Solar Power?

[Andy Mink]

Mental note...no need for the frame.

 

[pete]

In case others seek out some solutions. A co-worker of mine has me seriously thinking a 10KW set up before Fed Tax breaks go away.

Good thing is if I can't figure something out, he can. He's bought a mechanically reconditioned wind generator that came from the foothills near Pasadena. Guy erected a 80 foot tower, rebuilt the electronics and been selling excess back to the rural co-op who installed all the transformers and cut over switches for free. He said he happened to be early in the planning by our local electric companies with the CEO was pushing to support wind for little/no cost for tying into the grid.

He bought a set up from these folks and added to his off grid capabilities, noted he loves not having had paid a bill in the last 10 yrs or so. He doesn't worry much about storage with batteries as in his case, he's ahead in selling the excess. Power company, other than equipt isn't out much as last I heard he got 3 cent/KWH but he buys power back at 11.5 cents KWH. Anyhow, on a sunny breezy day he's running some 40KW to 50KW.

Needless to say, he noted he doesn't worry much about heating his home in the winter.

 

[Philpug]

Mental note...no need for the frame.

Not for our application but for mobility it makes sense. Left the lights on for over an hour last night before they shut down and that was without no real charging time. For $130, this solves our needs in the shed.

 

[pete]

oh, forgot that I did a cheap light solution for my kids play house using a Home Depot brand security light that has a small solar panel and tiny battery. But Phil's solution is pretty nice for $130.

 

[Doug Briggs]

You may wish to consider a battery box for your battery. Dropping a metal tool across the posts could create a problem and a shocking experience. (couldn't resist)

 

[Philpug]

You may wish to consider a battery box for your battery. Dropping a metal tool across the posts could create a problem and a shocking experience. (couldn't resist)

Negative, Ghost rider....I will positively do that along with securing the battery in it's spot.

 

[WheatKing]

I've been screwing around with solar myself. Used commercial panels (and new ones with slightly damaged frames) can be snapped up for about 50 cents a watt.. I've got 1KW of panels on my barn now and a 3000W inverter so i can run lights, well pump, tools etc. Charge controllers are cheap off of amazon or ebay (i'm using a 40A renogy one.. seems to work great).. MPPT is definitely the way to go. commercial panels put out significantly higher voltage (30+V) than the stuff you find at home depot so you need a special controller so you don't blow up your batteries. I'm constantly amazed by how a little bit of sunshine can provide so much energy.. I'm just around $1000 for my setup.. but i've run welders, compressors grinders etc.. stuff is magic. Now if it would only feed the animals.. that'd be awesome. Next year i'm trying to pick up enough to move my pool pump to 100% solar. When the sun is shining the pump will be running . It doesn't need to run at night.

 

[Tricia]

You may wish to consider a battery box for your battery. Dropping a metal tool across the posts could create a problem and a shocking experience. (couldn't resist)

Negative, Ghost rider....I will positively do that along with securing the battery in it's spot.

I think the idea was to make sure this was the battery we're going to use long term before creating a permanent space for it.

 

[Doug Briggs]

Did you get your current battery new or are you re-purposing an older one? Is it a deep cycle or just auto?

 

[pete]

You may wish to consider a battery box for your battery. Dropping a metal tool across the posts could create a problem and a shocking experience. (couldn't resist)

"couldn't resist"

 

[Tricia]

Its a battery we had around and is not deep cycle, which is why we're planning on getting a different battery before we create a permanent box/position for it.

 

[Philpug]

I have a question on invertors. We have a Rigid shopvac I wanted to use in the shed, I hooked it to our invertor which is a 500/1000w, and the invertor said it was too much draw, is that because the panels didn't have 3 days to fully charge or the invertor isn't powerful enough. Plus the invertor was plugged into the 12v on the front of the controller and not directly to the battery, should I connect it to the battery?

