Cargo Trailer Camping Converting

[Sunking]

So where are we at now for things I need to figure out?

Waiting for you to figure out your daily watt hour requirements. Once you know what the fridge uses, you need to estimate what else on top of that you will need. Example lighting, entertainment, and fluff. Some loads like charging a cell phone are so insignificant can be ignored. If you have lighting, determine how many watts total the lights use, then calculate daily watt hours. Watt Hours = Watts x Hours.

Add all the watt hours up, then calculate battery size. Hope it fits with your fixed panel wattage and charge controller limitations.

we know I have 2x 320 watt solar panels, I'm looking to stay in that 40A MPPT charge controller range, my fridge on average draws below 50 watts while running, and I would like to dry camp for 2 days without solar to be safe to camp over a weekend without a worry about weather.

Any other info im missing or going to need?

OK this is where you have limited your choices. Basically you have a 40-Amp battery charger. That dictates the minimum and maximum size battery it will support. You really do not have much choice and left with take it or leave it. The smallest battery is roughly 300 AH, and in a trailer with less than optimum tilt and orientation I would go no larger than about 400 AH. Assuming a 3-Day reserve capacity with 2-Day usable means your daily watt hour use is limited to 1200 to 1600 watt hours. Understand what that means? If your fridge uses that much or more, you have shot yourself in the foot. OTOH if your fridge only use say 800 wh/day, then you have a lot more to work with.

Last piece of the puzzle is Inverter size. Inverter size is dictated by battery size. Assuming you use a Rolls Battery, they can handle up to a C/4 discharge. So if you have say a 300 AH battery is 300/4 = 75 amps, or 400 AH / 4 = 100 amps. That is a range of 750 to 1000 watt Inverter maximum. You can use anything smaller, just not larger.

[Mike90250]

.....
Last piece of the puzzle is Inverter size. Inverter size is dictated by battery size. Assuming you use a Rolls Battery, they can handle up to a C/4 discharge. So if you have say a 300 AH battery is 300/4 = 75 amps, or 400 AH / 4 = 100 amps. That is a range of 750 to 1000 watt Inverter maximum. You can use anything smaller, just not larger.

This is where the "Theory" parts from Practice. Since you have a fridge, you need an inverter that can supply the required starting surge. A fresh, undersized battery can supply the 5 sec surge to start the fridge. BUT - you have to balance the large inverter's "overhead or tare" losses, against the rest of your system capacity. You can't just throw a 4Kw inverter in, say "I'll only use 300w of it, and starting surge will be duck soup". No No No - that 4Kw inverter will suck 60-90w just keeping the electronics warm, and if you throw 20w of Lighting on, you are sucking 80W+ from the oversize inverter. So you need to shop for a inverter that can meet your starting surge requirements (generally 6-10x running load, for 3-5 seconds), is not any larger than you need, and is a highly efficient, pure sine inverter, Sadly, my favorite, overbuilt, 12v inverter, Morningstar's SureSine 300, can't supply the starting surge for a fridge. It has very low self-consumption, highly efficient, and has 600w surge for 10 min. Some of the high quality 800w inverters can manage, and nearly all of the good 1-1.3Kw inverters can start a fridge - If the battery cables are sized (beefy enough - #4 or even #2) and the battery is in good shape.
But remember, it has to be enough of an inverter to start the fridge at 11pm, when the laptop is charging, the DVD playing, and the mood lighting is on. and too large and it flattens the battery from it's own self-consumption.

[Sunking]

Mike I think we have that covered. The fridge consumers 50 watts, so a 500 to 750 watt TSW Inverter should work fine. I would not go any larger than a good 1 Kva TSW Inverter like Samlex SSW-1000-12A with Soft Start.

[UrbanElite]

When the fridge is running its around 44 watts, so I'm shooting for 50 watts to be safe in my calculations. So far with 3 days and almost 11 hours on the counter, I have 3.423 kWh used.

Other than using some LED lighting on the inside and outside of the trailer that will be all I will be powering other than charging a couple phones, camera or some things like that. Right now we won't have a tv or anything.

