Another way to skin a cat.

[Hader]

Any suggestions about gluing FRP to luan walls? Should I paint, or leave luan as is?

[hankaye]

Hader, Howdy;

Any suggestions about gluing FRP to luan walls? Should I paint, or leave luan as is?

Depends on which surface you want to glue the FRP to, ... the wood , ... or the paint???

hank

[Hader]

Depends on which surface you want to glue the FRP to, ... the wood , ... or the paint???

hank

Thanks Hank.

Never did that before and wanted to make sure.

[Hader]

We’re slowly getting there!
Got all the insulation and paneling done, doing priming right now.
Waiting for the black and grey tanks (25 gallons each) before we start the raised floor and the 2 bathroom walls.

Due to back problems, it’s taking a bit longer than it should.

We are watching Don’s Slinky setup to so we can tweak it a bit, it will be on the tongue (part of, and under the battery box) instead of under the trailer. That will help with the back and bending problem.

[Hader]

This is what I'm thinking: 40"x20"x12" box.

(side view)

[Hader]

This is what I came up with so far for the tongue box. I'm leaning toward the one on the right.

[Hader]

I just read this on another forum: "Also didn't know how long the deep cycle battery/inverter would run the fridge, 26 hours and I was still showing 11.8v and the fridge was running."!
[GE GDE03GGHWW 3.1-cu ft Compact Refrigerator with Freezer Compartment (White) ENERGY STAR]

Would this be possible on just 1 battery? Any thoughts?

[hankaye]

Hader, Howdy;

It may be possible, but I wouldn't think it to be practicable. By discharging the battery that low
you are going to cause it to have a shortened life if you do that repeatedly. It also depends on
the total number of amp hours the battery is rated, how old the battery is, wither or not you
are using 2, 6 volt Golf cart batteries or a single 12 volt deep cycle battery. Lots of variables to
consider. Here's a link to an outstanding article about 12 volt life.
http://www.marxrv.com/12volt/12volt.htm

hank

[McDave]

The key here is to eliminate the loss incurred by inverter. RV refrigerators are purpose built. They are more expensive to purchase, but add the cost of the inverter to your walmart "energy star" reefer, or AC, multiply by retrofit of adaptation costs, divide by reliability and quality issues, and subtract from the square root of the P.I.T.A. quotient and you will likely find that the right tool for the job is like money in the bank. While inverters do have a place, they add a layer of risk and inefficiency to your critical functions. HVAC, water and waste systems, lighting and food storage are critical functions.
Quality over quantity in these areas. Do it once, do it right. You really do get what you pay for.
I have a Norcold RV frig. It draws 3.5amps/hr at 12volts. At 80f cabin temp, it cycles for about 1-1.5min every 12min. this equals .38amps/hr x 24 = 9.33 amp hrs /day. With one 125ah deep cycle at 50% max discharge you are talking 6.5+ days of reliable refrig. before recharge is required. Now, you will be using battery for other purposes, pumps, lights, fans etc. so factor those in and you still get 3 days + before recharge is required.
The inverter alone in standby mode is more than 2amps/hr and must run 24/7. The math doesn't lie.. so, do your math and find your answers. Rube Goldberg wasn't really an engineer...just sayin'

McDave

[Gonefishin]

The key here is to eliminate the loss incurred by inverter. RV refrigerators are purpose built. They are more expensive to purchase, but add the cost of the inverter to your walmart "energy star" reefer, or AC, multiply by retrofit of adaptation costs, divide by reliability and quality issues, and subtract from the square root of the P.I.T.A. quotient and you will likely find that the right tool for the job is like money in the bank. While inverters do have a place, they add a layer of risk and inefficiency to your critical functions. HVAC, water and waste systems, lighting and food storage are critical functions.
Quality over quantity in these areas. Do it once, do it right. You really do get what you pay for.
I have a Norcold RV frig. It draws 3.5amps/hr at 12volts. At 80f cabin temp, it cycles for about 1-1.5min every 12min. this equals .38amps/hr x 24 = 9.33 amp hrs /day. With one 125ah deep cycle at 50% max discharge you are talking 6.5+ days of reliable refrig. before recharge is required. Now, you will be using battery for other purposes, pumps, lights, fans etc. so factor those in and you still get 3 days + before recharge is required.
The inverter alone in standby mode is more than 2amps/hr and must run 24/7. The math doesn't lie.. so, do your math and find your answers. Rube Goldberg wasn't really an engineer...just sayin'

