Cargo Trailer Camping Converting

[UrbanElite]

Ok, now that we got the pissing matches out of the way lets get back to the topic, as I have an Update with some specs from the fridge. :P

Here are the specs for my panels again, with some other details I got off the spec sheets, as well as data I collected so far off monitoring that fridge.

Solar Panels: 320 Watt, 72 Cell Panels

Positive power tolerance from 0-5 W
Nominal Max. Power (Pmax) 320 W
Opt. Operating Voltage (Vmp) 37.1 V
Opt. Operating Current (Imp) 8.63 A
Open Circuit Voltage (Voc) 45.08 V
Short Circuit Current (Isc) 9.10 A
Module Efficiency 16.5 %
Max. System Voltage 1000 V (IEC) or 1000 V (UL)
Max. Series Fuse Rating 15 A
Power Tolerance 0 - + 5 W

FRIDGE DATA:

I started my testing with the fridge warm with nothing in it to start up, I then loaded the fridge with all different drinks, packed it right full as it will be that way once we go camping. My test results were any different after resetting the test 5 hours later with a cool fridge and cold drinks. I was opening the door on the fridge every so often as well. Here are the numbers

In 7.5 hours I used 0.367 KWH, 122.2 Volts plugged in, 0.68 Amps, 58-46 watts ( When it kicks on, then lowers slowly to run around 46 watts on the lowest. The fridge isn't on often from what I hear either, It has 5 power settings and just through testing I've been running it on 4 to get stuff really cold to see how much it actually pulls. Lowest wattage recorded is 1.1 watts, the highest spike is 748.3 watts.

So from what I get from this so far is that the fridge will spike under 800 watts to kick on, but during operating it is under 60 watts, as low as 46 watts.

[Sunking]

Ok, now that we got the pissing matches out of the way lets get back to the topic, as I have an Update with some specs from the fridge. :P

Here are the specs for my panels again, with some other details I got off the spec sheets, as well as data I collected so far off monitoring that fridge.

Solar Panels: 320 Watt, 72 Cell Panels

Positive power tolerance from 0-5 W
Nominal Max. Power (Pmax) 320 W
Opt. Operating Voltage (Vmp) 37.1 V
Opt. Operating Current (Imp) 8.63 A
Open Circuit Voltage (Voc) 45.08 V
Short Circuit Current (Isc) 9.10 A
Module Efficiency 16.5 %
Max. System Voltage 1000 V (IEC) or 1000 V (UL)
Max. Series Fuse Rating 15 A
Power Tolerance 0 - + 5 W

FRIDGE DATA:

I started my testing with the fridge warm with nothing in it to start up, I then loaded the fridge with all different drinks, packed it right full as it will be that way once we go camping. My test results were any different after resetting the test 5 hours later with a cool fridge and cold drinks. I was opening the door on the fridge every so often as well. Here are the numbers

In 7.5 hours I used 0.367 KWH, 122.2 Volts plugged in, 0.68 Amps, 58-46 watts ( When it kicks on, then lowers slowly to run around 46 watts on the lowest. The fridge isn't on often from what I hear either, It has 5 power settings and just through testing I've been running it on 4 to get stuff really cold to see how much it actually pulls. Lowest wattage recorded is 1.1 watts, the highest spike is 748.3 watts.

So from what I get from this so far is that the fridge will spike under 800 watts to kick on, but during operating it is under 60 watts, as low as 46 watts.

You still do not have the data you need. As I said you need to run the fridge a week to get accurate date, 12 hours is not going to cut it. I suspect you will find it uses roughly 1 Kwh/day. Just that alone wil require a 12 volt 400 AH battery alone. Keep in mind you are not running a Part Time System. All the junk Weybread does not apply to a full time system. You don't have the luxury of letting the system rest and recharge for 3 or 4 days every week. You are going to need an alternate source of power. Otherwise you have no means to CYA for cloudy spells and no way to Equalize your batteries every 30 days or so.

Panel specs are useful, but all I need to know is how many cells and total power All 72 cell panels Voc is 45 to 47 volts, and Vmp of roughly 36 to 37 volts. Given that Imp is easily calculated from Power. 320 watts = 37 volts = 8.6 amps. Exactly what the spec says. What is very important is the Voc as it is critical in determining the controler minimum Voc rating. To maximize efficiency and keep wiring cost low you want to wire the panels in series unless you have shade issues. Minimum correction factor for your panels is 125% so that turns your panel Voc from 45.08 x 1.25 = 56.35 volts. 2 in series put you at 112.7. That eliminates any 100 Voc controller. At a minimum 120 volts, higher is better. At 640 watts you are looking at a minimum 45 to 50 amp controller, and that wil not allow any growth at 12 volts. Go to 24 volts and you can grow to 1200 watts.

