|Fitted Solar Panels|
After having installed 2x 100w solar panels on the roof of our van, I don't know why I didn't do it sooner. It wasn't nearly as complicated as I envisaged and the install came in at just under £280. It could have been up to £50 cheaper had we chosen a cheaper solar regulator; but Adam wanted one with a remote display.
The truth is our 2x 125AH batteries actually seem to outlast our requirements. We don't watch TV very often, all of our lights are LED and we have two laptops with an 8 hour battery life (Asus UL30A) both with 12v chargers. I can only recall one occasion where we've run out of power - and that was after three days of running the blown air heating while attending the Harrogate motorhome show in a foot of snow.
So why have we gone down the solar route at all? Partly for the challenge and partly because the flexibility that it could offer us in the future; should we return to longer term touring. Our dependency on the internet if anything has increased over the last couple of years and so having the ability to run our laptops and charge our devices for extended periods without electric hookup could be advantageous.
In addition we spent 10 days on site in Lake Bled in glorious sunshine and could have saved 40 euro on hookup had we not required it to charge our devices. With the amount of sun that was present, it would likely have been possible to run the fridge via the inverter with the excess power that could have been generated.
Lets start with the panels. If you're going to be installing solar, it's no harder to install a 100w panel then it is a 20w panel and so it makes sense to install the most that you can either afford or have available roof space for. In our case I measured that we could fit 2x 100w panels down the right hand side of our van and still have enough roof space to get onto the roof without having to step over the panels.
Two possible downsides to this was it is possible to see the panels from ground, but no big issue as the aluminium brackets matched the panels themselves and look fairly neat and tidy. The other is that the small roof light over the bed could cast a small shadow on the panel at certain angles - but I think the effect of this will be minimal.
Parts Required - all bought from eBay
2x 100w Solar Panels - £140
Morning Star RM25 Regulator with Remote Display - £70
8x 50x50x3mm Aluminium Angle £15
16x M5 Threaded Inserts £3.50 (pack of 20)
16x M5 Stainless 15mm Bolts - £1.70 (pack of 20)
1x Tube Sikaflex 512 - £10
1x IP66 Weatherproof Junction Box - £5
2x 20mm Glands - £2 (pack of 6)
2x 5m Pre-Crimped MC4 PV Solar Cables - £20
2x 2-1 MC4 Connectors - £5
1x Inline Blade Fuse Holder ~ £1
2x Spade Connectors ~ 50p
2x Copper Nut Battery ~ £2
2x 1m of 8AWG Cable ~ £4
Cable Cutter / Crimp Tool
Threaded Insert Tool
7mm Drill Bit
5mm Drill Bit
30mm Hole Cutter
Our solar panels were purchased from German eBay, where prices seem cheaper and sellers more reliable. 2x panels were £142 including DHL shipping to the UK. Most solar panels seem to be monocrystalline now and so that's what we opted for.
The second major part of a solar install is a regulator. These can be bought for as little as £20, but I really wanted one with a display so I could measure the benefit and detect any issues. Originally opting for one with a display on the regulator itself, I soon realised that for a tidy, wire free install I would need a remote display and choices are somewhat limited. Morning Star have a superb range of regulators, I opted for the Sunstar RM-25 bought from Beco on eBay for £70 delivered.
The regulator has the ability to charge two battery banks, meaning I can charge the cab battery in addition to the habitation one should it be required. This can be undertaken either 50:50 or 90:10 in favour of the leisure battery, which is what I've selected. The only downside is that it is 'only' 25A which means I can only put another 50w of solar on the roof before I need to change regulators for the higher amperage Tri-Star regulator - but I'll see how we get on.
For me by far the most stressful decision was the brackets. The location of the panels dictated that the brackets would be positioned with the feet tucked under the panels which meant for a custom bracket install. I also wanted the ability to remove the panels from the roof if required - which meant I couldn't permanently attach the brackets to the panels.
|Mastic still to tidy up!|
The solution was found in installing threaded inserts into the aluminium frame of the panel, using a threaded insert rivet gun and attaching to the bracket with a stainless steel M5 allen key bolt.
The brackets themselves are made 8x 150mm lengths of 50x50x3mm aluminium angle, purchased for £15 for 8 pieces from www.forwardmetals.co.uk
- a company geared up towards small orders such as this. They arrived next day with no sharp edges; highly recommended. I would advise for the price, you should purchase a spare bracket just in case.
The bracket allows for a 2cm gap beneath the panel, which is perhaps slightly less than optimum. I drilled the aluminium brackets first and used it as a template to mark the holes for the threaded rivets. Drilling the aluminium brackets free hand was tricky, if you had a bench drill it would be much easier, but this method means that any misalignment can be compensated for in the positioning of the rivets.
Once attached, the roof was marked where the brackets would be located and the panel removed again and area prepared. Given the amount of dirt on my roof I used a bit of fine grit sandpaper before applying Sikaflex 512. I actually used almost a whole tube for two panels as each panel had a nice bed of Sikaflex.
Once in place, I located a gap between two panels inside the van in which to drill the 30mm access hole. Drilling from inside the van first, I marked the central point and drilled up out of the roof, then from the roof back down into the van. This was surprisingly simple, although care has to be given to miss any embedded cables. Once drilled, you can breath a sigh of relief.
I got a deal on a 2x 5m length of pre-crimped MC4 PV cables. MC4 is the type of connector common to solar installs and PV cable is a semi rigid cable which doesn't deteriorate in extreme weather. Its not necessary to run this all the way to your regulator, some installers favor terminating this just inside the van or not using it at all, but given the connectors and crimp tool, junction box etc were a good deal more than this pre-crimped cable; that is what I went with. If using the PV cable, be sure to mark the positive cable internally before you cut the end off! You can actually get two installs from this - I will be using the shorter length for my fathers Autotrail most likely.
|Fitting of the panels & brackets|
I also wanted a junction box on the roof that gave me flexibility to install other roof mounted hardware in the future, so opted for an IP66 unit with 4 screws on the top to access the internals. It has 10 20mm gland holes, so plenty of opportunity to install other equipment. I needed to remove a couple of lugs on the base so that it could be seated flush with the roof - and drilled a 30mm hole on the base to match the one through the roof.
|Cupboard nearly tidy and iBoost in place|
I ran a fair amount of cables at the same time as the solar cables. I ran cab power and RF cables up to the roof for a roof mounted FM radio antenna to overcome the poor cab radio reception (see other post), as well as RF cable for a roof mounted 3G antenna. In addition I ran 12v habitation power up to the same locker, RJ11 cable for the remote solar display (supplied with it) and a separate fused 12v for a 2x cigarette, 2x USB charger unit installed in the same location to run my Motorhome WiFi iBoost
, Huawei MiFi
device and charge our phones.
|FM Radio Antenna and some cable trunking|
The regulator was installed next to the battery and the positive 12v connection was fused with a 30A spade fuse. This is the last thing to be connected once you have checked all of your wiring.
It’s too early to tell what the gains are, but I know that in three weeks of pretty gloomy December I've generated 60Ah, so here’s hoping that summer allows me to generate much more.
At the same time I installed an FM radio antenna - some more information on this blog post (here).
Tips for Next Time
- A bench drill (or a template) will make drilling the aluminium angle much easier.
- Purchase a 'spare' piece of aluminium angle just in case (it's cheap enough).
- I purchased a cheap threaded rivet tool for £10, which was about knackered by the time I had finished with just 8 inserts. It was replaced but might be worth looking for a mid range one.
- Don't try and fit them under a pine tree shedding needles!
- Take more photos during the install, or have someone take them for you!