Watch on YouTube: https://www.youtube.com/watch?v=d9NxFVOwccI
My DIY Solar System Part 2 - Improvements And Considerations Based On Your Feedback!
Introduction
A few weeks back I released a video looking at an Eco-Worthy “off grid” solar panel kit, which I used to create a DIY solar system on my house. It was much more popular than I expected, so I decided to release this update addressing some concerns about safety, wiring, and planning permission discussed in that video, as well as talking about a few upgrades I’ve already made, including a Renogy Rover MPPT solar charge controller, a Renogy battery monitor and 2 more Eco-Worthy 120W solar panels.
I may not be a “prepper”… But it doesn’t hurt to be prepared 😉
Script
We need to talk about this solar video!
So over the summer I decided I wanted to learn a bit more about solar power, and I watched a load of videos - as you do - and there was so much information out there that I got a bit overwhelmed by it all, if I’m honest. So I thought the best way to learn would be to buy an off-the-shelf kit and I thought that documenting my experiences with it would be of interest to my small community of 7000-odd subscribers, specifically the 3-4000 people who regularly watch my videos.
So you can imagine my surprise when - just over a week later - that video has been seen by over 250,000 people, and I’ve had so many new subs off the back of it that it’s pushed my channel over the 10,000 mark, which is just insane - and thankyou all so much for taking an interest in my little channel.
I wasn’t going to do an update on this project until the winter and I had a few months’ worth of data to talk about, but there are a few issues with that initial video that I really want to address, and with so many eyeballs on it I feel I have a responsibility to do that sooner rather than later. I’ve also already made some improvements to the setup and there have also been a few questions off the back of that video that I want to talk about.
Now, probably the most important thing I need to talk about is a safety issue to do with this charge controller - in the instructions it states that the battery should be connected first, then the panels, then what they call the “consumer” - ie the load - and in part 1 the panels and controller had arrived a few days before the batteries showed up, so I hooked it up and plugged a phone into it to test whether the panels were working.
I do mention the correct sequence later in the video but I think that showing it set up in this way probably gave a lot of people the wrong impression and of course a lot of people who know even less than I do about solar did come across the video and unfortunately we can’t edit them after they’re uploaded, so I pinned a comment with a warning and have been doing my best to address this in the comments.
Of course I’ve seen plenty of videos on these systems and I’m well aware that running a normal charge controller in this way can damage it, but in my defense Eco-worthy do sell this particular one bundled with quite a few portable kits that don’t include batteries - it has those USB ports on the front after all - and nowhere on their website or in any of the included manuals is there any kind of warning about this. But as I am a complete beginner I think it’s always best to err on the side of caution, and I just want to make it very clear - NEVER CONNECT SOLAR PANELS TO A CHARGE CONTROLLER WITHOUT CONNECTING THE BATTERIES FIRST.
There’s a type of device called a DC to DC converter that’s designed for this, so do your homework and shop around if that’s the kind of setup that you’re interested in.
And on that note I just wanted to add that I’ve never been afraid to show my mistakes on this channel or to admit to them because ultimately that’s how we learn.
Now, in slightly more cheerful news, lets talk about some upgrades.
I came to the conclusion in my first video that the charge controller is basically a load of rubbish, and quite a few in the comments agreed. So on the recommendation of a few people, I’ve now upgraded to a Renogy Rover MPPT controller which was around £130. Yep, solar stuff is expensive in the UK, as pointed out by a few international commenters and I don’t want to get political on this channel so let’s move on swiftly.
MPPT or Maximum Power Point Tracking is a technology that continuously alters the electrical characteristics of the load that it puts on the solar panels so it can squeeze as much out of them as possible and the cool thing about this particular unit is that it logs everything and has a Bluetooth interface and an app so I can keep track of what it’s generating. Longer term I’d like to look into using something like a Raspberry Pi or an Arduino connected to the serial port to gather this data as I’m a programmer in my day job and I’m not too keen on tying myself into other people’s proprietary apps. But the app will certainly do until I can get that set up - and supposedly - according to the manual - this controller is 92-95% efficient so hopefully it’ll help me to get the most out of my panels in the coming winter months.
Certainly today it’s been pretty overcast and damp and miserable - unlike when I made that first video - and as you can see with the addition of two more panels which I’ll talk about in a second, the system is putting out about 60W of power, with my laptop, amp and shelf lighting drawing about 45W.
I’ve mounted the new controller on the wall using the supplied brackets, in a place where it’ll have plenty of room for ventilation - no double sided velcro this time - and of course I followed the golden rule of connecting the batteries first before anything else. Interestingly enough the excellent Renogy manual does include a scary warning about this right on the first page and then again a few more times on some other pages, so that’s great to see.
