Wednesday 23 October 2013

We No Longer Need to Eat Green Meat - A Solar Panel Review


Bleached turtle bones attest to the abundant sun in Oman,
perfect for a solar powered 12V fridge system
I well remember the look on my fellow campers faces when, on the fourth day of a particularly warm spell, I pulled some lamb chops from the cooler and they were tinged with green, the ice having long since melted. It was the last food we had, so I just cooked them well over the fire that evening and my son and I ate them. Although we were fine afterwards, eating greenish chops was the catalyst for me to look into a 12V fridge and some means of powering it for extended camping periods.

Fast forward to our latest trip to the east coast of Oman, a fairly remote region where you need to be self sufficient. This trip was a shakedown for  my new set-up for keeping food fresh and drinks cool, and with my wife and two kids along I couldn't really afford to fail.  So what follows is a personal review of the equipment I've used in preparing my Land Cruiser for multi-day camping trips, focussing on using a solar panel for powering 12V equipment.

Our base camp where the desert meets the beach,
somewhere south of Al Ashkarrah, Oman. 

In my Land Cruiser I have:
  • a dual battery setup, one main starting battery and an auxillary 12V battery for powering stuff.
  • a solar panel to keep the batteries topped up while we're not driving.
  • a fridge/freezer for keeping food and drinks fresh for a few days.
In a future post I'll do a detailed review of my 12V fridge/freezer, I want to use it a bit more to get a good idea of it's strengths and weaknesses. Suffice to say that for this trip I used a 52 litre National Luna Weekender. At the start of the journey I set the thermostat at -6 C and despite the daily temperatures reaching 35 C the NL coped admirably. Most importantly, the adult beverages where always nicely chilled! 

Obviously, you can't run your fridge freezer from your starter battery and so I have a dual-battery system, using a National Luna split charger and dual battery monitor. Despite what you may be thinking by now I have no affiliation with National Luna and chose their split charger with dual battery monitor simply because I was able to buy it off the shelf and fit it myself even though I'm no auto-electrical boffin. On starting the car the split charger first ensures enough charge is restored to the starting battery before it also directs charge to the auxillary battery after a few minutes.

My split charger is mounted on the left fender, just behind the starter battery.
The red canvas flap folds down to cover it and keep it protected from grease and dirt.
I've had the split-charger for over a year now and so far it's proved simple and reliable, my only gripe is that the connector that slots into the dual-battery monitor is flimsy and could do with beefing up. This was made obvious when I compared the auxillary battery read-out on the monitor to the battery indicator that is built into the fridge, the former indicating a far lower charge until I jiggled it a bit to make better contact. From then on I used the fridge indicator for checking the charge of the auxillary battery.

The dual battery monitor mounted out of the sun next to my gear lever.
The white connector could do with some beefing up.
While we're on the road the fridge/freezer runs off the auxillary battery and the battery is, in turn, kept charged via the split charger from the dynamo. From Dubai to where we camp on Oman's east coast is a good 10 hour drive, so the whole system works well. But it's when you reach your destination that things are a bit more tricky and I needed a method of keeping the battery charged while stationary for days at a time. Seeing as the Middle East is abundant in sun the obvious choice was to go for a solar power, and so I set out to find a suitable solar panel.

Oddly enough, despite year round sunshine, finding a good solar set-up in Dubai was neither easy nor cheap. Off-the-shelf units, like those made by GoalZero, while seemingly well made, where very expensive and only delivered 30W. I'd need at least three for my requirements which put them way over my budget (as an aside, my wife gave me a GoalZero portable panel for charging my phone and iPod and I find it very useful.)  I also wasn't too keen on a rigid panel so spent time combing 4x4 magazines from South Africa for ideas and found suppliers of flexibile panels that you can roll up and stow away, like the Kalahari from Flexopower. I liked these, especially the 166W power output, but the rolled-up size seemed to take up a lot of packing space which is something I don't have in abundance.
It was a business trip to South Africa and a chance visit to an Outdoor show that finally put me in contact with a company supplying fold-up solar panels and after a series of emails between me and the owner (answered VERY promptly*) I decided this was the route to go and I ordered a 90W folding panel from Just Solar. The owner, Theo, embodied good customer service and went out of his way to drop the panel off at the hotel I was staying at, despite it being after hours and well out of his way, he even soldered a second battery coupling for me there and then in the back of his 4x4. I was really impressed.

Six individual panels make up the full 90W panel. 
The Just Solar folding panel consists of 6 individual cells and according to Theo these are made by Kyocera but I was not able to verify this. Once folded for packing, the surface area is the size of one cell plus the surrounding laminate. As can be seen below I was able to lay it open on my car's bonnet** without it hanging off the edges. On an earlier test run at home I placed it on my roof rack and left it there to top up the main battery while I was away for a few days, it worked perfectly.

