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jb802
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# Posted: 8 May 2024 03:11pm
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Looking for suggestions regarding efficient utilization of two wiring set ups, 120 & 12v, that were pre existing in the cabin we purchased in northern Vermont.
Here are some details:
1. Gas generator powers cabin (120) which we use for tools, mostly
2. The cabin has 12 Volt wiring too evidenced by different outlets (photos below), switches, wiring and 12 volt fixtures in the cabin and an old 12v water pump
3. The 12volt battery (auto) appeared to be wired to genny power so when the generator was on, the battery would stay charged (I think?)
Ideally we'd like to use the 12volt system to flip a switch on in the hallway or in the bathroom when it's dark (right now we use portable solar lights) and have the 12volt power a water pump, maybe a fan at night.
Can we integrate (or are they already) these two systems seamlessly? Or, do we just connect the 12volt system to a tiny solar panel and figure out which fixtures are wired 12v and run the genny for tool power and recharging in a pinch, essentially leaving the two systems working in parallel fashion? Any suggestions?
Thanks!
JB
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Brettny
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# Posted: 8 May 2024 08:22pm
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You just need a inverter to power your 120v lighting and outlets. Size and other features are determined by your needs and battery size.
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gcrank1
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# Posted: 9 May 2024 12:55am - Edited by: gcrank1
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Ime using the 12vdc taps on the gen to charge a battery is far from ideal. If that is what you have get an automotive charger with some real output plugged into the 120vac on the gen.
An automotive 'starting' battery is the wrong bat to use in anything other than a last ditch stand.
Given you are in N Vermont with winter freezing temps I can't recommend the LFP batteries, you would be better off with a 12v 100ah 'deep cycle/marine (trolling motor)/rv lead acid battery. 2 hooked up in parallel would be even better.
Another option would be to use 2 of the 6v 'golf cart' batteries hooked up in series to make them a 12v.
Btw, LFP bats would be fine for above freezing temps but you might want to get some 'basic' battery experience before jumping into the high buck bats.
With good bat(s) you can find out if you are getting the kind of use/performance from your 12dc system to suit your needs (and it is already wired for it). Some folks like having the simple 12v for basic needs.
At one time I did too, then I had a split 120vac/12v then gave up the 12v and did as Brett suggests, use an inverter off the 12 bat(s) to make it all 120vac. That really simplified my life, ymmv. Thing is, with a good 12v battery 'power base' you can always grow into the inverter.
Advantage for us with the 12v and inverter is that we can run everything that is low draw (most stuff; ie, lights, TV/dvd, fans, tool bat chargers, any usb chargers, even a toaster) off a quiet battery and only use the gen for big power tools, microwave, etc And whenever the gen runs have that charger pumping amps back into the bat-bank.
Solar can come later once you have all this working.
Oh, costs? 2 12v/100ah deep cycle bats from Walmart are about $100-$125 each, some good heavy gauge cables to parallel them, maybe some DC fusing (is there any now?).
A good automotive min.20a charger is $? I suggest the new-gen smart chargers.
If you choose to get an inverter at some point we should talk about that separate 
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toyota_mdt_tech
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# Posted: 9 May 2024 01:13am
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Quoting: Brettny You just need a inverter to power your 120v lighting and outlets. Size and other features are determined by your needs and battery size.
Bingo, scrap 12V, use 12VDC to 120VAC inverter to make 120VAC and run AC circuits like home.
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ICC
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# Posted: 9 May 2024 01:15am
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Auto batteries belong in a vehicle and never for use in a cabin power system. I prefer 2 x 6 volt golf cart batteries for simple 12 volts.
As gcrank1 states, maybe forget LFP until you have learned more about handling batteries. LFP have critical "must-not-do" things.
To charge a battery from a generator you need a good (multi-stage smart charger) battery charger made to charge lead-acid batteries (or LFP). Again, as grank1 stated the 12-volt line feeds on a generator are not really meant for serious battery charging.
Fuses (or breakers)... Yes, fuses are safety devices. They are used t protect the wiring from melting or burning.
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gcrank1
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# Posted: 9 May 2024 03:13am
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Something not mentioned thus far...the wire gauge used (as in your pic) looks too small for dc to me unless the runs are very short. You have 'line losses' to consider for the dc power required by a device at the end. The lower the voltage the bigger the wires need to be, that is another reason I went 120vac from inverter, much longer runs with std 14/2 w grd Romex for 15a circuits.
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Brettny
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# Posted: 9 May 2024 01:10pm
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Quoting: toyota_mdt_tech Bingo, scrap 12V, use 12VDC to 120VAC inverter to make 120VAC and run AC circuits like home.
I figure by the time I buy all the 12v wireing, breakers, appliances, lights, switches I could have just added a bit more battery capacity and ran standard 120v stuff. Halfway through my cabin wireing I decided to scrap all the 12v stuff becids a USB and cig lighter plug in each bedroom.
