Taking only part of your homes electrical service off grid

[BroncoLera]

Still...10 x 100watts = 1000watts = ~5-6 kWh / day as I see it. Bigger panels just mean more cells per panel. ( and sure...less cabling)

Watts is watts. Go with what you gots.

So if putting $45,000 worth of solar power in your home will never see a return on the investment, is it really worthwhile? Just for backup purposes?

As far as that other guy.....will who? I like that guy in Australia.....off grid garage. Great sense of humor too.

[bcroe]

As I see it, the present large scale grid connected PV solar was made possible by
mature economy of scale, and 3 technologies which all trace back to the transistor.

The 6 in square PV cell has a far better performance to cost ratio than earlier cells
(typically round) based more on electronics production.

Large Field Effect power transistors have been developed, and used to build
sophisticated, large PV array DC to line AC inverters.

The Integrated Circuit is used for micro processors or controllers to operate the
inverters.

When solar cell prices became within reach of the public, they were quite expensive
per watt. Panels targeted lower power apps such as the 12V RV industry, and
required an absolute minimum of electronics to control (no AC involved). The 100W
PV panel worked where there was no alternate line source. They may still be used
in places where the larger, far more economical panels will not fit. Also work for
educational purposes. Bruce Roe

[Ampster]

If you consider the panels recommended and tested by Will Prowse as "Toy Solar Panels" then I guess I have toy solar panels.
Thanks for letting me know that.

I am fairly active on Will's forum and he or most posters on that forum are pretty clear that 100 Watt panels are not economical for grid tie. They are used effectively on RVs and the recomendations are in that context. Space can be limited on the roof of an RV and smaller panels can be effectively used. Most RVs also run at 12 volts. An efficient GT inverter often runs string voltages of 300 volts or more.
As also noted by others the cost per Watt of 100 Watt panels is more than larger panels. In that case it is NOT the "cost of his toys that proves a man's wealth."

[SunEagle]

I read that 10-15 years ago, 100 watt panels was "the standard" since bigger panels were not as readily available and cost a small fortune.

Not sure of that is true.

The 100 watt panel may have been the standard that long ago. Most only had about 36 cells which generated 0.5 VDC each with a total or Vmp = ~ 18VDC. The science and cost of solar panels has changed a lot since then and you can find Grid tie panels above 300 watts.

[BroncoLera]

I read that 10-15 years ago, 100 watt panels was "the standard" since bigger panels were not as readily available and cost a small fortune.

Not sure of that is true.

[Mike90250]

.......Perhaps this forum is more geared towards people doing entire home systems and not hobbyist or DIY ers .....

Totally off grid here, self designed, hired "Larry with a ladder" to do the bulk of the wrenching.

[foo1bar]

If you consider the panels recommended and tested by Will Prowse as "Toy Solar Panels" then I guess I have toy solar panels.
Thanks for letting me know that.

Never heard of him before - but I see he has a youtube channel.
JMHO, but anyone who has a youtube channel I immediately assume that any recommendation they give is influenced by the manufacturer of what they're recommending. Maybe with free samples of the product, maybe with advertising, maybe with early access to new products.

Maybe they're great panels for some applications. But usually 100W or less isn't real useful for everyday living type situations IMO. They're likely to be something for helping keep your car battery charged, or "easy to setup solar panels" to supplement power when you're boondocking with your RV, or maybe supply power for a solar-powered water pump.

Perhaps this forum is more geared towards people doing entire home systems and not hobbyist or DIY ers

I am a DIYer. I installed my grid tie system on my home.

Since you're talking about payback time, I assumed you aren't looking at this as just a hobby.

[SunEagle]

Thanks.
I'm not really looking to go all in at this time.

I just happen to have 10, 100watt panels, several Epever and Xantrex charge controllers and a few LiFePo4 battery packs and was wanting to put them to use.

A small scale setup just to offset a small bit of electrical use and also (maybe more importantly) to be there during a power outage.

Perhaps this forum is more geared towards people doing entire home systems and not hobbyist or DIY ers

I have not been able to come up with a reasonable ROI for a full grid tie system. I do have a couple of small solar/battery systems but using one off grid will never pay for itself because the batteries just don't make sense unless your rate is above $0.30/kWh.

For emergency power I use my small solar/battery system but have a 12kw gen set for the home. The cost to run that the few times I may need it is still better then a large battery system to maintain.

