how to size your solar power system if money doesn't matter

[willprowse]

Panel is cheap, the least expensive parts of the systems, use that to your advantage. You will appreciate it when the sun is low in winter, the nights are long and a few cloudy days in a row can easily munch a bank designed to meet your needs on long sunny summer days. Refilling that bank AND meeting your needs can be a chore especially in the winter.

Covering the roof also removes the "if I just added one more panel" syndrome.

Now I do contest the biggest inverter that you can afford concept. A microwave is the largest load most of us employ and if you need it, you need it. Should you not need it then larger quality inverters are huge, cost a lot and suck a lot of juice running or in stand by. So much so that some advocate having the big inverter but running it only for the big load while using a smaller inverter that can be left on to run small loads. A work around to the stand by draw is to have a load sensing inverter that will shut itself off when not needed.

Yeah thats true about inverters. good point. but it does depend on the inverter. My last zantrex was 2000 watts and it used .3 amps at 12 volts during standby. Very small. But yeah, that inverter cost a lot more money than most. and yes! small inverter for small loads is the best! I love doing that. thanks for pointing this out. and load sensing inverter is super smart option.

 

[willprowse]

Will, that whole process assumes that the newcomers all have unlimited funds and maximum power needs.

It's a 'shotgun' approach that never even considers what the person needs to power. 

Your solution is at one end, and one corner, of a sliding 3 dimensional scale and not as useful for others in different parts of the country, with different power needs, limited budgets, restricted building and wiring skills, and do not yet know whether they want to camp in the desert, or in the forest under a canopy of trees, and with or without refrigeration.

What we try to do here (in the threads about solar power), is focus our advice to the specific needs, wants, abilities, and budgets of the people who are not yet familiar with solar power and its benefits and limitations. In these threads, I learn as well as help.

And while I agree that a roof filled with panels is a beautiful thing in the desert on the top of a boondocking RV, it might not be needed (or wanted) by an urban camper in a minivan parked under some trees most of the day, or a beginning part timer who only needs to recharge a laptop or a power pack, or keep the vehicle starter battery topped off.

I think you're trying to help everyone solve everything in one post, and it just won't happen. We are running an information marathon here, not a sprint. 

Yeah great point. How can I change the title on my thread? I cant seem to find that option. And I agree with what you said!

 

[willprowse]

I cannot for the life of me figure out how to edit the title of this thread. Why is this so difficult to do? I cannot edit the orginal post, or it is not showing me a button to do so. Can someone point me in the right direction? Very frustrating.

 

[WanderingCanuck]

I like the idea of starting with the amount of space available for solar panels, but such a simple solution obviously can't be applied to everyone. How would you modify the calculations based on the geographical location of most use? My eventual application will be in SW Ontario, Canada or on the west coast of Canada somewhere in BC. My current location is cold and cloudy in the winter and at at about 44° N, the efficiency of the panels would certainly suffer. Snow fall is significant and often due to lake effects, so exposure to what sun there is when it's snowing would be limited during the times when the panels couldn't be kept clear. On Canada's west coast, my impression is that the temperature is much improved but the cloud cover and precipitation are increased overall.

I know the common solution to this is "move somewhere else", but let's assume I either can't or don't choose to at present. How do you figure this into the solar equation? I have another thread here that discusses the use of LiFePO4 batteries and a high output alternator with about 1-2 hours of run time per day, but if solar starts to make sense I'd consider it. I'm trying to determine how it might figure in to the master plan.

Thanks

 

[willprowse]

I think I will make a youtube video instead with a proper title/ more information about this sizing method. It works really well for a lot of people, but it doesnt seem to be liked here. And I still cannot change the title of this thread. You guys can delete this thread if you guys do not seem to find it useful. Sorry that so many people here do not like it. Bummer.

 

[WanderingCanuck]

I cannot for the life of me figure out how to edit the title of this thread. Why is this so difficult to do? I cannot edit the orginal post, or it is not showing me a button to do so. Can someone point me in the right direction? Very frustrating.

I seem to recall seeing something about a 15 minute time limit for editing.

 

[willprowse]

I seem to recall seeing something about a 15 minute time limit for editing.

Someone needs to change that. Why would they do that?

 

[WanderingCanuck]

Someone needs to change that. Why would they do that?

Here it is:
https://vanlivingforum.com/showthread.php?tid=18836

You seem to like going against the grain, which from what I've seen in my limited time here doesn't go over well. This is, however, offset by a wealth of knowledge to be found here.

I think you really should have a stab at creating your own forum. You've made yourself into enough of a personality through YouTube to have some success with it, I'm sure. I'd join and give it a go.

