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Tim_Ohio
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# Posted: 25 Jan 2021 11:18am - Edited by: Tim_Ohio
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Hi, everyone.
I've started wiring the cabin I built last fall. I've installed a 100 amp panel. I went with the smallest panel I could buy that had a main breaker. I changed out the main to a 60 amp, the smallest I could find.
I'm only going to run two 20 amp circuits, leaving 4 extra spaces in case I need more in the future. I'm wiring it with the anticipation of possibly bringing in utility power from either the electric company or from my building (both are 400 yards, plus away).
So, because of the distance it may never happen.
However, I'd rather wire it for the possibility, either
by me or if I ever sell the place. For the time being,
I plan to use a generator. Anyway, I've installed what they call a generator transfer switch outlet (50amp, with male connection under the cover) and wired it into the panel (with #6 wire) as if it were a
main service coming in. So, both sides of my panel will be hot from 3-wire plus ground wiring and I can balance the load off of the two breakers. Anyway, it will allow me to connect the generator in a temporary way and remove it when I'm not around.
Now, for the real question. Although I plan on making an insulated baffle box for the generator, to reduce the noise, I'd also like the option of going
quiet off of batteries that I can charge from another
source and bring up with the generator as an alternative, such as at night. Now, I realize the current off of the batteries is going to be DC, unless I use an inverter. I'm also aware that there are DC lighting and other option for it. What I'm wondering is, are there other people powering up with a generator and also switching to batteries when not using the generator? Are you using an inverter directly into the service panel, or are you wiring up for DC as well?
I'm curious to hear about how others have done this.
Thanks,
Tim_Ohio
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ICC
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# Posted: 25 Jan 2021 12:15pm
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Since the building is wired for 120 VAC as in a grid tie, the easiest solution is to use an inverter that has builtin battery charging and switching. They ae wired with an input from the batteries (DC) and an input from a generator (AC) and have a single output connection of 120 VAC that goes to the standard service panel.
With generator off the 120 VAC to the panel coes from the batteries through the inverter section. When the generator is started the inverter/charger usually waits a warmup period and then starts charging the batteries if they need it. The inverter/charger will also switch the incoming 120 VAC to go straight through to the 120 VAC going to the service panel. Probably cost $1600+ for an inverter/charger. They are pure sine wave.
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gcrank1
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# Posted: 26 Jan 2021 10:36am - Edited by: gcrank1
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Tim, I run primarily off a small solar charged bat-bank inverted to 120vac to the cabin some 90' away.
As background, when I bought the place it was a hacked together 10ish yr old system 50' from the cabin running both 12vdc and inverted 120. It was apparent he ran the old Coleman gen to recharge sometimes, as well as for tools.
Btw, I have also hauled batteries to swap out. Batteries wont care how they are charged on the upstream side (given appropriated charged on home grid, solar, wind, gen running an ac smart charger) so for now I do understand you are not trying to charge at the cabin.
2 sets of wiring/fixtures, a spaghetti mess and unsafe.
I rewired, reworked, abbreviated....both. Ummm, 3 times? In a fit of desperation, or maybe inspiration, one day I ripped it all out thus forcing myself to start all over.
Ours is also far and expensive for going grid. And my solar prime exposure is limited to am thru about 1pm in the place I would like the array.
The panel location for more better is a min 50', better 100' away from the cabin. Trying to do 12vdc would require huge wires, far more than the 10ga. he had run considering the line losses (50ish' to cabin and what, another 20' inside wires?). 12vdc stuff is available, but generally not inexpensive, especially fixtures and switches (marine stuff the best).
Inverted at the array/powerhouse c/w charge control, bat-bank and inverter to run 120vac solves ALL of that.
At the power house I can plug into the inverter with my heavy duty 12ga. contractor's ext. cord and run it to the cabin to an rv in the wall cord inlet (amazon).
I dont have a service box yet, but if I did that inlet could run into the fuse/CB box to be distributed within. As is, for my small set up, it goes to a switched 'power strip'. The fusing/CBs are at the inverter.
Now, more to your point, if/when I want/need more power (like for our microwave, toaster, small ac) I can manually unplug the ext. cord at the inverter and plug it into the warmed up 1600/2000w peak genny.
This is way easy and after initially hooking it up in a trials/test fashion I wondered why I, and he, had made it more complicated.
I will be refining this (I really only got it together like this late last fall and we are currently snowed out) but for our minimal needs this has been way satisfactory.
For you gen or battery/inverter 120:
Where is your transfer box? (Note: Im no electrician).
I think wherever the t-box is you should do it there as the main feed. As I get it the one side of the t-box would be, say, the gen feed would emulate the grid input and the bat-inv input the other side.
That would give you the option but you would need to keep your cabin ac use low when switched to the bat-inv side.
Also, dont use too large an inverter off the battery(s). A 1000 continuous inverter will peak higher and your fuse and wiring for that load into the inv. are BIG (do the math and check the charts for 1500w) for the bat to inverter. And the big inverters suck up a fair bit of amps whenever turned on; and require a lot of battery bank.
Oh, on the simple, quick and easy side you can 'build' a gen baffle out of straw bales, just point the hot exhaust away from you and the bales.
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mj1angier
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# Posted: 26 Jan 2021 04:50pm
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I use an inverter/ charger. Main panel is wired to it, batteries are wired to it and genny is wired to it. When genny is running it powers the cabin and charges battery. When genny is off, cabin is powered by battery that also has solar feeding it. It is pretty much a seamless transfer between genny and battery, just beeps to let me know its happening.
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