 

[Philpug]

Did you get your current battery new or are you re-purposing an older one? Is it a deep cycle or just auto?

Repurposed an old Miata battery. If we say with the system, we will probably get a deep cycle one.

 

[Doug Briggs]

I have a question on invertors. We have a Rigid shopvac I wanted to use in the shed, I hooked it to our invertor which is a 500/1000w, and the invertor said it was too much draw, is that because the panels didn't have 3 days to fully charge or the invertor isn't powerful enough. Plus the invertor was plugged into the 12v on the front of the controller and not directly to the battery, should I connect it to the battery?

The inverter likely isn't powerful enough. I doubt moving the connection of the inverter will make a difference. The power from the 12v jack is basically a straight pass through from the battery. The issue is that the inverter isn't designed to generate sufficient AC amps for the shopvac. At startup an electric motor briefly uses considerably power than when it is running. I'm presuming that the inverter wattage rating is for the 120v output. Is that correct?

You can test the inverter by using it attached to your car's battery with the motor running. This will be providing an amount of DC energy in excess of what a battery could provide on its own. If the inverter balks with this setup, then it simply isn't capable of handling the load of the shopvac.

 

[Doug Briggs]

"couldn't resist"

That was a freebie.

 

[Andy Mink]

I have a question on invertors. We have a Rigid shopvac I wanted to use in the shed, I hooked it to our invertor which is a 500/1000w, and the invertor said it was too much draw, is that because the panels didn't have 3 days to fully charge or the invertor isn't powerful enough. Plus the invertor was plugged into the 12v on the front of the controller and not directly to the battery, should I connect it to the battery?

Not enought juice from the inverter. If you move to a larger one you'll suck that little battery down quickly. It may be worth looking into one of the small battery operated (Dewalt etc) vacs for the shed. I have one of the blowers and it's very handy which means I'll use it more often. I'll bellowing into a vacation next.

 

[Philpug]

Not enought juice from the inverter. If you move to a larger one you'll suck that little battery down quickly. It may be worth looking into one of the small battery operated (Dewalt etc) vacs for the shed. I have one of the blowers and it's very handy which means I'll use it more often. I'll bellowing into a vacation next.

I had a feeling that was it. I will keep an eye out for a small shop vac like that, if you see one in your consignment/thrift shop travels, grab it.

 

[WheatKing]

You like numbers Philpug.. so time for some electrical math..

Watts are watts.. generally.. doesn't matter if they're AC watts or DC watts.. it's a measurement work.

To figure out what's going on with your inverter.. lets do some math.. Watts is generally simple math.

Watts = Amps * Volts. Watts / volts = amps. Watts / amps = volts.

your shopvac probably runs in the neighbourhood of 950 watts. so at 120V 950/120 = 7.9 amps.. give or take.. seems like a reasonable amount.

So at the AC side of your inverter. is 120V @ 8A.. lets do the math for the 12V side now.. because.. watts are watts remember.

950W / 12V = 79.16A.. or nearly 80Amps. Now.. looking at the wires you have hooked up between your battery and your inverter.. they're a bit on the small side to handle 80 amps.. and that doesn't account for losses in the inverter as well. If you have some 6~8 gauge wire around, try running that from the battery to the inverter.

This is the downside to low voltage solar. Also why commercial solar runs 600-800V DC. Low voltage and usable power requires high amperage.. and big amps = big wires.

 

[pete]

I'd agree, seems the lowest Rigid Shop vac is at 3.5HP (peak) which shows 7.8A, that's not turn on amperage. at 7.8 your close to 1KW (7.8 x 120V = 936W), inverter or as Wheatking noted, is a bit hamstrung.


pete

 

[Dave Marshak]

Mission creep! What a surprise, Three days in and you have already exceeded the capability of your solar system.
What are you going to do when you get a Wintersteiger next year? You should have just pushed a 220 50 amp UF-B circuit. You're going to do that eventuallyt anyway.

dm