120v lights, fridge, water pump and 120v control circuit on our propane water heater. All standard stuff I can easily find at a big box store.
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jb802
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# Posted: 10 May 2024 05:17am
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Copy on all of that. Thank you, very informative. Seems like prevailing sentiment is going 120 off 12v via inverter but trying to work w/ 12v system in short term. We'll do that as it is wired to see what it can do. We do have an 18watt panel that can keep bats topped up. Definitely looking for simplicity.
Regarding the wiring gauge, that is good intel, did not know that.
I appreciate all the feedback, thank you! Will return with some updates, hopefully soon!
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gcrank1
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# Posted: 10 May 2024 11:41am
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An 18W solar panel will not keep a 12v battery (of the size needed for a cabin) charged up. That is a size used as a 'trickle charger'/battery maintainer; ie, to keep a fully charged battery charged in a storage/non-use situation.
Example: a 100ah battery needs about 200w of solar array to recover from a typical day's power use. And more is better. Depending upon location you only get about 4 hrs of good solar, 10am-2pm, on good days.
A common mistake is underestimating one's power use and overestimating the solar recharging.
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Brettny
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# Posted: 10 May 2024 12:37pm
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Ard there also 120v lights in your cabin? I take it theres no lighting at the moment becids what's shown(120v). If so just buy a solar generator and plug it into your 12pv feed line. It's going to be the simplest and most fool proof option.
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paulz
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# Posted: 11 May 2024 05:49pm
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I’m still running 12v mainly, use inverter sporadically for toaster, nuker, skill saw, washing machine. 12v LED lighting, water pump, TV, modem, fridge. After reading this maybe I will switch at least the pump and fridge over to 110 when they quit.
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jb802
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# Posted: 17 Dec 2024 08:44pm
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Quoting: Brettny Ard there also 120v lights in your cabin? I take it theres no lighting at the moment becids what's shown(120v). If so just buy a solar generator and plug it into your 12pv feed line.
Yes, all the lights, are 120v. We run the gas generator, flip the power on in the cabin turn the lights on as if we were at home. We have a goal zero solar generator (built in inverter). Want to connect that to the 120v wiring. You mentioned "12pv feed line." I don't know what that is or where. Sounds like that would be the final link.
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jb802
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# Posted: 17 Dec 2024 08:47pm
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We have a solar generator, goal zero, with a built in inverter. Don't know how to wire it to the current 120v wiring system. Not going to use 12v dc after all.
We would need a way to use the generator power for bigger loads, like tools but the solar generator would run our lights and water pumps, charge devices. Fridge is propane. Would this require a transfer switch?
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gcrank1
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# Posted: 17 Dec 2024 11:36pm - Edited by: gcrank1
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Use a standard male plug on the input line to your 120v 'fusebox' to distribute to the circuits (they are your load).
That gets plugged into your 'solar gen' like any other 120v device (it is a 'source'); so is your generator.
Do Not run that and the generator at the same time!
A simple way to separate that is to have a female plug/receptacle coming from the generator to the inside. You plug your 'fusebox' male plug into either the generator feed OR the solar gen unit (in essence You are the 'transfer switch').
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jb802
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# Posted: 18 Dec 2024 10:15am
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Quoting: gcrank1 A simple way to separate that is to have a female plug/receptacle coming from the generator to the inside. You plug your 'fusebox' male plug into either the generator feed OR the solar gen unit (in essence You are the 'transfer switch').
Maybe it's been under my nose the entire time. The fuse box pictured, you see the toggle is up, which means the generator is on and the fuse box is receiving power to the rest of the cabin. I understand not using solar genny and gas genny at same time. Are you saying I can plug my goal zero into that fuse box and it will be the same as running the gas generator, potentially? There is that outlet you see in the picture, right next to the fuse box. (Remove the battery from this photo, we won't use that here)
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jb802
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# Posted: 18 Dec 2024 10:18am - Edited by: jb802
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Not sure why but you can't see the rest of the photo.
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gcrank1
Member
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# Posted: 18 Dec 2024 01:53pm
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Which of those Romex from the gen feeds the fuse/cb box?
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ICC
Member
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# Posted: 18 Dec 2024 04:44pm
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Sorry, but the image means nothing to me. Can't see what is connected to what.
Maybe we cam simplify the thought process. To be sure I understand the issue at hand.... Is it correct that we want to send 120 VAC power into a cabin wiring system? And is it also true that we want to be able to use either a portable gasoline generator or a portable battery-inverter power box to supply thT 120 VAC?
