1st solar system.

[skwirl]

Hello everyone, just joined.
I'm getting ready to install my first system in my shed. I'm still waiting on delivery of a few parts yet, I should receive them this week.
Heres what I got...
Batt is a Power Queen lifepo4 12.8v 100ah self heating unit.
Charge controller is a PQ unit also.
Panels are from Renogy. I bought 2 100 watt panels.
Hopefully I'll get a nice weekend and get everything setup and working. I'm sure I'll have questions at some point.
Free electric, what's not to like.

 

[400bird]

Congrats and welcome!
Post pics and questions when you get the parts.

 

[Bud Martin]

What is the spec of the PQ Solar charge controller?

 

[skwirl]

I havent recieved it yet. But its listed as being set for their lifepo4 batts. The spec on the site says 30 amp mppt controller. It should arrive this week. I'll know more then.

 

[ShaneC]

Have you picked out an inverter yet or is this purely for 12v loads?

 

[skwirl]

I have an inverter, a relatively cheap unit from tractor supply. It's a 1500 watt unit.
Should be ok, I think. I'm running 2 led lights, a small fan and this summer I'll add another temp controlled exhaust fan. Gets pretty hot in the shed.

 

[Rednecktek]

I would highly suggest another panel and maxing out that controller. A 12v 100ah batteri is about 1200wh, and you're only going to see about 75w per panel. With 2 panels in good sun you're looking at about 150w per hour. Multiply that by the rule-of-thumb 4 hours of GOOD sun per day and that's only half a battery. Adding a 3rd panel will help and is pretty cheap.

 

[Bud Martin]

I have an inverter, a relatively cheap unit from tractor supply. It's a 1500 watt unit.
Should be ok, I think. I'm running 2 led lights, a small fan and this summer I'll add another temp controlled exhaust fan. Gets pretty hot in the shed.

I would suggest to run 12V LED lamps and Fan instead of using the 1500W inverter to run them on 120Vac; it will more efficient since the inverter can easily draw 10~15W without loads running.

 

[skwirl]

I would highly suggest another panel and maxing out that controller. A 12v 100ah batteri is about 1200wh, and you're only going to see about 75w per panel. With 2 panels in good sun you're looking at about 150w per hour. Multiply that by the rule-of-thumb 4 hours of GOOD sun per day and that's only half a battery. Adding a 3rd panel will help and is pretty cheap.

I may end up with that, I want to see what happens with the 2 panels. I'm only in the shed on the weekends, no time during the week. But if this works out well, I may do some sort of portable batt bank for some of the house loads.

 

[skwirl]

I would suggest to run 12V LED lamps and Fan instead of using the 1500W inverter to run them on 120Vac; it will more efficient since the inverter can easily draw 10~15W without loads running.

I didnt know that, thanks. I'll try and check for a draw. I did buy a small meter that I found on DIY web page.
Lots to figure out.

 

[skwirl]

Question on using a fuse for the pv wires.
At what point with panel amp should a fuse be used?
I bought a fuse for the batt loads, but not the PV wires.

 

[Rednecktek]

Question on using a fuse for the pv wires.
At what point with panel amp should a fuse be used?
I bought a fuse for the batt loads, but not the PV wires.

For 2 strings/panels you don't need a fuse but a disconnect breaker can be handy for troubleshooting and service. At 3 you need a fuse for each panel string and it's not large. There is a rating on the panel called Vmp that is the max amperage the panel can produce so just go 20% over that with in line fuses or a combiner box.

I didnt know that, thanks. I'll try and check for a draw. I did buy a small meter that I found on DIY web page.
Lots to figure out.

If you're going to get a meter, might as well get something that can do DC amperage while you're at it so you can have all the useful functions. Amazon Commercial has a decent one or you can grab one from Harbor Freight for a little more. It's a REALLY handy tool for playing with solar.

I may end up with that, I want to see what happens with the 2 panels. I'm only in the shed on the weekends, no time during the week. But if this works out well, I may do some sort of portable batt bank for some of the house loads.

