Solar MC4 connectors - needed? Why?

[bpounds]

I'm in the early planning stage of doing a solar install on our fiver. I see the MC4 connectors and combiners are commonly used, and I wonder why, and if there is a reason why I could not just solder and seal the conductors between panels, and even between the array and the leads down to the controller. It doesn't seem like a common thing to have to replace a panel. At least not common enough that you would need a quick disconnect. I understand the connectors also make it idiot proof as far as polarity, but so what?

The MC4 connectors are cheap enough, so that's not an issue, but it just seems like a lot of fooling around with pins and housings, for no benefit. I like soldered joints when practical.

Opinions?

[bpounds]

To add, the pic directly above is close to the max charge amps I have observed, about 18a @ 14.6v, or 250w out of the 400w rating panel sum. I am not sure if that is good or bad. It seems reasonable to me, considering they are flat mounted, and in the autumn season, and a high pv to battery amphr ratio.

[bpounds]

At this point I am very happy with the system.

We spent the last week of Sept in the Sierra, no generator at all, but the temps were mild and we ran the heater little. Not much of a test.

I just got back from 12 days in the Sierra, and nights were in the teens to low 20s at night. After a scary morning with ice in the toilet and slush in the faucets, I ran the heater 24/7 to keep things thawed. The solar easily kept the batteries recharged by midday, and the SoC did not taper down over the trip.

This would not have been fun using a gen. It would have meant running for hours every day, and my butt anchored in camp. Or more likely going home. The convenience of solar is worth the cost.

These batteries are 10 years old, and for most of that were undercharged by a WFCO junk converter. They are doing the job but don't have their rated capacity.

The Epever CC seems fine. No complaints and having the remote monitor inside the cabin is nice.

Would I do anything different? I probably would not use the Renogy panel mounts, and just make something myself. I chose a path that left options open. I could easily double the panel count, and the CC would handle it. Or I could double my battery bank, and it would handle it, including the wire sizing. I don't see any changes or additions any time soon.

[SpringerPop]

Now that you've had the system in operation for a couple of months, and have at least one field trial under your belt, do you have any additional thoughts?

Do you still like that MPPT controller, and would you change anything?

Pop

[bpounds]

Got it up and charging today. This is what I ended up with, 4@ 100W x 12V Mono panels. Still got some anchoring of cables to take care of, and I will do some roof maintenance at the same time. I've got plenty of space for 4 or even 6 more of these if the mood strikes me. But we'll see how these handle our needs, and I think they are going to be plenty.

The panels on the right are wired in series, as are the panels on the left, and the sides are paralleled prior to dropping down.



I went with the EPever 40a Tracer AN MPPT controller. Their newer "N" model with negative chassis/common.


I will move the remote meter inside, but I've got to get some ribbon cable to extend the length. It only came with 2 meters of cable. I need about 25 feet.

Nice sunny (hot) day today.

[bpounds]

Definitely going MPPT. S vs P TBD.

[Almot]

Now the big decision is whether to wire MPPT in series or PWM in parallel.

[bpounds]

Pulled the trigger on 4x 100W panels. Figured out I could get 8 of them up there easily. Easy to expand later if I choose.

A little more expensive per watt than those big panels, but the little ones ship for free so it's about a wash I think. Cost wasn't a priority anyway, but I did want to get something coming before market prices go up, and right now it looks like that's going to happen.

These 4 will easily avoid shade from the stuff on the roof, which might more than make up for a sum of 100w less than the big panels, depending on where we've parked.

Good point above about that front sloped area on the trailer. If you think about your typical campsite within trees, the one area that you can be sure will have the fewest trees, is going to be the driveway you backed into. And there is plenty of space for 2 of these panels end to end. I'm not locked in on choosing to put them there, but it's a good option.

[Almot]

I would rather watch old movies and shows on my 2TB hard drive than free broadcasted channels. Ridiculous amount of advertising.

Don't ignore that sloped front area. Panels must have at least a few degrees slope to drain water and debris, doesn't matter to what side, you are parked differently every time and it's only few degrees. Panels on the flatter rear area of the roof need a little slope too.

Check AZ Wind&Sun, they might have something.

2*24V panels isn't bad, but nobody regrets installing more.

That little plumbing vent few feet from antenna can be covered with a panel lifted few inches off the roof - I did. Panels must have an inch or two clearance from the roof anyway.

[bpounds]

Same here on the antenna. If we're in a park (almost never) they have cable. If we're "out there", too far from any broadcast TV anyway.

I might not give up so fast. I can still get 100w 12v panels and I can get at least 4 of them up there. You guys had my head in the clouds for a while with those big panels. That was a very economical way to go for a lot of watts.

I was concerned about the shade from protrusions from the start. But there just isn't much free space on our little trailer.

[time2roll]

As often as we use the antenna I would just assume remove the blasted thing.

Shade from the A/C and middle vent could really put a squeeze on your power. Even one cell partially shaded will have significant power loss. Although it will not be as bad as it looks on the cardboard once you mount the panel with a little elevation.

[bpounds]

Solar Blvd is pretty much out of everything. A few 80w is all they have. The trade tariffs have everything shut down.

I guess I'll just put this project on hold and see what happens. Too bad, I was just starting to have fun.

[bpounds]

This thread has wandered from my original question, but I'm good with that. I have benefited from all the comments.

This weekend I did a CAD layout of the roof and all the projections. Then today I made a template of the 24V x 60 cell panels. I can get 2 of them up there for sure. I could get a 3rd one forward of the most forward roof vent, but the roof curves down so sharply that I don't like that idea. Too much of a wind sail, and too visible from the street. Besides, 500w is so much more than I was looking for, I just don't see a need. We have learned to be very frugal with the DC juice, since we boondock almost exclusively.

In this view you can see how much arc there is on the bow. One of these panels would extend about 2/3 of the distance from the vent edge to the front cap seam. The 100w lay there pretty well, but not these big panels.


Our TV antenna is in an unfortunate location, and ruins a lot of available space. I don't think I am up for relocating that. But a panel does fit next to it on the right side.




Then there is space, barely, in front of the A/C unit. The shadow will be unfortunate at times I'm sure.

[time2roll]

bpounds wrote:

time2roll wrote:
https://www.solarblvd.com/product-category/solar-panels-systems/24-volt-solar-panels/

This company is near you and I. Have you been to their warehouse?

I had them deliver in their truck for about $50 (gas money).
I would place the order by phone for a will-call to verify the equipment will be on site.

[Almot]

I believe Solar Blvd have 2 warehouses in different locations. Call them.