McDave

I love it!

[flboy]

We’re slowly getting there!
Got all the insulation and paneling done, doing priming right now.
Waiting for the black and grey tanks (25 gallons each) before we start the raised floor and the 2 bathroom walls.

Due to back problems, it’s taking a bit longer than it should.

We are watching Don’s Slinky setup to so we can tweak it a bit, it will be on the tongue (part of, and under the battery box) instead of under the trailer. That will help with the back and bending problem.

Hader, the slinky setup worked great when I made my first official dump last weekend. Very convenient where it is mounted. Slips right in. I followed up the blackwater dump with the gray water dump and the hose was very clean after. No stench that I could detect.

I just read this on another forum: "Also didn't know how long the deep cycle battery/inverter would run the fridge, 26 hours and I was still showing 11.8v and the fridge was running."!
[GE GDE03GGHWW 3.1-cu ft Compact Refrigerator with Freezer Compartment (White) ENERGY STAR]

Would this be possible on just 1 battery? Any thoughts?

I'd get two batteries in any case since you can really only draw them down around 60% without starting to impact the longevity. Two batteries will last longer before you need to replace them than one alone, all else being equal. It is better to have the "larger" tank. Two will run your fridge fine for any weekend trip if that is all you are running. The bottom line is: AC or DC... watts is watts and if both fridges have a compressor and are the same in size... they draw very close to the same power these days with the Energy Star rating.. MCDave is absolutely right about the inverters; however. If you go that route, choose one that does not have a fan that runs constantly (should only run when driving larger loads) and check the NL (No Load) spec and the Efficiency. I got a real nice 1500W Pure Sine inverter, which I needed in any case for other 115VAC needs (computer,microwave, HW heater backup, etc). It is spec'd at <800mA No Load and >85% efficiency. I don't have the means to check the input and output power when running to measure efficiency, but the No Load draw was actually about 580mA or about .51A (that is ~13ah a day cost for the inverter on standby) . My (4.3 cu ft.) ran overnight and didn't phase the batteries. It only draws 54W when running (plus 15% inverter loss loss ... 63 watts total).. The Fridge probably only runs a total of 15 minutes every hour max. You can run a small fridge days like that with the two batteries. I measured run time a few times and it seemed consistent. In any case.. I always say "there is no replacement for displacement"... get a second battery for capacity... if your fridge don't need it... something else will. Eventually, you'll want to have the means to charge that battery if you stay out longer. Once you can do that... you only need to worry about what power you need to get you through the dark hours with some reserves.

Take care... Your build appears to be coming along great.

[Hader]

Hank,
Thank you for the very informative link.
You are right about "By discharging the battery that low you are going to cause it to have a shortened life if you do that repeatedly.”



McDave,
Thank you for the input! All well taken. My only concern is that I prefer to have 2 or 3 low-tech gizmos, that I can replace at any Walmart or Truck-stop than 1 Hi-tech, Hi-dollar gizmo that I have to order parts for, or send if repairs are needed.




Don,
Good to hear that the slinky worked as expected.
Thank you for sharing your experience with fridge/batteries.


I will probably go with Don’s suggestion.
It will be interesting how it would work with 2 or 3 batteries, $99 fridge and a 100 or 150 Watt 12 volt solar panel.

