Our first real usage of Solar at Lostock Dam

In New South Wales, Australia, it’s a well-known fact that it rains over Easter. Sounds like a perfect opportunity to go camping and test out our new solar gear.

The Easter holiday period is between 3^rd and 6^th of April, so we’ve planned a trip to Lostock Dam Caravan Park (http://goo.gl/uFtQld) between the 2^nd and 7^th of April. A few friends (and some of their friends) will be joining us so it should be fun.

Lostock Dam is privately owned, located on the Paterson River in the Hunter Valley. The dam itself offers boating, fishing, canoeing and swimming. The overflow from the dam runs into the Paterson River which runs parallel to the park, providing additional swimming and canoeing opportunities.

According to the weather predictions we have prepared ourselves for a mixture of sunshine and rain. Accordingly, I’m looking forward to collecting some data with the hope of being able to better predict energy requirements when faced with less than ideal conditions in the future.

The following is a list of everything I took on this trip for the purpose of running everything off solar:

• One 240W solar panel (3-way, folding)
• One Ctek 250S Dual Charger
• One ArkPak unit with a 100Ah battery
• A second 100Ah battery (connected in parallel to the ArkPak)
• Two voltage / current monitors so I can track energy captured and consumed
• LED lighting
• One Engel fridge / freezer unit

Our solar testing was focused primarily on the use of our Engel fridge/freezer and some LED lighting. Prior to the trip we made sure the Engel unit had been running for several days (it's actually been keeping my stock of beer chilled for several weeks) and we powered it from the car's cigarette lighter during the trip itself.  It's also worth noting that the thermostat was on the maximum setting of 5 when at home but was reduced to 3.5 when connected to the solar.

We arrived at the Park just before 3pm and the first thing I did was connect the solar panels to the Ctek charger and two 100Ah batteries. According to the ArkPak's LCD, the battery level was at 99%. Both batteries were fully charged before we left home so I'll use this as a reasonable indication of the initial state.

By the time our site was completely setup and dinner was done, the sun was pretty much ready to fall behind the trees and mountains so I packed the panels away and reduced the Engel's thermostat to 2.5 (the temperature was probably around 20C).

In the morning (3rd April) the batteries were at 92% capacity. The weather conditions had turned for the worse - it's now completely overcast and there's intermittent rain. I could only guess the sun's position based on where I observed it setting the previous evening.

I did some experimenting with the orientation of the solar panels relative to the sky (it was glaring cloud in all directions) and didn't notice any great difference in energy being captured. I'm guessing the diffused light is being reflected off all clouds in all directions (much like a photographic diffuser) so it won't matter which way I face it. I just put it out of the way of the kids and let it do it's thing. I checked the output at random times of the day and noticed I was lucky to get up to 1A (most of the time it was around 0.4A to 0.8A).

Ok, it was time to get serious. The configuration of everything hangs together like this:

At 10:20am (3rd April) I reset the two monitors (shown as M1 and M2 in the diagram) so I could better track (and compare) energy going in compared to the energy being consumed. All readings were taken while the fridge was idle to ensure there was no bias due to a heavy load being present.

Here are the readings I took during the course of the day:

The monitors I'm using record the cumulative current output by the Ctek (M1) and consumed by the Engel (M2). These values are noted in the 3rd and 5th columns respectively. For the purpose of a per-hour comparison I have calculated the A/Hr values in the 2nd and 3rd last columns.

So, at 10.20am the battery was reading 91% capacity and almost 7.5 hours later it was at a reasonable 87%. As for the energy, I had captured an average of 0.81A per hour over the course of the day, while the Engel had consumed only 0.69A per hour. This low current draw of the Engel is attributed to the low ambient temperature and the fact I turned the thermostat down to 2.5.

4th April 2015
The following day was worst than the previous. The cloud cover is heavier, lower in the sky and there's a little fog. It was too wet and cold to do much so we pretty much sat around chatting with our friends, kept the kids entertained with games and enjoyed a beer or three.

I noted the following data during the day:

You'll notice I've added additional columns for the freezer thermostat setting, temperature and current battery status.

The energy consumption of the Engel is approximately the same for both days (which makes sense considering the conditions were pretty much the same) but what's not immediately apparent is that for the elapsed period of 32 hours, 18 hours of that time has been spent collecting rays from the sun (I pretty much left the panels out until the monitor was reporting next to no current being produced). Although the quality and quantity of sunlight was poor I've still managed to replace approximately 50% of what has been consumed this far.

It has been quite a dreary day. Nothing but cold wind and loads of rain. Here's hoping for a better day tomorrow.

5th April 2015
It's a brand new day and the clouds still haven't cleared but at least it isn't raining too much.

More importantly, it's Easter Sunday. Even in the rain the hunt must go on.

Oh yeah, daylight savings has also ended today. The times recorded from this point forward have an additional hour added to ensure the calculations remain relative.

Fortunately, the clouds started to move on (mostly) just before lunch, allowing us to once again see the sun. It's time to start generating some real energy from the panels.

Now the numbers start to get exciting:

Up until 11:20am (12:20 in the table) you can see the "Solar A/Hr" is roughly the same as the previous day. As soon as the sun come out though the Ctek started to push some real energy into the battery. At 11:55am (12:55 in the table) the rate had already increased to 0.37 - more than the average calculated for the end of the previous day. And by mid-afternoon (15:44 in the table) the energy produced from the panels was finally exceeding the energy being consumed. We can finally see the battery capacity being restored.

In my past experiments I was stoked to achieve a maximum of 196W from these 240W panels, but today we've managed to peak them at just over 217W. And compared to the cloudy days of around 1.0A, seeing that peak of over 16A is truly beyond what I was expecting.

This trip was my first real usage of the Ctek charger. Worth every dollar.

6th April 2015
A nice early rise (6.10am) has given me the opportunity to go for a walk and capture some wonderful photos of the bushland surrounding our site. Check these out.

Until now I hadn't really had the opportunity to go for a good walk and explore this park (mostly because the ground was so soggy from all of the recent rain). I'm sure glad the sun came out yesterday and has appeared once again today. As it turns out though, there is a storm predicted for tomorrow so we've decided to start packing up around lunch time and make our way home while everything is dry.

We experienced it all on this trip. Two days of constant rain and overcast conditions meant lowering the Engel's thermostat was the only sure of of preventing rapid battery depletion. Not know if the sun was ever going to show itself we managed the usage of battery power as conservatively as possible. We got lucky on the third day and was able to recover the battery depletion quite rapidly. At least now I know that when we go camping in hot weather it's a pretty sure bet we'll be able to keep the beer nicely chilled !

Most importantly though, in-between all of the data collection we found time to sit back and relax with each other, play games with the children, explore the bush land, do some kayaking and even ride an inflatable down the river's rapids.

I reckon we might come back here again one day.