Can I power my home with my Sporty?

[panion]

Trying to tap the vast expertise out there.

I have 360 watts of solar on my sportsmobile and a 2500 watt inverter. I live in Arizona where the sun is almost always shining. My van will sit for weeks at a time in the sun with all that free energy wasted.

Is there any way to pipe some of this excess power into my home. If it was relatively simple and safe I'd love to at least run a computer or two with the vans powerplant.

I was thinking of a gadget that only allowed current from my van to enter the home when it sensed that the power in the home was on. I don't want to knock any utility workers off their poles. Could it be as easy as the above mentioned gadget on the shore power line, then shore power plugged into the home????

Thanks for any info.

[Ford_6L_E350]

Typically, electrical code requires a main line disconnect before the aux power can come into the system. And, it has to be either automatic or failsafe - i.e. either the main power comes into the house or the aux (SMB) power comes in, but never both. You don't want to zap a tech on power lines. You power company will take a very dim view of it and you may face criminal charges.

I wouldn't want to hook the SMB to the house power. It's only 360W max. After solar controller and inverter losses you would be lucky to get 2.5 amps into the house. Even if everything worked at 100% you would still only get 3 amps. That might be enough to power one computer, maybe not - it depends on the computer. A desktop with a 300W power supply and powered speakers and a monitor, probably not. A laptop, ok.

Still, you won't save much electricity, not enough to pay for the electrician to install the disconnect, or even to pay for the disconnect either. Usually the only time you have a service disconnect is when you have unreliable power and you have a backup generator.

Mike

[Joanna]

Didn't I read that the Qatar vehicles were able to power out buildings?

[yvrr]

Originally Posted by Joanna

Didn't I read that the Qatar vehicles were able to power out buildings?

Yes, but they carry traditional very large portable generators specifically for this purpose. In the event of a major emergency where all power is out, they can disconnect a hospital from the power grid and hook it up to one of their generators...

[Ford_6L_E350]

Originally Posted by Joanna

Didn't I read that the Qatar vehicles were able to power out buildings?

Joanna,

On a side note, did you intend your signature to mean the SMB 4x4 cost alot of money, or was that a Freudian slip?

Mike

[Greg In Austin]

This is an intersting idea....

By comparison, there are many folks that are modifying their Toyota Prius to do this very same thing. This is a little different since the Prius gas engine will come on and charge the hybrid battery when the charge drops to far (40% SOC). Through the use of an inverter and transfer circuits folks are able to use the Prius as a home power source.

Our SMBs do not operate that same way, so what you are really looking at is utilizing the solar capabilities to your maximum benefit.

I have no doubut that it is do-able, and that it would be beneficial.
Here is why I say that...

I installed a 'guerilla' solar array of only 100watts about 5 or 6 years ago. This was termed 'guerilla', because I wired it in by just plugging it in to an outlet. I did not know if this would be producing enough to even tell, but after a few months I could tell. We have charted our electric use by month over the past 8 years. This tiny little system was enough to knock the peaks off of our usage.

We have since installed a 2.2KW grid connected system. This has a made a HUGE difference.

The guerilla system connection would not work for our SMBs since there are other things in the van that could/would be drawing power. The other thing is that the solar system is specifically designed to charge the batteries.

I am sure that with some modifications the solar capabilities of a SMB could be used as a guerilla solar system.

Our inverters are set up to provide power when there is a need for power. THis is probably the biggest change. We would need an inverter that would produce AC and just flow it back onto the grid.

Our guerilla system utilizes an inverter that I do no think is still sold (or at least was not in the US). It was a Trace (now Xantrex) MicroSine inverter. It was 100w and was specifically for grid connection; this means that it will only put power onto the grid when there is power on the grid already. We found two in someone's excess inventory, and there may be others out there somewhere (or there may be new versions as well).

That would be one way... Guerilla solar.

If you were specifically looking for how to power the house when the electrical grid is down, this solution would NOT work.