[flboy]

My only concern is that I prefer to have 2 or 3 low-tech gizmos, that I can replace at any Walmart or Truck-stop than 1 Hi-tech, Hi-dollar gizmo that I have to order parts for, or send if repairs are needed.

This is a huge deal if you are off somewhere and something breaks.... The fridge is cheap and a standard size. You can pick one up at any Home Depot Depot or Wal Mart and toss the old one if and when it does break.. I have a small ~3Cu Ft one in my office at work that I got at Walmart for $89.00 and it has been running 24/7 for the last 6 years..

That was one of my considerations for the Air Conditioner (besides running on a small Honda EU2000i Generator). The AC is cheap enough to toss when it breaks and I can get one anywhere.

Hader... do make sure to buy a pure sine-wave inverter when you get one. Most people experience premature failure of the Fridge and AC due to dirty power that approximates what it would see plugged into the house (funky looking stair stepped voltage looking at it on the Oscilloscope) . Inductive motors hate the cheaper modified sine wave inverters. Pure sine wave inverters... like the Honda EU2000i put out power cleaner than the utility companies... You will have no problem with your appliances if you do that.

[Alan_H]

The key here is to eliminate the loss incurred by inverter. RV refrigerators are purpose built. They are more expensive to purchase, but add the cost of the inverter to your walmart "energy star" reefer, or AC, multiply by retrofit of adaptation costs, divide by reliability and quality issues, and subtract from the square root of the P.I.T.A. quotient and you will likely find that the right tool for the job is like money in the bank. While inverters do have a place, they add a layer of risk and inefficiency to your critical functions. HVAC, water and waste systems, lighting and food storage are critical functions.
Quality over quantity in these areas. Do it once, do it right. You really do get what you pay for.
I have a Norcold RV frig. It draws 3.5amps/hr at 12volts. At 80f cabin temp, it cycles for about 1-1.5min every 12min. this equals .38amps/hr x 24 = 9.33 amp hrs /day. With one 125ah deep cycle at 50% max discharge you are talking 6.5+ days of reliable refrig. before recharge is required. Now, you will be using battery for other purposes, pumps, lights, fans etc. so factor those in and you still get 3 days + before recharge is required.
The inverter alone in standby mode is more than 2amps/hr and must run 24/7. The math doesn't lie.. so, do your math and find your answers. Rube Goldberg wasn't really an engineer...just sayin'

McDave

This is both great advice and extremely amusing at the same time!

Well put!

[McDave]

The key here is to eliminate the loss incurred by inverter. RV refrigerators are purpose built. They are more expensive to purchase, but add the cost of the inverter to your walmart "energy star" reefer, or AC, multiply by retrofit of adaptation costs, divide by reliability and quality issues, and subtract from the square root of the P.I.T.A. quotient and you will likely find that the right tool for the job is like money in the bank. While inverters do have a place, they add a layer of risk and inefficiency to your critical functions. HVAC, water and waste systems, lighting and food storage are critical functions.
Quality over quantity in these areas. Do it once, do it right. You really do get what you pay for.
I have a Norcold RV frig. It draws 3.5amps/hr at 12volts. At 80f cabin temp, it cycles for about 1-1.5min every 12min. this equals .38amps/hr x 24 = 9.33 amp hrs /day. With one 125ah deep cycle at 50% max discharge you are talking 6.5+ days of reliable refrig. before recharge is required. Now, you will be using battery for other purposes, pumps, lights, fans etc. so factor those in and you still get 3 days + before recharge is required.
The inverter alone in standby mode is more than 2amps/hr and must run 24/7. The math doesn't lie.. so, do your math and find your answers. Rube Goldberg wasn't really an engineer...just sayin'

McDave

This is both great advice and extremely amusing at the same time!

Well put!

Ya, that guy thinks he's real funny. A bucket of yuks. Class clown at MIT. Those 12 year old PHD's looked at me er, him..him like he was from another planet. Not even a courtesy chuckle. Rough crowd.