• Biblical Families is not a dating website. It is a forum to discuss issues relating to marriage and the Bible, and to offer guidance and support, not to find a wife. Click here for more information.

Modifying Leased Solar

NetWatchR

NetWatchR

Member
Real Person
Male
We've recently had solar installed via Solar City. It provides 100% of our power, so far. It is designed, for safety reasons, to shut down the inverter when the Mains go offline.

I verified this myself by disconnecting the mains breaker and then fired up the inverter. It refused to engage because it could not detect "the grid".

The question is, how can I go about bypassing or fooling the inverter into thinking there is a grid in order to power the house? I'm thinking I could connect a small generator just to get the 240 to the panel and then the inverter should see that as "the grid".

This is not intended to be a daily activity, just in case we have a long outage. We have freezers that can only go a day or two without power before spoilage.

I do have some rudimentary electrical knowledge but self taught and may be missing something.

Comments on this idea or any other ideas?
 
First, if this is only for emergency operation, buy a small gas generator to run the freezers. Cheap, easy, reliable, done.

Second, unless you are an experienced electrician, don't make any major changes yourself. You're dealing with more than enough power to kill you.

Third, do not try to "fool" the inverter. See previous comment about "more than enough power to kill you".

Solar is not reliable, insofar as it doesn't work at night, so you need to add a battery storage solution. Your solar array (and/or the grid) feeds the batteries, the batteries feed the inverter, the inverter runs the house.

You mentioned Solar City. Your lease probably does not give you the option to go off grid, as selling the surplus electricity back to the grid is part of how they make money. Instead, give them a call and tell them you want to add a battery backup. They have systems designed to work with the equipment you already have (which is to say, will not kill you, burn down your house, take over your garage, etc).
 
If it's leased equipment, don't mess with it. If you stuff it up you'll have a major legal mess on your hands. Quite apart from the risk of killing yourself!

I agree you need batteries. Batteries don't just run the system overnight, they act as a buffer during the day. In other words, say you're using a lot of power, and then the sun goes behind a cloud. The power needs to come from somewhere else for a few minutes, otherwise the voltage would drop and various appliances could even break. Or, if you switch on something with an electric motor that has a large power requirement for the first few seconds as it starts (e.g. a fridge or freezer), more than the panels can provide, that start-up power has to be drawn from somewhere. Currently it comes from the grid. Or it could come from batteries. But it can't come from nowhere. You need either the grid or batteries as a buffer to cover fluctuations in both generation and load to give reliable steady power during the day - and then to provide all your power overnight.

The best option is to talk to the provider as Jeff suggested and get a proper battery backup installed.

The cheaper option is to forget the panels entirely and set up an independent backup system - a generator, or even cheaper an inverter running off your vehicle battery. You can even have a full home battery backup system that is completely independent, float-charges from a 120V plug in your house, and then if the power fails you just plug into it. To start thinking laterally about this, see this webpage and listen to a few of the radio shows mentioned, they are all brilliant.
http://solar1234.com/

The long-term prepper version of that would be to make your own home battery backup system as outlined on that website, but also add a solar charge controller to it that would plug into your solar panels, or a small number of them, and have the appropriate cables just sitting around. So if the grid went down long-term, you'd simply climb on the roof, unplug the panels from the house inverter and plug them into the solar charger for your batteries. You'd need a bit more electrical knowhow to make sure you got the voltages right, but it's not too difficult. I wouldn't do this though unless things really were down near permanently, the lease company would get rather upset about it, and depending on your local laws and the peak voltage of the panel array it would probably be illegal.

I have a fully off-grid home solar power system, feel free to ask any questions.
 
Thanks appreciate the multifaceted feedback. Was just wondering what I could get away with on a longer grid down scenario without actually touching the leased hardware. Looks like the simple solution really would be to use the small Gen hooked directly to the freezers.
 
The least expensive and less noisy is an inverter connected to your vehicle (diesel engine is best for ultra efficient idle fuel usage). On a vw tdi you can idle all day and almost not notise a dent on fuel quantity.
I have done it before and connect it to a long heavy extension to the freezers etc.
Also, have a modest off grid system on part of the house, for 12v cob led light fixtures etc. Hope to add a bigger one for the well with bigger battery capacity.

Don't keep batteries inside dwelling. I had made that mistake and regret it.
Batteries I would say are the heart of a system, most maintenance too.
Cheap gas generatos with carbs, gum up and are hart to start, unless you are super dilligent, not me. Lol
Gas here in the states is more chemically unstable because of modern cracking and ethanol.
Diesel is best for long term standby, propane is cheaper but more finite in emergencies because of supply and tranfer issues.
Diesel is about 130,000 btu per galon, propane 90k. Pure gas 105k, ethanol only 60k. So those are your conventional fuel choices.
There is a reason commercial transport uses diesel and kerosene.
We hope to go half off grid. Central AC is a beast (about 5000 watt hour just for the outside condenser unit on a 3 ton) and not cost effective to do for the average people. At least this little guy.
Hope this is useful..
 
Last edited:
You can hack the leased one with a tiny inverter where grid gets detected but, have to know what you are doing technically and legally.
If you do, make sure you are not back powering grid or can accidently kill a line guy doing repairs.
If there is no battery, of course the system is useless at night..
 
What are the best batteries for the money?
Something one person can lift..
Here we use lead acid because we have them. Next time hope to get the best for the money we can still move and maintain.
 
