Weekend cabin for cold weather advice

[12VoltInstalls]

could just have heard to Walmart or cosco and picked up a new $100 battery or 12 of them honestly.

Sometimes with small systems the walmartha (Johnson Controls sourced) marine deep cycles do make sense. They did for years for me, still probably could but low sun hours and cloudy winter days on end really suck the life out of lead acid batteries.

With cheap LiFePo availability at 20 cents/Wh and everspark deep cycles at 14 cents, though, in some circumstances LiFePo is a better choice. With big systems LiFePo is basically a no-brainer on a ten year scale with lead acid being a 3-5 year life cycle on cheap batteries.

Of course you can buy good lead acid and do much better lifespan, but the cost factor exceeds the dubious cheapo LiFePo. Then again, in certain setups where freezing temperatures and need for charging exist lead acid takes the prize imho

could have definitely built a robust bomb proof simple 12v system for what I have spent trying to chase my tail.

Maybe you should regroup and do that? Get the battery warranteed and sell them, sell the 24V AIO, and buy some EverStarch batteries. 2-5 years with care, 1 year with long periods of low state of charge.

I just bought 2 LiFePo 140Ah but I’ll keep them inside to not freeze. I got them because last November/December hit my walmartha batteries hard with four weeks of cloudiness. With LiFePo they won’t care if they’re not fully recharged.
I will select two, three or four of my lead acids (by 24-hour-rested hygrometer readings) to run lights, phone charger, etc and just have the lithium’s run the furnace fan and fridge to begin with. After I have a sense of things I may opt out of lead acid altogether. Athough I think it’s so painless to run two systems, why not?

 

[Scoutmaster]

Thanks for the perspective.
I bought my cabin 1 year ago and have spent countless hours watching videos and trying to research the best solution.
Last winter I barely got the doors and windows back on before 3 feet of snow covered everything.
The generator made winter possible and pretty hassle free. I bet I burned about 25 gallons of fuel at a cost of about $100-125.
I have propane lights/stove/heat so I can minimize battery usage.

I really just need enough power to run 100watts of lights/tv/charge phone for 6-7 hours each night before I go to bed. I’d say 200w for 7 hours so 1400wh per day. Any idea how long I need to run the generator to charge 4x12v led acid to maintain this?

Currently i run the generator 1-2 hours in the morning and evening as needed. I have 400w Solar but I get very little sun in the winter.
I’m still tempted to try a server rack 200ah/24v 5000wh for $1500 just to see. I think i could insulate it and use it when the cabin warms up.

 

[12VoltInstalls]

power to run 100watts of lights/tv/charge phone for 6-7 hours each night

TV is 60W? Phone is minuscule.
Can you go to 12VDC led’s for lights?
That might cut the Wh a lot.

1400wh per day. Any idea how long I need to run the generator to charge 4x12v led acid to maintain this?

How many amps will your charger do?
Lead acid needs a higher voltage ‘bulk’ followed by a few hours of ‘absorb’ at like 13.2/13.4; at 12.8V nominal that’s ~110Ah or 5-6 hrs of charging, minimum, rough ballpark, at 20A rate. In practice it will probably be half that time at ‘surface charge’ but it will settle lower than you want. So you need the absorb time. 400W of panels in practical terms is 25% to 30% of what you need in winter at high latitudes though the math suggests 400W is enough. And it maybe is for 7 months of the year or so.

think i could insulate it and use it when the cabin warms up.

You can discharge it below freezing, you just can’t charge it below freezing. Ever.

 

[Stiffler]

It’s been humbling and sort of expensive trying to navigate powering an off grid cabin.

So far the cheap 12v inverter and generator have been flawless… it isn’t sexy. Honestly everything else has struggled with the lack the sun, cold weather, or technical issues. I could have definitely built a robust bomb proof simple 12v system for what I have spent trying to chase my tail.
Now I have to shut down the 24v to wait for parts from Sok. I could just have heard to Walmart or cosco and picked up a new $100 battery or 12 of them honestly.

