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Installing a Renogy 200 Watt Solar Kit
My friend Dandelion’s very nice conversion van and her two new Renogy 100 watt panels.
However, in the last few years all that has started to change as the price of solar has dramatically dropped. Suddenly solar prices were reasonable and the average person could actually afford it for their homes, van or RV. But that still left the problem of how to get it installed. If you paid someone else to install it the costs would skyrocket and most people didn’t know what to buy or how to install it. So it still remained out of reach for most of us.
One company set out to change all that and to an amazing degree they have succeeded. Renogy (http://renogy.com/) came into existence in 2011 but in just 4 years they have revolutionized solar power. I know at least a dozen people who own Renogy solar panels or complete systems and they are all totally satisfied with them. What makes them unique is the fact that you can order a complete kit for a very low price right off Amazon.com and get free shipping on it as well. That eliminates most of the decision making and cuts the high cost of shipping out of the picture.
My friend got her 200 watt complete kit directly from Renogy in these two boxes.
Here are the two boxes opened up: Two 100,watt panels, MPPT controller, wiring and mounting feet.
You can’t go wrong with a Renogy kit but you still have to make a few choices. If your budget is tight, then that will be the deciding factor and it makes the decisions for you. In fact today we are taking a look at how a friend of mine (she’s known as Dandelion on my forum) installed her Renogy system.
These are the parts they added because they didn’t come in the kit. Renogy doesn’t send you any fuses and you really do need to fuse everything. They also didn’t include any quick disconnects so they bought an SAE quick disconnect to mount to the controller. The rest is to be able to use the extension cord.
How much solar do I need?
Renogy mainly sells 100 watt panels which helps keep their prices low. You decide how large your system is by how many panels you buy. Here are my recommendations on what you might need:
- A 100 watt kit is probably enough if you have very minimal power needs like a LED light, your cell phone, laptop and a few other small devices; a single 100 watt panel will do that just fine. Renogy 100W Mono Starter Kit: 100W Panel, Charge Controller
- But if you want to watch TV, use a 12 volt compressor fridge or run a fan a lot, you need 200 watts: two 100 watt panels. 200W Mono Starter Kit: 2pc 100W Solar Panels
- If you want to use a microwave or have Satellite TV you need 400 watts: four 100 watt panels. RENOGY® Solar Panel Starter Kit 400W Mono:
My recommendation is very simple; buy all you can afford. Why? Because you need to plan for the worst weather conditions, not the best. You will run into storms and clouds and if you don’t want to run out of power you must have more solar than you need in good weather. If you buy all you can afford, even if it seems like too much, you’ll be ready for bad weather and able to add extra electrical devices you didn’t even know you wanted.
For most people, 200 watts is the sweet spot with enough power to meet your needs for the least amount of money. Start there if you can afford it and if you can’t then get a 100 watt kit to see if that’s enough and if it isn’t you can add a second 100 watt kit when you can afford it. My friend Dandelion bought a 200 watt kit.
By placing the panels away from the van, you can park in the shade while they are in full sun.
Where to mount the panels?
Dandelion who has a conversion van with a high top. Like most high-top vans, her fiberglass roof is very convoluted and she had a hard time finding a place to mount even one panel much less two. So she decided to do what a lot of people do and not mount them on her roof at all, instead she carries them inside her van until she gets to where she’s camping and then she takes them out and sets them on the ground. Not mounting them on the roof has lots of advantages:
- It makes installation so much easier that most people can do it by themselves with a little guidance. Dandelion was fortunate in that she had a friend here in camp who led her through the whole process making it much easier.
- You don’t have to drill holes in the roof which is a very scary idea for a lot of people and eliminates the risk of leaks.
- You can park the van in the shade and move the panel out into the sunshine, keeping it much cooler in the summer.
- It’s easy to tilt the panels, you just lean them up against something like the side of the van.
- It’s easy to turn the panels to always be facing the sun. The combination of tilting and tracking the sun with your panels will give you a lot more power into your battery at the end of the day.
What are the disadvantages of not mounting the panels.
The main disadvantage is you can’t use them while you’re traveling and you can’t use them in the city. It’s also a hassle to have to store them away every time you need to run into town. We each have to measure the pros and cons for ourselves. For city dwellers or frequent travelers it’s a bad choice; for boondockers it’s a great choice. For boondockers another very good option is to buy the 100 watt folding suitcase solar panel from Renogy; we’ll talk about that in my next post.
The MPPT controller that came with the kit. It’s made by Tracer and is a good quality unit.
Should I buy a PWM or MPPT controller?
