A/C that runs off a battery...

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BOAT
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Re: A/C that runs off a battery...

Post by BOAT » Mon Jun 14, 2021 3:07 pm

would it help to just fill an air mattress with water from the outside and sleep on that to feel cool?

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Jimmyt
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Re: A/C that runs off a battery...

Post by Jimmyt » Mon Jun 14, 2021 3:12 pm

BOAT wrote:
Mon Jun 14, 2021 3:07 pm
would it help to just fill an air mattress with water from the outside and sleep on that to feel cool?
Great idea! Dehumidify with a small unit and cool people directly with a waterbed concept.

I've missed you BOAT! Glad to see you're ok.
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Re: A/C that runs off a battery...

Post by Inquisitor » Mon Jun 14, 2021 3:40 pm

Jimmyt wrote:
Mon Jun 14, 2021 3:06 pm
...
Don't mistake me for a naysayer. I'm cheering you on, and only injecting a taste of numbers when absolutely necessary. You've got a great concept. After all, they're selling something remarkably similar for $1,000. A water-cooled version could probably beat the efficiency up a few points.
...
Never give up; Never Surrender! 8)
Naysayer... not a chance. I didn't. I think you're one of the most optimistic and encouraging members here and always supportive. I totally took it as constructive criticism and I certainly needed and respect your expertise.
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Re: A/C that runs off a battery...

Post by OverEasy » Mon Jun 14, 2021 5:12 pm

Hi Inquisitor

It’s close enough :D
The efficiency of charge get me an idea of charge rate.

Was sort of ball parking how much solar power wattage would be required to recharge different battery types.

So considering starting with amorphous solar panels that we could easily mount 100 Watts and then up to a maximum of possibly up to 250 Watts.
So with the assumption of 4 each 650 A-hr (~2600 A-hr total) 12 VDC batteries how long would it take to recharge at several different levels of solar wattage available? :o :?

8) 8) 🐩

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Re: A/C that runs off a battery...

Post by Inquisitor » Mon Jun 14, 2021 6:20 pm

OverEasy wrote:
Mon Jun 14, 2021 5:12 pm
Hi Inquisitor

It’s close enough :D
The efficiency of charge get me an idea of charge rate.

Was sort of ball parking how much solar power wattage would be required to recharge different battery types.

So considering starting with amorphous solar panels that we could easily mount 100 Watts and then up to a maximum of possibly up to 250 Watts.
So with the assumption of 4 each 650 A-hr (~2600 A-hr total) 12 VDC batteries how long would it take to recharge at several different levels of solar wattage available? :o :?

8) 8) 🐩
Are you mixing A-hr and W-hr? 2600 A-hr is like ten of my big-honk'n batteries... I'll do my situation and let you re-group. :D :D

I have two of these https://www.amazon.com/Richsolar-Polycr ... B07DNP14JY. When I tested them back in January viewtopic.php?f=8&t=28020&start=15#p347194. I should hang them out and re-test them now and see what I get. That'll make it rain for sure! 8) I can easily image they'll get full rated power even here. Your place... even better!

I can't place my hands on the reference, although its a bell shaped curve, it seems like I recall that over the entire "sunny" day in the South, in the summer, you can expect a sum total of about 5 hours at their rated power. So in my case, I can estimate getting about 100 watt-hours ===> 76 Ahr. So nearly 4 days to charge my depleted battery (if I don't use them). So... I could use the A/C once every 4 days. :P :|

BTW - I just finished the last shingle thirty minutes ago.
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Re: A/C that runs off a battery...

Post by OverEasy » Mon Jun 14, 2021 9:59 pm

Hi Inquisitor

The consideration is a “what if” one decided to replace water ballast weight with battery ballast weight (~650 A-hr = ~1480 lbs).

(Yeah, it would pretty much kill trailering it with the minivan :D :D )

So if one did that then how long would the functional recharge time be with solar at 100 watts? 200 watts? 250 watts?



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Re: A/C that runs off a battery...

Post by Jimmyt » Tue Jun 15, 2021 4:35 am

Inquisitor wrote:
Mon Jun 14, 2021 6:20 pm
BTW - I just finished the last shingle thirty minutes ago.
Great news! Glad to hear you wrapped it up without incident. Now, maybe, you can get back to sailing/boat stuff, or at least something more fun than roofing. :D
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Re: A/C that runs off a battery...

Post by Be Free » Tue Jun 15, 2021 10:19 am

OverEasy wrote:
Mon Jun 14, 2021 9:59 pm
Hi Inquisitor

The consideration is a “what if” one decided to replace water ballast weight with battery ballast weight (~650 A-hr = ~1480 lbs).

(Yeah, it would pretty much kill trailering it with the minivan :D :D )

So if one did that then how long would the functional recharge time be with solar at 100 watts? 200 watts? 250 watts?



8) 8) 🐩
Off the top of my head I'd say the answer is "too long" but give me a few minutes to sharpen my pencil and I'll give you a better estimate.
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Re: A/C that runs off a battery...

Post by Be Free » Tue Jun 15, 2021 10:37 am

Assumptions: 650AH lead acid, 50% discharged, solar panels deliver 100% rated power all the time, no losses and 100% of panel output goes to charging the batteries.
250W would take just shy of 19 hours in a perfect world. In the real world probably 30 hours, maybe more.
Bill
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Re: A/C that runs off a battery...

Post by OverEasy » Tue Jun 15, 2021 4:50 pm

Hi Be Free

Thank you! :) :)

8) 8) 🐩

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Re: A/C that runs off a battery...

Post by OverEasy » Tue Jun 15, 2021 5:46 pm

We were ‘exploring options’ on ‘how to’ cruise in Summer Southern Waters.

