How much solar do I need?

[Vanlifedreamer]

BGotSmartFirst.  The electric heater is out.  That will kill a battery bank in no time.  Most use propane.

Second.  The blender is a power hog.  You will need a large inverter to handle that.

Third.  Fridge.  With a good 12 volt unit you can get away with 100w to run it.  This is assuming you stay in the southwest.  To be safe go with more than that.  A week of clouds will not be kind to solar.  

100w will run the rest.

I have 200w of Renogy panels, and over 400 AH of batteries. (I found an exceptional deal) no fridge yet but I never go under 13v on my batteries.






Thank you for replying. I am in North Carolina(southeast) do you think I need a regular generator as a back up to my solar or should I opt for a generator as my main power source. The blender I said essential I make most of my meals with it.

 

[rvpopeye]

If you have room for one , a generator is never a bad idea ............

 

[GotSmart]

If you have room for one ,  a generator is never a bad idea ............

A small honda is best.  Nice and quiet.  Be sure to check amp draw on the blender. Since you will be only using it for short runs you might get away with using the small appliance.

 

[karl]

Started with a Renogy 100w panel, pmw controler, 800w Cobra inverter, solenoid managed alternator charging and a used deep cycle battery.
As time, finances, and needs changed I upgraded/added another 100w panel (200w total) MPPT bluesky control, 2 Trojan 105 GC batteries, 12v Indel fridge, 55a smart charger for shore/genset charging, Attwood propane (electronic controled) furnace. Typically there are a few LED lights on, phone and laptop charging, and a Dewalt 12v charger on most of the time.
I also use an immersion blender daily, Most immersion blenders use less power and require less space than the countertop versions.

Typically I drive every other day for a couple hours, and find shore power every couple weeks.

 

[duckwonder]

Hi All.  I am working on repairs on a 2004 PleasureWay Excel, but I think I need to look at solar next because when I do finally get to go out on the road, I plan to be out for 6 months and spend the vast majority of that time boondocking.  The deal with that is that I'd like to see if I can do it solo, and to see if it's as enjoyable as I believe it could be.  So I'm pretty sure I need to look at the solar I already have from the previous owner and see how I can add to that.  There is really only room for one panel on the roof.

The Current Setup is a single 100w panel and a 12v deep cycle battery.  There is an inverter.  I am gathering more details on the existing set-up.

The Desired Setup?  I don't know.  I am wondering what my options are.  If I added a portable suitcase system that's 200w, seems like that would give me 300w overall somehow.  Problem is there is no more space in the van.  It seems silly to replace the 100w panel with a 200w panel (is there such a thing?) if keeping the existing panel means 100w more solar power.  I would love to have more than 200w overall if that is possible with only one panel on the roof, just don't see an option for that.

What can I do?

 

[jimindenver]

how much space for a panel is there?

 

[jonsun]

Hi All.  I am working on repairs on a 2004 PleasureWay Excel, but I think I need to look at solar next because when I do finally get to go out on the road, I plan to be out for 6 months and spend the vast majority of that time boondocking.  The deal with that is that I'd like to see if I can do it solo, and to see if it's as enjoyable as I believe it could be.  So I'm pretty sure I need to look at the solar I already have from the previous owner and see how I can add to that.  There is really only room for one panel on the roof.

The Current Setup is a single 100w panel and a 12v deep cycle battery.  There is an inverter.  I am gathering more details on the existing set-up.

The Desired Setup?  I don't know.  I am wondering what my options are.  If I added a portable suitcase system that's 200w, seems like that would give me 300w overall somehow.  Problem is there is no more space in the van.  It seems silly to replace the 100w panel with a 200w panel (is there such a thing?) if keeping the existing panel means 100w more solar power.  I would love to have more than 200w overall if that is possible with only one panel on the roof, just don't see an option for that.

What can I do?

are planning to park in the sun 365 days a year? if not you should look at a suitcase. the 100w can stay to charge when you're in town and driving down the road. the suitcase you can setup out in the sun and camp under some trees. you can always add an hitch carrier for more room. and lastly you can hook your alternator up to give your batteries an extra charge.

 

[duckwonder]

how much space for a panel is there?

if only I knew!  I can't get up there.  When a ladder is here next week, I will learn more of the space and current set-up, but I am 90 percent sure I only have room for one panel.

 

[duckwonder]

are planning to park in the sun 365 days a year? if not you should look at a suitcase. the 100w can stay to charge when you're in town and driving down the road. the suitcase you can setup out in the sun and camp under some trees. you can always add an hitch carrier for more room. and lastly you can hook your alternator up to give your batteries an extra charge.

Thank you.  The suitcase looks awesome because of those benefits and I would be able to keep my current setup too.  The problem is space in the van.  I just do not see how it is possible to carry the suitcase with everything else I have to carry.  Is there another way?
Oh, my engine does charge the house battery when driving, but once camped, that's all the battery I have.  I would love to get another 12v in there so that I'd have two.  That might be possible, not sure, but don't need to do that if I can't figure out how to get another panel.  Is a suitcase the only way to go?

 

[jonsun]

prolly be best for space and ease of use. does your van have a hitch?

 

[duckwonder]

prolly be best for space and ease of use. does your van have a hitch?

Sadly, no hitch. I will look into that though, thank you.  Otherwise it will be a game of what's gotta go?  The Viair?  The tent?  The dog? Lol.  I don't understand why I cannot find a 400w panel, or 300.  Then it might be worth replacing the 100 that's up there.

 

[GotSmart]

300w is 3 times the size of 100w.