I won’t go into details but the main difference between the two kinds of controllers is that the MPPT is more efficient and will get 25% – 35% more amps into the battery than a PWM controller will. That should make it an easy decision except it costs so much more than a PWM. For example, Renolgy sells the same 200 watt kit with either a PWM or MPPT controller and the PWM controller is $320 Renogy 200W Poly: 200W 30A with PWM controller
Which should you get? An MPPT controller will give you about 33% more power into your battery but will cost much more, so many people argue that instead of buying the more expensive controller, you should just buy a third solar panel which will give you 33% more power. But that means you have to have enough room on your roof for a third panel, which dandelion didn’t have, or she has to carry and store a third panel and take it in and out every time she drives. She didn’t want to have to do that so she ordered the kit with the nice MPPT controller that is currently $480 at Amazon You can get it from Amazon here: RENOGY® 200 watt Solar Panel Kit Mono 20 amp MPPT Controller
The kit includes :
- Two Renogy 100 Watt Monocrystalline Solar Panels
- 20 Amp High Quality Renogy MPPT Charge Controller
- Uniquely Designed Z brackets for Mounting on Flat Surface;
- UL Listed 20′ Solar MC4 Adaptor Cables: AWG 12
Because she didn’t mount the panels on the roof the Z brackets were unneeded and to make it easier to connect and disconnect the panels she adapted a standard 110 volt outdoor extension cord instead of the MC4 extension cord so she didn’t need the it either. Fortunately, Amazon sells a 200 watt kit with a PWM controller and without the feet or extension cable for $309: Renogy Solar Panel Bundle 200 Watt. For many of you on a tight budget, this kit is your very best choice. The kit doesn’t come with fuses so you will need to buy them separately. Get them from Amazon here: In-line Fuse Holder – 10 AWG–$3
Dandelion’s Installation:
First thing to do when you start the installation is to decide where you are going to mount the controller. Because you don’t want to draw the voltage of your battery down below 12.2 volt (50% of capacity) you need to monitor it’s voltage every night. For that reason I recommend you put the controller somewhere in easy eyesight so you can see it’s voltage at a glance. Also because she wasn’t mounting her panels on the roof she wanted to put it close to a window that opened so that she could just put the cord through rather than drill a hole. She had a wall near her back door that was perfect.
The extension cord ready to use.
In a laer post I’ll give you details on how to adapt the 110 volt cord to use it with your solar panels. I’ll also talk about connecting your panels in series instead of parallel
to reduce the voltage drop over a distance.
She stripped and crimped regular 110 plugs onto the wires so they plug directly into the extension cord.
The two panels come down and connect to the extension cord.
Bob, I like the idea Dandelion is using with the extension cord. From a safety standpoint it may be wise to wire the plugs so the female plug end is on the panels. As it is now the male plug will be “hot” any time sun is hitting the panel. If it shorts against anything metal it has the potential to be dangerous. Just an observation.
Greg
Greg, that’s a great point! It should always be done that way.
Bob
Did you know that AC travels better then DC. Think about that when you buy 50, 100 foot extension cords for your DC. You loose part of your charging ability. Had to put inverter near panels then 200 feet to house. FYI
Bob. I want to set up a 400 watt system. How many AGM batteries will I need? Thanks in advance.
He created a video where he setup up his current van with 2 batteries daisy-chained to be come two 12 volt batteries. He used 4 AGM boat batteries? the non maintenance models
sorry, Golf cart batteries. he has 4 that he daisy chained to create 2 12 volt batteries.
Wow, thank you! That’s the first set of instructions that didn’t make my eyes glaze over! I think I can do this!!
Janis, it is much simpler than it seems. It’s just connecting positive wire to positive post and negativie to negative all the way through the system. I think you can do it to!
Bob
Timely article. This is the exact set up I intend to use in my van.
It’s a good choice GoldCityGuy!
Bob
Great info!
Thanks
Thanks CAE.
Bob
Please tell about the deep cycle battery and inverter. I am very new to this stuff. The article is great otherwise – thank you.
Adam, that’s a very big topic and I’ve written a lot about it before. At the top of the page is a pull-down menu called Electrical and another called Solar and Wind. Read trough some of those posts and you’ll get a good introduction.
A brief answer is I recommend a ratio of 1-1 for watts of solar on the roof and amp-hours in your batteries. So if you have 200 watts of solar you need about 200 amp-hours of battery. I recommend a pair of golf carts which is about 220 amp-hours.
An inverter wires to the battery and turns 12 volt to 110 volt. If you have low-to average draw a 400 watt inverter would be a good choice. For medium user 600-1000 watts would be good, for heavy use like a microwave you need a 2000 watt inverter.
Bob
I’m glad you added this info about batteries, because having enough storage is what gets you through periods of bad weather and low sunlight.
Thanks Al!
Bob
Your brief answer is exactly what I needed to know. Now I get it. Thanks so much.
The way to figure watts is volts x amps. So 120V refrige using 5 amps takes 600 watts.
You want to have a short run and fat wire between the battery and the inverter. Here’s an example
To size the cable from the battery post to the inverter, you are using 12V
cable and probably need a 1200 watt inverter (600 watts x 2) so you need to size your wire (battery to inverter) for 1200 watts/ 12 volts, or 100 Amps, this means you need somewhere between 6 and 4 gauge wire, depending on length. Internet has tables
Bob,
Thanks for breaking everything down in such a way that people feel they can actually do this themselves. When people start adding up all the prices, it may seem like alot. Then you compare that amount to spending money to stay in RV parks or State parks and you see how small the initial investment really is. Why would the satellite tv require so much more power,because of the receiver box? I’m not talking about high def. Thanks for the great info, looking forward to the next post.
