New to Solar

[pbennison]

Hello Everyone,

I am new to solar. My wife and I bought a cabin with no access to Grid electricity. The cabin is located in northern NY and will be used mainly during the spring, summer and fall. I am planning to use propane as our main source for heating, cooking, etc. with electric appliances kept to a minimum.

My initial thoughts include using a gas generator to charge a battery bank while we are there and then to have a small solar system to trickle charge and keep a charge on the batteries while we are not there.

I have googled and found a ton of resources, but, am still looking for advice from people that have done this before.

 

[newbostonconst]

Some Minisplits are more efficient then Natural gas and way cheaper then propane on all levels....and they air conditioning also....and they work well with solar and batteries...

I always thought I would do what you are doing and make a trailer with solar/batteries on it that could be drove to both locations and used....

Good luck, sounds like a great project....jealous...up state New York is so beautiful...we used to live in the 1000 islands but are in Michigan now.

 

[Japera]

Can you list the appliances you're gonna be using on this system? Based on that people on here can recommend a system size. I've seen systems from 100A to 400A. I know it can be greater or less.

 

[rhino]

Need more info about your situation. How much solar exposure you have would also be really important to know.

 

[pbennison]

We have an RV that I am trying to sort of replicate. Here is the list of items. I am sure I have left something out so I was thinking whatever the below list requires I can add a 25% factor to it, maybe more? Would also like to have capability to expand.

2 Fans
15 Led Lights
Microwave
Vacuum Cleaner
TV 48 inch LCD
Well Pump (future)
Stereo
Laptop/Phone chargers
Refrigerator (I have also looked at propane refrigerators if this breaks the system)


I have a 3500W and a 2000W generator. The southern exposure is against a tree line so I do not think it will be a great source of power, which is why I was thinking of just putting in a system to maintain as opposed to charge.

 

[pbennison]

Some Minisplits are more efficient then Natural gas and way cheaper then propane on all levels....and they air conditioning also....and they work well with solar and batteries...

I always thought I would do what you are doing and make a trailer with solar/batteries on it that could be drove to both locations and used....

Good luck, sounds like a great project....jealous...up state New York is so beautiful...we used to live in the 1000 islands but are in Michigan now.

Thanks. Can you give me some background on what a mini split does?

We have an RV and have been to 1000 islands before and agree upstate NY is beautiful. We are planning a trip out west and Michigan is on the plan. Thinking of doing something similar, maybe a bit smaller for the RV. I like your idea of having a trailer so it can be utilized at the cabin and with the RV.

 

[newbostonconst]

Mini Splits are like an air conditioner that is reversible so it can either heat or cool....Geo thermal used to be the most efficient to heat/cold and now Mini Splits are the a lot better then geo. They don't have big motors so work well with inverters.

A simple google search will tell you a lot.

 

[Japera]

We have an RV that I am trying to sort of replicate. Here is the list of items. I am sure I have left something out so I was thinking whatever the below list requires I can add a 25% factor to it, maybe more? Would also like to have capability to expand.

2 Fans
15 Led Lights
Microwave
Vacuum Cleaner
TV 48 inch LCD
Well Pump (future)
Stereo
Laptop/Phone chargers
Refrigerator (I have also looked at propane refrigerators if this breaks the system)


I have a 3500W and a 2000W generator. The southern exposure is against a tree line so I do not think it will be a great source of power, which is why I was thinking of just putting in a system to maintain as opposed to charge.

I have heard of people who live off grid full time and you're always gonna need your generator as standby. You would need to know how much power each appliance draws by looking on the nameplate for amps/watts/volts.

 

[pbennison]

Hmmm......the problem here is that I don't have the appliances yet, we actually have not even closed on the property...and with winter approaching I will not get to this until spring...I took a quick google and have the following estimates...at this time it is my engineering (mechanical) background kicking in and trying to plan as best I can....Thanks everyone for the input...it is starting to make more sense than simply googling everything...

App Power (Watts)
Fans 300
LED Lights 70
Microwave 1500
Vacuum 1500
TV 100
Misc 250

Total 3750
25% 950

Total 4700 Watts

 

[HRTKD]

In my mind, the big question to answer first (after knowing what you need to provide power for) is are you going with a 12v DC or 120v AC system for the appliances in the cabin? If the cabin is off-grid now, it probably isn't 120v AC unless the prior owner ran a generator. If it is 120v AC, I would probably keep it that way and design around that. A sufficiently large inverter and battery bank would be needed to handle inefficient appliances.

How much sun is available? Is there a lot of shade? A system could certainly be designed to support 120v AC, but if you don't have enough sun then a generator will be needed. It all depends on how much you want to spend on this. Are you looking for a budget solution or an optimal, never-have-to-worry-about-it solution?

