My Small Solar Project in Progress

[SunEagle]

Thanks for posting those pics. You are giving me good ideas. Those are very nice!. My panels are 72 cells, very heavy panels, about 50 lbs with the 4x2 pieces of wood. I want to tilt them in the right position/direction to get the maximum power, possible I may install some wheels to move them around.

I built my panel supports about 4 years ago when I thought (I was wrong) getting panels in the 80 & 90w range would be smart. They are light and can be stored in my RV but cost about $2/w and yet only produce about 340watts total for the 4. Getting the larger panels makes more sense but they can be an issue when it comes to making them portable yet sturdy.

[john95]

I built my panel supports about 4 years ago when I thought (I was wrong) getting panels in the 80 & 90w range would be smart. They are light and can be stored in my RV but cost about $2/w and yet only produce about 340watts total for the 4. Getting the larger panels makes more sense but they can be an issue when it comes to making them portable yet sturdy.

My idea is to make portable the batteries on wheels, with the charger and the Inverter so I can take power closer to where and when I need it to avoid long runs of cables. I could even have an extra set of batteries/charger/inverter charging while I use the one charged the day before.

[SunEagle]

My idea is to make portable the batteries on wheels, with the charger and the Inverter so I can take power closer to where and when I need it to avoid long runs of cables. I could even have an extra set of batteries/charger/inverter charging while I use the one charged the day before.

That is what I built. While my first set of 12v 50Ah AGM batteries and are parallel wired my next set will be a couple of 6v 232Ah batteries wired in series.

I have a fiberglass basket with the batteries inside and a wood cover that has my cheap 30A PWM CC, a DC disconnect and my Xantrex inverter. All that sits on one of those hand carts I purchased from HF. It is heavy but it can be moved.

[john95]

It will work well in Alaska in the winter. The panels are nearly vertical, and they should be tilted to be perpendicular to the sun, Otherwise, you are only going to get 40% of nameplate or less.

Mike, so according to the data of these 320 watt panels (see attachment), how many watts should my outback FM80 charger be getting from these 4x 320 watts panels? What readings should I get on my charger? Thanks.

PD. The panels are wired 2S2P (2 in series and 2 in parallel).

[littleharbor]

John, do yourself a favor and connect one panel up to a multi meter. Set it for amperage. aim it toward the sun, now tilt it up and down and watch the amperage rise and fall with the changing orientation to the sun. Any panel, even in doors will show an open circuit voltage close to its rating. In a perfect world you would see 17.4 amps and 74.8 volts from that configuration. If it were really cold and bright sunny skies you might see more, but expect less. Watts is voltage times amperage. do the math to find out what you are actually getting into your batteries. When your CC is in bulk charging you should see all available power going into the batteries/loads. When in absorb mode you will see less.

[john95]

John, do yourself a favor and connect one panel up to a multi meter. Set it for amperage. aim it toward the sun, now tilt it up and down and watch the amperage rise and fall with the changing orientation to the sun. Any panel, even in doors will show an open circuit voltage close to its rating. In a perfect world you would see 17.4 amps and 74.8 volts from that configuration. If it were really cold and bright sunny skies you might see more, but expect less. Watts is voltage times amperage. do the math to find out what you are actually getting into your batteries. When your CC is in bulk charging you should see all available power going into the batteries/loads. When in absorb mode you will see less.

Thanks, I'll do that when I get home, I'm at work now.

The charger IN is 79 V
OUT is 29.6?
Absorbing

[Mike90250]

Mike, so according to the data of these 320 watt panels (see attachment), how many watts should my outback FM80 charger be getting from these 4x 320 watts panels? What readings should I get on my charger? Thanks. PD. The panels are wired 2S2P (2 in series and 2 in parallel).

Well aimed at solar noon on a clear cool day, about 1,000 watts average hot sunny day, maybe 850W. As you have them in the pic, about 300W..

[littleharbor]

Thanks, I'll do that when I get home, I'm at work now.

The charger IN is 79 V
OUT is 29.6?
Absorbing

29.6 is probably absorb voltage. Depends what you have it set at. Check it at mid morning after you have drawn down your batteries to 70 - 80% state of charge the night before. You'll likely see something in the 25 - 27 volt range and all available amperage going to charging and loads.