WTXCal
WTXCal, the big thing is the amount of time it runs. Generally I turn the TV on at about 6:30 at night and it’s on till 11:30, so it’s on for 5 hours. I don’t know how much it draws but I’d say probably at least 10-20 amps per hour which is somewhere from 50-100 amps out of the battery. A 200 watt system with a pair of golf carts can’t handle that with everything else I need.
Is it worth the money? It’s abundant, free power for the rest of your life!!!! Not a month, not a season, not a few years–the rest of your life!! How much is that worth to you?
Bob
Bob, I agree with you 100%! With the info gained from your posts people can save a tremendous amount on installation charges. This sort of reminds me of a craps table in a casino. At first it tends to imtimidate, but once you go for it it’s much simpler than you thought it would be. Just my observation as an old gambler. Have a great day and thanks again.
WTXCal
Thanks WTXCal!
Bob
If you are just running a TV, use just the TV ampps, if you are running a box or computer to fee the screen, you need to add everything.
Here’s your sizing – say 10 Amps at 120 volts.
this would take 10 x 120 watts per hour – 1200 watts
Assume 75% usage on your battery 100 amps at 12V gives you 1200 watts x 75%, or 900 watts, or 45 minutes of run time. 2 batteries will give you 1.5 hrs.
You need a generator or to learn how to enjoy reading.
I’m not sure that you are accurate on 2 batts. for 1.5 hrs. I have 2 124 amp hrs. batts. powered by a 160 watt solar panel and i run my van’s stereo Pioneer 4201 with 300 watt booster and my laptop, phone, phone mods, hair trimmer, toothbrush, and charging, miscellaneous stuff batts. A,AA,AAA,D etc. with a pure sine wave 1000 watt inverter that are directly hardwired to my batt. bank. I have never have had a low batt. issue.
thanks for keeping us updated on what is new in the world of solar. Things keep improving and getting cheaper. Have any of your vandwelller friends played around with lithium yet?
Ming, yes, I have a friend who has switched to Lithium. It has advantages but it also is very expensive and has a very steep learning curve. Very few people will benefit from them this early in their lifetime.
Bob
Technomadia has been using lithium batteries for over three years. Here’s a link to a report:
http://www.technomadia.com/2015/02/living-the-lithium-lifestyle-3-5-year-lithium-rv-battery-update/
I have always respected the Technomads’ technical abilities in almost every field. I followed their lithium (LFP) battery experiment as best I could; my own technical abilities are far less. Having read their report, I think I could use their experience to improve my own, but for now I’ll wait a few more years even if I get the money. LFP batteries are improving quickly, but I’ll wait for a plateau before I join in.
they sure have a complex system, don’t they? I was wondering if anyone else had tried lithiums and what the simplest configuration might be. They do seem to be a superior battery technology and I especially like the size and weight.
My two 12V AGM batteries theoretically provide 208Ah. I can effectively use half of that, leaving me 104Ah. With lithium batteries, I can theoretically use 100% of the amp-hours. My two AGM batteries cost me $590. A 100Ah lithium pack would cost $620, and that’s without the monitors and other stuff. Now, lithium is supposed to last longer than lead batteries, so the extra cost would be amortized. Maybe. Right now the incentive isn’t enough to switch. Maybe by the time my current batteries reach the end of their service life. Or after their replacements. I’m in no hurry. What I have now works just fine for my purposes.
I’ll be starting from scratch… months from now. Thanks for the rundown on your system, I’ll likely need similar capacity.
Ming, it’s the best bang for your buck!
Bob
Lithium may not be living up to it’s promises. Check out Technomadias blog for real world experience. Check out the first blog post I have listed. Dark clouds on the horizon:
http://www.technomadia.com/2015/02/living-the-lithium-lifestyle-3-5-year-lithium-rv-battery-update/
http://www.technomadia.com/lithium/
Bob
Ooops! I re-posted this link. I’m not recommending the Lithium batteries yet for these reasons:
* The learning curve is much too high for most of us.The majority of vandwellers haven’t really mastered lead-acid/AGM batteries.
* They are so expensive that if you do mess it up the first time (which is very likely) you could really be hurt financially.
* They are in their infancy for boondcockers.
Bob
good points!
if you connect them in series, do you double the voltage and half the current that you can get from the panels? Is the idea to offset voltage drop from long wire runs?
Ming yes, putting them in series doubles the voltage which only needs a wire half the size. But it only works with a MPPT controller that can handle that voltage. So these panels are 18 volt panels so they will double to 36 volt. The controller will then step the voltage down to 14 volt for your battery and increase the amps so all the power gets in the battery.
Bob
ok, I’m still not clear on this in a real life scenarios, maybe you can help me understand.
Say for example, each panel is able to put out 5 amps per hour. If they were in parallel, you would get 10 amps to the battery, in series you would only get 5 amps to the battery. With real life voltage drops, what would happen in each scenario that would make it worth halving your amps with the series connection?