You'll find pretty quick that you need a lot more panel than you think, especially when weather gets involved. If nothing else it's a starter system. I was just suggesting it because you already have a 30a PWM controller and a 3rd panel would max that out to help compensate for the lower efficiency of the PWM over the MPPT. It also lets you re-use the panels when you go to upsize later.

 

[skwirl]

Thanks for that info. The cc I bought is a mppt type. I go look up some fuses and get them on the way.

 

[Rednecktek]

Thanks for that info. The cc I bought is a mppt type. I go look up some fuses and get them on the way.

Is it This Guy by chance? I don't know why PWM was stuck in my head. OK, If you have the money & space you could over-panel that guy to 400w of panels in a 2s2p and still be fine without needing fuses. That would buy you more production in lower light, winter, and max out what your SCC can provide to the batteries. For now with 2 panels you still don't need fuses and you could do a 2s or a 2p if you wanted.

 

[skwirl]

Is it This Guy by chance? I don't know why PWM was stuck in my head. OK, If you have the money & space you could over-panel that guy to 400w of panels in a 2s2p and still be fine without needing fuses. That would buy you more production in lower light, winter, and max out what your SCC can provide to the batteries. For now with 2 panels you still don't need fuses and you could do a 2s or a 2p if you wanted.

After doing some reading, I'm understanding a little more of this.
Here comes the question, lol.
Why dont I need fuses?
Is the scc internally protected?

 

[Rednecktek]

OK, the fuses we're talking about are actually kind of unique to solar. Most of the time a fuse is designed to protect the wires and devices down the line, but in this case the fuses are to protect the panels from each other. The amount of amperage coming out of 1 or 2 panels can't really do too much to hurt the other panel, but if you had say 3 or 5 or 12 panels and one of the panels had a short or other type failure, the current from the working panels could get shuffled through the bad panel and cause it to catch fire/melt/release greasy orange smoke.

So in the case of multiple parallel strings, the fuses are there to protect the other panels.

 

[skwirl]

I didnt get anything done yesterday on my system, lol. Girlfriend wanted a loft area in the shed, so got that done.
This morning I realized I'm missing some wiring. Need the wires to charge the batt from controller.
I just ordered those wires, terminal end kit, a meter and the power queen ac batt charger.
Be here next week for those items.

 

[skwirl]

I do have a few questions I havent read an answer for, so here goes.
Charge controller mounting. It's going on a piece of plywood inside shed, should I add a piece of aluminum sheet to help dissipate heat ?
I ask cause the info on overpannelling says the controller will operate near max. I know that causes heat.

Next question,
The panels are going on the roof of the shed. The roof is shingled. I was thinking of putting the Pv cables in conduit, to protect them from being rubbed thru. I'd use a white or gray colored conduit to try and limit heat.
What's the thoughts on this?

 

[MisterSandals]

I ask cause the info on overpannelling says the controller will operate near max. I know that causes heat.

With 200W of solar, even 20% loss would only be 40W of heat. Mounting it vertically and with washers or spacers to hold it off the wall surface will promote good air flow.

 

[Rednecktek]

I do have a few questions I havent read an answer for, so here goes.

OK, shoot.

Charge controller mounting. It's going on a piece of plywood inside shed, should I add a piece of aluminum sheet to help dissipate heat ?
I ask cause the info on overpannelling says the controller will operate near max. I know that causes heat.

As long as there is airflow between the SCC heat sink (fins on the back) and the plywood you'll be fine. If you're really paranoid you could throw some spacers on the screws between the plywood and the SCC to give it more air space. If you're in the desert you may want a small DC computer fan involved but otherwise you'll be fine.

Next question,
The panels are going on the roof of the shed. The roof is shingled. I was thinking of putting the Pv cables in conduit, to protect them from being rubbed thru. I'd use a white or gray colored conduit to try and limit heat.
What's the thoughts on this?

Make sure the pipe is large enough to easily get the wires through. The heat is going to be negligible so it's more about the hassle of pulling wires than anything else. White PVC will break down in the sun faster than the gray plastic.