Please help! Solar confuses me so much.

[WhenIm64]

I don't know how much I will need. I will have a fridge to power. I would like to grind coffee occasionally. Perhaps use a microwave for a couple minutes a few times a week. I will have a phone, tablet and laptop to keep charged. Perhaps watch a little TV or pay DVDs. What I really want to be able to power is my sewing machine and a very small iron. I'm sure there are things I have not thought of but I hope this covers the most important things.
Since I don't understand how the solar system works, I hope someone can advise me. I have been advised to buy as much solar as I can afford. I will be pulling a small fiberglass trailer with a sloping roof and do not want to put solar up there. So, after watching Bob's video on "briefcase" solar panels, I thought I could buy 4 200 watt folding solar panels. 
I don't know how many batteries (preferably lithium) that i will need. There is room for two batteries built in to my trailer. Can I somehow add more if that's necessary for my proposed total of 800 watts of solar?
It would be so lovely if someone could advise me. Does this plan sound plausible? Thank you so much.

 

[Elbear1]

800w is good for 2 batteries and should do you fine. Especially if you get lithium.

 

[tx2sturgis]

Many of those 200w folding panels cost as much as a low end 1000w inverter generator.

Your microwave oven is going to be the main power hog, although if only a few times a week, but you will STILL need a large inverter, a substantial battery bank, heavy cables and fuses, etc, and plenty of solar input meaning lots of moving of the panels all day long to track the sun, trying to replace the juice you used to power the microwave for 15 minutes the night before, plus all the other loads. Positioning and re-positioning four 200 watt folding panels multiple times per day, plus storing them in a small trailer, will get to be a pain after awhile.

In other words: Consider buying only 2 of the 200 watt folders, and supplement your power needs with a nice quiet inverter generator in the 2000 watt range. This will charge your batteries when needed, power the microwave when needed, and give you backup power when you need it most.

Many of the gensets are equipped with a 30amp RV plug, presumably your trailer has a 30 amp connection.

If you can make do without the microwave then you very likely wont need the generator or the large inverter. It just all depends on how you want to do your cooking...and how much you consider the microwave a necessity, especially if you only use it a few times a week. That will kinda prove how little you really need it.

 

[highdesertranger]

don't buy anything until you get a grip on what you need. and keep this in mind,

it is always cheaper and easier to conserve energy then it is to make it.

back to your solar. take these three steps in order
1. figure out your daily usage
2. size your battery bank according to number one
3. size your solar to number 2

so first off lets get your usage. everything should have a consumption rate either in watts or amps. list the items you want to power and for how long per day.

couple of hints,

heating with electricity is very inefficient so things like the microwave and iron are going to be big draws. in other words they are going to add a lot to cost and complexity.
using 120v appliances means running through an inverter which adds losses.

highdesertranger

 

[regis101]

Minor point to add.
Part 3a. With regards to your location.

 

[DannyB1954]

Panels may put out their rated amount of power if you are at the equator at noon. I have 960 watts of panels which is about 80 amps at 12 volts, but the most that I have seen come out of them in direct sun was 50 amps. The iron is the major problem that I see. Using electricity to heat anything takes a lot. If you only turn the iron on for the time that you need it, you may be OK. They heat up pretty quick. So 5 minutes here and there is probably OK. Leaving it on for an hour may not work.

I tried a microwave for a short time with only two batteries. The voltage of the batteries dropped quickly and the inverter was not having any part of it. I don't remember if my panels were in the sun at the time, but I figured I needed the space more than I needed the microwave anyway. The sewing machine is maybe a 100 watts, but that is only while the pedal is pressed. Most of sewing is in the getting ready to sew time zone, (yes I sew. To me it is just as challenging as welding. You fit small pieces together and end up with something useful).
I also carry a small inverter generator. A 1,000 watt unit will run a good sized battery charger. Maybe 40 amps.The only thing that gets plugged into my generator is a battery charger. Everything else runs off of the inverter. There will be days were you are stuck inside because of weather maybe and solar won't work.

 

[DannyB1954]

I was thinking about the iron. If you used a candle or small camp stove to heat a plat,e and then kept the iron on the plate, it would take no time at all for it to come up to temp when you needed it. In the old days that is what they did. The iron was just that, a big chunk of iron. They kept it on a stove to turn it on.

 

[rvwandering]

I have this little iron - https://www.walmart.com/ip/Steamfast-SF-727-Travel-Mini-Steam-Iron/186719139  - 420 watts at the highest temperature
setting. I don't use it a lot but it works great.

We have 240 watts of solar and 4 lead acid batteries. Our inverter is only 400 watts but it's never cut out.

 

[MeiraNomadRN]

back to your solar.  take these three steps in order
1.  figure out your daily usage
highdesertranger

 Pitifully ignorant question here: would that daily usage be in watts? Watts per hour divided by 60 multiplied by minutes in use?  (I've read some but the info hasn't wanted to stick previously.  Maybe this time.)