Ming, the main thing is you have to have a MPPT controller to work with high voltage panels. The magic of MPPT is it drops the voltage down to 12-14 volt and then doubles the amps equally. That’s the difference between it and a PWM controller. The PWM will not increase the amps, it just drops the volts. Nearly all 12 volt panels are actually 18 volt or higher, with a PWM controller it just steps the amp downs and then throws away the amps–they never get in the battery. But if a MPPT controller decreses the voltage by 66 percent from 36 to 12 volt, it then increases the amps by a 66 percent so it all goes in the battery.
That’s why they are worth the extra money.
You’ll always get more amps into your battery with a MPPT controller and you can also use a smaller wire from the panel because of the higher voltage in series. You win in every way.
Bob
wow, thanks Bob, I actually understand it now! And I’ve read more than one post trying to explain this.
Glad to help Ming!
Bob
I expect that with MPPT and panels in series the low light performance would be much better. Adding a 3rd panel to make up for the 33% difference would not help there in low light. I also thought a two to one solar watts to battery amp hours might be a better ratio, with 5 hours light and 50% max depth of discharge, though I would have to do the math again.
foofoodog, I basically agree. I’m a big fan of MPPT and think most people should buy it. 2 to 1 panels to bbattery ah is a very good way to get the longest possible life out of your battery. They are nearly certain to get full every day. But, it also means you have less holding power for long periods of rains or storm. The more ah in your battery bank, the better during storms and winter.
The middleground is a 1 to 1 ratio with good power management. Use most of your power douring the day and a minimum amount at night. If you can do that, 1 to 1 is better for rainy days. If you can’t, then 2 to 1 is better.
Bob
Bob, I have learned so much from your site! Thanks for the time put into it.
You’re very welcome Jessy!
Bob
Bob, I was just talking to a friend today about the Renogy 100 watt suitcase solar panel. I am looking forward to your next post about it. The price seems very reasonable and it seems simple enough that I can actually understand it.
Kathy, I am a big fan of them and highly recommend them to you!
Bob
Well shoot. Somehow I managed to attach this comment to the microwave post instead of here where it belongs. I am repeating it here so it makes sense in context. Sorry.
I look forward to your comments on the suitcase 100W Renogy units. I ran across them on Amazon last fall, and after testing one out for a couple of weeks bought another one, to make 200W. They fold up pretty flat in a nice case with a handle, and store flat in a compartment on my 17 foot trailer. They will also fit folded behind the seat of my pickup, if necessary.
No muss, no fuss. Extremely well thought out for a boondocker, and fairly priced. The only problem I see is a convenient way to keep them from being stolen. I think a bicycle cable lock will discourage casual thieves.
I have resisted solar since I retired in 2002, at first because a small quiet Honda generator cost about half what a suitable solar array cost back then, and given the effects of weather and shade the generator was much more dependable. As solar got cheaper over the years I reconsidered but still the hassle of installation put me off. And the fact was I kept changing rigs too often to justify a permanent installation.
The Renogy 100W suitcases overcame my last objections. From what testing I have been able to do this winter, they should reduce my generator use to once a week or so even in bad weather, and eliminate it entirely during long bright days in the desert.
The units came with quick release connections to a short end section with a couple of clamps for the battery posts. The url below will show you what I mean. The only improvement I made was to clip off the clamps and permanently install the short side with O rings. The battery covers allow the ends to run outside about six inches, where the quick releases make hooking up the solar panels a matter of click and go. There’s nine feet of cord on each, so I think I can still park mostly in the shade and manage to maneuver the solar panels to one side or the other of the trailer and catch the sun.
I look forward to putting them to a real test on my usual 4 month jaunt up into the Rockies this summer.
Bob G
http://www.amazon.com/gp/product/B00HR8YNK6/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1
Bob, I am a big fan of the Renogy suitcase panels. They are a little more per watt for the convenience but they are truly plug-n-play so for a lot of people it’s worth it! You’re like everyone else I know with them and are very pleased with them. I’ll get that post up very soon and I’ll highly recommend them!
Like you my solar has kept growing and now I almost never use my Honda–I’m giving thought to selling it!
Bob
There’s one thing I didn’t explain well above. There’s actually 15 feet of cord. The 9 feet are what you have left as a radius for placement after allowing for routing the cord straight down from the batteries, making sure it lies flat on the ground so you don’t trip on it, and then going up to the controller.
In full hot sunlight I get a maximum of 7 Amps from each set, but as you know the slightest puff of cloud or partial shade from dancing leaves brings that down quite a ways. That’s with my flooded GC batteries. The controller is electronic so it has different settings for AGM. Or you can set it like you want within a range.
From experimenting over time in my driveway, I figure on average a real output of about 20 Ah from each unit per day on partly cloudy days. I can get by on that if I watch my use like a hawk. But if I relax a bit I use more like 30Ah per day. If I watch any TV, maybe 40. Having two suitcases paired with a couple of golf cart batteries at a nominal 200 Ah capacity seems to work pretty well in partly cloudy conditions.
Two suitcases keep them topped up. In the open desert I’d probably get by with one.
