Another DIY Portable Solar Project

[ab1985]

Like several others I am in need of a portable solar system for my vehicle, but I don't like the size and weight of the suitcase-style units available for purchase. I've pieced together most of my DIY setup, but I have couple of questions on the last few bits.

My planned setup:

- HQST 100W flexible solar panel. My plan is to store this in the bedding of my pop-top when not in use. http://www.amazon.com/HQST-Monocrys...&redirect=true&ref_=oh_aui_detailpage_o00_s00
- Renogy 10 Amp PWM control charger. Honestly, I looked at so many I finally just pulled the trigger on this one to get started. I may change it out at some point if I find out it's not the best for my application: http://www.amazon.com/Renogy-Amp-So...&redirect=true&ref_=oh_aui_detailpage_o08_s00
- Makerfire power analyzer: http://www.amazon.com/Makerfire®-Pr...&redirect=true&ref_=oh_aui_detailpage_o08_s00

I don't want anything hard mounted, so I bought a small, waterproof tackle box to house the charge controller, power analyzer and assorted cables (pics below). The dimensions on the box were intentional. I wanted something low profile that was just large enough to fit everything, and it's clear so I can see what's going on inside without having to open and close. I recently replaced my Coleman camp stove with a Tembo Tusk Skottel, so this box will fit the stove's old spot perfectly with room to spare (roughly 14 x 9 x 3).

I have 50' of 12 AWG wire with MC4 ends that I will cut in half to make a 25' cable so the panel can be setup away from the truck in the sun (I think I would have been fine with plain old 12 AWG wire - read on). I plan to drill holes in the end of the tackle box to run SAE connections to/from the charge controller so everything is quick disconnect. Another expo member posted a great flanged SAE connector that would work perfectly for me, but it's only available in 12 AWG ( http://www.ebay.com/itm/SAE-flanged...-recreational-vehicle-portable-/391399826815? ). Reading other's recommendations here I planned to run 10 AWG from the controller to the battery where another SAE quick connect will be located, and unfortunately this bit is only available for a 12 AWG connection.

So my questions: 1) Would I be fine with 12 AWG between the controller and battery? That would make for a cleaner install. 2) Can I get rid of the MC4 ends all together and replace with SAE disconnects so I have them at both ends? 3) Anything glaringly obvious I am missing or thinking about incorrectly? I'm a solar newbie so advice/suggestions are welcome.

TIA

 

[Semi-Hex]

If you are not married to the SAE connectors, you should try Anderson Powerpoles. You can get the parts for 10 awg wire with ease (link) https://powerwerx.com/anderson-powerpole-connectors-45amp-bonded they also make a waterproof receptacle https://powerwerx.com/panelpole-panel-mount-powerpole-housing Which I like quite a bit. You have a data meter already, using APP's on that you can see you usage for each appliance.

Hope it helps.

 

[ab1985]

I've heard of these but never used them. Looks like they would be perfect for my application. Thanks, Semi-Hex!

 

[jonyjoe101]

12 gauge is ok for the controller to the battery if the distance is not too far.

Another inexpensive connector (10 sets for less then 10 dollars) that is available is the xt60, thats all I use, it can handle up to 60 amps and easy to connect/disconnect. You need to solder the wire to it but its not hard to do. The xt60 and powerpole , the positive and negative are always in the same place, no way to mix them up, with the SAE connectors, you can get them mixed up.

picture of xt60 connectors

 

[ab1985]

Thanks, jonyjoe. I may have used the wrong terminology. These are the connectors I purchased: http://www.amazon.com/Quick-Disconn...&redirect=true&ref_=oh_aui_detailpage_o03_s01 How could these be mixed up assuming initial setup is done correctly.

 

[ab1985]

Also, I've come across your pictures while researching. I love the use of the baking pans

 

[ikk]

I've heard of these but never used them. Looks like they would be perfect for my application. Thanks, Semi-Hex!

