MPPT Solar Charge Controller
In my last post I described how I decided to change my batteries and why I went for a set of Trojan T105’s. Check it out here.
Now that I had some expensive new batteries I wanted to look after them as best as I could to keep them lasting through the years. Trojan list the voltages for the different charge stages on their website, they also recommend an equalisation charge periodically. I’d not heard of this before and it is basically a deliberate overcharge to remove sulfate crystals that build up on the plates over time. My original solar charge controller was fairly basic and didn’t allow for equalisation charging or for the voltages to be set on the other charge stages so I got looking at other chargers.
It was a struggle to find any budget chargers that had an option for equalisation, I did eventually come across several that did. The one I chose to purchase was a Fangpusun MPPT 100/15. At the time I could only find it for sale in china so I had to wait 2 weeks for it to arrive.
One of the features I was most excited about was that you can plug the charger into your phone or computer and see live how much power you are producing, using and the state of your batteries. You can also change all the charging parameters to exactly match what Trojan recommend in their literature. This includes equalisation charging, you just set how often you want it to do so ranging from every day through to once every 250 days. Trojan recommend every 30 days so that’s what I chose.
Once the charger came I changed my panels so they were connected in series rather than in parallel as this way you get the most out of MPPT charging. I then connected up the charger to the solar panels and my batteries and had a go with the app. The first thing it did was upgrade the firmware on the charger and then I could use the app fully. Below are a few screenshots.
I’m very impressed with the charger so far and as it’s MPPT I can expect to get upto 30% more power than a PWM charger is cool / very hot / cloudy conditions.
I have been experimenting with hooking it up to an arduino which I use with an android app to view the temperature, tank gauges etc for my van. You can view my process and some info about a cheap cable hack in this post.