Bob, I think you’ll be really pleased with them, they are great units! In the summer you will be amazed by how much power you get out of them!
Bob
“Like you my solar has kept growing and now I almost never use my Honda–I’m giving thought to selling it!”
Don’t do it, Bob. It’s paid for and you are used to carrying it around. Solar is nice and all, but you never know when something might blot out the sun. Volcanic eruptions, for instance. Giant alien spaceships! Pterodactyls! Or even just weeks of boring rain….
Bob, I have been pretty concerned about volcano eruptions!! Two summers ago was the rainiest time I’ve ever had (I avoid the PNW in the winter!) and I never did run out of power or have to use the Honda.
It’s been a year or two since I used the generator for myself, I’m just carrying it to loan to friends. I’m not sure I should keep it.
Bob
Sounds like you’ve pretty well got it figured out, then.
But what if they bring back the carrier pigeons? Did you think about that? Nothing but dark skies and droppings for days on end. Must’ve been something to see, if you could afford to look up.
On the one hand, I got $400 for my first Honda 1000 after a couple of years use. Seemed like a good idea at the time.
On the other hand, you might someday need electricity away from the van. Fishing lights, for instance. Or, if you have a 2000, you might be able to use an electric chainsaw.
Call it seller’s remorse, but I sure missed mine when it was gone. I replaced it with a Honda 3000i for a while, but that heavy thing wasn’t nearly as portable. Eventually sold that and went back to a little one.
You have a different situation than I do. I am often away from the trailer in the truck, and have need of electricity right there with me. Mostly for tools rather than lights, as in an upscale air compressor, or a portable high volume water pump to run water from my traveling water tank to fill up the trailer. That way I don’t have to move the trailer for weeks on end once I get situated.
A van is another kettle of fish. And you’ve got a big inverter and lots of batteries. There are always pluses and minuses. We grow our solutions to fit our situations.
Bob, every situation is different and ours are very different. All that matters is that we each find what works best for us.
Bob
Bob you are hitting this new series of solar powered articles out of the park. Literally the first common sense, get to the point no mumbo jumbo know-how information I have found on the web. I know what I want in my own rig and this is the first source of easy to understand non-convoluted material I have found.
Thank you and much appreciated.
You’re very welcome Dan!
Bob
I just got your email Bob, thanks for directing me to this great article,I can’t believe i missed it.
Craig
Craig, I’m glad you liked it!
Bob
Bob, I purchased two panels 100watt by renogy, without the kit..aside from the z brackets, any advice on a component kit with necessary parts to complete installation.fuses etc?..thanks Craig
I see you got it figured out Craig. I’ve known a couple people who contacted Renogy customer service and they all spoke highly of them. I’m glad you’re getting it figured out!
Bob
Nevermind Bob, I’ve been communicating with The support staff at Renogy and they’ve been very helpful.I have the necessary parts to complete this project.
I’m glad to here it Craig.
Bob
Hi Bob
very close now to going off grid full time in AZ.
and just wanted to let you know the suitcase kit i purchased from you
3-4 years ago is working fine and will be set up to keep the van batteries charged up as i will be using the vans radio and stereo of an evening also the renogy 100 watt panel does a great job of keeping my truck battery ,phone,razor and Laptop charged
Thanks for all the articles they have helped me a bunch
Roy
Royz, I’m glad to hear they re serving you well. They are a good system, but when cheaper ones came out I tied to get my distributor to drop the price and he wouldn’t. So now I recommend the Renogy because they are very good quality and much lower price. With 200 watts you should have all the power you need!
I’m very glad I could play some small role in helping you follow your dreams!
Bob
Ahoy Bob!
We’re getting set to purchase and install as many panels as will fit on the roof of our 28′ Bounder.
Brian and I are in study mode (AKA Dummy Mode) concerning photovoltaics, and one of the many things I don’t yet understand is how one switches from relying exclusively on solar power to using 30 amp RV-site power, which we’ll need to do when recording. I have not yet internalized volts and amps (how one calculates them), but I’m not too worried about that at the moment. I AM wondering whether or not it’s possible to use both solar AND a standard 30 amp RV hookup concurrently. Is it?
Also, Brian and I are, of necessity, heavy computer users, and we run a small HD TV and a Blue-ray player at night – usually for a couple of movies. We’re hoping that 600 watts of panels will be enough. We have enough room on the roof for them, I think (we tossed our A/C, as we haven’t once used it in the three years that we’ve had BUSTER (our rig)), but I haven’t quite figured out (yet) where to put six batteries.
As for batteries, are deep cell marine or golf-cart batteries best, in your view?
Thanks in advance, and thank you SO much for this thread. May GOD bless you for helping so many of us who’d be pretty much lost without you.
Love, and All Good Things,
Jesse.
Hi Jesse, 600 watts should be plenty for what you described–it really is a lot of power. I have 580 watts and I never even begin to use it all. I suggest you get golf carts. There are true 12 volt deep cycles, but unless you know the manufacturer it’s hard to be certain how good they are or if they are true deep cycles. But you will always know that a golf cart is a true deep cycle. You don’t want a marine battery, they are a hybrid battery and not great at either job, starting or deep cycle.