 

[desertdog]

First, before you do anything else, go up on your roof and measure to see how much room you have. You should only buy what will fit on your roof. Then see what different panels have for different sizes, maybe you can fit more small ones, or, maybe you can only fit one big one.

Of course you can always buy a portable suitcase system or flexible panels and not mount them on the roof, that's another discussion.

Many people suggest you add up all your electrical use and get enough to meet those needs. But solar has gotten so cheap I say start with your wallet and buy all you can afford to spend right now. After all, if you can't  afford it, why bother finding out what your needs are? 

Also remember that you are buying for the worst day of the year--a storm that lasts for a week in the winter when the days are already short and the sun never rises very high. If you buy JUST enough for the summer, you WILL run out in the winter. Plus, you are buying for latitude, northern cities get less sun that southern cities.
 
Here are my recommendations. 
 
Minimal Power User = 100 watts. This person mainly recharge his phone, laptop, camera and a few other devices. Buy the 100 watt kit and adjust your use to it. If it's all you need, then you are done.
 
Average Vandweller = 200 watts. The majority of vandwellers need and can be satisfied with 200 watts. It meets all the basic needs plus, 12 volt compressor fridge, fans or even TV.I have 190 watts on my trailer and I've never been unhappy with  it. If you have the money, buy a 200 watt kit. If it's not enough, buy another 100 watt kit. Yes, you have two systems, but I consider that a blessing since you have redundancy; if one system fails you still have power. I have three distinct systems and I like it! Or, get the 200 watt kit and get the upgraded controller so you can add another one to it later when you can afford it. But controllers are so cheap now I think just buying a new cheap one is better.
 
Power user = 400 watts. If you have the money, start out with a 300 or 400 watt. You'll never have to worry about power even in a storm and nearly all of us can find a way to use extra electricity. I use my extra power to run a microwave and watch Satellite TV. [img=21x21]file:///C:/Users/Bob/AppData/Local/Temp/msohtmlclip1/01/clip_image001.gif[/img]
 
Why increments of 100 watts? Because you can get 100 watt Renogy panels cheap with free shipping. If you jump up to the big panels like 200 or bigger, they are cheaper per watt, but the cost of shipping is so high it will end up being much more. 
 
But, if you are near where you can get big panels and they fit your van better, get them instead.
 
Be aware that higher watt panels are usually higher voltage and require a MPPT controller. 
 
Starting with your wallet is just my personal bias, lots of people will disagree, hopefully they will speak up and explain there thinking.
Bob

 

[user 15722]

I have found This page valuable to determine what my power needs shall be, and proper equipment to provide it.

http://gpelectric.com/go-power-calculator

In the RH column of the page you will note a Learning Center block with many info topics.
All good to read, imo.

Yes, I'll need more/better than my uneducated guessing had tallied.

And then, a cloudy sky changes everything ! lol
Good luck with that !
wheels

...searching for best ideas to mount a tilt mechanism on a class A fiberglass roof...

 

[jonsun]

Sadly, no hitch. I will look into that though, thank you.  Otherwise it will be a game of what's gotta go?  The Viair?  The tent?  The dog? Lol.  I don't understand why I cannot find a 400w panel, or 300.  Then it might be worth replacing the 100 that's up there.

you realize you can just put multiple panels up there and hook them together, right? you dont need one big panel.

if you're that cramped you definitely should get a hitch and carrier tray.

 

[jimindenver]

There are large panels out there but they come with a price premium. This Helios is a example yet hard to find as it has become discontinued. There is also the 435w that I have on my truck but getting those is next to impossible.

https://www.solarpanelsonline.org/Solar-Panel-400-Watt-Helios-9T6-400-p/9t6-400.htm

What may be easier to find is a 300 + watt panel. At times I see them on craigslist for stupid low prices.

In all of the discussions between MPPT vs PWM there is one benefit to PWM that is often ignored. Mixing panels of different types can have terrible effects on the ability of a MPPT controller in that a weaker panel will limit the stronger in series and even in parallel it can inhibit the ability for the controller to track the power point. Even mixing two similar wattage and voltage can be bad if one is a mono and the other a poly. They react to differing light so the poly may weaken the mono in bright light while the mono may do it to the poly in low light.

With a PWM system you can have a 100 watt here and a 50 watt over there literally putting whatever panel will fit in the spaces you have as long as they are close enough in voltage and in parallel their amp output just combines. I could fit much more on my roof filling every little open area.

This is why the discussion between the technologies should not be what is better but rather what is better for you.

 

[John61CT]

With controllers so inexpensive these days, can use 1:1 per panel, match them appropriately, best partial shade handling as well.

 

[jimindenver]

I use to use three MPPT controllers in parallel to a bank. They worked but getting them all to see the same voltage even with identical leads to the battery was near impossible. Also consider that not only is there multiple battery leads, fuses and switches, that there is also multiple leads coming down from the roof too. It doesn't take too many sets before the rats nest becomes mind numbing to keep sorted out. It is a viable solution but has its down sides to consider.

I will add that it is not the quality of the controllers. My two Morningstar MPPT controllers have identical voltage sense lines and they still do not always see the same bank voltage resulting in one being in a different mode than the other. Morningstar says it is okay but it ticks me off that I spent the big bucks and end up with the same result. I mistakenly thought that the fact that their communication abilities made it so the 60 amp would slave the 45 amp and control it. Instead it just means that one remote panel can see both controllers.

 

[user 15722]

Jim, have you tried the Victron line yet ? Info declares they are comprehensive, yet tedious to set up. wheels

 

[jimindenver]

No I have not. I may try one if I replace the demonstration portable that I sold off.