Cabin Solar during Winter

[BoNeil]

That is all you can expect from 400 watts with 2-3 hrs of indirect sun lite. When you say 20-30 watts is that what your panels are producing while in the sun? if possible relocate panels to capture more sun light. I have an off grid cabin on a lake with 4 x 250 watt panels. In the winter we get about 4 hrs of direct sunlight. I do not get enough power to fully charge the batteries ( 12 x 2 volt ) so the generator has to make up the difference unless the sun is out all day everyday. Of course your electric power consumption comes into play

 

[Scoutmaster]

After a very long…. ..epic winter…… I have to say the Generator won the war. Solar panels were buried under feet of snow most of the winter.

The 2 - 12v Sok batteries seem to not be holding much of a charge. The 400w of Solar didn’t seem to ever fully charge the batteries and most of time were submerged in feet of snow.

I think a combination of cold temperatures and endless storms with metric tons of snow just overwhelmed everything.

My Winter in review:
Just my quick thoughts and story!

I ran about 15-20 gallons of gas through my generator for a total cost of about $75-$100. I would estimate I get about 8-10 hours per 2 gallons and I ran it around 100 hours this winter. On a normal weekend I would run it 3-4 hours per day. Most weekends I barely used 2 gallons of gas. I would arrive Friday night and run it for 2 hours until the cabin warmed up from the wood stove and I was ready to go to bed. 2 hours in the Morning making coffee and just sitting around waiting to go ski. 2-3 hours on Saturday night and briefly Sunday morning charging batteries and running various appliances and a quick vacuum. I never used a full tank of gas. Approximately 2.5 gallons.

The 2 SOK 12v lithium batteries wouldn’t accept a charge since they were well below 30 degrees when I arrived. I think this almost makes them a liability or almost worthless with Solar in the mountains during the winter.
I had a few old deep cells i ran LEDS with just to make some background light.

I would run the batteries to watch TV run 4 sets of Costco string lights until I went to bed and they normally would take a charge after a few hours. They didn’t seem to have much power this winter. I didn’t test them, but I felt they barely would run lights and a TV for 3-4 hours before they would almost need a charge.

My system has been a mess since I tried to build it. Most of this is probably my fault. I have 400w of Solar from Renology 4x100w panels. A cheap Renology solar charger, 2 SOK 12v and a 2000w Inverter, with 2 x 15amp car chargers for the batteries. Overall the generator has been my best purchase as far as cost and reliability.

After 2 Winters and 2 summers I estimate I’ve used about 100 gallons of gas at a cost of about $350-400 and I paid $800 for the Gen. I have 2 years of weekend power for about $1200.

I’ve spent about $2000-3000 on misc Solar/batteries and have had a few great days where it works like magic and several others just shoveling snow or pulling my hair out. I do like having the battery power the evening and daily miscellaneous stuff.

I’m going to revisit the entire project this summer when the snow melts and I can access the entire cabin. I’m hoping to add a shed which might help with mounting a few panels and building a better insulated battery bank. I probably need to start over but I’m keeping the generator for sure.

 

[OffGridForGood]

Hope you folks will be okay as all that snow rapidly melts - it has to all go somewhere. Keep the ESS charged, stay safe neighbours.

 

[Scoutmaster]

It’s probably going to leak through the walls probably along the bottom few logs.
I’ll be curious if we get any serious damage.

Last year I had minimal snow and this year is just insane.

 

[Johneb]

If I may ask. Where is this cabin located?

 

[12VoltInstalls]

If I may ask. Where is this cabin located?

right under that snow drift

 

[Johneb]

I kind of figured that.

 

[Johneb]

The reason I put that there was the manual states there must be a fuse within 7 inches of the inverter. Should I have two fuses then?

 

[Scoutmaster]

“right under that snow drift” ?

We are in the Uinta-Wasatch-Cache National Forest which has seen record snow fall all winter. It makes travel and maintenance tricky in the winter. Our cabin is several miles from the closet road about 6 months of the year. The other six months it’s easily accessible.

 

[Scoutmaster]

Quick update and question…
My 2 lithium SOK’s 100ah seem to be working this summer with 400w of panels. I can charge the ebike run lights and tv for a full weekend. I rip the generator on for a pot of coffee and microwave.

I was just basically just given 6 golf Cart 6v batteries.
They are used but I only paid $7each. I’m out $42.

I haven’t tested them yet but i think they should give me some juice during the winter when the lithium’s have sort of disappointed.


I’m curious if I should set them up as a totally different system…I can easily buy 2-4 panels/inverter/solar charger or just hook them up to my current system with a switch.
I already have the switch but need to pick up a solar charger and a few panels.

 

[RJuelfs]

Set up two battery banks with a quick connect (like a forklift battery uses). Use one FLA when it is cold and lithium when you can. Be sure to keep them both topped up.

 

[OffGridForGood]

What about one of those selector switches the boating people are using, "1-off-2" , you can pick Lead-Acid or LiFePO4 or none with the turn of the switch?

 

[12VoltInstalls]

What about one of those selector switches the boating people are using, "1-off-2" , you can pick Lead-Acid or LiFePO4 or none with the turn of the switch?

The BlueSea switches work good, are quality products, and are likely to have an appropriate amp rating that’s believable.
This one will not let you connect both batteries at the same time so it’s an advantage here.

 

[Scoutmaster]

Quick update and question…
My 2 lithium SOK’s 100ah seem to be working this summer with 400w of panels. I can charge the ebike run lights and tv for a full weekend. I rip the generator on for a pot of coffee and microwave.

I was just basically just given 6 golf Cart 6v batteries.
They are used but I only paid $7each. I’m out $42.