 

[pbennison]

In my mind, the big question to answer first (after knowing what you need to provide power for) is are you going with a 12v DC or 120v AC system for the appliances in the cabin? If the cabin is off-grid now, it probably isn't 120v AC unless the prior owner ran a generator. If it is 120v AC, I would probably keep it that way and design around that. A sufficiently large inverter and battery bank would be needed to handle inefficient appliances.

How much sun is available? Is there a lot of shade? A system could certainly be designed to support 120v AC, but if you don't have enough sun then a generator will be needed. It all depends on how much you want to spend on this. Are you looking for a budget solution or an optimal, never-have-to-worry-about-it solution?

There is nothing in the cabin. Looks like they may have had a generator right outside since there is a small refrigerator with an AC plug through the wall. That is literally the only thing I can see that was powered, they must have used small lantern lights. My thoughts are to go with 120v AC.

I would estimate that the sun is 50% since there is a lot of shade. I really don't think there is enough sun to power everything, but, I am a complete newbie on this. Also, I already own two generators so at least for the initial stages I was planning to use them. Don't want to run them 24/7 which is why I was thinking of a battery bank.

 

[HRTKD]

You can work around the shade by installing more solar so you get the maximum charge in the least amount of time. Then again, chainsaws aren't that expensive.

Here in Colorado, fire mitigation is a big issue. Trees too close to the dwelling will raise red flags with the insurance company. That would be a good excuse to cut down some trees and expose the dwelling to more sun.

 

[Japera]

Since you more than likely won't use the microwave and vacuum at the same time if I were you I'd size my system for 3000. thats cuz 3700-1500=2200 + 25% will be 2750. Just my two cents.

 

[FilterGuy]

Hello Everyone,

I am new to solar. My wife and I bought a cabin with no access to Grid electricity. The cabin is located in northern NY and will be used mainly during the spring, summer and fall. I am planning to use propane as our main source for heating, cooking, etc. with electric appliances kept to a minimum.

My initial thoughts include using a gas generator to charge a battery bank while we are there and then to have a small solar system to trickle charge and keep a charge on the batteries while we are not there.

I have googled and found a ton of resources, but, am still looking for advice from people that have done this before.

A few thoughts.
1) The first thing you should do is create an energy audit of your expected power needs. There are several on-line audit tools or you can use this: https://diysolarforum.com/resources/system-energy-audit-and-sizing-spread-sheet.12/
The challenge you will have is that since you do not have the appliances, you can not measure the actual current or power draw. All you can do is look up the power rating for the device. This will *always* be higher than the actual usage so the number the spreadsheet gives you will be too high. You can probably get away with de-rating the specified power usage by 10% -15%.

Once you have the audit complete, you will have a reasonable ballpark of your needs and can plan from there. It will also allow you to do some 'what if' scenarios for different plans.

One great side benefit to the audit is that it will point out where your big usage is.... and that will be valuable to know when you are living there and trying to manage the power budget.

Note: I have a very similar situation with a hunting cabin in Montana.

• Stove, Hot Water and Refrigerator are on LP.
• Heat is with a wood fired stove
• Everything else is 120V AC (TV, lights, microwave, computer, etc)

The system uses 8 200Ah cells wired for 24 volts and it works well for me. Since you are charging via Generator, you may want to have more storage than that so you don't have to run the generator as often.

2) How cold does it get at the cabin? Northern NY sounds like it can get *very* cold so you have to worry about both charging temp and absolute temp. You will certainly need to have some type of insulated battery box and a warmer. At my cabin in MT, I completely disconnect the battery from the system and I unhook the BMS balance leads. (Absolutely no loads on the cells). Since LiFePO4 has a 2-3%/month self-discharge rate, they can sit like that for several months. Furthermore, I don't have to worry about a system failure of the trickle charger while I am not there.

With the cells completely disconnected, you only have to worry about storage temperature. I have researched this a lot and do not have a definitive answer, but it seems that storage down to -20C is OK. -20C is 'only' -4F so for storing the cells over the winter, I use the heater system I documented Here:
https://diysolarforum.com/resources/simple-indipendent-battery-box-heater.115/

Note: Make sure the battery box is well insulated and sealed up. I am talking something like R30 all the way around.
As an added precaution, I added two large freezer packs inside the insulated battery box. If the inside gets below freezing, the phase change energy release of the freezer blocks will hold the temp at freezing for a couple of days. (You can't charge, but the batteries are not getting colder either). The down side of this is that when the freezer blocks thaw out, they will absorb just as much energy so it will take longer to warm up.

BTW: Watch for videos from @Will Prowse about cold charging. He recently bough a freezer and plans on testing some Winston cells that supposedly can handle cold charging better.

 

[newbostonconst]

I run a 7000 sqft house with a constant load of 500 watts with 6 people living there(yes, peaks are higher)....I have a 4000 watt inverter that runs what we need in backup. Well pump, lights, frig's, and other small loads. We have Natural Gas for heating and cooking.