Here is what the Anderson Plugs looks like on my battery box. You can use different colors for different applications. as you can see the green and white are for my solar panel. They are a bit more expensive on a project I started using them on all my 12 volt equipment. even made a few adapters in case I need to use an SAE or 12 volt Socket I have an Anderson plug on the other end.

 

[ikk]

I've heard of these but never used them. Looks like they would be perfect for my application. Thanks, Semi-Hex!

Here is what the Anderson Plugs looks like on my battery box. You can use different colors for different applications. as you can see the green and white are for my solar panel. They are a bit more expensive on a project I started using them on all my 12 volt equipment. even made a few adapters in case I need to use an SAE or 12 volt Socket I have an Anderson plug on the other end.
View attachment 346885

As for the MC4 connectors. You could cut it and add an Anderson plug if you go that route. or you can also buy a small MC4 cable and cut it in half and that way if you ever decide on selling it or adding more panels its and easy plug and play.

 

[Herbie]

The other advantage to Anderson connectors is that you can build multi-connector "plugs" in different orientation. When I was building Battlebots we'd configure the different power connections in such a way that they were mechanically "polarized", so that you couldn't mis-connect things if you weren't paying attention.

 

[4x4junkie]

I have SAE connectors on my 170W solar setup, as well as for the connection to my fridge, I've never had any trouble out of them. Yes, you do have to make sure the positive of the "live" side is the insulated side, but it's not possible to hook them up reversed (unless you were to use the wrong side of a Y-adapter).

#12 between the battery & controller should be fine out to about 3-4 feet, which should work well if you plan to simply have your box right near your battery. For longer runs (to about 6 feet), IMO #10 would be better (my controller has 3' of #10 with battery clips on the end)


View attachment 153772
View attachment 153773

 

[calicamper]

I have SAE connectors on my 170W solar setup, as well as for the connection to my fridge, I've never had any trouble out of them. Yes, you do have to make sure the positive of the "live" side is the insulated side, but it's not possible to hook them up reversed (unless you were to use the wrong side of a Y-adapter).

#12 between the battery & controller should be fine out to about 3-4 feet, which should work well if you plan to simply have your box right near your battery. For longer runs (to about 6 feet), IMO #10 would be better (my controller has 3' of #10 with battery clips on the end)


View attachment 153772
View attachment 153773

Just an added interesting side note. The harness on my house system at the panels is 12 guage. Max allowed is 16 panels at 285 watts with micro inverters under each panel. I would say 12 guage for a single or two panels is perfectly fine. My longest harness is 40ft long.
Total system is 29 panels on 4 strings

 

[4x4junkie]

Household systems typically use much higher operating voltages than off-grid (vehicle & RV) systems, so it's easier to get away with smaller gauge wiring in various places.

#12 indeed should be fine on the solar side of a small (12V) 100W system up to a few dozen feet or so. However the wiring between the controller to the battery is much more critical. You want to keep the voltage drop here to a minimum if the battery is to recharge quickly as possible before the sun goes down. This is because a controller typically cannot detect and compensate for voltage drop on the battery side of the circuit (though if your controller has a remote battery voltage sensing lead, then this can provide a bit more leeway in what size wiring you can get away with to the battery).

 

[4x4junkie]

I have SAE connectors on my 170W solar setup, as well as for the connection to my fridge, I've never had any trouble out of them. Yes, you do have to make sure the positive of the "live" side is the insulated side, but it's not possible to hook them up reversed (unless you were to use the wrong side of a Y-adapter).

Welp... As luck would have it, over the recent holiday weekend the SAE connector at the backside of my solar panel gave out... (another one of the many failures of crimp-type connections I seem to have difficulty getting away from). I had to cut a notch into the side of the molded connector so that I could reestablish the connection using solder.


The earlier post about the XT60 connectors is a great idea. Being they are soldered this type of failure should not happen with them.
I've used XT60s on a few of my R/C models, they're definitely good stuff, though I am a little dubious of their 60A rating (at least 60A continuous anyway), but they do seem to do quite well up to 30A cont. The buck or less per pair price (male & female) is just icing on the cake. I may slowly start converting all my stuff over to XT60s.