[UrbanElite]

I was just updating you guys with the data so far to let you know what it is running at as it. So far I know I the fridge rubs under 60 watts while running and will need an inverter that can handle a spike of 800 watts and above. The fridge is still running and I am still recording data from it as well.

like I said for the most part I will be camping over the weekend and sometimes I will do 4 day trips when I have holidays or more time to camp. I'm aiming for having 2 maybe 3 solid days of power without recharged so if I camp over the weekend in crappy weather I will not have to worry about sun being great or at all. For the most part I will have 4-5 days beaten using the system to recharge and get the battery's up to full strength without a load on them, and sometimes I might not camp for a week or more until my next trip.

[Wrybread]

Poor Grandpa, still doesn't realize you're building this for camping.



Anyway, a 60 watt part time load is dead simple to power. One thing I was thinking about, I used to have a printer that would kill my inverters when it powered on sometimes, because of a spike. That all ended when I started buying pure sinewave inverters, not sure if that was a factor (could also just be that the sinewave inverters are better in general).

[Sunking]

Poor Grandpa, still doesn't realize you're building this for camping.

OK my bad. Part time is different. At 3 days no solar is really needed if the battery is sized correctly. You can save a ton of money and headaches.

Anyway I can say one thing you cannot, I have been thanked 4 times today already and counting, Happens almost everyday when folks have good questions and take time to listen.

One thing I was thinking about, I used to have a printer that would kill my inverters when it powered on sometimes, because of a spike. That all ended when I started buying pure sinewave inverters, not sure if that was a factor (could also just be that the sinewave inverters are better in general).

I rest my case.You are dangerous because you do not understand what you are working with.

There is absolutely no doubt or questions TSW is far superior. Fact is anything with a motor like a fridge, or non linear loads like a printer can burn your fridge and printer up with a MSW Inverter. Not to mention the Inverter may not start and trip off-line if you are Lucky. You got lucky again your Inverter shut down. You could have easily started a fire or burnt your equipment up.

In an RV or any application today you should only use a TSW Inverter. About the only thing a MSW Inverter can power up today without damaging the equipment, unnecessary Inverter tripping off-line, or risking fire is incandescent light bulb, or electric resistive heating element as those are linear loads. The last thing you would ever want to use in an RV is incandescent lighting and resistive heating for hot water or heat. Everything in an RV is either going to have a motor, or non linear electronics. Even LED lights are non linear loads. A MSW Inverter will burn the driver out. If they are cheap chi-com LED's like most things made for RV's can catch fire if powered by a MSW Inverter. Lastly anything powered by a MSW Inverter is going to use a lot more power off the batteries unless it is a Linear Load. Where is all that extra power going you ask? It is being burned off as extra waste heat in your gizmos cooking their power supplies and motor windings burning them up.

Ever hear that buzzing sound in a electric motor when being ran with a MSW Inverter and wonder why? Its your motor windings beating against each other damaging the insulation for a short circuit in your future. The process is speeded up because the MSW is heating the winding up more than they were designed for weakening the enamel insulation.

[Wrybread]

Take it easy grandpa, I've been using sine wave inverters ever since they've become available and would use nothing else. Was just mentioning it in case he has a non TSW. As I've said a few times in this thread, I love and highly recommend the Xantrex TSW inverters. And on a sidenote, those blow over time too, inverters are by their nature a bit fragile.

Anyway I can say one thing you cannot, I have been thanked 4 times today already and counting,

Hilarious! And what do you think your tally would be if this forum had a thumbs down button next to postings?

[UrbanElite]

From what I can see from my research I'll need a minimum MPPT controller of 40A and wire the panels into series.

What wattages should I be looking at for an inverter when it comes to the wattage and peak wattage?

[Sunking]

From what I can see from my research I'll need a minimum MPPT controller of 40A and wire the panels into parallel.

What wattages should I be looking at for an inverter when it comes to the wattage and peak wattage?

Why parallel? That defeats a lot of the purpose of using a MPPT controller, and will add wiring cost.

640 watts \ 12 volts = 53.33 amps.

[UrbanElite]

Why parallel? That defeats a lot of the purpose of using a MPPT controller, and will add wiring cost.

640 watts \ 12 volts = 53.33 amps.

Sorry I edited it late, I meant in series.

im guessing I'm wrong about the 40amp then?....

[sensij]

Sorry I edited it late, I meant in series.

im guessing I'm wrong about the 40amp then?....

No, 40 A mppt is fine for that wattage. In the real world, your panels won't produce at their STC rating. In those rare moments you get a cloud reflection, the mppt controller will just peg at 40 A.