Personally me if I were you this is what my plan is to do is you see my propane hookup you can direct email me at Stifflerjj4u@AOL.com or in here but I checked my emails more than I did this for him but when you want to run your microwave and stuff like that in the evening you start your generator run it for a while which lights running I have a car charger that charges the batteries when the generator is on to charge the batteries and everything I have inside my fifth wheel all runs on 12 volts it's the easiest solution that generate supplied in the picture can run 22 hours at 25% load on a 20 lb propane tank the generator has a remote start so inside the cabin or fifth wheel I just hit the start button generator starts I got all the power I let it run in the evening from 6:00 to about 9:00 maybe even 10:00 shut her down finish watching the rest of my show or lights or whatever and then go to bed and the batteries will hold long enough till the next day solar coming in and repeat the process but I just bought 8 6 volt batteries golf cart that are $232 amp hour batteries and I'm purchasing the eg4 6500 AIO and that's going to be hooked up to my generator to automatically turn on wouldn't bad as you get low I'll put it in standby mode and use all my loaves during the day turn it off at night and bought two buck inverters that use almost have no standby consumption to reduce my 48 W battery bank system down to 12 volts to run my 12 volt light at night to run my 12 old fridge at night and to run the 12 volt furnace fan so instead of having those loads on top of the idle consumption of 80 Watts for the AIO turn the AIO off at night and just run your buck converter will mention it about bringing a small inverter like the victron Phoenix so you can still get 110 v power for your overnight loads that are very small so you don't have a high idle consumption but most of my camper runs 12 volt anyways so a buck converter is even a cheaper solution 35 bucks Amazon and I've got 12 volts from my 48 volt system come daytime you can get a 110 volt automatic timer that turns on by the day that will turn your AC connection back on autonomously the AIO sees a load from the camper being now connected and the inverter turns itself back on and you're just utilizing a cheap 110 volt timer like a switch to make it more autonomous

 

[12VoltInstalls]

holy punctuation, batman​

 

[Stiffler]

holy punctuation, batman​

Yea I do voice txt... I'm lazy lol

 

[Scoutmaster]

TV is 60W? Phone is minuscule.
Can you go to 12VDC led’s for lights?
That might cut the Wh a lot.

I need to look into some 12v lights.

I think my TV & 5 sets of 110v string lights from Costco’ run about 100-150watts combined.
These are the main usage for about 8-14 hours per day while at cabin in winter. I shut the system down when I’m skiing. so some days it’s just 1-3 hours in the morning and from 6pm-12 at night. I run my auto-start generator when making coffee/microwave/toaster.

When it’s full blown winter with 3-6 feet of snow I’m in the cabin for longer sections of time. I’m rarely there for more than 2-3 days in a row.

How many amps will your charger do?

I currently have 2- 15amp Car chargers.

I bought the lv2424 hybrid hoping to use that charger/inverter. So far I fear the idle consumption and low battery sensitivity of the unit might make it unusable for me.

Lead acid needs a higher voltage ‘bulk’ followed by a few hours of ‘absorb’ at like 13.2/13.4; at 12.8V nominal that’s ~110Ah or 5-6 hrs of charging, minimum, rough ballpark, at 20A rate. In practice it will probably be half that time at ‘surface charge’ but it will settle lower than you want. So you need the absorb time. 400W of panels in practical terms is 25% to 30% of what you need in winter at high latitudes though the math suggests 400W is enough. And it maybe is for 7 months of the year or so.

This summer the 400w with just 2 batteries was working out great. As fall has come it is obvious I don’t get the watts needed.

You can discharge it below freezing, you just can’t charge it below freezing. Ever.

I was thinking the server rack and a “battery switch” and/or the server rack connected
To the lv2424 and only turn that on when the cabin warms up. I would run the 12volt or generator system when I first arrive for the first few hours. My cabin warms to 60 degrees in about 2-5 hours after I fire up the wood stove and propane heater.