For a grid down scenario, I think we have to go back to a piece of the Prius solution. At that point, if you have transfer circuits, I would think that you could plug the SMB in, and power would be provided by your inverter on an as needed basis. There would be some loss to go from solar to battery to inverter to house, but you would have some power.

You would need to do some calculation to determine how long your batteries would last under the load without solar, and it may not be very long. Solar would extend the time some, but you can't count on it.

A normal home solar system for off-grid use would have a large bank of batteries for those times when it is cloudy or days are short.

If you have transfer circuits, you can also utilize a generator directly for powering those circuits, ....our I supose you could use the generator through the SMB to power the SMB and the house.

ok... a little rambling, but there are a few ideas....

.

[yvrr]

Keep in mind that if Greg is talking about 100 watts at 120 volts, that is very different than a 100 watt solar panel on our vans which runs at 12 volts. That 100 watt/120 volt panel is putting out 0.8 amp and can, at best, run a 100 light bulb. But a 100 watt/12 volt panel, if hooked up to a 120 volt system, is only putting out 0.08 amps and can only power a 10 watt CFB...

[Ford_6L_E350]

Originally Posted by yvrr

Keep in mind that if Greg is talking about 100 watts at 120 volts, that is very different than a 100 watt solar panel on our vans which runs at 12 volts. That 100 watt/120 volt panel is putting out 0.8 amp and can, at best, run a 100 light bulb. But a 100 watt/12 volt panel, if hooked up to a 120 volt system, is only putting out 0.08 amps and can only power a 10 watt CFB...

Not really. 100 watts is 100 watts. 1 watt = 1 amp X 1 volt or 100 watts = 1 amp X 100 volts or 100 watts = 100 amps X 1 volt.

100 watts @ 12VDC is the same amount of power as 100 watts @ 120VAC. The only trick is to convert the voltages and the DC to AC.

Mike

[Greg In Austin]

The key is in the inverting, but also what voltage you are putting into the inverter.

Our guerilla system consists of four 70 watt panels, 2 in series and then the pair in parallel. This gives us 140 watts at 24volts into the invterer.

Figuring I am rarely going to be operating consistently at full output, I hooked these up to the Trace Microsine inverter that has a maximum output of 100w at 120volts AC. This was simply wired to an extension cord and plugged into a wall socket. If there were no power requirements at the house on a bright sunnu day, you would have seen the meter slowly move backwards

(now with the larger system we see the meter spin backwards almost daily)

The key to the whole thing is the little inverter, which I think is discontinued, but I bet some can be found.

Microsine PV Module Inverter
Designed specifically to "sell back" power into a utility grid (no battery backup available). Mounts directly to the back of a solar PV module. This weatherproof, modular inverter includes MPPT and islanding protection. It is designed to meet Utility Tie standards. multiple units can be paralleled and will synchronize. UL/ETL listed. NEC and Utility requirements are pending. Dimensions 5.4" x 4.2" x 1.2". Weight 1.5 Lbs. 2 year limited warranty. Discontinued
Model No. Description Price Qty 2 Qty 6
PI/TE-MS100 Microsine Inverter, 100 W, 24-50 VDC in, 120VAC / 60 Hz $345.00

I had not thought about using it with our SMB, but since I happen to have an extra Microsine, I may have to put this on the project list. We have two 130watt panels sitting on the SMB doing essentially nothing when the SMB is sitting in the driveway plugged in.

[Ford_6L_E350]

Originally Posted by Greg In Austin

This is an intersting idea....


Our inverters are set up to provide power when there is a need for power. THis is probably the biggest change. We would need an inverter that would produce AC and just flow it back onto the grid.

You will need a specialized inverter, like the one you had in your little system. The inverter needs to synchronize the AC power produced with the AC power system. If you just connect a standard inverter to the power grid you will likely get a big bang.

120VAC (AC is Altenating Current) is a constantly changing voltage. It varies from +170V to - 170V 60 times every second. Unless the two power sources (grid and inverter) are both delivering the same voltage at the same time - poof. And the inverter in the SMB is probably not precisely 60 Hz. So if it were in proper phase with the power grid, it may change in a few minutes to out of phase.

Mike