 

[willprowse]

Here it is:
https://vanlivingforum.com/showthread.php?tid=18836

You seem to like going against the grain, which from what I've seen in my limited time here doesn't go over well.  This is, however, offset by a wealth of knowledge to be found here.  

I think you really should have a stab at creating your own forum.  You've made yourself into enough of a personality through YouTube to have some success with it, I'm sure.  I'd join and give it a go.

Thanks for the advice. Yeah it seems that my thoughts do not float well here. Darn. And great point about starting a forum. Will probably have to do that next.

 

[willprowse]

Can an admin delete this thread? I would rather not have to respond to a long list of people saying "title is misleading" if I cannot change the title...

 

[John61CT]

Step 1: Fill the roof with as many solar panels as you can (example: 4x 100 watt solar panels can safely fit on your roof)

You assume.

Many people here are camping in very small vehicles that can barely fit two.

Others have huge RVs or a school bus.

I agree with the principle, but most here are very limited in funds, so looking to spend the minimum at least to get started.

Step 2: Purchase a solar charge controller that can handle the power produced by the solar panels.
It is best to buy a solar charge controller that is larger than what you need. This way you can scale your system later if you need to. (example: for 400 watts of solar, I would stick with a 40 amp mppt charge controller)

Another option is to base your design around a great value high-end controller, e.g. 75/15 Victron under $100, and then find high-efficiency panels that maximize power output per SC. A 1:1 ratio is the best way to handle partial shading.

Step 3: Choose a battery large enough to work with your solar panels. Typically, for vehicle mounted solar power systems, for every 100 watts of solar power you have on your roof, you should have 75-100 amp hours of sealed lead acid batteries. (example: 400 watts of solar on the roof means a 300-400 amp hour sealed lead acid battery). Be sure to check with the battery manufacturer to see how many solar panels they recommend, or find the datasheet and determine the "safe charge rate" in amps.. (or check out my website)

Unless you're staying in the south and never get cloudy weeks, a higher watts - AH ratio is better, like 200W per 100AH. The battery mfg will never have that sort of advice, and max charge rates are completely irrelevant.

Remember lead needs to get to 100% full for longevity. And you ignore how important proper deep cycle batteries are, which are afaik unavailable in sizes under 200AH in lead.

Step 4: Buy the largest inverter you can afford. Most people do well with a 1500-2000 watt inverter. Pure sine wave inverters are ideal and worth the money. Spend extra money to buy some thick inverter cables.

Most people are better off with no inverter at all, they are very wasteful especially in large sizes and good ones very expensive.

If you have a truly necessary device that must run off AC only (this is very rare) then the smallest inverter sized to run just that one device will be most efficient and cost-effective.

If you need more power, scale your system (not easy to do if you filled your roof to the rim with solar panels, so you may need more batteries instead)

If you need more daily power input, a bigger bank will only make the problem worse, unless you're regularly getting back to shore power.

For boondockers a small genny is the better, often only solution.

Other than cutting consumption, being as energy efficient as possible.

Which you should be striving for from the beginning anyway, call it Step zero.

But otherwise, great overview! Sorry I'm so nitpicky. . .

 

[tx2sturgis]

Can an admin delete this thread? I would rather not have to respond to a long list of people saying "title is misleading" if I cannot change the title...

I think the thread now contains a lot of good information....you can request it to be closed, which keeps the information here, but stops any further responses.

That way the information is retained, and is still valuable to others. 

And yes, there is a 15 minute edit limit....so be sure what you type is what you want posted for eternity!

 

[kllcbosmetris]

I think I will make a youtube video instead with a proper title/ more information about this sizing method. It works really well for a lot of people, but it doesnt seem to be liked here. And I still cannot change the title of this thread. You guys can delete this thread if you guys do not seem to find it useful. Sorry that so many people here do not like it. Bummer.

Do not be discouraged by the negative or argumentative comments here. [Many people (whether they say it here or not) appreciate your contributions here.] I suspect many people are just bored and prefer to say OP is wrong than answering actual electrical/solar questions (i.e. similar to the ones I asked) posed on the thread, which is not really productive. 

As for the 'this is a cheap RV living forum' protesters --

People need to realize 'cheap' is relative term and not everyone is at a retirement age or on a social security budget (not that there is anything wrong with that). There are many people, in working age or with traditional jobs, who want to test this #vanlife lifestyle -- primarily to save money, whether it is lowering their monthly living expenses or travel budgets. Many would consider that being cheap. Still. For them, investing in a decent solar energy system is a sound investment as electricity is more valuable to this city/work lifestyle (compared to van dwellers who don't mind boondocking in BLM lands with no or limited power or via loud generators). Using such a sustainable & low-maintenance system for 10+ years might as cheap as any other option (i.e. buying/maintaining/fueling a Yamaha 3000i generator, which by the way may not be useful to an urban dweller who wants to stealth in the city).

