Solar power

Greenman

Lifer
Oct 15, 1999
20,281
5,054
136
I'm going to install a 6 to 8 kw solar system on my house. Being a general contractor (and a pretty good electrician) I'll obviously do it my self. But I'm starting from scratch, I don't know anything about the different brands of panel or inverts.
Have any of you already done the homework on solar systems? I'm aware that a few hours and some googlefoo would answer all of my questions, but if one of you has already done the leg work I'd rather pick your brain than reinvent the wheel.
 

herm0016

Diamond Member
Feb 26, 2005
8,385
1,011
126
Solarblvd.com has pretty good prices on pallets of panels I have purchased from them with no issues for systems on campers. Have used solarcynergy and renogy panels, I think most of them come from the same few places. I have done 2 systems on campers, and we have a 4500 watt system on our house. I would like to upgrade our inverter with a new one with storage and off grid run capability. Our system is about 20 years old and will not run without grid sync.
 

Brovane

Diamond Member
Dec 18, 2001
5,271
1,441
136
I'm going to install a 6 to 8 kw solar system on my house. Being a general contractor (and a pretty good electrician) I'll obviously do it my self. But I'm starting from scratch, I don't know anything about the different brands of panel or inverts.
Have any of you already done the homework on solar systems? I'm aware that a few hours and some googlefoo would answer all of my questions, but if one of you has already done the leg work I'd rather pick your brain than reinvent the wheel.

Be careful with a DIY and the 30% Solar Tax Credit. You will want to make sure you get the Tax Credit.

I had an 8kw system installed a couple of years ago.

For your local Utility, have you researched what the Solar Plans are? How does your utility do Net Energy Metering?

Are you going to do ground mount panels or roof mounted?
 

Greenman

Lifer
Oct 15, 1999
20,281
5,054
136
Solarblvd.com has pretty good prices on pallets of panels I have purchased from them with no issues for systems on campers. Have used solarcynergy and renogy panels, I think most of them come from the same few places. I have done 2 systems on campers, and we have a 4500 watt system on our house. I would like to upgrade our inverter with a new one with storage and off grid run capability. Our system is about 20 years old and will not run without grid sync.
Pretty much everything I clicked on their site said "out of stock". Prices look good though.
 

Red Squirrel

No Lifer
May 24, 2003
67,195
12,025
126
www.anyf.ca
I'm not familiar with any brands but been doing some research myself and have built a small portable system.

Basically you need:

- Solar panels with a Vmp higher than your nominal battery voltage, Vmp is the voltage output when it's operating at it's most efficient output. Since they are constant current and not constant voltage, the voltage changes based on output/draw and there is a sweet spot where it's the most efficient (more about later). So ex: a "12v" panel might be like 16 volts. You want it to be higher than actually 12v because you need to account for the actual charge voltage of the battery and efficiency losses. You can of course string multiple together in series and then multiple sets (of equal size/voltage) in parallel.

- MPPT charger controller. There are various types, but go with MPPT. That's for Maximum Power Point Tracking. What this does is it will regulate the output voltage of the panel (by drawing more or less power) so that it hits the best efficiency curve. So basically it will try to squeeze out as many watts as it can out of it based on the condition. This is always tracking, to make up for changes in sun light conditions.

With these two devices you now have a fairly regulated output voltage. Next two items:

- Inverter. This is what will give you your AC power. There's different types like simple 120v ones and 120/240 ones.

- batteries: This is important because the output of solar is rather sporadic due to clouds etc, the batteries will store the energy and then continue to provide when a cloud passes over, or at night,depending how big you want the battery bank. You want at least a small battery bank to start with. Gold cart batteries are actually pretty decent.

- Rectifier(s): This is optional, but basically if your solar is not producing enough power you could then use generator or hydro service to top up the batteries.

Then choose a nominal system voltage. The main ones are 12, 24 and 48. For a big enough system I'd go 48. At a higher voltage you are drawing less current so you don't need cables as big as if you had the same wattage system in 12v.

Keep in mind this info is just based on my own basic knowledge and some research so I could be off on some things. Of course you can also skip the batteries and charge controller and use a grid tie inverter. Personally I'm not really a fan of that style setup because you're basically in the dark if the power goes out and you're selling all your power only to buy it back at a higher price later. It makes more sense to store it and be a bit grid independent.


