diy solar

diy solar

Installing 400 watt system on my class A diesel pusher...parallel or series?

Browneye said:
And a gas-absorption fridge can be troublesome as hell, all depending. ;)

It sounded like OP was considering getting a 12v compressor fridge. For most people, if they take out a RV gas-absoption fridge, they put a regular residential refrigerator in there - a smaller one that fits. They're still big, but pretty energy efficient and can be run on a smaller inverter. The newest luxury motorhomes all have residential refers. And no oven. Two things that kill the deal for us.

There are three key upgrades for a gas-absorption fridge to make them work well:
A temp controller board from ARP.
With the chimney fan.
And an internal fan sitting on the cooling coils.
Click to expand...

Another key to have good working absorption fridge - don't buy a RV with the Fridge in the Slide-out - that's a big no no.
It's almost impossible to get a good working propane fridge in a slide.

They need to have stack above to get rid of the air.

When I'm boondocking I get months of fridge service out my propane tank. To switch the fridge to residential and add enough batteries to support that - I've measured my small fridge:
12VoltInstalls said:
I remember the new 120VAC household fridge runs on 60-80 watts.
Click to expand...
My 2.6 cubic fridge needs about 800wh in a day - and 12 cubic feet needs almost 2kwh / day.

While this is not much - it's still energy I need to produce with solar. Wasn't worth the headache to throw out my good working LPG fridge. Sure should it ever break I'm going to get a 12V fridge -but until then I'm burning a few bucks worth of propane every year for the time I'm not on the grid.
 
The ARP vent fans address the slide-side refer chimney...check it out. For those they recommend two fans, one on top to pull and one on the bottom to push the hot air out of the stack.

Since I have a straight stack out the top, so just one fan. And it usually runs when on LPG, but not on 120V. I guess the gas burner is a little hotter. Works really slick, and adds a lot of safety to the whole absorption cooling process.

Check 'em out - ARP fridge defend. I've had mine for about seven years. The cooling unit and boiler were replaced under warranty when the coach was fairly new - Norcold 8-series. Got the ARP not long after that, been great ever since.
This last year I took the ice-maker out which gave us a little more room in the freezer. It sure works great till it gets to about a hundred out, then fridge temps creep up to forty or so.

Fridge Defend by ARP Protects your Dometic or Norcold

Fridge Defend by ARP® controls the high temperatures that can lead to fridge failure and safety issues, our fan controller improves efficiency and repairs fan problems without removal of the fridge in most cases for Dometic, Norcold & Amish RV Refrigerators.
www.arprv.com www.arprv.com
 
Browneye said:
In a recent power upgrade on our motorhome, the 600W inverter which draws 50-60A max on 12V got 4 gauge wire and a 80A ANL fuse.
The charge controller outputs max 30A and got 8 gauge wire and a 40A switching breaker. All connect to the house battery bank - 2 GC2's which will soon be upgraded to a 230A LiFePO4 pack. My solar panels are wired in series, two sets on two controllers, so they are not fused.

Panels should have a disconnect for safety and servicing. A mini double-breaker in a box works great on two legs, saves you going up on the roof to unplug panels should you want to stop their power input. The switching breaker can also shut down the charge controller.

My second set of panels - portables, have their own controller, it got 10 gauge wire and a 20A breaker to the same battery bank.


Your golfcart batteries are like 210-220A each, in series to make 12V they are still the same amperage, and two banks of two makes double that. However flooded lead acid (FLA) batteries should not be discharged more than 50% or they suffer a very short life. The plates sulfate over and will no longer hold a charge.

You'll want to find out from the fridge specs what it's draw is, estimate running time, and that will tell you how much battery capacity it will use. And then based on what your charge sources will provide to charge them back up. If it's an ammonia absorption fridge with a propane burner (2-way) and AC burner then the board uses about an amp and a half when it's on propane. I'm not sure what the 120V burner uses, but I would not try to run it that way on battery power - it could well use 50amps 12V.

Here's how I setup my two charge controllers in the entry step - gas coach so it's at mid-point on the coach instead of at the very front. A lot of folks like to hide them in a battery compartment and install a remote display. I operate on the KISS principle. :)

IMG_4111.HEIC


Portables deployed, they're 160W feeding a 10A mppt (left, above):

IMG_4113.HEIC


And the new panels on the roof - 2@ 215W feeding the 30A mppt controller (right, above):

IMG_4114.HEIC
Click to expand...
That is awesome. Well i got all set to knock this out this morning but always a but. So there was existing older panels and i removed all of them and was some existing wire couldnt get a size on it but when i cut it to put connectors on it was 14/3 110 wire and what they did was strip all the wires and combined them to make one wire. So that is outa here so question is i have less than 10ft to controller mppt 40 amp what size wire can i use to make this all work? I appreciate all the help you guys have been a big help!!

thanks
rick
 
40A SCC to battery should be 6 gauge with a 50A breaker or fuse. A switching breaker can be used as a disconnect as well.
 
great thank you! as far as the fuse for the inverter i was told i need a 250 amp looking for one i can bolt to the battery itself than to inverter cable. i see on amazon 250 amp stud mount fuse 32v will that work for my application?

thanks
 
Many of the BlueSea or Buss components are higher-voltage rated, as in 'up to' 58V. As far as I know amps are amps, so they're good for your 12v system as well. Surely a more knowledgeable type will happen along here and confirm.

Those stud mount fuses are pretty handy. They are 'MRBF' or marine-rated battery fuse.

I got the more traditional SPARTAN ANL blocks and fuses for my setup - battery main, one for inverter, and one for charger, and each solar charge controller has their own circuit breaker.

Inverter instructions say Type T or ANL fuses, I'm not sure where that stud fuse or MRBF falls in here. I know you want a fast acting fuse so if there's a short it shuts everything down. So you're fusing for the wire you use, and 2000W will generate 200A of 12V - you need 2/0 wire. That's some serious current.

EDIT: Here's another forum thread discussing these fuses and it has been claimed the stud-fuse MRFB type is compatible with your inverter lead.

Overcurrent protection: ANL vs terminal fuses vs class T-when to use what?

Hi all, How does one choose between different types of DC overcurrent protection devices? For example, DC feed to: inverter, fuse box-are the types in the title interchangeable? AM solar said they have seen ANL fuses fail too many times and thus use T fuses exclusively for inverters. Is...
sprinter-source.com sprinter-source.com

EDIT 2: Some good reading here on fusing house and starting batteries on yachts:
www.pbase.com

Battery Bank Fusing by Compass Marine How To

www.pbase.com
 
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