The Solar Roof Hole

[Alpine06]

Looking good !!
I placed mine under a panel as well however I had to put a spacer under the panel attachment as my box was just 1/4” too tall. So far I am happy I did it this way and I already changed my wiring once around making the combiner box well worth it.

[Brianna]

The conduit was originally intended to cover the cables that would be inside the closet. Because the cables are now behind the wall, the conduit has no purpose.
Sometimes my hands work faster than my brain.

[Alpine06]

Ha same here mine still lays in the garage. The wires run behind the washer/dryer and there is so much going on back there that I just tied them to the existing wire loom.

[Brianna]

I installed 600 (6×100) watts of panels and it's a sunny day. I wired 3 +3 series parallel.
This is what the mt50 display says is going on.
The voltage is correct at close to 60. Each panel tested at 19.9v.
But I was expecting more amps.

[wolfe10]

Originally Posted by Brianna

I installed 600 (6×100) watts of panels and it's a sunny day. I wired 3 +3 series parallel.
This is what the mt50 display says is going on.
The voltage is correct at close to 60. Each panel tested at 19.9v.
But I was expecting more amps.

The real test on output (amps to battery) is with the batteries discharged down to 50% or so.


Said another way, if the batteries are close to or fully charged the controller SHOULD reduce amps and 14.7 VDC is as high as you want voltage to batteries and only under bulk/absorption NOT float.


So, run the batteries down to 50% and see what you get.

[paul65k]

Originally Posted by Brianna

I installed 600 (6×100) watts of panels and it's a sunny day. I wired 3 +3 series parallel.
This is what the mt50 display says is going on.
The voltage is correct at close to 60. Each panel tested at 19.9v.
But I was expecting more amps.

Remind us again about the type of batteries you have installed??

if they are lead-acid and are not deeply discharged your solar controller is probably throttled back to at least absorb mode and maybe even float as these MPPT chargers are "Smart" and will only put out what your batteries need at a given time.

[Brianna]

As an interim step (until I can afford lithium) I put in 4 brand new flooded 6v batteries.

Maybe there is confusion with what this monitor is showing us.

The instruction manual is vague on this point. Does the display show the total PV potential that is available? Or does it show what the batteries are receiving at any given moment?

The batteries are at 100%+-

[paul65k]

Originally Posted by Brianna

As an interim step (until I can afford lithium) I put in 4 brand new flooded 6v batteries.

Maybe there is confusion with what this monitor is showing us.

The instruction manual is vague on this point. Does the display show the total PV potential that is available? Or does it show what the batteries are receiving at any given moment?

The batteries are at 100%+-

Well not sure about that one but on my Victron, it only shows what is being produced and put into the batteries at a given time. My controller only calls for what it needs not what is available unless it is charging at 100% such as when the batteries can accept a bulk charge.

[John Lorang]

Originally Posted by Alpine06

Hi Brianna,
so my recommendations for the wiring / roof hole.

# Get a combiner box that is large enough. I have a DIN rail in mine to configure all the wires So I can add panels or change my series / parallel layout.
# The box itself has a way it fastens the lid. Take a look at that, sometimes the holes going into the body of the box extend all the way down. This means that you should not add sealant around the outer perimeter of the box as water can find a way under the box and into the roof. Only seal under the box avoiding the holes so water runs in the top and out the bottom. You will know what I mean when you hold the box in your hand.

# Use a small drill bit from the inside of the coach first and then finish with the large bit from either side to prevent blowout on the fiberglass / wood. Especially a spade bit likes to do that.

# Stud-finder is your friend to double check.

# In a superb installation you would install a short piece of PVC conduit from inside the box into the roof leaving it up 1/4 - 1/2" above the bottom of the box. In case the lid seal would ever fail water will not go right away into the hole and into the roof. I did it this way as I have seen this very type of failure on an antenna box before. Alternative you can build up a dam of sealant just around the hole perimeter.

# Use a good cable gland for the wire penetration and only one wire per gland otherwise it will not seal properly.

That is all I can think of in the moment.
Joerg

Using a step drill works great for driilling fiber glass or plastic.
Scrpes a hole rathather than grabbing in ripping through.

[Alpine06]

This is one of those moments where you look back on something and think:” Why in the world did I not think of that” ? Awesome idea I used the step drill to make all the holes in the combiner box; it would have worked really well on the fiberglass.
Thank you for that suggestion!!

[Brianna]

Using a very long bit, i simply drilled a 3/16" pilot hole from the inside. Then drilled up (half way) from the bottom and then down the rest of the way from the roof with a cheap hole saw. Perfectly clean edges both inside and out.