Now why would you do THAT?

Last time I introduced my new solar power project.  By the end of that post we were monitoring the power flow from the solar panel to the battery in a simple test environment.  This time we're going to dive in and start trying to control the charge power. What's MPPT? Maximum Power Point Tracking (or Transfer , depending on whom you ask) is a condition where we can transfer the highest power from the solar panel into the battery.  The key here is power, rather than voltage or current on their own.  Remember that power is the product of voltage and current, so it is possible that you will find that perhaps higher current and lower voltage (or vice versa) is the most efficient. What makes this a little problematic is that the peak power point varies constantly depending on the battery state of charge and temperature, so it is not a set and forget operation. This is why the first thing we did was to build a power monitor.  Now we can determine at any point of time...

I've got a new shed... And even though it's wired for power, my 16x9m shed is going to be powered as much as possible from solar panels and batteries.  Given that I have more than a few computers and radios in there, this is going to be a challenge. The house already has a set of panels and a big inverter, so this is really my own personal R&D project.  For safety, I am not attempting to connect my work to the house wiring, or feed into the grid.  I will be running separate wiring to power this gear. A note on safety Electricity is dangerous.  Contact with live wiring or components can be fatal.  I can't state this clearly enough, electric shocks can, and do kill people.  Batteries contain dangerous chemicals and can give off flammable gasses, which in a confined space can be explosive.  Connecting or disconnecting batteries can cause sparks, which could have very bad side effects. I will detail steps to mitigate these risks, but ultimately it is u...