 

[WhenIm64]

I have this little iron - https://www.walmart.com/ip/Steamfast-SF-727-Travel-Mini-Steam-Iron/186719139  - 420 watts at the highest temperature
setting. I don't use it a lot but it works great.

We have 240 watts of solar and 4 lead acid batteries. Our inverter is only 400 watts but it's never cut out.

Yes! That is the iron I have. Thank you for the advice.

 

[WhenIm64]

800w is good for 2 batteries and should do you fine. Especially if you get lithium.

Thank you. I hope you're correct. 
Hehe.... now I just have to figure out inverters, converters, 12V, 120V, amps, watt hours etc. 
This is so frustrating. I take pride in teaching myself whatever I need or want to learn. I have done this my whole life. But but solar and electrical terms and processes really have me confused.
Thanks again for your comment.

 

[WhenIm64]

Panels may put out their rated amount of power if you are at the equator at noon. I have 960 watts of panels which is about 80 amps at 12 volts, but the most that I have seen come out of them in direct sun was 50 amps. The iron is the major problem that I see. Using electricity to heat anything takes a lot. If you only turn the iron on for the time that you need it, you may be OK. They heat up pretty quick. So 5 minutes here and there is probably OK.  Leaving it on for an hour may not work. 

I tried a microwave for a short time with only two batteries. The voltage of the batteries dropped quickly and the inverter was not having any part of it. I don't remember if my panels were in the sun at the time, but I figured I needed the space more than I needed the microwave anyway.  The sewing machine is maybe a 100 watts, but that is only while the pedal is pressed. Most of sewing is in the getting ready to sew time zone, (yes I sew. To me it is just as challenging as welding. You fit small pieces together and end up with something useful).
I also carry a small inverter generator. A 1,000 watt unit will run a good sized battery charger. Maybe 40 amps.The only thing that gets plugged into my generator is a battery charger. Everything else runs off of the inverter.  There will be days were you are stuck inside because of weather maybe and solar won't work.

Thank you for your comments. My iron is a very low watt one and I will have to be conservative in my use of it. I am debating the use of a microwave. Initially, I was not going to use it but when I heard that even some van dwellers use them I had to rethink that. My use would be only for a minute or two at most. I would use it to reheat food. I could live without it. 
I know that there may be days that I won't be able to use a lot of power due to weather. I am hoping that I can overcome some of that by having as much solar as I can afford.
It is interesting that you sew. I would love to learn welding. It would be useful in jewelry making. Perhaps we'll meet someday and you can teach me. Thanks again for your comments.

 

[WhenIm64]

I was thinking about the iron. If you used a candle or small camp stove to heat a plat,e and then kept the iron on the plate, it would take no time at all for it to come up to temp when you needed it. In the old days that is what they did. The iron was just that, a big chunk of iron. They kept it on a stove to turn it on.

I have thought of that but I fear the plastic parts may not tolerate that method. My iron is tiny and very low watt. I think it uses 450 watts. I could be wrong. My challenge will be to find ways to conserve my use of it. 
I appreciate your comments. Thank you.

 

[WhenIm64]

don't buy anything until you get a grip on what you need. and keep this in mind,

it is always cheaper and easier to conserve energy then it is to make it.

back to your solar.  take these three steps in order
1.  figure out your daily usage
2.  size your battery bank according to number one
3.  size your solar to number 2

so first off lets get your usage.  everything should have a consumption rate either in watts or amps.  list the items you want to power and for how long per day.

couple of hints,

heating with electricity is very inefficient so things like the microwave and iron are going to be big draws.  in other words they are going to add a lot to cost and complexity.
using 120v appliances means running through an inverter which adds losses.

highdesertranger

I hear what you are saying but I think that I was not specific enough. My trouble is I don't understand volts, watts, watt hours etc. What's a 120 v appliance? How about 12volts? What's that? And then there are inverters, converters, generators and battery packs. I don't understand how they connect or if they do. 
I have always been able to teach myself anything I needed to learn but the electrical system of my trailer is throwing me for a loop. I also have a bad habit of not thinking far enough ahead. If I buy too much solar and too many batteries, I may find they are useful down the road. 
I really appreciate your input. Thank you friend.

 

[bullfrog]

There is a lot to consider when trying to power everything when you are not able to just plug it in like at your house and pay your power bill. There the power is pretty much limited by the size of the service to your house which by code is usually plenty to do most anything. In your trailer out on BLM land you must make your own electricity. It is a lot of work, expensive and hard to store therefore the less you need the less work, expense and storage you need. A generator makes electricity while running on fuel you supply, it does not store electricity and it usually supplies a rough form of 120 volt alternating current electricity that you have in your house and some supply 12 volt direct current like you have in your car battery as well. Some old style generators will not work well with the new computers and computer controlled devices and therefore the new inverter generators have started to replace them when a pure form of electricity is necessary for those computer controlled devices. They still run everything the old ones did as well as the new stuff and can be used to charge a battery. Solar cells produce varying amounts of direct current electricity which can be stored in a battery which can then be changed to 120 volt alternating current by an inverter so that you can use the same devices you used in you house or with the generator. How much power you can produce will be limited by how much work you are willing to do, how much money you have to spend and how much space and weight your trailer can hold or provide. Watts are the unit we use to measure power. Most things that use power have the number of watts written on them somewhere. You can buy a meter that plugs in the plug that will tell you exactly how many watts are being used while whatever it is is being used. Finding out and making a list of is the first step in making sure you size and design you power system properly.