The biggest issue I've found is that solar panels are incredibly expensive to ship due to their size. I found a few sites that ship to Canada but shipping is like double the cost of the panel itself. When I'm serious about it I will probably try to source out a reliable source for cells and then build my own as even if I need to buy any special tools it will end up cheaper.
 
Last edited:
  • Like
Reactions: killster1

herm0016

Diamond Member
Feb 26, 2005
8,385
1,011
126
Keep in mind this info is just based on my own basic knowledge and some research so I could be off on some things. Of course you can also skip the batteries and charge controller and use a grid tie inverter. Personally I'm not really a fan of that style setup because you're basically in the dark if the power goes out and you're selling all your power only to buy it back at a higher price later. It makes more sense to store it and be a bit grid independent.

This is not necessarily true. In most places, your meter just counts both ways and your rate is lower at night than during the day if you do have time of use pricing. We just got time of use, and we are selling back at the highest rate and using at the lowest most of the time.
If you don't go for grid tie it becomes very difficult to use what you are generating efficiently. How do you use the electricity you produce? have one outlet in the house hooked up to an inverter?
Some grid tie inverters now have options for a backup / storage battery that will prioritize charging and will work when the grid is down, but still allow the efficiency and usefulness of using the grid to store your extra power and not having 2 systems that are not tied together.


also, trying to tie a storage system into the grid without using a grid tie controller/inverter can have issues because you are not synced to the frequency of the incoming power.
 

Red Squirrel

No Lifer
May 24, 2003
67,195
12,025
126
www.anyf.ca
This is not necessarily true. In most places, your meter just counts both ways and your rate is lower at night than during the day if you do have time of use pricing. We just got time of use, and we are selling back at the highest rate and using at the lowest most of the time.
If you don't go for grid tie it becomes very difficult to use what you are generating efficiently. How do you use the electricity you produce? have one outlet in the house hooked up to an inverter?
Some grid tie inverters now have options for a backup / storage battery that will prioritize charging and will work when the grid is down, but still allow the efficiency and usefulness of using the grid to store your extra power and not having 2 systems that are not tied together.


also, trying to tie a storage system into the grid without using a grid tie controller/inverter can have issues because you are not synced to the frequency of the incoming power.


Basically you would choose a load (maybe all the constant run stuff like fridge, furnace etc) and have it run off the solar. You then have a rectifier to charge batteries if solar is not keeping up.

With grid tie the issue is, you get to use the power you need immediately, ex: it won't go to the grid if you are using it, but when you're not, it goes to the grid. 5 minutes later a cloud rolls by, and now you need to rely on grid power, so that 1kwh you just sold to the grid at 5 cents or w/e they pay, you are now buying it back at 30 cents or w/e you pay. But with a battery setup you're always running off batteries and putting power into it.

I guess an ideal setup would be to have some grid tie inverters that run off the batteries, that you setup to only run if batteries are fully charged and solar panels are still producing.

This also all depends on your rates. If they are buying solar power at the same price you pay or close, then perhaps it does indeed make sense to just do grid tie as the initial cost is cheaper.

I looked into it where I am and they won't even buy power off you, they show the grid as being at capacity for buying power. So it really depends on area too. I was toying with idea of starting a small solar farm but it's not viable where I want to put it.
 

herm0016

Diamond Member
Feb 26, 2005
8,385
1,011
126
Most places have net metering, not what you describe. Say you use 500 kwh per month, you produce 300, then you pay for 200. No buying and selling back and forth. This is how ours was for 20 years. Last owner of the house put owned solar on about 20 years ago.

Now we get "credits" during the day that are worth let's say 1.1 per kwh that is put into the grid, and then we get to use those credits at night at a 1 to 1 ratio. It's a trial of a new time of use structure for our utility. This has been the last few months, most meters do not have this kind of live measurement, our old "smart" meter was not capable and the utility upgraded to the latest when we started this trial pricing program.


I have also designed several systems.
 

herm0016

Diamond Member
Feb 26, 2005
8,385
1,011
126
Basically you would choose a load (maybe all the constant run stuff like fridge, furnace etc) and have it run off the solar. You then have a rectifier to charge batteries if solar is not keeping up.

and put up with significant conversion losses.
 

PssstComeHere

Junior Member
Sep 2, 2018
2
1
1
New here so be patient. I want to use solar in my yard for lighting, accent lighting. Sidewalk lighting but not limited to just that. You know those little stake light. My question is could I just not use a solar panel battery and just go D/C for all the lights? Or is there a reason I need to go from D/C to A/C. I am new to all of this. Any help would be appreciated.
 