The material surrounding the panels is very robust and Just Solar's website describes it thus "The polymer encapsulation is partially constructed of durable ETFE, (example, Tefzel®) a high-light-transmissive polymer." I'll have to take their word for it.
On the face of the unit are small 'bubbles' between the outer laminate and the solar cell and Theo took great pains to point out that these are a normal part of the manufacturing process and do not affect the efficiency of the unit. In my experience this was the case and they seem to be aesthetic issues, not practical ones. When I get the opportunity I'll look at flexible panels from other suppliers and see if this is a common trait.
Small imperfections on the face of the panel did not seem to affect performance in any way.
Each corner has a grommet allowing you to fix it down or hang it from a tree (can you see the great forest where I was camping? Ha!) I would have liked one more grommet at the middle of the longitudinal edge, just for peace of mind, but I don't think there is enough space between the cell and the edge (unless one uses a smaller grommet.)

The surrounding material is very robust and has grommets on each corner.
All in all the whole unit is solidly constructed and looks set for years of use (and, in my case, abuse.) Pretty much like my Land Cruiser, really.


As portability and packing volume were strong criteria in choosing a fold-up, rather than a roll-up, panel I took out my tape measure and old fishing scale and here is what I found:
  • Opened up, I measured the panel at  88.5cm x 83.5cm (34.75" x 33.5".) On one end is an additional flap with the power cables, this is also edged with velcro and wraps around the panel to hold it closed when folded.
  • Folded closed, I measured it at 42cm x 30cm (16.5"x 11.75") and about 3cm thick (1.25") not including the regulator. It comes with a carry bag that also holds the regulator and cable, the bag is well constructed and not flimsy, an area often overlooked by gear manufacturers. A good quality YKK zip down the side would be desirable as the bag is a tight fit and it takes a bit of jiggling to get the panel to slide in. 
My old Leatherman gives you an idea of the size when in its carry bag
  • With the panel, controller and cable in the bag my scale showed a total of about 5kg (11lbs.) Easy enough to carry around and load in and out of a car or lift on to the roof rack.

At 5kg it's a very portable unit and combined with the compact size makes it easy to stow.
A Charge Controller is supplied with the unit and Theo took great pains to emphasize that the correct connection procedure was to first connect the regulator to the battery and only then connect the panel to the regulator, using the mnemonic 'BP' (Battery before Panel.) He also told me to ensure that the regulator was set for 'Volt' and not 'State Of Charge' (SOC) but to be honest I forgot about this and can't really tell you what setting I had it on during operation, but things seemed to be OK. I'll take more care next time. The picture below is how NOT to use the controller, I didn't have time to mount it anywhere before the trip so at first just hung it from the hood ornament (all Gulf spec Toyotas have these.) Later on I moved it under the bonnet to keep it out of the sun. The long term plan is to attach it with velcro so I can remove it easily when not charging. I just need to figure out where.

The Controller - Battery cable (grey) routed through the grille.
The Controller - Panel cable (orange) draped on the Toyota badge.
A full review of the Controller is beyond the scope of this post, it comes with a 15 page instruction manual giving all the various readouts and features. I would have liked to mount it permanently under the bonnet but the manual says the maximum permitted storage temperature is 80 C which is below the 86 C operating temperature listed in my engine workshop manual, so I'm not taking any chances.

The panel has two types of connectors and two cable colours:

  • Attached to the flap is a pair of Photovoltaic connectors and running from these is a long orange paired cable that plugs into the controller. I could not see any makers marks or logos on these but assume these are ones made by Anen. (see bullet point below next photo.)
  • The flap on the panel showing the PV connectors and start of the orange cable.
  • The orange charging cable was roughly 7 metres (23') long, allowing you to place the panel quite far from your vehicle. As I didn't want anyone walking on the panel I placed it on the bonnet and draped the cable over the hood ornament. The length and the fact that it's two separate cables means it tends to get a bit tangled, I'd have preferred a single length of bonded wire (two strands joined together) but I'm not sure if you get it in the required gauge. I might cut it shorter in the future as I think the bonnet, or sometimes the roof, will be my standard placement.
My auxillary battery on the right fender showing the Anderson type connector.  
The Controller's connector simply plugs into this and has another for the panel.
The cables at the back run to the  fridge and the split charger.
  • All other connectors, Controller and battery, are of the 50A Anderson SB type. A close inspection of the connectors revealed them to be made by Anen Power and a quick Google search didn't seem to reveal any link between Anderson Power and Anen Power but perhaps one makes these for the other. Either way, the connectors are very solid, fitted tightly and look to be of top quality. 
  • A nice touch is that the cables coming from the Controller had their wires colour coded, orange for the panel connection and grey for the battery connection.  A simple visual aid during setup and this may be why a bonded wire was not used. Colour coded connectors and bonded wire would be a good combination.

