My DIY Solar Installation

[drboyd]

Well, it's Officially Started. How fast it will progress is another question entirely, but if y'all don't mind a thread that's updated at a leisurely pace, I thought I'd post pictures of my DIY installation. Keep in mind that this trailer sits outside in the Arizona sun all summer, so some of the things I do for heat and UV resistance may not be necessary for your installation.

This first picture is my uber-heavy-duty Hoffman combiner box, which weighs about four pounds more than I'd really like to mount that high on the trailer, but it will be dust proof and water proof. This box was selected for highly technical reasons, mostly because I had it laying around in the garage. It's in the process of being painted white on the outside for heat reflectivity. The cable glands are just sitting on top - no holes drilled for them yet, as I don't know where panels and stuff will be mounted yet.

The second picture is the interior of the box. I'm only painting the outside, not because I'm lazy (No,sir-ee!), but because I don't want to screw up the door gasket. On full zoom, you can see the DIN rail mounting screws coming in through the back.

The third picture shows test fitting the two panel breakers (10 amps each), the two voltage reading breakers (3 amps each) and the series/parallel relay in the box. These are all mounted on a chunk of DIN rail I scored at the salvage store for about a buck. The DIN rail mounting screws are flatheads countersunk on the back. Two of the green negative/ground wires are spares; the remaining wire is connected to one of the coil terminals on the relay. All of the connections shown are both crimped and soldered.

Suggestions, comments and smarty-alec remarks are mostly welcome.

Tomorrow (hopefully) I'll be on the roof!

[Jaxon]

[QUOTE=drboyd;1437728]Well, it's Officially Started.
The cable glands are just sitting on top - no holes drilled for them yet, as I don't know where panels and stuff will be mounted yet.
comments and smarty-alec remarks are mostly welcome.
/QUOTE]

“Cable glands”?

[drboyd]

LOL!

That's the Official Name for 'em.

[drboyd]

Today:

Up on the roof!

Believe it or not, I've had this trailer over 10 years and I've never been up on the roof. The first order of business was a Ladder Padder, so I could get up there without denting the sides. The old upholstered board from along the front of the gaucho came in handy, along with some screw eyes and cable ties.

The next picture is test fitting the panels. Looks like I've got a zillionth of an inch to spare, so it's good to go.

The next photo is the back of a panel. No, I don't think I'll use the thin aluminum wire, even if it is crimped nicely, thankyouverymuch. I'm putting in an additional diode in parallel for each existing diode, just in case one decides to croak on me.

The final photo is the 6 gauge copper soldered in to the panel connectors, along with the parallel diodes.

[drboyd]

.,.is to get the panels ready to go up.

Here we have the mounting feet that come with the panel, with some of the Official 3M tape. The bolts holding the panel and legs together are stainless steel. I actually used 6 strips of tape on all the rest of the legs instead of the 4 shown here..

Photo 2: I think these are supposed to be tight.

Photo 3: Per Lewster's excellent advice, I ran a bead of Trempro around the joint area, to keep old mean Mister Water from getting in and eating the tape.

All day tomorrow is busy, so next Saturday will be the next opportunity to work on it. Hopefully, my 3 amp voltage reading point breakers will be here from China by that time, and I can get the combiner box finalized.

[Wolfe]

you need to have 1"-2" stand off from panel to trailer skin, for convection.
A&m solar has a custom roof top cable made to live on top of trailer's.
Are the brakers up top ???. If they trip how do you git up to reset.

[aquinob]

Looks good, I wouldnt mind doing something like this with my rig down the road.

One thought though, where you made the connections from the wire to the panel connectors, did you make some sort of mechanical connection like a crimp to the wire before you soldered them? Without that, you are relying on the solder which is very soft and prone to fatigue (can you say cold solder joint?) from all the vibration running down the road, not to mention the fairly high temps from being on the roof inside the panel.

I zoomed in on the box where you made the connections and to be very honest, they don't look very good. Solder joints sound be smooth and shiny and the solder should coat the copper wire up to the insulation. The extra diodes could have had their wires passed through the holes of the crimp connectors for a mechanical connection rather than just tacking them on top with solder. Easy enough to fix and it will save you headaches down the road.

[drboyd]

Dang. I had a whole reply written, and the computer ate it. Once again....

Wolfe - I won't have as much stand-off as I'd like, particularly in the center of the panel. The curve of the roof puts it either touching or too close to tell the difference. I looked at ways to add height to the brackets, and I didn't come up with anything. Ideas?

On the breaker location - it's clearly more convenient to put them downstairs, but then I'd have all the wire running down the fridge vent with no breaker protection. It's more convenient to put the breakers downstairs, but it's safer to put them on the roof.

I'm planning to put wire loom over the bare wires - i'll probably have to replace it about every year. What else could I use there?

aquinob - Yeah, those solder connections aren't making me real happy either. (They are, however better than they look - and I did check them both mechanically and electrically) I tried un-crimping the original connections, but they were serious when they made those. My soldering iron just doesn't have enough wattage to get that much 6 gauge wire hot enough to fully coat all the strands. The wires do fit tight in the "glands," so there isn't any mechanical strain. I'm extremely open to ideas about how to make those connections better.