Raizinman

Platinum Member
Sep 7, 2007
2,349
71
91
meettomy.site
I'm in the middle of my solar install. We signed with a solar company after interviewing 7 or 8 of them. Wow, what a difference in prices and service. Our power company even suggested many solar companies to interview. The solar company took care of all the engineering, designs and permits. We just finished that stage. Next is ordering the panels. We picked JASolar brand panels. We will be installing 42 panels (ground mount) at 355 watts each making a total of 14,910 watts. In our area, we are limited to a maximum of 15,000 watts. We will be grid tied and will have ability for batteries in the future, but no batteries at this time. In our area, whatever we overproduce in the day we get back at night. Only problem is that any excess at the end of the month is purchased back by the power company at the wholesale electrical rate of around 2 cents per KwH. Not real good since we are paying around 12 cents per KwH, but that is why you don't want to overproduce. Like you, I was going to do the install myself, but with all the red tape and such, we decided to let another do the work.
 

herm0016

Diamond Member
Feb 26, 2005
8,385
1,011
126
New here so be patient. I want to use solar in my yard for lighting, accent lighting. Sidewalk lighting but not limited to just that. You know those little stake light. My question is could I just not use a solar panel battery and just go D/C for all the lights? Or is there a reason I need to go from D/C to A/C. I am new to all of this. Any help would be appreciated.

No reason to convert to AC. Keep it all at 24 or 48 volts. this will keep limit your conversion losses and line losses. see if you can find an old forklift battery or just use a bunch of deep cycles.
 

Raizinman

Platinum Member
Sep 7, 2007
2,349
71
91
meettomy.site
I'm in the middle of my solar install. We signed with a solar company after interviewing 7 or 8 of them. Wow, what a difference in prices and service. Our power company even suggested many solar companies to interview. The solar company took care of all the engineering, designs and permits. We just finished that stage. Next is ordering the panels. We picked JASolar brand panels. We will be installing 42 panels (ground mount) at 355 watts each making a total of 14,910 watts. In our area, we are limited to a maximum of 15,000 watts. We will be grid tied and will have ability for batteries in the future, but no batteries at this time. In our area, whatever we overproduce in the day we get back at night. Only problem is that any excess at the end of the month is purchased back by the power company at the wholesale electrical rate of around 2 cents per KwH. Not real good since we are paying around 12 cents per KwH, but that is why you don't want to overproduce. Like you, I was going to do the install myself, but with all the red tape and such, we decided to let another do the work.

Just a quick update. Last year for November we used 1250 kWh. We are now about half way through November and our Solar production is a bit over 700 kWh. We are expecting that solar will take care of virtually all our electrical needs.
 

Red Squirrel

No Lifer
May 24, 2003
67,195
12,025
126
www.anyf.ca
I recently put a small 400w system for my shed, mostly as a pilot project but also because I just wanted to do something different for lighting etc. Have room for 3kw on my house, but that's it. My property is too small and awkward for ground mount and not a lot of spots that get sun long enough. That one section of roof gets sun but rest get too many shadows. So I think the money that would go towards a 3kw system I'm better off saving to buy an off grid property as that is my ultimate dream. Then I'd have more room to build a proper ground mount system that is easier to access for maintenance and snow removal.

Still early to gauge and other than manually looking at the charge controller as I don't have any monitoring setup yet, but I figure I get around 50-60w out of the system on a good day. My panels face west so it's not optimal, and we don't get lot of sun here, so basically I'm relying on light from the sky in general and not direct sun. There was like 1 day with actual sun since the system has been installed.

As for going all DC, the issue with that is DC stuff is harder to find and more expensive. Breakers, switches, fuses, etc. Need thicker wiring for everything too. If you go DC straight to AC, then all the stuff you need for AC is easy to get at any hardware store, and the wiring can be smaller as the voltage is higher too. When I finish up wiring my system I will pretty much make it purely AC except the Raspberry Pi that monitors and controls everything will be DC. That way it can shut off the inverter but keep running.

One thing with a solar setup is snow removal too, that's extra work you need to be ready for. I've been going out mostly every day to clear the snow off. I need to build a platform to stand on so it can bring me high enough as right now I can barely reach it with the long pole broom. Something to consider if doing a whole house you need a way to get to them to take snow off.