I’m considering ditching the lv2424 and just going back to 12v and buy inverter/charger from Victron. Or keeping what I have and just getting a battery switch and run 2 sets of batteries. 1 set of lithium and 1 set of lead-acid. Run the lead acid for a few hours and when they die run the generator/chargers and lithium as the cabin warms up?

 

[Scoutmaster]

 

[12VoltInstalls]

only turn that on when the cabin warms up

It it could take several hours for the battery to begin to warm up. There’s a lot of mass there, and if it’s at say 22° battery temperature it might take all day and part of the next or more before the battery warms up.
Not saying you can’t do what you propose, but what I’m saying is you need to be aware that it’s not just warm air temperatures the battery has to be thoroughly above 32°F

 

[12VoltInstalls]

Yea I do voice txt... I'm lazy lol

You can say things like, “period,” “comma,” “quote,” “semicolon,” and “hyphen.” Then it won’t be a rambling jumble of words like a drunk man doing cocaine.

 

[12VoltInstalls]

fear the idle consumption

Like over a kW/day.

 

[Scoutmaster]

It it could take several hours for the battery to begin to warm up. There’s a lot of mass there, and if it’s at say 22° battery temperature it might take all day and part of the next or more before the battery warms up.
Not saying you can’t do what you propose, but what I’m saying is you need to be aware that it’s not just warm air temperatures the battery has to be thoroughly above 32°F

Good point.
Sometimes I ski in…and the cabin is frozen ? solid. It’s at 7000ft. It’s colder inside than outside.
I have to fire up the wood stove, fireplace, and propane heater. Normally by the morning the entire place gets up to 50-70. I bet it will take 6-12 hours for the batteries to warm up safely.

 

[Checkthisout]

Didn't read your whole deal but lithium batteries are not for you.

Your system needs to be generator-based with solar assist like mine.

In your case the solar should be treated like a battery tender with the side benefit of sometimes saving generator fuel.

Get a big charger and the gen to juice up the bank then run the rest of the day/night off the batteries then do it again. Charge the batteries with the Gen before you leave then allow the solar to keep them tended when you're not there.

And also, you guys need to stop purchasing these AIO's with horrendous parasitic draws and just get separate components.

 

[Scoutmaster]

Like over a kW/day.

Agree that’s basically idle consumption of one 12v 100ah battery assuming it is fully charged. So if I wanted to leave the 2424 turned on most of the day in the coldest part of winter with very little sun.. I’d need 1200wh for just the inverter and 4800wh for my basic load of 200watts.

I really need 5- 12v 100ah lithium’s or 10- lead acid.
1 server rack battery 5000wh would run this in the summer maybe 2 of them for 2-3 days.

I think even with some Solar I won’t get more than 2-3 hours most days. There are dozens of 100ft pine trees all around my cabin.

What I’m realizing is I need a “great” battery charger or 2…during the winter.

Anyone recommend a “charger/inverter” I can pair it with my generator. I have a 4500w gas generator and 2500w dual fuel generator as a back-up.

 

[Checkthisout]

Agree that’s basically idle consumption of one 12v 100ah battery assuming it is fully charged. So if I wanted to leave the 2424 turned on most of the day in the coldest part of winter with very little sun.. I’d need 1200wh for just the inverter and 4800wh for my basic load of 200watts.

I really need 5- 12v 100ah lithium’s or 10- lead acid.
1 server rack battery 5000wh would run this in the summer maybe 2 of them for 2-3 days.

I think even with some Solar I won’t get more than 2-3 hours most days. There are dozens of 100ft pine trees all around my cabin.

What I’m realizing is I need a “great” battery charger or 2…during the winter.

Anyone recommend a “charger/inverter” I can pair it with my generator. I have a 4500w gas generator and 2500w dual fuel generator as a back-up.

A victron Multiplus is a nice one.

Otherwise just get separate components and use a transfer switch

 

[Scoutmaster]

Didn't read your whole deal but lithium batteries are not for you.