[john95]

Well aimed at solar noon on a clear cool day, about 1,000 watts average hot sunny day, maybe 850W. As you have them in the pic, about 300W..

In the best position gets 7 Amps maximum, in the position the I have it in the pic gets 6 Amps.
So even if I get 6 Amps x 3=18x72=1296W

The panels are in 2S2P meaning that 2 panels double 6 Amps to 12 and the other 2 in series stay on 6 amps, this is 18 Amps total.
These are real life numbers at 5:15pm California. Rated curret of the panels is about 9 Amps.

[Mike90250]

In the best position gets 7 Amps maximum, in the position the I have it in the pic gets 6 Amps.
So even if I get 6 Amps x 3=18x72=1296W

The panels are in 2S2P meaning that 2 panels double 6 Amps to 12 and the other 2 in series stay on 6 amps, this is 18 Amps total.
These are real life numbers at 5:15pm California. Rated curret of the panels is about 9 Amps.

Hang on to those magic 1296W panels. You have 1280 nameplate watts of panels. Normal expectation when toasty in the sun is about 80% of that(1,000w), when well aimed,
I cannot explain how you are surpassing nameplate power, other than measurement or math error.

[max2k]

In the best position gets 7 Amps maximum, in the position the I have it in the pic gets 6 Amps.
So even if I get 6 Amps x 3=18x72=1296W

The panels are in 2S2P meaning that 2 panels double 6 Amps to 12 and the other 2 in series stay on 6 amps, this is 18 Amps total.
These are real life numbers at 5:15pm California. Rated curret of the panels is about 9 Amps.

panels in series double voltage, not current so if each of them is 36 V x 6A for 2S2P you'd get: 6x2 x 36x2 = 864W for 4 panels used.

[littleharbor]

[QUOTE=john95;n357405]


The panels are in 2S2P meaning that 2 panels double 6 Amps to 12 and the other 2 in series stay on 6 amps, this is 18 Amps total.
QUOTE]

The way I read this has me confused. Do you have 2 panels in parallel , connected to the controller, then, the other two in series, connected to the controller? I may be comprehending your words incorrectly but if that's how you have them connected it's time to start over.

[Sunking]

The panels are in 2S2P meaning that 2 panels double 6 Amps to 12 and the other 2 in series stay on 6 amps, this is 18 Amps total.
These are real life numbers at 5:15pm California. Rated curret of the panels is about 9 Amps.

No Sir that makes no sense and why you are getting so much flack.

[john95]

[QUOTE=littleharbor;n357451]

The panels are in 2S2P meaning that 2 panels double 6 Amps to 12 and the other 2 in series stay on 6 amps, this is 18 Amps total.
QUOTE]

The way I read this has me confused. Do you have 2 panels in parallel , connected to the controller, then, the other two in series, connected to the controller? I may be comprehending your words incorrectly but if that's how you have them connected it's time to start over.

This is how I have the 4x 320 watt solar panels wired:
Each panel produces at least 6 Amps
2 are wired in series and 2 in parallel to get 72 Volts all combined. From all 4 I get a positive and a negative that are attached to the charger.

The readings on the charger @ 12:00pm are:

IN:
68.6 V
4.9 Amps

According to these previous readings the panels should be producing 336.14 watts?
Even at 9 Amps max which the panels are rated will not produce even 80% of their capacity.

OUT:
25.5 V
12 Amps

[littleharbor]

Your description wording is still confusing. You should have 2 series wired PAIRS which will have one positive and one negative wire coming off of. Now you should have the two positive leads, one from each PAIR connected to each other by way of a combiner box or parallel branch connecter . You should have the two negative leads from each pair also connected together in the same fashion. when all is said and done you would have a single positive and a single negative wire going to your charge controller.
I hope this is making sense and this is what you have. because what I am hearing is you have one series wired pair and one parallel wired pair connected to your controller. The key point being that you start with 2 pairs of series wired panels and these pairs are then parallel wired or combined.