 

[future_vandweller]

I have this little iron - https://www.walmart.com/ip/Steamfast-SF-727-Travel-Mini-Steam-Iron/186719139  - 420 watts at the highest temperature
setting. I don't use it a lot but it works great.

We have 240 watts of solar and 4 lead acid batteries. Our inverter is only 400 watts but it's never cut out.

In SI Units, energy is measured in Joules (= 1 Watt-second).  Common units are Watt-hrs (=3600 Joules) or Amps-hrs.  When expressed Amp-hrs, the voltage at which the current is delivered is implied (for example, 12 Volts).

If you have an appliance consuming 100 Watts, it's energy use in one hour is 100 Watt-hrs and 2400 Watt-hrs in a day.

 

[highdesertranger]

120v = 120 volts AC(alternating current) this is what you have in your house. a 120v appliance is anything you plug into household current(120v) like a fan, toaster, or anything else that plugs into a household outlet.

12v = 12 volts DC(Direct current) this is what your car runs off of and what you get with solar charging 12v batteries. so this will be your starting point unless you run a generator.

so list what you want to run and how long you want to run it everyday. include with this if it is 120v or 12v and how many watts or amps it uses. almost everything has a watt or amp use on it's label or in the instruction. write this out in a list form like this,

iron = 120v 450 watts 10 minutes a day
cell phone charger = 12v 2.1 amps 30 minutes a day
and so on

so make this list and post it here if you get stuck on something ask for help. we will help.

highdesertranger

 

[bullfrog]

Voltage is the amount of electrical pressure.
Amps are the amount of electrical current.
Watts are the amount of electrical power
Watts are determined by multiplying the voltage times the amps.
The amount of time the watts are being used will determine the amount of electricity you must have available which therefore will determine the size of the generator, solar system and battery bank or a combination of both as determined by amount money, work, space or weight you have available.
The list is something people seldom consider until electricity gets really expensive. Producing your own electricity is expensive which is why people here will start to suggest different ways of doing things which will use as little electrical power for as short as time as possible. A generator is usually the first choice as you just get one big enough to run all the 120 volt alternating current things you had at home, but people soon find out how restricted run times, expensive, noisy, and trouble prone they are if not maintained so they start to look at solar to charge 12 volt direct current batteries and use 12 volt direct current things and an inverter if some things must be powered by 120 volts alternating current. Depending on the solar system, storage batteries and weather they can be quiet and almost maintenance free but are limited by size, weight, and high power needs that can make them impractical. For many this leads to as big a solar system they can afford or fit and as small an inverter generator that they can keep their storage batteries charged up with in bad weather.

 

[future_vandweller]

 Pitifully ignorant question here: would that daily usage be in watts? Watts per hour divided by 60 multiplied by minutes in use?  (I've read some but the info hasn't wanted to stick previously.  Maybe this time.)

In SI Units, energy is measured in Joules (= 1 Watt-second).  Common units are Watt-hrs (=3600 Joules) or Amps-hrs.  When expressed Amp-hrs, the voltage at which the current is delivered is implied (for example, 12 Volts).

If you have an appliance consuming 100 Watts, it's energy use in one hour is 100 Watt-hrs and 2400 Watt-hrs in a day.

 

[DannyB1954]

Another term that seems confusing is battery amp hours. In theory a 100 amp hour battery can put out 100 amps of power for an hour. In practice you do not want to discharge a battery more than 50% as this greatly reduces the life of the battery. If you have two 100 amp hour batteries, you only have 100 amp hours that you can use, (50 amps hours from each battery), and then they need to be recharged.

Watts is amps times volts. In general at 12 volts a device will use 10 times the amps that it would at 120 volts. There are losses involved in the inverter also. so you will actually use a bit more. 450 watts / 120 Volts = 3.75 amps. 450 watts / 12 volts = 37.5 amps. You might be able to run the iron for a couple of hours without power coming in. If you only turn it on when you need to press a seam then turn it off, you should be fine.

If you have a rain day and discharge the batteries, they will still be discharged the following morning. Until the solar recharges them, your electrical activity will be limited. If you have two rainy days, better have a couple of good books.

There was a company that made a small 12 volt iron that only used 60 amps. ACAR Industries Mini Travel Iron, Model RV-449. ( you can search Youtube for the video looking for 12 volt iron). Maybe someone still makes one. When I googled it several came up from Alibaba, but you had to buy like 30 of them https://www.alibaba.com/showroom/12v-clothes-iron.html A truck stop or RV store may carry them.