I haven’t tested them yet but i think they should give me some juice during the winter when the lithium’s have sort of disappointed.


I’m curious if I should set them up as a totally different system…I can easily buy 2-4 panels/inverter/solar charger or just hook them up to my current system with a switch.
I already have the switch but need to pick up a solar charger and a few panels.

Quick question what’s the best way to connect 6- 6volt batteries to get 12v?

The BlueSea switches work good, are quality products, and are likely to have an appropriate amp rating that’s believable.
This one will not let you connect both batteries at the same time so it’s an advantage here.

The BlueSea switches work good, are quality products, and are likely to have an appropriate amp rating that’s believable.
This one will not let you connect both batteries at the same time so it’s an advantage here.

Thanks again I’ll pick up that switch.
I have a cheap one I bought last year I never used. I like (12vinstalls) ideas about redundancy and I had tricky winter with 2 lithiums and way to much snow and zero Solar.

I’m curious if I use all 6 …6v batteries what is the simplest way to charge and connect/hook them all up? I found this diagram for 6v by 6 batteries. With 6 batteries any concerns with solar input or special charger or cables? I’m using a 15amp battery charger now and just 4x100w Renology panels with a basic solar charger.

 

[sunshine_eggo]

Use this diagram:

 

[12VoltInstalls]

6v batteries what is the simplest way to charge and connect/hook them all up

No good way to do that when after your voltage is achieved (2S) the multiplier (3P) is a prime number.

That diagram would work, but I’d do this one making each cable to busbar equal length

 

[Scoutmaster]

Make 3 separate 12v and send that to a Bus bar. Connect positive to positive ….and negative to negative. Making sure I see this correct.

 

[Daddy Tanuki]

your lithium's stopped working due to temp. if you can keep them warm you can use them year round. it gets down to -18º~20ºc in my area or about -1º ~ -4ºf so not as cold as you probably but cold enough. when i first built my system i used agm's because they are pretty good at dealing with cold temps and self heat while charging and discharging. problem was they did not charge fast enough in the winter and died at the 3 year mark. when i went lithium my batteries charge way faster I am now completely over paneled at my cabin. but with the lithiums I had to build a battery heater. there are many ways to do it. one thing if your in the cabin, and the batteries are in the cabin they should be fine. you could always take them home when you leave and bring them up to a full charge just prior to going back to the cabin... or you can build a battery heater. in the winter months while using the genset in the morning for coffee and what not you could juice the LiFePo4's in an hour and let the system run off of the panels until you lose sun... a lot of different ways to skin the cat.

 

[Scoutmaster]

your lithium's stopped working due to temp. if you can keep them warm you can use them year round. it gets down to -18º~20ºc in my area or about -1º ~ -4ºf so not as cold as you probably but cold enough. when i first built my system i used agm's because they are pretty good at dealing with cold temps and self heat while charging and discharging. problem was they did not charge fast enough in the winter and died at the 3 year mark. when i went lithium my batteries charge way faster I am now completely over paneled at my cabin. but with the lithiums I had to build a battery heater. there are many ways to do it. one thing if your in the cabin, and the batteries are in the cabin they should be fine. you could always take them home when you leave and bring them up to a full charge just prior to going back to the cabin... or you can build a battery heater. in the winter months while using the genset in the morning for coffee and what not you could juice the LiFePo4's in an hour and let the system run off of the panels until you lose sun... a lot of different ways to skin the cat.

Yeah I really struggled hard this winter with the lithium. My cabin is cold below 32 for 3 months…and 3-5 miles from the nearest road in the winter. Unfortunately I have some limitations on adding Solar. My cabin sits against a 2000ft of mountain above it…and has some massive trees that block the sun. The panels just got buried this winter in a few storms and I completely gave up. Next winter I might just mount a few to the exterior walls just for the winter.

I can’t build anything on the land for legal reasons so my panels are just 4x100w currently. I’m going to add at least 4 more to face different angles next winter so i can attempt to harvest a few extra watts. Last winter I think the batteries were to cold to recharge during the days I wasn’t there. Last winter I only had a car charger of 15amp and focused on just running the generator morning and night but the batteries were often to cold to take a charge. I have propane lights and wood heat so I can survive without the electricity but I really like having the lights and tv.
Next winter I’ll try and insulate the batteries and make some sort of a heater. I’m going to add a 2nd bank of lead acid just to have a backup and I might double my 2 SOKS to 4 just to make sure I can keep the lights on for the weekend.

 

[HarryN]

Looks like you have come into the hard truth about using LiFe in an area that gets winter.

It just does not make sense to use Li batteries in those types of conditions. Insulation will slow down the heat transfer but it will not stop it.

As far as the Trojan T 105s, those are a deep discharge, low current style battery. They are very good, but designed for use with things like fans, lights, the DC power needed for a fuel heater, etc. They are not really designed for use with the power demands of an inverter.

For an inverter, you will want a marine style battery, which is a sort of hybrid between a deep discharge and a starter battery. They are designed to keep up with the serious power draw of an inverter. Examples of this are Lifeline GPL series and Vmax tanks, there are a few more - will try to think of them.

Rough numbers design around the concept of 1 battery per 500 watts of inverter capacity as far as ability to delivery power minimum. You can add more capacity as needed for total needs, but it takes that to keep up with the inverter.

Nothing wrong with SOKs for the correct application - but your cabin is completely the wrong application for them.

___________

A 24 volt system will be more tolerant of cold weather conditions than a 12 volt system as it is less sensitive to voltage sag from the cold.

Poly panels tend to be better at collecting sunlight in over cast conditions - at least in my testing of some solarland ones with a bogart controller.