[Wrybread]

Here's a handy chart for figuring your wiring:

https://www.bluesea.com/resources/1437

Use the 3% loss column of the graphic.

If you wire your panels in parallel, that's 640 watts @ 36 volts = 17.7 amps (640/36 = 17.7)

In series, that's 640 watts @ 72 volts = 8.8 amps

So parallel wiring your panels (17.7 amps) requires at least 12 gauge wire for up to 10 feet. Personally on my system with the same specs I use 10 gauge since it gives me room to expand, on the off-chance I want to add a 3rd panel (which would be 26.6 amps), which would give me more power in the winter for example.

I've been really happy with this pre-crimped wire, very easy to connect to the panels:

https://www.amazon.com/dp/B01D7VBJNA...ing=UTF8&psc=1 (I use the 10 foot lengths of 10 gauge, which costs $23)

Cut it to the length you need, and strip the wire to connect it to your charge controller.

parallel will add wiring cost

Yup, about $5 (see link above).

paralel defeats a lot of the purpose of using a MPPT controller

While I agree that all things being equal of course series wiring is better, when you add real world considerations there's good reasons to wire panels in parallel sometimes. Wiring in parallel lets him use a much cheaper 100v charge controller, which saves about $310 ($160 versus $400 for the controller plus $30 versus $100 for the display screen). Another way to look at it is that it cuts the total cost of the solar system (except batteries) almost in half. That's pretty substantial.

And in buying 72-cell 320 watt panels he's getting at least an extra 140 watts (70 watts per panel) more power than if he used similarly priced 250 watt 60-cell panels.

And in practice there's no significant loss of power between parallel and series wiring of two 72-cell panels. I swap the wiring back and forth on my system (same specs) pretty often and my setup graphs the output, and there's absolutely no difference in wattage when the sun is reasonably high. Remember, it's still 36-46 volts, which is plenty high for MPPT to do it's thing with a 12 volt system. There's probably a slight difference when the sun is very low, but I haven't tested that since I don't really care as I don't get much power then anyway (though I do plan to test it eventually). And with real world considerations, the extra watts from my 72-cell system more than offsets it.

640 watts \ 12 volts = 53.33 amps.

If he's using a 40 amp charge controller the maximum is 40 amps, meaning a minimum of 8 gauge wire up to 10 feet. Personally I use 6 gauge, which is the fattest that my Tracer 4210 charge controller will accept, which still gives me plenty of overhead. Obviously keep that 40 amp run as short as possible, ideally well under 10 feet. With the Tracer you can get the remote monitoring box for an extra $30, which lets you see the status of your system and make configurations without having to physically access the controller.

For inverter, you're sure about the 800 watt spike when you turn on your fridge? I power a fridge part time too, and don't have that spike. Anyway the Xantrex ProWatt inverters are tried and true and excellent:

https://www.amazon.com/Xantrex-806-1.../dp/B002O5P8BA (600 watts)

https://www.amazon.com/Xantrex-806-1.../dp/B002I04A74 (1000 watts)

You might also look at the Samlex inverters:

https://www.amazon.com/Samlex-Solar-.../dp/B00AYH6BSO

Whatever you get, make sure it's a true sine wave inverter (TSW). If whatever you get comes with wires, make sure they're at least 6 gauge for the 600 watt and 3 gauge for the 1000 watt. On the off-chance it comes with a cigarette lighter socket, throw it away. This is the 6 gauge wire I use for my 600 watt ProWatt:

https://www.amazon.com/EPAuto-20-Inc.../dp/B01J8WKVIG

Mount the inverter as close to the battery as possible and get the remote on/off switch so you don't need physical access to turn it off and on.

By the way here's the joiners I use when wiring in parallel:

https://www.amazon.com/gp/product/B019ZM0TZE

And I should mention that if you wire 3+ panels in parallel you need to add inline fuses to the + side of each panel, since otherwise a short in one of the panels could cause a fire. Personally I use them even with my 2 panel system to be safe:

https://www.amazon.com/gp/product/B019YP0G1O

[Mike90250]

For inverter, you're sure about the 800 watt spike when you turn on your fridge? I power a fridge part time too, and don't have that spike. Anyway the Xantrex ProWatt inverters are tried and true and excellent:

If you are using a standard compressor fridge, you have a spike of about 10x running current when the motor starts.
Just because you can't see it with a meter that costs less then $300, does not mean it does not exist.

