one that was most efficient and to heck with the size, little one you run for more hours, bigger one for less hours.
Gut feeling is smaller and longer run time removes more humidity than larger and shorter run time. I just assumed being "energy Star" it met some kind of efficiency requirement.

I believe a 30 pt would be more than adequate, the 50 that I have knocks the humidity down pretty quick

You'll acclimatize, trick is to start in the cool months and as it warms up you become accustomed to it. It's tough starting in Summer. One of my trips to Q8, I arrived in Summer, and it was tough, another one was Winter and it was a whole lot easier

[Ribbit]

I confess the initial prospect of 2 x 2 hour sessions, also providing up to a gallon of distilled water a day, was also a factor, as for washing clothes and showering, etc., it will help stretch the water tank capacity quite well. Yes nice machine that Frigidaire. 100 amps for 5 pints a day isn't too bad either. I won't waste that water.

I should have been in Florida about now, but a hearing specialist appointment turned up out of the blue (I have been on the waiting list a long time, and have had to grab the opportunity while it is there). All things being equal, I should now be in Florida about 4 weeks from now. So shouldn't be too bad still. Plus I aim to anchor out in the Trade Winds as much as possible (getting valuable wave movement benefits while at anchor), while heading South.

Fingers crossed anyway.