I’m sorry, I can’t help you about the RV and solar. I’ve never owned an RV or installed solar on one. But if you ask on the forum LOTS of people can help you!
Bob
Will do. Thanks, Bob. 🙂
Jesse.
Bob (and all),
I’ve been studying a lot about RV solar applications and came across a couple of points I thought worth mentioning – well, they gave me pause….
1. Installing panels in sequence versus installing them in a linear fashion. (Experiment that was conducted on the effect of shade (or even shadow) on generation of power).
We have two RVers, who each have the same solar panels and controllers. They ended end up parking side by side in the desert by chance. One of them had four 100 watt solar panels in series and the other had four 100 watt panels in parallel. They decided to see how the two systems compared since they were both in the same climatic conditions. They looked at the charging amperage when both systems were in full sunlight with no shade on the panels and found the guy with the paralleled panels had a slightly higher charging amperage. Then they had their wives monitor the charging amperage while they went up on the roof of their RVs. They stood so that their shadows fell on one out of the four panels on each of the arrays. The guy with the four panels in series had a drop in charging amperage that was very dramatic, almost to the point of having none! The guy with the four panels in parallel found that his charging amperage only fell by one quarter. The three unshaded panels kept on cranking out their power. The message here is that in the world of RVs (where shade can happen depending on where you park and where you place the panels), it is better to have your solar panels wired in parallel.
It turns out that even the shadow of an antenna can decrease power generation by 33%, so if the batteries are in sequentially installed, y’lose 33% from every panel you have.
I’m inclined to go with linear installation… unless you can give me a reason not to. (I may have been studying but I’m still a newbie when comes to actually *using* solar power, so your thoughts are most welcome.)
2. Batteries.
Agree that golf cart deep cell batteries are best, BUT since I’m married to a brilliant musician and computer genius and NOT a handyman, when it comes to anything practical outside of his field, the words ‘maintenance’ and ‘Brian’ don’t often collide in the same sentence – not pleasantly anyway. 😉
I like the sound of these batteries:
‘Absorbed Glass Mat Batteries.
There is a “new” battery out there that has proven to be a valid option to the traditional Flooded Lead-Acid Deep Cycle Batteries. They cost about twice as much but may be worth it given their special benefits. I have been using these batteries over the past decade and find myself appreciating them more and more. They are sold under the name of “Lifeline” for mobile applications and are made by Concourde (the same company that supplies the batteries for our Military Aircraft).
They are still lead-acid batteries but are sealed instead of vented. The electrolyte is held captive in a fibrous glass mat that can’t be spilled and therefore can be shipped without hazardous material restrictions. This glass mat also provides pockets that assist in the recombination of hydrogen and oxygen gasses (that are generated during charging) back into water.
I found their charge acceptance to be greater than flooded batteries and it requires significantly less time to recharge these AGMs. This translates into higher efficiency which means a shorter generator run time during those times when you find it necessary to recharge quickly. They also hold up better and at a higher voltage when heavy loads are powered by them. Like when you fire up the microwave through the inverter.
These batteries have very thick positive plates and belong in the true Deep Cycle class. They don’t outgas (unless severly overcharged) and because of this they don’t corrode terminals and don’t need to be watered. The savings in maintenance alone will be worth the extra cost to some.’
Sounds great to me. What d’you think, Bob?
Jesse. (Still on a learning curve.)
Jesse, I almost always recommend wiring the panels in parallel because it’s simpler and most people don’t need the advantage series has to offer. AGMs are very good batteries, I have a pair of 6 volt golf cart AGMs in my trailer and they are working very well. They cost about twice as much. I don’t worry about lead acid off-gassing so I have them in my van.
Lifeline is a premium brand of batteries and they are very expensive. They need to be charged at a very high rate that your solar panels probably can’t give them, so they wouldn’t be my first choice.
Bob
Really? What brand do *you* use/recommend? (Must be available in Canada.)
Jess.
I’m assuming you are asking abut batteries. I recommend Trojan batteries, I assume they are in Canada.
Bob
Using solar panel these days sure help lots of people. Saving energy is a good thing. Preventing your electricity bill to rise and even the electric company will pay. When you have lots of solar kit.
How would you add portable panels to an existing rooftop system? The existing system is 2 – 100w panels in parallel and has an mppt charge controller. The portable system would be 2-100 watt panels in series ( to reduce resistance in the cable)
Would you use a separate (additional) charge controller for the portable system and then attach the wire from this additional charge controller to the existing battery bank on the same permanent system? Or, if the MPPT controller is large enough, is there a way to run the cable from the portable panels to the existing mppt controller? ( both the permanent and the portable running to the same charge controller.)
Battery bank (440AH)
Bill, there are several factors come into play:
1) All the panels need to be very close in voltage or it won’t work. The two in series are probably different than the ones in parallel?
2) The controller has to be large enough to handle the 400 watts
3) You don’t want the voltage to drop from too long a line from the portable panels.
