Solar power

If you have read about the mobile workshop you will know that part of the plan was to have some solar panels on it. This is not for environmental reasons. It is to try and ensure that the mobile workshop has as much power available to it as possible. During a long pop-up sharpening event looking at the battery monitor I was getting down to 50% of my calculated capacity which was within safety margins but it is one boo boo away from it being an issue.

As I am running bargain basement flooded cell lead acid batteries then you really don’t want to be discharging them too much. I have two 120 amp hour flooded cell lead acids. Go below 50% and they are rubber ducked but in an ideal world you want to keep them as charged as posible. Due to this I have set up my battery monitor to have a capacity of 110amp hour which gives me some wiggle room.

The current way of working is coming home and plugging into the mains every night to charge up the batteries. I have a 20 amp charger so an overnight charge is enough to bring the batteries back up to full charge. I have a rated capacity of 120amp hour so 6 hours at 20 amps gives me 120 amp hours. More then enough.

Adding the solar means that I can during daylight have a constant current charging the batteries. This means they are topped up which is good for battery health and also means I can be slightly less paranoid.

I added the system on a Friday before a pop-up sharpening event and with typical scottish weather I maintained a charge level which rarely dropped below 90% and after the drive home it was sitting at 100% this was from Solar and also the charge socket off the discovery.

Overall I am very happy with it.

Which should of been the end of this blogpost.

So what is it?

After consulting with David at a local company Haven off grid touring i choose two victron 115 watt solar panels and a victron 100/20 solar controller and he gave me a very good price. This gives me an installed system of 230watts which isn’t very big

Of course I installed them myself.

Solar panels

The solar panels where fitted onto the roof of the trailer and are connected in series so that you get a higher voltage and a lower amperage in the cables.

For the front panel the roof supports fitted in wonderfully to get it fully supported on 4 points

The rear one, not so good

Solar Controller

The solar controller fitted into the gap between the charger and the inverter.

I also spliced into the cables from the charger

It’s almost like I had planned it :)

So why did i go for Victron?

The rest of the system is the cheapest of chinese garbage where as victron is much more expensive.

Basically quality and support. I expect the magic blue smoke to escape from the inverter in about 6 months as then it will be just over 6 months of use. The victron units I expect to last alot longer but when I first built the workshop the budget was tight.

The other feature i really like of the Victron is that it has a bluetooth module onboard as well as a brain so it can tell you what is going on.

Screenshot below

Looking at the above you can see for 3 days it has been averaging about 360Wh (watt hours) per day. Waving a roughly calibrated finger in the air 120amp hours at 12.5V gives me about 1500Wh. So this is about a quarter of the battery capacity which sin’t too bad.

When you consider that the solar controller will pull back on the charging rate when the batteries are full then I could be getting alot more.

The 4th day is today when it has been snow and/or rain all day with constant cloud cover

I still got 120Wh which is a useful amount of power.

As to cost i’m not saying but it was a very good deal but based on the current daily average and the cost of a KwH from the mains then I can expect to be making a profit based purely on energy costs about 2028