Here's the surge rating for the Prowatt series (straight from Xantrex) https://www.xantrex.com/power-produc...rowatt-sw.aspx
600 / 1000 / 2000 watts maximum, 1200 / 2000 / 3000 watt surge capability
So the 600w inverter can supply a couple cycles of 1,200 watts, which is what starts the fridge. Most fridges need about a 1Kw inverter to
supply the starting current, Xantrex has some of the best overload/surge ratings around.

[UrbanElite]

If you are using a standard compressor fridge, you have a spike of about 10x running current when the motor starts.
Just because you can't see it with a meter that costs less then $300, does not mean it does not exist.

Here's the surge rating for the Prowatt series (straight from Xantrex) https://www.xantrex.com/power-produc...rowatt-sw.aspx
600 / 1000 / 2000 watts maximum, 1200 / 2000 / 3000 watt surge capability
So the 600w inverter can supply a couple cycles of 1,200 watts, which is what starts the fridge. Most fridges need about a 1Kw inverter to
supply the starting current, Xantrex has some of the best overload/surge ratings around.

Yeah, that's why on my meter I had a spike of under 800 watts when the main running wattage is around 50 watts. So what size should I be looking at to run my fridge and other 110v stuff if I choose too?

Thanks!

[UrbanElite]

Great reply Wrybread, I'll reply to it with some questions in the morning what I have my laptop out! Thanks!

[UrbanElite]

[QUOTE=Wrybread;n351931]Here's a handy chart for figuring your wiring:

If you wire your panels in parallel, that's 640 watts @ 36 volts = 17.7 amps (640/36 = 17.7)

In series, that's 640 watts @ 72 volts = 8.8 amps

So for this set up what is the better bet then to go parallel? Only big reason I like parallel is the fact of not loosing all your panels if somehow there was a problem with wiring, panel maulfution or shaded ect..


While I agree that all things being equal of course series wiring is better, when you add real world considerations there's good reasons to wire panels in parallel sometimes. Wiring in parallel lets him use a much cheaper 100v charge controller, which saves about $310 ($160 versus $400 for the controller plus $30 versus $100 for the display screen). Another way to look at it is that it cuts the total cost of the solar system (except batteries) almost in half. That's pretty substantial.

And in buying 72-cell 320 watt panels he's getting at least an extra 140 watts (70 watts per panel) more power than if he used similarly priced 250 watt 60-cell panels.

If he's using a 40 amp charge controller the maximum is 40 amps, meaning a minimum of 8 gauge wire up to 10 feet. Personally I use 6 gauge, which is the fattest that my Tracer 4210 charge controller will accept, which still gives me plenty of overhead. Obviously keep that 40 amp run as short as possible, ideally well under 10 feet. With the Tracer you can get the remote monitoring box for an extra $30, which lets you see the status of your system and make configurations without having to physically access the controller.

I was looking at buying this controller, seems its very popular in the solar world for the price, efficiency and such. Buy the controller and the separate monitor:

https://www.amazon.ca/dp/B01BY7XV8A/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=17W1KTKS60DD4&coliid=I2SV43XC908O5W&psc=1

For inverter, you're sure about the 800 watt spike when you turn on your fridge? I power a fridge part time too, and don't have that spike. Anyway the Xantrex ProWatt inverters are tried and true and excellent:

Yes, thats why in my testing i had 731 as my highest watts showed so far, I'm guessing that would only happen when the compressor kicks on.

https://www.amazon.com/Xantrex-806-1.../dp/B002O5P8BA (600 watts)

https://www.amazon.com/Xantrex-806-1.../dp/B002I04A74 (1000 watts)

You might also look at the Samlex inverters:

https://www.amazon.com/Samlex-Solar-.../dp/B00AYH6BSO

Whatever you get, make sure it's a true sine wave inverter (TSW). If whatever you get comes with wires, make sure they're at least 6 gauge for the 600 watt and 3 gauge for the 1000 watt. On the off-chance it comes with a cigarette lighter socket, throw it away. This is the 6 gauge wire I use for my 600 watt ProWatt:

Ok, so what would be the inverter I would be needing for this project to run this fridge how I need too, as well maybe some other 110v stuff if i have too as well?

Mount the inverter as close to the battery as possible and get the remote on/off switch so you don't need physical access to turn it off and on.

Your talking just a master switch to turn it off and on?

And I should mention that if you wire 3+ panels in parallel you need to add inline fuses to the + side of each panel, since otherwise a short in one of the panels could cause a fire. Personally I use them even with my 2 panel system to be safe:

I was looking at using fuses for sure to be safe, ones like in my link below. What all sizes should I be getting for my system and where would they go into the system at?

https://www.amazon.ca/dp/B01EUHRSNK/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=17W1KTKS60DD4&coliid=IA2CQ8SED749I&psc=1