If all of that works, there is no problem running an extra line into the controller from the portable panels. But, I prefer redundancy and when I’ve faced your decision, I just bought another controller.
Bob
I can see that.
Could this be a problem with two controllers? The voltage will most likely be different so will one sense enough voltage from the other to shut it off before charging is complete? .
Bill, I don’t understand, do you mean having two controllers feeding into one battery bank? Of so there wont be a problem, they read the battery and feed it with whatever power it needs and can take.
Bob
Good. I think it’s best to go with two controllers.
The system would be two 100w permanently mounted panels in parallel and two 100w portable panels in series (24v). Would there be a problem if I bought a PWM controller to take care of the existing 12 volt system and ran the portable system (24v) into my existing mppt controller.? The controllers should both put out @ 12v.
I primarily camp in the Northwest Mtns for the summers. This past summer the 200w worked well but there were times I wanted to park in the shade. I use about 60 amps a day. My goal is to be able to park in the shade and still get enough power from the portable panels placed out in the sun. It would be great to lounge in the shade and still get power like I was parked directly in the sun.
Bill, as long as the portable system was the same voltage as whatever is already going into the MPPT controller it should be fine. Just be sure you don’t let the combined total be too many watts for the controller.
I think it should work fine parking in the shade. I’d get a standard 110 volt, 10 gauge, heavy outdoor extension cord to run the power from the portable panels back to the van.
Bob
Thanks for all the help!!
You’re welcome Bill!
Bob
Hi Bob, and thank you for being so patient. I recently bought a 10ga extension cord that I intended to use with a 2k generator I was going to buy for my 25ft TT. Then you gave me the idea to use the extension cord to connect to a couple of portable panels. I have a Trimetric battery monitor so I going to buy the Trimetric 30 amp PWM solar controller, it will communicate with my monitor to and coordinate the re-stuffing of my (two Trojan 105’s) I plan to put the controller inside the TT because I installed a waterproof box on the front wall of the TT for power, in case I ever needed it. I can’t see how the wires are connected in the pictures of Dandelions install, and I don’t have to go through a window, but can I install a pigtail through the front of the new box. I’ll then plug the 10ga. extension cord into the pigtail and into the panels with a concoction of M4 (?) connections of connectors on the other end. The would make using/storing reasonably convenient.
Hi Steve, you need a sacrificial extension cord that you cut the ends off. Then strip the ends off of one end and pick a color to be positive and one to be negative. Say black is negative and green is positive. Strip and crimp connectors on it to go to the solar controller. With the other end of the sacrificial cord you do the same to go to the solar panels. As long as you always use the same color for positive and negative it will be all good.
Bob
I guess what I’m trying to say is. I want to mount the solar controller in the TT. The cables to the batter will be 1 ft long. Then two 2ft 6ga cables will go from the controller to form a pigtail on the front of the electrical box on the outside front of the TT. Then I can simply plug in the 35ft 10ga extension cord and plug the other end into the solar panel(s).
Steve, just use the same color in the extension cord wire and it doesn’t matter what they connect to. Pick a color and make it positve and negative and always stick to that. Whenever you plug an extension cord into it the colors will match-up and carry positive and negative to the other end.
Bob
Got it, thanks. I am lucky you are such a knowledgeable and patient man. I’ve learned a lot.
Steve, it sounds so trite but I really do love to be helpful to people, it’s my greatest joy.
Bob
Thanks for the reply Bob. I guess given the almost dollar for dollar equivalence of tank ah vs. pump watts one can decide if they want a slow filling big tank or a fast filling small tank and the money comes out the same. There is always a big alternator under the hood to make up for any shortcoming of the pump.
With almost everything now being LED and/or charging off of 5 or 12 volts I question the need for an inverter above, say, 200 watts, which will run off of my 25 amp fuse accessory socket no problem. If you want heat, burn something, if you want cool run DC fans.
Note that I do have big ass batteries, big panels and a Honda I gen set but I consider that to be more like base camp gear than stuff I would carry around all the time.
foofoodog, I basically agree with your analysis, but I still have a 2000 watt pure sine wave inverter for my microwave. I rarely burn propane to cook, it’s almost always free from the sun–no cook meal at lunch and microwave dinner.
Bob
I was shopping for solar and agm batt, the amazon price for the 200w mppt kit is over $700 now, also what is a good site to buy agm batteries…or brick and mortar store. I dont see trojans on amazon anyway…vmax?
Billy, I’m confused, here is the Renogy 200 watt kit for $340
http://amzn.to/1TphXq5
Best places for batteries are Batteries Plus, Sam’s club or Costco.
Bob
ok i was asking if i needed a trojan battery because vimax is selling on amazon not trojan.
secondly, the second 200w mppt kit you link to in the article is $780 on amazon, Do you know why or how to get that kit for the price mentioned around $480???
Billy, trojan is a better battery, get it if you can afford it. Renogy 200 watt kits don’t sell for that much in the USA. Are you in a different country? If you are in the USA I have no explanation, it’s a mystery to me.
Bob
ok trojans then, re the renogy kit im just quoting the link you put in the article, did you check it?