 

[SoulRaven]

100 watts?? What are you powering?? That is so tiny. I would die if I had to live off a single 100 watt panel. Unless I had a big alternator and high charge rate lithium battery. Is there any reason you choose to have such a small system?

I have to chime in here on this point.  Admittedly, I am also just starting this endeavor.  I've only been at it for two months.  I use a minimum amount of power on purpose.  I try to use the ultra-lightweight backpacking philosophy, but I fail on that front when it comes to shoes and binder clips.  You can't have too many binder clips.

I'm an instructional designer.  I create educational videos with the Adobe suite as well as Camtasia, Captivate, Storyline and other HTML5 platform type things like JQuery, AJAX blah blah blah and so on.  In other words, I do digital work for a living and am most of the time in an urban setting.  That means I'm working in a public library or Starbucks.  I don't have a ginormous monitor to power and I am not rendering anything that is cinematic quality.   When I do need a second monitor and I am out in the boonies, I use a PicoPro and project the monitor onto a bin top which is white. My laptop is a nearly gaming grade ASUS.


I cut all my hair off so I didn't need to style it with anything electrical and the rest of what I run is run on Ryobi One batteries, also charged at the library.  I have four of them.  I don't have a microwave, hot water heater, or even a fridge unless a Koolatron counts as a fridge.  I shower at Anytime Fitness.  In the boonies, I heat my water with propane and use a Zodi shower, although the solar spray pump solution is looking like a better alternative.

My panel is only 100w and I am using a 55 ah AGM battery.  I never run out of power.  See my conversion description here: https://vanlivingforum.com/showthread.php?tid=28027

I will never live in a van in a place like Seattle because it is dangerous and stressful. My stays at national parks have been lovely...and I still had internet.  Lately, I have been in Lake Havasu City which is urban but also has BLM land available nearby.  That is an ideal situation for me. Eventually, I will "settle" in Taos which is similar, but has an energy that is more in alignment with my own.

So I guess my point is - the first step in designing your solar system is determining how much power you are going to need, then determining where you are going to be spending most of your time (especially the climate), what power alternatives you are going to have access to, and how much time you plan to be driving and will be using your car engine to charge your batteries.

 

[SoulRaven]

Do not be discouraged by the negative or argumentative comments here. [Many people (whether they say it here or not) appreciate your contributions here.] I suspect many people are just bored and prefer to say OP is wrong than answering actual electrical/solar questions (i.e. similar to the ones I asked) posed on the thread, which is not really productive. 

As for the 'this is a cheap RV living forum' protesters --

People need to realize 'cheap' is relative term and not everyone is at a retirement age or on a social security budget (not that there is anything wrong with that). There are many people, in working age or with traditional jobs, who want to test this #vanlife lifestyle -- primarily to save money, whether it is lowering their monthly living expenses or travel budgets. Many would consider that being cheap. Still. For them, investing in a decent solar energy system is a sound investment as electricity is more valuable to this city/work lifestyle (compared to van dwellers who don't mind boondocking in BLM lands with no or limited power or via loud generators). Using such a sustainable & low-maintenance system for 10+ years might as cheap as any other option (i.e. buying/maintaining/fueling a Yamaha 3000i generator, which by the way may not be useful to an urban dweller who wants to stealth in the city).

Thank you for that last paragraph.  There are many reasons why a person would choose this lifestyle.  Some don't have a choice.  Some do.  Some do it for philosophical, emotional or mental health reasons.  It is nice to have other people to talk to who are here for whatever reason - and to get a window into their perspectives.  If nothing else, it is an exercise in cultivating humility.

 

[willprowse]

I like the idea of starting with the amount of space available for solar panels, but such a simple solution obviously can't be applied to everyone.  How would you modify the calculations based on the geographical location of most use?  My eventual application will be in SW Ontario, Canada or on the west coast of Canada somewhere in BC.  My current location is cold and cloudy in the winter and at at about 44° N, the efficiency of the panels would certainly suffer.  Snow fall is significant and often due to lake effects, so exposure to what sun there is when it's snowing would be limited during the times when the panels couldn't be kept clear.  On Canada's west coast, my impression is that the temperature is much improved but the cloud cover and precipitation are increased overall.

