Any electricians help regarding off grid solar power lighting

[Grower2020]

If I want to run an 800 watt draw Led grow light from solar directly to an inverter without battery banks to save money on elec what would be the basic slightly overkill setup I would need . Brand of inverter or panels I'm not fussed on just the specs of inverter and how many panels I would need and whether to rig it in series or parallel. Thanks in advance

 

[bobrown14]

Not a simple answer and its going to depend on your panels and your setup.

You want to run OFF GRID a battery is helpful. You can get a nice size deep cycle made for what you want to do. Look to batteries that are made for larger boats (not bass boats although that would work). You can get a big deep cycle for a few hundred that is made for this type of application.

We have a 27kw hybrid system - Grid tied and batteries. So it runs off the batteries at night until the batteries get discharged then system switches back to grid when batteries discharge down to like 15-20%. The next day batteries charge while we generate and repeat.

We have 2 sets of inverters. One for batteries and one to convert to AC grid so we can feed back. Also inverters work the opposite when the grid goes down converting battery DC to 120v ac keeping lights on for a little while. We probably can get up to 8 hrs on batteries. Should be better but weed have to shut a lot of stuff (not lights) off. I don't know when the grid goes down. Unless it does and our batteries run out several hours later.

Panels are hooked up series and parallel - this is done to keep size of wires/wire runs down to manageable sizes.

I looked around you can get an 1800w solar off grid system without a battery. Problem comes when there's no sun. You won't have enough energy to run your lamps.

That's the downside of off grid and not battery.

The industry still going thru growing pains now with all of this. Tesla in the biz charging crazy money for batteries too as are others. Problem is they are not able to meet their marketing claims. Which is pretty much industry standard nowadays. Companies want their batteries to perform but they are not there yet.

We have a salt water battery that is 100% recyclable and generates ZERO heat and cant start on fire.

 

[Emilya Green]

I will echo what Bob said... without batteries, and without grid backup, there will be large chunks of time, especially in the winter, when you will not be able to run your lights. Being able to count on your lights for even 12 hours at a time will be problematic. Also be prepared for partly cloudy and overcast days when even my large $26,000 system, would not be able to run your lights full time. Solar is nice and can definitely help save money on electricity costs, but it is not yet a standalone off grid capable solution, especially in the real world when you have to deal with shadows from your neighbors trees, snow on the panels and less than full sun days.

Here are the slap in the face numbers... I own a system capable of 7.68 kWH per day... real world, I get about 5.2 kWH on a bright sunny day after inverter and wire run losses. 800w x 12 hours, that alone is 9.6 kwh of energy. I have a 600w light, a 500w light and a 300w light... so I never will generate all the energy that I am using, and the powers that be would not let me build a solar system capable of generating more than what I have now due to rebates and all the incentive programs that were designed to draw me in. I told them I needed 18KWH... they laughed and said no.

 

[BeccaBuds]

Check out Renogy on eBay. Without batteries your power output is pretty much controlled by the weather. That said, I would plan on a system that provides at least double the load you expect. Add several hundred more watts for environmental controls for the garden. 3kW system, min. 4kW with batteries and you can run power tools.
Also note monocrystalline cells put out more power than amorphous.

 

[Grower2020]

What about those grid tie inverters ? The ones that plug straight into the wall from the inverter? If I run it on a stand alone circuit so it doesn't overload the already used circuits in the house? As @Emilya said I won't be able to put back in the same power I'm drawing but it will cut my costs right ?

 

[Emilya Green]

What about those grid tie inverters ? The ones that plug straight into the wall from the inverter? If I run it on a stand alone circuit so it doesn't overload the already used circuits in the house? As @Emilya said I won't be able to put back in the same power I'm drawing but it will cut my costs right ?

every little bit helps... it just depends on the time of year how much that will be.

 

[Grower2020]

every little bit helps... it just depends on the time of year how much that will be.

Cool thanks I've been reading mixed comments on the safety of the grid ties that plug into the wall . They seem fairly safe to me but some others don't think so ?

 

[Emilya Green]

You can not legally or safely tie into the electrical grid by yourself. Electrical contractors have licenses for a reason. Charging separate batteries from the mains and then using separate inverters is a common practice though... I do that with my ham radio station and my aquarium, so that they never go without power. I rest assured that part of that power does indeed come from my solar panels.

 

[bobrown14]

Grid tie is a safety issue. There are regs that insure safety for linemen in case grid is down and workers working on the line.

I'm feeding 27kw max to the grid.

Lineman thinks the wire is cold and bam....

When the grid goes down my system needs to be clamped off as soon as the grid goes down.

It will sense the grid is back on and IF I still have battery power my inverters will switch onto the grid and start sending/receiving power.

If my batteries are discharged completely, I have to manually switch everything back on.

My inverter clamps the line @255v or 210v and wont check to reconnect for 5 minutes.

We sometimes get more than 255v from the grid when the supply company gives too much power to the grid on really cold or really hot periods.

We loose power usually in the summer on hot sunny days and wont know we were running on batteries.... until the power rolls off. ... then panic. Lol

That feeling like when your inna boat and you loose power.... at night.

 

[Grower2020]

Grid tie is a safety issue. There are regs that insure safety for linemen in case grid is down and workers working on the line.

I'm feeding 27kw max to the grid.

Lineman thinks the wire is cold and bam....

When the grid goes down my system needs to be clamped off as soon as the grid goes down.

It will sense the grid is back on and IF I still have battery power my inverters will switch onto the grid and start sending/receiving power.

If my batteries are discharged completely, I have to manually switch everything back on.

My inverter clamps the line @255v or 210v and wont check to reconnect for 5 minutes.

We sometimes get more than 255v from the grid when the supply company gives too much power to the grid on really cold or really hot periods.

We loose power usually in the summer on hot sunny days and wont know we were running on batteries.... until the power rolls off. ... then panic. Lol

That feeling like when your inna boat and you loose power.... at night.

Laughing at last couple of comments lol
In my honest opinion it's so tempting to save money and use one anyway because it has the island safety feature where it shuts off feeding into the grid when the grid goes down.
And I'm home all the time anyway so if the power goes out or I made a quick trip into town I can easily pull the plug on the inverter to the wall so that there is no feed into the line and putting anyone's life at risk. I think it would be 100% safe In my hands. But on the other hand I still don't know if I will do it or not

 

[Grower2020]

You can not legally or safely tie into the electrical grid by yourself. Electrical contractors have licenses for a reason. Charging separate batteries from the mains and then using separate inverters is a common practice though... I do that with my ham radio station and my aquarium, so that they never go without power. I rest assured that part of that power does indeed come from my solar panels.

Nice rig

 

[Edzzed]

Go to the wreckers, see if you can buy a written off Tesla.