Billy, I don’t undertand, this is a picture of what I see when I go to the Amazon sit and look at Renogy 200 kits:
also do i need a 20 mppt or 40 if i plan to top out at 400w?, and do i need 6v batts or are 12 v good enough? why 6v in the first place?
Billy, you need a 40 amp controller for that. I recommend 6 volts because you know for certain they are a true deep cycle. Most 12 volt batteries that say they are deep cycle really aren’t the are a hybrid like a marine.
Bob
Trying to find out what kind of reenforcing I need to do to my camper while I’m rebuilding it to install three or four solar panels for off grid hunting and maybe living going to be running four or five 12v battery s replacing all rafters so mite as well reenforce to mount for panel while I’m at it.
Roy, I’m afraid I’m not the person to ask, I have little engineering aptitude. But, I’d strongly suggest you join my forum, you’ll get all the ideas, help, encouragement and friends you could ever need. They will tel you exactly how to do it the very best way. Find it here:
http://www.cheaprvliving.com/forums
Bob
The link for the 200 Watt MPPT controller system does take you to an Amazon seller that charges $720. This package comes with a monitor, but that does not justify a much higher price. If you click on the link for the 200 Watt Pwm, and then choose MPPT it is a more reasonable cost.
Thanks Daniel, that makes sense, I’ll look into it.
Bob
Renogy now offers an additional ” Premium” 200w Kit. It consists of the smaller/more efficient Eclipse 100w panels, a 40 watt MPPT Commander charge controller that has adjustments you can make according to battery wants, an MT 50 digital battery meter.. And a couple other things. $769. http://www.renogy.com/renogy-200-watt-12-volt-eclipse-solar-premium-kit/
That seems too high to me. I’d contact Northern AZ Wind and Sun and get a 250 watts panel and Blue Sky controller for that kind of money–it’ll probably cost less and be better. Bob
Hi Bob. What size fuse did you use on Dandilion’s installation, and what gauge cable was on the fuse holder? Does cable gauge have to match fuse holder gauge? Also, did you fuse the hot line from the battery to the inverter? If so, how?
Everything (including the inverter) should be fused on the positive wire coming off the battery very close to the battery. The fuse holder should be the same size as the cable. 200 watts of solar would be fine with a 30 amp fuse.
I don’t remember which inverter she had so it will depend the size of the inverter. Here are three ways to do it:
http://amzn.to/2e0W7ZI up to 30 amps
http://amzn.to/2ddmkFV Maxi up to 60 amps
http://amzn.to/2e5eko6 ANL up to 500 amp
Bob
Thanks so much for all the info!!
My pleasure Gail!
Hi bob,
First let me say I LOVE your site (even though I am a ways away from getting free…basically just starting the process and do not even have a van yet).
I am planning to go with the renogy system for power. However, I have a question on the controllers (PWM vs MPPT). After reading the article and literally all the comments I am convinced that MPPT is far superior. Only problem is, MPPT is expensive. What I am wondering is if it makes sense to start out with the PWM and just replace the controller with an MPPT at a later date.
Mark, I think that’s a good plan, start with what you can afford and then when you know what you need you can upgrade to something. I did exactly that with a cheap MPPT controller that worked great for 4 years and then failed. Then I could afford a better one that I’ve been using for the last 3 years and is really great.
Hi Bob,
Thanks for the post. Don’t you also need an inverter so it converts 12V to 120V?
Great information, as I continue to watch your video’s and read your material, I’m thinking a Lil Snoozy, 400 watts of solar with a little honda 2000 generator. The only thing, I’m not quite sure about, is the batteries for the solar. Would it be better to use two deep cycle marine batteries instead of using golf cart 6 volt batteries? Thanks for all you do and I do believe this is gonna happen!!
No, golf carts are the best choice!
Sorry to be a dunce, but why 6v batteries? And then, how many per a 200 watt suitcase panel?
Sorry to clarify … it’s the solar panel built for 12v? I’m so confused.
Hi Bob,
Great discussion on solar, Swanson’s Law much like Moore’s Law is providing much more power for less!
By doing a Google search for MPPT controller in “shopping” I found many inexpensive controllers one of particular interest is the Victron Energy Marine MPPT 75/10 Solar Charge Controller for $79.90 with free shipping. It does not come with a readout but offers a Victron VE.Direct Bluetooth Smart dongle for $49.30 on sale that will display everything you need and more including history on a smart phone!
Bob you mentioned that you watch TV all evening and that 2 golf cart batteries aren’t enough for all of your needs with the TV included. What do you have then?
Wow, great info. Easy to understand?
I couldn’t find the post on how to adapt the power cord. What post is it?
Hi Bob, the images on many of your solar pages do not load. Great stuff otherwise! Thanks!
Sounds like a good idea to install solar panels on an RV.
Bob – there is a little 1000 btu personal air conditioner that uses 250 watts. If I store 1000 watts does that mean I could run it for 4 hours? this is probably a stupid question, but I am considering buying it and getting dedicated batteries for it.
Hi Bob, thanks for your post