So far I’ve been really happy with this unit, and I’ll let you know how it performs longer term in the next update.
So as I mentioned I’ve also added 2 more solar panels - these are both 120W 12V units the same as the originals and were around £90 each, and I wired them in parallel initially as per the originals just to get things up and running, but now I have the Renogy I’m planning on rewiring them as 2 banks of panels in series for a 24V system, as this is supposedly more efficient and also a bit safer as it actually means less current flowing through the wires from the panels to the controller. I must admit I didn’t bother recording the build process this time as the frames are identical and attach to the wall in the same way, so here are a few clips from the first video just as a refresher on how they fit together.
Just going back to safety for a moment, while it is easy enough for me to lean out of the window and pull the plugs out if I need to disconnect the panels, I’m looking into adding a proper isolator switch, as well as fuses or circuit breakers just in case so I’ll cover that in a future update but I just wanted to mention that as far as I can see there’s no legal requirement to fuse a system of this size which explains why these don’t come as part of the kit.
Another piece of kit that just arrived today addresses another one of my complaints from the first video, and that’s not knowing the exact state of charge of the batteries. I mentioned that you can get a rough idea from the voltage, but it’s not entirely accurate so I decided to go with this Renogy shunt battery meter which was £75 and I should point out that far cheaper options are available, but this is professional piece of kit good for up to 500A and 120V systems, so along with the charge controller won’t need to be upgraded again for a long time if at all. It’s certainly not a necessity for a basic off grid setup like this, but as this project is all about gathering data I decided it would be a useful thing to have.
Of course having to spend all this extra money does mean that this is going to take even longer to pay for itself, but like I said in part 1, this always was more of a learning exercise for me than a money saving one, and ultimately the plan is to move this setup to a garden office or similar outbuilding in future to power my channel and various hobbies longer term, so it’s very much a proof of concept at this point and I don’t mind exploring a few different options to get the best result if we can all learn something in the process.
So now onto some questions that were raised off the back of my original video - and a few people were interested in how the fuse was wired in - the one that I found in the inverter box after I’d wired everything up. So here’s what that looks like and here’s the diagram from the Eco-Worthy website showing it on the positive side of the cable from the batteries to the inverter. I’m not entirely convinced that it does a lot, especially considering the inverter has blade fuses that slot into the back anyway, but it’s a safety thing and they presumably wouldn’t have wasted money on it if they didn’t think it was important so that’s that. Sorry for not showing it last time but as I mentioned I wasn’t expecting that video to get nearly as big a response as it did and I’ll try to be less lazy in future.
Another discussion was about how the inverter is grounded - or earthed as we say in the UK. I’ve done some continuity tests and the earth pin of the socket isn’t connected to the outer casing or to the negative terminal of the batteries as some viewers suggested, so it doesn’t seem that grounding either would help at all. There also isn’t a ground connector on the inverter anywhere to connect to a grounding rod as per some camping setups that I’ve seen. So I’m a little bit confused about how that’s supposed to work and whether there’s a potential safety issue here that I need to be aware of. It’s another one of those things that’s not mentioned in the manual so I’ll keep looking into that and post an update once it’s sorted.
Finally, just while still on the topic of inverters, I had a few questions about maybe connecting this into the house electrics and having it switch over automatically when the batteries get too low. With my setup I’ve found that I haven’t actually run out of power yet even using it all day and into the evening so it’s not proven to be an issue, but the phrase that you’re looking for for further research is grid tied inverter. It’s not my area of expertise and it’s not something I’m looking into at the moment, so hopefully that’s enough of a jumping off point if that’s of interest to you - but on that topic, I’ve also been asked if this is a good starting point for a full household system and the answer to that is very much no. If you’re looking for something to run your household appliances and actually be practical and economical in the long run you’d definitely be better off looking at getting a proper rooftop system installed but we’re planning on moving in the next couple of years so it’s not something I’ve seriously looked into for this house.
A commenter on the first video described this setup as the world’s most expensive phone charger - and that’s probably about right, even if you were intending to be mean. In fact maybe I should change the video title to that…
A couple of questions about the panels and whether they include bypass and/or blocking diodes. Bypass diodes yes, or at least that’s what the manufacturer claims - meaning that if the panels end up partially shaded they don’t shut the whole system down or worse - overheat - blocking diodes no, but from what I can see there shouldn’t be a requirement for them with a charge controller anyway, and they’re very cheap and easy to add inline if they’re required so let me know if I’ve got the wrong end of the stick there - politely if you could - and I’ll certainly add some.