The plan is to start cruising next year in the ICW north and south of Beaufort SC.
The past week heat has the Admiral fearing she might melt (heat is not her friend).

The baseline plan has been the use of a small portable A/C and small inverter (full sine wave) generator when needed on the hook. The potential noise aspect is a concern of ours for those surrounding us as well as within Over Easy.

The battery powered A/C option wasn’t something we have adequately investigated so far.
This thread piqued our interest.
Mini A/C units and buildityurself A/C sort of might make a solar-battery power option viable…..?
The problem is we would functionally be conditioning the interior of our Mac26X and not just an isolated berth.

So:
-> what would it take to run
-> what option of A/C that
-> would be able to run for how long on batteries
-> and could those batteries be recharged via solar cells

So far based upon a rear mounted arch it’s possible to mount up to 250 Watts of amorphous solar cells.
Note: Amorphous solar cells generate power even with indirect and low light levels.
Much more than 250 Watts becomes physically difficult to mount and still operate/sail the vessel.

While the engine can provide electrical charging power while in operation that isn’t always a valid option.

So far we are still looking into the options …..🤔

Fair winds and following seas,
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Re: A/C that runs off a battery...

Post by Inquisitor » Fri Jun 25, 2021 2:43 pm

I have an old house fridge from 80's. It was working when I purchased a new one about 5 years ago, and took it off-line. Its about to go to the dump and I'm wondering...

Just to learn about refrigeration and cobble things together... purely experimental. I want to experiment with
  • soldering
  • replacing the air condenser with a water or ground loop
  • replacing the evaporator with different radiator / computer fan units
  • use a vacuum pump and hi/lo gauge thingy to learn about charging and setting pressures for A/C usage
So...
  1. What is the likelihood of it using the 134a that we've been talking about as being "forgiving"?
  2. Is there some kind of identifying characteristics that tell my what fluorocarbon is in it?
  3. If not, I recall Jimmy saying different fluorocarbons require different oils and is it a problem using 134a in this old system?
Maybe, I'm biting off more than I can chew, but I'm just thinking out loud at the moment.
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Re: A/C that runs off a battery...

Post by Jimmyt » Fri Jun 25, 2021 3:24 pm

R12, or R22, or blends of R22 and other refrigerants. Some later used 134a apparently. Now, rumor has it that isobutane is the refrigerant of choice.

Now, if you are just going to do a backyard build for yucks, cut the compressor out and turn it upside down and try to pour as much oil out of it as you can. Pour it into a clean container and measure the amount. Pour about 125% of the measured amount of the correct oil back into the compressor. Put in a 134a compatible filter drier. Use clean tubing to make your condenser. Mind your solder and flux when you put the system together.

The stuff will work somewhat over a pretty wide range. However, if you want to spend a boat buck on a build, you'll want to do better.

I say go for it! And have fun.

Here is some light reading that may give further insight into your project, but remember this is a document for pros that have to make it right for a customer. You don't have to be so serious.
https://www.secop.com/fileadmin/user_up ... 20c102.pdf
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Re: A/C that runs off a battery...

Post by OverEasy » Fri Jun 25, 2021 5:47 pm

Hi JimmyT

I could be mistaken and pleas correct me if I’m wrong (don’t worry…thick hide …would rather learn than stay a fool :D ), but don’t you want to get a good vacuum pump to out-gas all the water/water-vapor that will inevitably sneak in. Can’t the water content freeze and potentially cause a blockage?

BTW: just a thought….. Several Community Colleges offer a course program in refrigeration servicing (Day & Night Classes). Generally all necessary equipment provided except maybe basic hand tools. Price is generally very reasonable. Courses are often broken down to 8 week blocks of one to three classes per week depending on complexity.

8) 8) 🐩

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Re: A/C that runs off a battery...

Post by Jimmyt » Fri Jun 25, 2021 8:46 pm

OverEasy wrote:
Fri Jun 25, 2021 5:47 pm
Hi JimmyT

I could be mistaken and pleas correct me if I’m wrong (don’t worry…thick hide …would rather learn than stay a fool :D ), but don’t you want to get a good vacuum pump to out-gas all the water/water-vapor that will inevitably sneak in. Can’t the water content freeze and potentially cause a blockage?

BTW: just a thought….. Several Community Colleges offer a course program in refrigeration servicing (Day & Night Classes). Generally all necessary equipment provided except maybe basic hand tools. Price is generally very reasonable. Courses are often broken down to 8 week blocks of one to three classes per week depending on complexity.

8) 8) 🐩
You are no fool. Inquisitor specifically mentioned vacuum pump usage, so I didn't pile on.

You are correct. You should never charge a system without fully evacuating it first with a good vacuum pump. You pull the vacuum to boil out any moisture that might be in the system. Water can react with refrigerants and oils and form fun stuff like acids that just don't make the system last very long. Cleaning a system up and trying to make it right again after it's been contaminated is a real drag.

I've never had ice form inside of the refrigerant circuit that I knew of, but I inherited one from a PO that acid had apparently eaten the filter drier and puked desiccant all over the system.

Most technicians use the evacuation step as a preliminary quick leak test. At the end of their evacuation, they shut the evacuation valve on the gauge manifold and note the vacuum reading. Then, they'll wait several minutes and read the gauge again the see if the system is holding a vacuum. It is not as good as a pressure test in my book, but it's quick and convenient (and exactly what I would do unless the system has a large charge).

Community college classes are a great suggestion.
Jimmyt
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2013 26M, Etec 60, roller Genoa, roller main
Cruising Waters: Mobile Bay, Western Shore, Fowl River

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