Last edited:
Start with a small system and grow from there. This way you are more encouraged and learn the most first, less mistakes.
Ebay has decent cob led panels and solar ones too. I don't know how to post a pic of a fixture i moded here.. But they are bright and affordable. You can retrofit in older fluorescent fixtures and will look like normal commercial or create your own.
More light per watt than t12 and last a long time. Anyways.. Stay tuned.. Lol
Our admin here is quite knowledgeable on this also.
 
Last edited:
cubanito said:
What are the best batteries for the money?
Something one person can lift..
Here we use lead acid because we have them. Next time hope to get the best for the money we can still move and maintain.
Click to expand...
Lithium ion. They make some where two batteries replace two large conventional battery banks. The only issue that I've found with them is cost. They can be about 2G each.
 
NetWatchR said:
We've recently had solar installed via Solar City. It provides 100% of our power, so far. It is designed, for safety reasons, to shut down the inverter when the Mains go offline.

I verified this myself by disconnecting the mains breaker and then fired up the inverter. It refused to engage because it could not detect "the grid".

The question is, how can I go about bypassing or fooling the inverter into thinking there is a grid in order to power the house? I'm thinking I could connect a small generator just to get the 240 to the panel and then the inverter should see that as "the grid".

This is not intended to be a daily activity, just in case we have a long outage. We have freezers that can only go a day or two without power before spoilage.

I do have some rudimentary electrical knowledge but self taught and may be missing something.

Comments on this idea or any other ideas?
Click to expand...
Hey very cool you are into solar. We are too here in the Philippines. Electricity is super expensive here.
I built my own solar panels using 1/8" glass (a mistake by the way), and using old broken solar cells 80%+ in tact I got on ebay and other places. It was a great learning experience. I'm still making them. I have some of my panels on a battery that I use for lighting, security (TBD), and emergency fans (dengue is a real problem here). I also made my own circuit to turn the lights on and off when we are out for day and night.

I have the other panels coming in thru Grid-tie inverters.

Now to answer your original question.
If you use a generator it must be a pure sine wave generator otherwise the circuitry in your grid-tie inverters won't be able to match the wave form of the power made by your generator (modified sine aka "dirty power") and it still won't trick the inverter into thinking mains is on.
***WARNING* SAFETY ISSUE ***
if you go this route you have to have:

1-a switch to disconnect your house from mains
2-the power from the generator must come in through the same breaker that mains does otherwise you can have an issue of power flow reversing through breakers, or bypassing breakers (melt, fire etc).

If you don't do number 1, you can end up electrocuting some guy from the power company who is working to restore power
(this is why the grid-ties go down in the first place). solar can actually power the mains in your block.
See what I mean? Blamo. Someone can get hurt.
I don't know your knowledge level and I know whenever someone makes a post like this lots of people will say don't do it, it's too dangerous etc. but I'm assuming you've got some intelligence so there is your answer.
Follow those 2 items I sent religiously and you'll should have your solution. You may need to check your specs to be sure there isn't a min Amperage requirement availability from mains and then make sure your generator can supply that.
Remember, gotta be pure sinewave because that's what the electric company sends and that's what the grid-tie circuitry is looking for.
There are also ways to pop open your invertor and bypass the safety circuitry but that'll void you.
BTW most communities don't allow in zoning to do what you want to do.

Let us know how it turns out!
-Ish Chayil "Man of Valor"
 
Last edited:
Auch.. But we we had a budget for them.. If we get more serious about it, maybe?.. I would hope we get at least 5 years service to make them worth while. Or somehow get some older ones out of a scrap electric car..
When some cells go bad, electric cars aren't usually economical to repair and get recycled, sadly.
Hence why, if you want to get longevity value in a car, pure electric won't do with today's batt tech. Even a 100+k tesla, sorry.. Lol
Imagine every 100 miles you journey on vacation, wait to refuel several hours. The kids would go stir crazy.
100 mile range new, then the dreaded battery fade creeps in, 80, 50 miles range like an old cell phone..
Won't see batt run semi trucks anytime soon either. Now electric trains are cool, no batteries and smooth motors.
Anyways..
 
Last edited:
Battery cars are perfect for day-to-day commuting, most people in or near cities drive far less than 100 miles a day. Ideally you'd have an electric car for the day-to-day commute and an economical diesel station wagon or van for the holiday.
 
Your original question was,
"The question is, how can I go about bypassing or fooling the inverter into thinking there is a grid in order to power the house? I'm thinking I could connect a small generator just to get the 240 to the panel and then the inverter should see that as "the grid"."

If you want to expand that to include making your system a hybrid system etc, let us know.
I assumed you were already considering those things.

Solar topologies can get complicated and batteries are expensive if you're looking for a full "run-everything-when-mains-is-out" solution.
Also your existing inverters may not be willing to run off a battery bank at night, many are spec'd for certain algorithms where the voltage is changing and they select a certain point etc (MPPT) and batteries provide fairly constant voltage so you can end up with an inverter not working at all if it's not designed to run off batteries.

If, however, you've researched those things or plan to research and the scope of this thread really is just your original question regarding how to trick the inverters then I think you are good to go for that piece of the puzzle.

pure sine-wave generator.
 
Thanks for the additional info and advisements, guys. It's still strictly in the theory stage and low on the project list. However, based on your feedback, I'd say it's a definite probably-would-but-if-not-this-may-be-why. :)

Besides, Tesla/Solar City has those Power Walls that are "relatively" inexpensive.
 
You must log in or register to reply here.
Back
Top