I’ve also been asked whether the panels work at night and I think you can guess the answer to that. Although it has been nice to see them generating a small amount of power in the early morning and late evening when the sun’s gone in, which, knowing nothing about these things I wasn’t really expecting. But I’ll hopefully have a bit more data on that later on. I should also mention that the panels perform better if they’re clean and they should be pretty much self cleaning at this angle but something to bear in mind if you’re mounting them flat on a shed roof or something - of course in my case it’s easy enough to just hop out onto the roof and give them a wipe down if they get dirty.
Speaking of that angle, another question I had was about planning permission. So here in the UK we’re not really supposed to just build things willy nilly, but there’s a fair bit we can do without having to notify the local council - known as permitted development - and rooftop solar panels are covered by that. However there is some wording in there about flat roofs and anything that protrudes more than 20cm above the roof line, which these do. I have some experience with the planning process and it’s something that can be done retroactively and easily so I’m making enquiries at the minute - mainly because I want to make sure everything is airtight for house insurance purposes. My friend Mark from the channel Mark Fixes Stuff sadly had quite a horrific electrical fire in his house last year - not related to anything solar I might add - so it’s something that’s certainly on my mind. I think my insurance company would take a pretty dim view if something I’d built illegally ended up burning my house down so I just want to make sure it’s all legit.
Finally, just some thoughts on what I could potentially do to get more out of this system - basically every kWh that I generate that doesn’t get used is wasted and even in bright sunlight the charge controller can’t generate any electricity if there’s no load on the system and the batteries are full - which I’m ashamed to say so far has been the case more often than not. Of course this is a big factor in how cost effective a system like this works out to be longer term.
A patron of mine who I’ve mentioned on the channel before - Woz - has been sharing some stuff on my Discord server about a similar setup that he has at home. Now the crucial difference in his case is that he’s charging a portable battery pack with an integrated inverter. So while his working from home setup runs from solar in the day when he’s there, the excess gets used for all sorts of stuff around the house overnight - charging portable devices just like I am - and yes, that includes an Atari Lynx because he is a fellow man of culture - and also to put a few bonus miles in his electric car and he’s even used it to cook his dinner. So definitely some cool ideas there and some - erm - food for thought.
But anyway, that’s pretty much all I wanted to cover in this update, and the main thing for me was getting that safety information out there that I mentioned at the beginning as I’d hate for us to start on the wrong footing. So my job for this evening is to install this battery charge meter, and longer term I want to look at maybe a 12 or 24V system in here that I can use to more efficiently run some of the low voltage DC stuff like the lighting rather than having to use the inverter.
I’m going to go back to my usual retro computing, gaming and electronics content for a bit now that’s all been addressed, I’ll carry on measuring the performance of all of this longer term and hopefully release another update later in the year when I have some more to share. A few people shared their favourite solar channels with me last time so thanks for those recommendations and I’ll link those down in the description if you’re looking for some further viewing. Big thanks to my patrons and channel members for your support as always - you can see their names on screen as I speak - and I’ll hopefully see you again next time.
Original Video Links
Support the channel!
Patreon: https://www.patreon.com/ctrlaltrees
Become a Member: https://www.youtube.com/channel/UCe7aGwKsc40TYqDJfjggeKg/join
Ko-Fi: https://ko-fi.com/ctrlaltrees
My Solar Setup (Affiliate Links):
Renogy Rover 40A MPPT Charge Controller (Amazon): https://geni.us/z8ySS
Eco-Worthy 120W Solar Panel (Amazon): https://geni.us/2CId1Ax
Eco-Worthy 240W Off Grid Solar Kit (Amazon): https://geni.us/qwcc
Renogy Shunt Battery Meter (Amazon): https://geni.us/ohciTa
“Maxico” Kill-A-Watt Energy Monitor (Amazon): https://geni.us/wDAJ
Eco-worthy DIY Solar Kit (UK): https://bit.ly/3UnVniK
Eco-worthy DIY Solar Kit (US): https://bit.ly/3DWDBxK
mobile-solarpower.com - MPPT controllers: https://www.mobile-solarpower.com/solar-charge-controllers.html
Further Viewing:
Solar Playlist: https://bit.ly/reessolar
Julian Illet: https://www.youtube.com/c/JulianIlett
Robert Murray-Smith: https://www.youtube.com/c/RobertMurraySmith
Off Grid Garage: https://www.youtube.com/c/OffGridGarageAustralia
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