[SunEagle]

If you consider the panels recommended and tested by Will Prowse as "Toy Solar Panels" then I guess I have toy solar panels.
Thanks for letting me know that.

Panels that are low in wattage (less than 200w) are not considered grid tie panels and in most peoples opinion they are 12v or "toy" type. They can be used for small systems but end up costing a lot to wire up so are not much thought of.

[bcroe]

I just happen to have 10, 100watt panels, several
Epever and Xantrex charge controllers and a few LiFePo4 battery packs and was
wanting to put them to use.

A small scale setup just to offset a small bit of electrical use and also (maybe more
importantly) to be there during a power outage.

A plan like that here, is to generate a small backup system, to run the antenna and
cable amplifiers, for the computer and a tiny battery TV. Maybe minimal LED lights
and some battery chargers. Running anything like major appliances will still require
starting the 3 decade old (but barely used) generator.

Experience with any size system will be highly educational. The big net metering
solar system here is useless in an outage. Bruce Roe

[BroncoLera]

One way to avoid PoCo agreements and actually save some energy, is to use
a mini split heat pump that accepts solar panel input, typically with AC line
backup. Such a unit may also be more efficient than an older air conditioning
unit now in place, doing its job just when you need it most, under max sun.

Such a heat pump can also save energy if you have resistance electric heat.
good luck, Bruce (completely heat pump operated) Roe

Thanks.
I'm not really looking to go all in at this time.

I just happen to have 10, 100watt panels, several Epever and Xantrex charge controllers and a few LiFePo4 battery packs and was wanting to put them to use.

A small scale setup just to offset a small bit of electrical use and also (maybe more importantly) to be there during a power outage.

Perhaps this forum is more geared towards people doing entire home systems and not hobbyist or DIY ers

[BroncoLera]

Off grid still requires paying for installation, permit fees, etc.
About the only thing you don't do is deal with the POCO.

10 of 100W panels? That sounds like you bought some toy/novelty panels.
Maybe you can set them up so you can charge some USB devices (phones, tablets, etc.)

If you want to do more than that, but you want to do off-grid, then you need a charge controller and batteries.
100 years to recoup is probably optimistic because batteries are expensive. Even if you count the panels as $0 cost.
And 4kWH per day from 1kW DC array is probably optimistic too - especially for an off-grid system because there's extra losses in charging the batteries AND you can only put so much energy into the batteries, so there's going to be some that will just not get collected.

If you consider the panels recommended and tested by Will Prowse as "Toy Solar Panels" then I guess I have toy solar panels.
Thanks for letting me know that.

[bcroe]

One way to avoid PoCo agreements and actually save some energy, is to use
a mini split heat pump that accepts solar panel input, typically with AC line
backup. Such a unit may also be more efficient than an older air conditioning
unit now in place, doing its job just when you need it most, under max sun.

Such a heat pump can also save energy if you have resistance electric heat.
good luck, Bruce (completely heat pump operated) Roe

[foo1bar]

Yes, that would be great. But after paying for installation, permits fees etc it'll take 100 years to recoup the investment.

I'm not concerned with back feeding the grid as they always will find a way to take your profits or savings.
I wanted to do something off the grid....and off the radar. Maybe 4 or 5 kWh per day.

Off grid still requires paying for installation, permit fees, etc.
About the only thing you don't do is deal with the POCO.

10 of 100W panels? That sounds like you bought some toy/novelty panels.
Maybe you can set them up so you can charge some USB devices (phones, tablets, etc.)

If you want to do more than that, but you want to do off-grid, then you need a charge controller and batteries.
100 years to recoup is probably optimistic because batteries are expensive. Even if you count the panels as $0 cost.
And 4kWH per day from 1kW DC array is probably optimistic too - especially for an off-grid system because there's extra losses in charging the batteries AND you can only put so much energy into the batteries, so there's going to be some that will just not get collected.

[BroncoLera]

The beauty of grid-tied solar is it maximizes the utility of your array. With our POCO, you can backfeed up to 1000watts of power without an interconnect agreement.
Just use a small grid-tied inverter or microinverters and start using the sun...

Yes, that would be great. But after paying for installation, permits fees etc it'll take 100 years to recoup the investment.

I'm not concerned with back feeding the grid as they always will find a way to take your profits or savings.
I wanted to do something off the grid....and off the radar. Maybe 4 or 5 kWh per day.

They do make inverters that do not back feed I believe?