I've got a little butane soldering iron somewhere - I may have to give them another shot with that.

Thanks for the input!! You guys rock!

[aquinob]

Get yourself a 25 or 30 watt iron, that should be more than enough to heat up the joint so it flows smoothly. If there is a radio shack around, they would have it, or probably one of the big box stores.

And if you don't mind, could you tell me about how much all this ends up costing, I wouldnt mind doing something like this a year or two down the road when I get the other parts of my restoration done.

[drboyd]

Originally Posted by aquinob

Get yourself a 25 or 30 watt iron, that should be more than enough to heat up the joint so it flows smoothly. If there is a radio shack around, they would have it, or probably one of the big box stores.

I've got one - actually a couple. I'll give that a shot later this evening. I'll let everyone know how that goes.

Originally Posted by aquinob

And if you don't mind, could you tell me about how much all this ends up costing, I wouldn't mind doing something like this a year or two down the road when I get the other parts of my restoration done.

Well, the panels were $150 each, the mounting legs were $13 per panel, the Hoffman box was free (or $15 at the electronics salvage store if you don't mind patching holes), the charge controller was $100, the circuit breakers were like $10 each, the DIN rail was a buck, the relay was $15 or so off Aliexpress, the 6 gauge wire is a buck a foot or so, and the stainless steel hardware is much cheaper if you buy it in bulk (like 1/4 as much as the local Ace hardware). The stainless steel rivnuts are on the order of a buck each, though. The rivnuts and hardware are all 1/4-20, for simplicity. Oh, and the tape was like another $10 or so as I recall.

Plus Trempro and at least ten more random trips to the hardware store. I'll probably have at least $700 in it by the time I'm done - not counting the additional battery I'll be adding.

[drboyd]

I tried the 30 Watt soldering iron. Same thing happened. :-(

I'll try to pick up a butane iron tomorrow - we'll see....

[drboyd]

I may have the answer. Some mechanical connectors are on will-call at Grainger for me to pick up on the way to work tomorrow. If they work asd I think, you'll get pictures. If they don't, it's back to the drawing board.

My gut hunch is that the soldering is good enough the way it is. However, it would bother me for the next 20 years, so I'll fix it.

[Mexray]

Ah, the challenges in life...

It's too late now, but I think it would have been better to solder the 6 ga wires first - especially if using a high wattage iron...

There's always a chance that too much heat conducted to the diodes could damage them...

While it's true that a good mechanical & soldered connection is usually best - a good mechanical connection where the connector is first crimped & soldered to the end of the wire - then mechanically fastened to the junction box lugs (SS screws) with some dielectric grease to guard against corrosion/oxidation can be just is good (and removable later for maintenance if needed)...

Git er' done and get out and enjoy...!

[drboyd]

I'll try the diodes with my VOM just to double-check. I ain't done with this yet!

[drboyd]

First of all, a big public THANKS! to aquinob! I did have a bad solder connection. I owe you a beer, amigo!

Second,

Originally Posted by Mexray

In other news, my favorite new toy is a butane soldering iron from Home Depot. Trust me - if you're trying to solder 6 gauge copper, it's between that and a Big Soldering Gun - and this is a bunch cheaper. By the way, forget the reviews. Mine lit off the very first time and worked perfectly.

Seriously, thanks for busting my chops on the bad soldering. I can (and will) do better than that.

[drboyd]

Well, the connectors from Grainger didn't work out, but they were close. However, I did manage (with the wire ends pre-tinned and the butane soldering iron) to get some decent solder joints.

[drboyd]

Update - box being pre-wired before it goes on the roof.

[carl2591]

Originally Posted by drboyd

Well, the connectors from Grainger didn't work out, but they were close. However, I did manage (with the wire ends pre-tinned and the butane soldering iron) to get some decent solder joints.

here's an "ideer".. take a bit of the cable to lowes or HD and see what size copper tubing, the soft stuff, it slides into .. buy you a foot of that and make your own connectors.. how.. cut the tubing about 3/4" longer than your cable connection, about 3/8", then hammer the rest flat.. drill a hole the size you need and connect to your bus bar. You can use a flat bit of metal to hammer or crimp the cable in the connector you made and if you want solder it as well.

[drboyd]

Good idea, Carl! The ring connectors I'm using at the relay with the 6 gauge are standard size yellow with the insulation removed, then opened, crimped and soldered with heat shrink to re-insulate. If I can't get that to work with the size 4 wires going down to the batteries, I'll try your copper tubing plan!!

Thanks!!

[scamp]

Looks good ,I think your breakers on the roof is a good idea as you want to protect as close to the output power source (as you mentioned ) and they will probably never trip ,my home solar has never tripped a breaker so far after one year of installation , as for your wiring I'm not sure if you used ( solar panel wiring ) as it is rated for outdoor use agains the suns u.v rays , or if your wiring was for something else as charge controller etc. or if the wire gauge was the right size , solar panel wiring is I think 8 or 10 gauge I will have to check , anyways your solar project looks good !