Do you think 4- 12v deep cells or 6 for the winter? There are 2 new ones on Craigslist for $100 total so I could pick up 2 more and only have $300 invested.

Your system needs to be generator-based with solar assist like mine.

In your case the solar should be treated like a battery tender with the side benefit of sometimes saving generator fuel.

Good point. I’m discovering that it’s painful.

Get a big charger and the gen to juice up the bank then run the rest of the day/night off the batteries then do it again. Charge the batteries with the Gen before you leave then allow the solar to keep them tended when you're not there.

What charger and battery bank do you have?

And also, you guys need to stop purchasing these AIO's with horrendous parasitic draws and just get separate components.

I have very limited solar hours and solar complex space issues since my cabin is on Forrest service land.

 

[Checkthisout]

Do you think 4- 12v deep cells or 6 for the winter? There are 2 new ones on Craigslist for $100 total so I could pick up 2 more and only have $300 invested.

Good point. I’m discovering that it’s painful.

What charger and battery bank do you have?

I have very limited solar hours and solar complex space issues since my cabin is on Forrest service land.

I have 3 8D 240 Ah batteries @ 12 Volts.

A 30amp RV transfer switch, a 3000 watt inverter, and 70 Progressive Dynamics charger and a 3000 watt yamaha inverter generator.

Generator runs about 4.5 hours and then I make it the rest of the day on 2400 watts of solar and battery juice.

When I have little solar output, the generator usually has to start twice so it runs about 7-8 hours a day in the winter when it rains and I am occupying the place.

The more battery the better.

The more solar panels the better.

The bigger the charger the better.

Etc.

Maybe grab 4 golf cart batteries from costco. They are cheap enough to experiment with.

 

[12VoltInstalls]

Maybe grab 4 golf cart batteries from costco. They are cheap enough to experiment with

And if you you don’t draw them down under 12.1V and pay attention to the electrolyte levels using distilled water only you could get substantial life out of them. By substantial I mean 5 or more years out of them.

If you have a contact in forest service office, some basic negotiation skills and asking the right questions in a careful manner (have them come up with the solution) the ‘argument’ of taking down a few trees under their direction to benefit the environment (less fossil fuel usage!) I’d bet your chances are way over 50% of pulling a few trees out. (I’ve talked my way into permissions to go camping in no camping public land areas, talked my way into state parks without paying, gotten access to boat-in camp sights without paying LOL. That’s not my modus operandi but when access is denied- or cutting trees not permitted- and the people responsible for enforcing rules come up with solutions rather than you outright asking, written approval can often be obtained)

 

[Scoutmaster]

Thanks ? for the advise. Sorry for delay I was out at the cabin for the first snowfall.
I’m going to look into the Victron golf cart batteries from Costco…and also some 12v lights.
Any good reviews on some good safe 12v lights?
My inverter said it was using about 100w-150w when the tv/lights are on. I doubt it’s accurate. When I’m running just the string lights the inverter says “0 watts” but it’s 5 strings so it must be more than that.

 

[Vigo]

I would definitely stick to lead acid in your situation.

While it was pointed out that you should never charge lithium while below freezing, with lead acid it's discharging while below freezing that can cause an issue.. lead acid in general you want to recharge as quickly as is practical, but if ambient temps in the battery area are far below freezing you also don't want to discharge them because the electrolyte can freeze and physically damage the plates. As the SG of the electrolyte changes so does it's freezing point, and how far below freezing the batteries will ever see is also the limit of discharge you'd ever want to see (at night, anyway). This is not so much an issue while you are there but your low voltage disconnect needs to be set to protect the batteries from freezing at the times you aren't there and the battery area is not a heated space.

Battery charging itself is not a heating strategy.. the heat generated will only be the inefficiency of the charging process, so maybe 10-20% of your charging watts. But at some point in the charging process a good chunk of THAT will be floating out the vent caps as well rather than heating the battery.