I know the common solution to this is "move somewhere else", but let's assume I either can't or don't choose to at present.  How do you figure this into the solar equation?  I have another thread here that discusses the use of LiFePO4 batteries and a high output alternator with about 1-2 hours of run time per day, but if solar starts to make sense I'd consider it.  I'm trying to determine how it might figure in to the master plan.

Thanks

Oh just saw this. And yeah if you are that north, you need to tilt those panels somehow. And if solar is not able to produce what you need, you may need the lithium iron phosphate and high output alternator. works great. 

solar is great for a lot of stuff, but in your situation, I wouldnt bother. but you may want to add a supplemental 100 watt panel and see how much it helps.

 

[willprowse]

I have to chime in here on this point.  Admittedly, I am also just starting this endeavor.  I've only been at it for two months.  I use a minimum amount of power on purpose.  I try to use the ultra-lightweight backpacking philosophy, but I fail on that front when it comes to shoes and binder clips.  You can't have too many binder clips.

I'm an instructional designer.  I create educational videos with the Adobe suite as well as Camtasia, Captivate, Storyline and other HTML5 platform type things like JQuery, AJAX blah blah blah and so on.  In other words, I do digital work for a living and am most of the time in an urban setting.  That means I'm working in a public library or Starbucks.  I don't have a ginormous monitor to power and I am not rendering anything that is cinematic quality.   When I do need a second monitor and I am out in the boonies, I use a PicoPro and project the monitor onto a bin top which is white. My laptop is a nearly gaming grade ASUS.


I cut all my hair off so I didn't need to style it with anything electrical and the rest of what I run is run on Ryobi One batteries, also charged at the library.  I have four of them.  I don't have a microwave, hot water heater, or even a fridge unless a Koolatron counts as a fridge.  I shower at Anytime Fitness.  In the boonies, I heat my water with propane and use a Zodi shower, although the solar spray pump solution is looking like a better alternative.

My panel is only 100w and I am using a 55 ah AGM battery.  I never run out of power.  See my conversion description here: https://vanlivingforum.com/showthread.php?tid=28027

I will never live in a van in a place like Seattle because it is dangerous and stressful. My stays at national parks have been lovely...and I still had internet.  Lately, I have been in Lake Havasu City which is urban but also has BLM land available nearby.  That is an ideal situation for me. Eventually, I will "settle" in Taos which is similar, but has an energy that is more in alignment with my own.

So I guess my point is - the first step in designing your solar system is determining how much power you are going to need, then determining where you are going to be spending most of your time (especially the climate), what power alternatives you are going to have access to, and how much time you plan to be driving and will be using your car engine to charge your batteries.

Oh wow very cool! You are awesome. And yeah, considering what you are doing, that makes total sense

 

[willprowse]

I think the thread now contains a lot of good information....you can request it to be closed, which keeps the information here, but stops any further responses.

That way the information is retained, and is still valuable to others. 

And yes, there is a 15 minute edit limit....so be sure what you type is what you want posted for eternity!

Great point! And an admin just messaged me and they said they can edit the title. Thank goodness!

 

[willprowse]

Everyone's needs here are different. 

In the year 2000 I bought my first 'large' solar panel for my Class A RV. It was 64 watts and $400! Back then, large solar panels were expensive. I powered the entire RV house systems that way for years, using propane for refrigeration and heating. I had no need for hundreds of watts of solar. 

And, now, for example, on my van, I have one 45 w panel to balance the parasitic loads while parked for days on end. Another, 120 w portable panel to power ham radio gear and the battery for it. The roof on the van only has room for the smaller panel, with vent fans, awnings, and luggage rack up topside. 

My cargo trailer, on the other hand, has a LOT of roof real estate available, but a 200 watt folding portable panel is plenty to power a multi-transceiver ham station and internal LED lighting, and I can aim it at the sun to get the maximum output, and cleaning is much easier. I also own 5 generators so I can choose which unit to bring depending on what I need for that trip. 

My situation is WAY different from say, a person on limited funds, in a small SUV, who needs to run a rice cooker and a cpap, and keep their medicine and fresh veggies cold in the middle of nowhere for 3 months. 

Just saying....

Yeah great point! I made a very misleading title. Oops! And yes, my first panel was nearly 600 dollars for a 120 watt panel. Crazy!

 

[willprowse]

Aww man I just tried to edit the title with an admin, and they missed the most important part of the edit! I told them to put "if money didnt matter" at the end of the title, and they didnt change it. Darn it. Hopefully they will fix the title on the second time around. I just sent out another message.