So the LED lights I have for the the trailer is 4x 12v 8W bar lights and 4x 12v 2.2W,

[Sunking]

OK pretty safe to say your fridge is using 1 Kwh/day, plus fluff, 300 AH should work. At 300 AH will give you up to 1200 wh/day and 3 day reserve. You can go as high as 400 AH. .

[UrbanElite]

OK pretty safe to say your fridge is using 1 Kwh/day, plus fluff, 300 AH should work. At 300 AH will give you up to 1200 wh/day and 3 day reserve. You can go as high as 400 AH. .

Sounds good, so what's the plan Sam?

What battery set up should I be choosing? Can I get away with the s290s?

Are we able to go with a 40a Traccer MPPT?

[Sunking]

Sounds good, so what's the plan Sam?

What battery set up should I be choosing? Can I get away with the s290s?

Are we able to go with a 40a Traccer MPPT?

A Rolls S290 is 230 AH @ the 20 hour rate. A bit light. Can you obtain a Rolls FC-420?

40 Amp controller is fine on a 300 to 400 AH battery.

[UrbanElite]

A Rolls S290 is 230 AH @ the 20 hour rate. A bit light. Can you obtain a Rolls FC-420?

40 Amp controller is fine on a 300 to 400 AH battery.

I can find out if I can, I will need 2 of them to make the 12v correct?

[Sunking]

Yes they are 6-volts.

If you want a compact size and AGM a perfect match is a Concorde PVX-3050T. They are Hazmat Free so shipping is reasonable and of course NO SPILLS or FUMES to worry about. Concorde AGM's are the best money can buy. They invented AGM technology for the military. The PVX-2050T is the same size as any GC2 size like the Trojan T-105, just taller. Kind of pricey at $383 with free shipping. They can do one thing no Flooded Lead Acid battery can do and not many AGM's can do. A pair of the PVX-3050T with an Internal Resistance of 1.2 milli-ohms (2.4 total) can deliver 150 amps @ 3% voltage drop. That means it can easily handle up to a 1500 watt Inverter. They are Brutes of the AGM battery world.

[UrbanElite]

Yeah googling them they are a nice battery on specs, but that's US pricing.... I would be a fair amount more for that here. So I have to find a battery that is around 300 ah. Too bad those S290 are too light was a good deal,

Still trying to find pricing on batteries, and waiting on quotes. I was looking at the Trojan J305E-AC, 20HR@ 305, I can get them at $315 a piece.

[Sunking]

Still trying to find pricing on batteries, and waiting on quotes. I was looking at the Trojan J305E-AC, 20HR@ 305, I can get them at $315 a piece.

Those are fine. Basically the same as a T-105 in the Signature Line-Up of Trojan products. They should meet your objective and then some.

[UrbanElite]

Perfect!

i ordered in my Traccer MPPT 40A charge controller, I have 2 of those Trojan 305s on hold. I ordered a few fuses 100A, 60A, resettable, blue sea 12 circuit fuse board, blue sea dual battery terminal fuse,

so just to clarify a few things:

How do I want to wire my panels again?

what gauges of wiring should I be looking for in my system?

What size of fuses will I need in my system?

should I have a master switch to kill power from the battery's going to the fuse board and inverter or no?

[Sunking]

Anything else? Wire sizes are minimum required.




DO NOT FORGET the GROUND WIRES shown in GREEN, otherwise all the fuses are useless.

should I have a master switch to kill power from the battery's going to the fuse board and inverter or no?

If you want, not required.

For distribution Fuse Block wire sizes use this chart 3%.

[UrbanElite]

So I'm doing my panels on parallel correct from the looks of it?

great diagrams that will make wiring a breeze now! Only thing I'm confused about for is example the charge controller. It looks like the positive wire is going to the battery as well as a negative wire going to the battery and a third (green) being a ground. Could you example me this or will I be using 2 wires coming out of the ground to go to the battery negative and a separate ground? Same goes for the fuse board and inverter

[UrbanElite]

Picked up a few items today. 2x Trojan 305 V6 batteries, Blue Sea 12 circuit Fuse Board, Blue Sea Dual Fuse MRBF, Switch Panel with a voltage meter.

Still waiting on the Epever Tracer 40A MPPT charge controller, some resettable fuses,