I don't agree with the listing of every component and then summing them up and saying that is what you need. I would need a 10,000 watt generator which isn't real.

 

[pbennison]

I run a 7000 sqft house with a constant load of 500 watts with 6 people living there(yes, peaks are higher)....I have a 4000 watt inverter that runs what we need in backup. Well pump, lights, frig's, and other small loads. We have Natural Gas for heating and cooking.

I don't agree with the listing of every component and then summing them up and saying that is what you need. I would need a 10,000 watt generator which isn't real.

I agree, in our previous house I ran a 3500W generator when we had outages. Same thing, heat, dryer, oven, etc. were all natural gas. I never had an issue. Of course, I had to warn everyone that their is no hair dryers, toasters, coffee makers when running on generator.

So, in this case, I am going to assume that 3000W will be what I need and design accordingly with the capacity to expand.

 

[pbennison]

A few thoughts.
1) The first thing you should do is create an energy audit of your expected power needs. There are several on-line audit tools or you can use this: https://diysolarforum.com/resources/system-energy-audit-and-sizing-spread-sheet.12/
The challenge you will have is that since you do not have the appliances, you can not measure the actual current or power draw. All you can do is look up the power rating for the device. This will *always* be higher than the actual usage so the number the spreadsheet gives you will be too high. You can probably get away with de-rating the specified power usage by 10% -15%.

Once you have the audit complete, you will have a reasonable ballpark of your needs and can plan from there. It will also allow you to do some 'what if' scenarios for different plans.

One great side benefit to the audit is that it will point out where your big usage is.... and that will be valuable to know when you are living there and trying to manage the power budget.

Note: I have a very similar situation with a hunting cabin in Montana.

• Stove, Hot Water and Refrigerator are on LP.
• Heat is with a wood fired stove
• Everything else is 120V AC (TV, lights, microwave, computer, etc)

The system uses 8 200Ah cells wired for 24 volts and it works well for me. Since you are charging via Generator, you may want to have more storage than that so you don't have to run the generator as often.

2) How cold does it get at the cabin? Northern NY sounds like it can get *very* cold so you have to worry about both charging temp and absolute temp. You will certainly need to have some type of insulated battery box and a warmer. At my cabin in MT, I completely disconnect the battery from the system and I unhook the BMS balance leads. (Absolutely no loads on the cells). Since LiFePO4 has a 2-3%/month self-discharge rate, they can sit like that for several months. Furthermore, I don't have to worry about a system failure of the trickle charger while I am not there.

With the cells completely disconnected, you only have to worry about storage temperature. I have researched this a lot and do not have a definitive answer, but it seems that storage down to -20C is OK. -20C is 'only' -4F so for storing the cells over the winter, I use the heater system I documented Here:
https://diysolarforum.com/resources/simple-indipendent-battery-box-heater.115/

Note: Make sure the battery box is well insulated and sealed up. I am talking something like R30 all the way around.
As an added precaution, I added two large freezer packs inside the insulated battery box. If the inside gets below freezing, the phase change energy release of the freezer blocks will hold the temp at freezing for a couple of days. (You can't charge, but the batteries are not getting colder either). The down side of this is that when the freezer blocks thaw out, they will absorb just as much energy so it will take longer to warm up.

BTW: Watch for videos from @Will Prowse about cold charging. He recently bough a freezer and plans on testing some Winston cells that supposedly can handle cold charging better.

Great info, thank you. I am going to try and replicate something like this.

Lake George - It gets very cold in winter. I live an hour away and suppose I could make weekly/bi-weekly trips to charge? Or I could make system portable to take with me during winter?

 

[FilterGuy]

I don't agree with the listing of every component and then summing them up and saying that is what you need. I would need a 10,000 watt generator which isn't real.

You are correct, particularly in larger situations. However, to do a proper audit, you do need to know what the total power usage will be in order to calculate Battery and Charge needs. In doing that you have all the data to easily calculate max load if everything is on.

On smaller cabin installs or mobile installs, the max load is often small enough that I go ahead and select an inverter that can handle it. On larger systems, it gets impractical to use an inverter that can cover everything.

 

[Japera]

I run a 7000 sqft house with a constant load of 500 watts with 6 people living there(yes, peaks are higher)....I have a 4000 watt inverter that runs what we need in backup. Well pump, lights, frig's, and other small loads. We have Natural Gas for heating and cooking.

I don't agree with the listing of every component and then summing them up and saying that is what you need. I would need a 10,000 watt generator which isn't real.

Certainly you want to list all components. When you do the 24/7 components are what you're gonna build your system around plus like he said a 25% increase. Where that 25% comes from I don't know. Also of importance is you're not gonna have everything on at the same time ie microwave/vacuum cleaner but you do want to have enough power so when you do run a 1500 watt appliance you have enough power.