If true then the cabin service panel or fuse box should have a HD flexible cord, such as a length of 10 AWG extension cord connected to the input side. That cord should have a male plug end with ground.. Let's call that the panel plug. When this panel plug is NOT plugged into any source there is no power in the cabin. That panel plug could then be plugged into a gas generator and the gen would supply 120 VAC. OR the panel plug could be plugged into the Goal Zero power box. Or any other source of 120 VAC. But because there is only one panel plug , only one source at a time = best safety..
Any DC should be completely separate, clearly marked and of different color wires if at all possible..
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travellerw
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# Posted: 18 Dec 2024 04:53pm
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Another thing that has not been brought up yet. Most standard hardware store switches are NOT rated for DC (e.g. 12V).
DC switches have a faster "break" action due to DC not ever crossing zero volts. If AC rated switches are used on DC they will fail prematurely due to contact corrosion. In rare cases they can actually weld the contacts together.
Now with all that said, do I think it will burn your cabin down.. NO.. but just something to be aware of. You can actually by DC rated "house" switches but you usually have to search them out!
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gcrank1
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# Posted: 18 Dec 2024 05:00pm - Edited by: gcrank1
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That is the way I see it, Izzy
One other thing I may be seeing is the gauge wires used for dc may be too small for the load and distance (that was one of the probs I had with my Po's wiring).
There are charts readily available online.
Imo, with a Goal-0- that may have a 12v 'tap' and maybe USB ports there may be no need for any other 12v outlets in the cabin.
120vac cheap LED lights will be way more efficient than incandescent 12vdc bulbs and fit standard cheap fixtures and switches. Fwiw, in mine I used pull chain fixtures rather than wall switches (way simple).
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jb802
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# Posted: 18 Dec 2024 06:51pm
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Quoting: gcrank1 Which of those Romex from the gen feeds the fuse/cb box?
The pics is terrible it was cut off when I uploaded. I am trying again. The Romex that feeds the gen into the fusebox comes up from the bottom of the pic.
Quoting: ICC To be sure I understand the issue at hand.... Is it correct that we want to send 120 VAC power into a cabin wiring system? And is it also true that we want to be able to use either a portable gasoline generator or a portable battery-inverter power box to supply thT 120 VAC?
Yes, the 120v LED lights seem like the way to go which is why we want to use the existing cabin wiring but not use the genny running all of the time.
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ICC
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# Posted: 18 Dec 2024 06:53pm
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Quoting: travellerw Most standard hardware store switches are NOT rated for DC (e.g. 12V).
Excellent point. If we're switching low amp loads like LEDs there is less chance of a switch failure. I use Carling brand DC rocker switches if there is no need to meet code. They are excellent switches, just not put through the testing ($$) for NEC approval.
Thay do require cutting a rectangular hole in the switch plate to be mounted, or use of some other mount. Carling makes the nice BlueSea rocker switches.
If I use Romex for the wiring I pigtail to stranded wire in the wall box and use an appropriate connector to the switch terminals.
FWIW, an AC approved switch with a definite audible Snap is probably better suited to some DC use than the silent type.
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jb802
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# Posted: 18 Dec 2024 06:54pm - Edited by: jb802
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This is how we found it. Can't explain why the battery is there. I am thinking an inverter is missing somewhere in that picture ;)
To sum, we have 120v power from genny, powers lights, charges devices, maybe a projector and a fan once in awhile, eventually a small water pump. We just want a solar source that can tie into existing wiring in the cabin.
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gcrank1
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# Posted: 18 Dec 2024 07:20pm - Edited by: gcrank1
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What Id do:
Move the dbl outlet box under the fuse box.
Feed it with the generator wire now in the bottom of fuse box, that will give you the 2 outlets powered by the gen.
As ICC said make 10 AWG male cord into the bottom of the box where the gen wire went in.
When the gen runs you can plug that fusebox male into one of the outlets below.
When you want to run off the Goal-0- unplug the fusebox male from the outlet and into the G-0-.
Just make sure the male plug cord is long enough to comfortably reach where you want to put the G-0-.
Oh....that other wire from the outlet box must be your 'circuit' wire? That should be wired into the fusebox to where that stubby wire to the outlet box comes from.
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ICC
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# Posted: 18 Dec 2024 07:20pm - Edited by: ICC
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Is that box you called a fuse box the only fuse or breaker box?
Does the generator feed into that box? How?
Have you used the GoalZero hooked into the cabin witing? How?
gcrank1 and I are trying to keep what you do safe which is one reason we are 'harping' on there being only one source in use at a time
Can you try to map out the circuits?
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gcrank1
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# Posted: 18 Dec 2024 10:01pm
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The gen feed comes into the bottom left of the fuse/switch box; looks like the one circuit output goes to the dbl outlet box for convenient power there then out to ? (the rest of the place).
If that fusebox is like my two it has two fuses for two circuits and the lever is positive on/off. Not a bad box imo for a small place.
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