The flap wraps right around the folded panel and keeps everything tight and secure.
All I needed to do was wire a matching coupling (also supplied) to the battery and it would be ready to be connected to the coupling on the controller. A minor gripe I have is that I would have preferred the battery connectors to have red and black cables for positive and negative respectively, rather than have both cables being grey. While the couplings have '+' and '-' markings, colour coded cables would have prevented me from connecting them to the wrong battery terminals the first time round, luckily I double check before hooking everything up.
If you study the photos you'll see that I routed the cable through the grille, this was in order not to pinch the cable when I closed the bonnet. It worked well but was a bit fiddly to do.

So, the big question: How well did it all work?

Before answering, I must confess that the auxillary battery was not a proper deep cycle unit, as it should be, but just a plain old starter battery rated at 95Ah. Also, despite the pictures showing us in splendid isolation, a group of friends arrived later and I repositioned my car with the bonnet facing north instead of south (Oman is in the Northern Hemisphere) which meant the panel was not truly facing directly into the sun but tilted slightly away, reducing it's efficiency. Despite these two 'faults' the setup worked surprisingly well, far better than I expected.

We drove all night to get there, arriving just before sunrise, so I had a full day's worth of testing for the first day. So on the first day I experimented by attaching the panel to my main battery and letting the split charger handle the power requirements between the starter battery and the auxillary (I have a current leak in my starter circuit that drains the battery over a few days requiring me to run the engine periodically, and I'm damned if I can find it.) I wasn't sure if the split charger would handle this but it kicked in after a few minutes of charging the main battery and started routing charge to the auxillary as well. Even with charging two batteries the panel provided far more power than the fridge/freezer could draw, ensuring that both remained fully charged and the drinks ice-cold.

The second day went just as swimmingly, all battery indicator lights showing full charge as long as there was sun, even if the panel was never quite at the correct angle. The panel was surprisingly efficient even in the early morning and late afternoon. However, after sunset on the second day the auxillary battery charge dropped more than expected (but not into the 'red' zone) and I ran the engine for a few minutes to charge it for the night. Once again the charge dropped a few notches but never drained the battery entirely overnight.
In the morning, the panel kicked in again and I had full power all day, even with the fridge being regularly opened to slake 4 people's thirsts while mid-day temperatures hovering around 35C.
I put the sudden drop in charge in the evening down to the fact that the battery is not a deep cycle battery (nor very new.) Over the 4 days we camped it never drained completely or even dropped below the fridge's cut-out level which I'd set at 'Medium' and not low. As long as the sun shone there was power aplenty. Our last package of meat, having spent 3 days and 3 nights in the bottom of the freezer was still frozen when I took it out and I had to thaw it for that evening's fire.

I have a few tweaks to do, firstly I need to find a proper deep cycle battery that can handle slow current draw. I''m certain this will address the sudden drop in battery power after sunset. Secondly, I need to have a better mounting system for the Controller as mentioned above.
Thirdly, I want to make sure the Anderson coupling fixed to the battery is dust and water protected, I've seen dust caps for these units and intend to fit one.
And finally, I will start adding some lighting for the evenings, a 12V charger for my Maglite and maybe even a small inverter to charge camera batteries.

All in all I'm very pleased with the set-up and particularly pleased with the solar panel, although not very cheap I think it was money well spent. I was concerned that 90W might not be enough, but it was ample, and these panels can be daisy chained if one is not enough.
And once gain, I was very impressed with their customer service.

So next time you see me out there, stop by for a cold one.

*Any supplier that takes more than 24 hours to respond to an email query gets stricken from my 'buy from' list. If they can't answer a simple email quickly then they'll probably be laggards in sales and service.
**American readers, we use 'bonnet' where you would use 'hood'.

sunburnt ... and in need of a shave








Wednesday 16 October 2013

No Chance To Surf, So Break Out The Camera.



Once again I found myself in Oman over the Islamic festival of Eid Al Adha, but unlike other Eid trips I didn't witness the death of goats at dawn. Instead, we spent a few days on a remote beach on the east coast of Oman, a favourite area for surf.  Due to unforeseen circumstances I had to leave my surfboards behind so spent the days sipping Tiger beer, playing with my kids, spooning with my wife and enjoying the company of (non-surfing) friends. It also meant I had time to whip out my camera and tripod and to take a few images.


Seascapes are some of my favourite pictures, but they're not easy to get 'just right'. Waves have a mind of their own so it takes a few tries to get something worthwhile. Both images above where made within 20 minutes of each other, notice the dramatic change in colour temperature as the sun went down.


sunburnt ... and in need of a shave