Home brew Arduino MPPT controller

Taking all this to its logical conclusion, having a completely electric RV, even the motor (or perhaps have each wheel be its own independent motor) would be interesting. The gas engine can be completely chucked and a high wattage, variable RPM, inverter generator with common-rail fuel injection be put in its place. The batteries can be merged into something like the packs on the Prius/Volt/Tesla/Leaf, with a high wattage inverter used for all subsystems (dash A/C, overhead A/C, etc.) On shore power, it would not just be ready for boondocking, but ready for the road.

Now add some electric grid smarts, and when it is in storage, it slowly charges from shore power. If there is a blackout, and the electric company gives the signal, it would have the ability to backfeed, perhaps running the generator (assuming the owner gave permission) to help keep parts of the grid online for a good long while (well, until the gas gets to 1/4 tank or so.)

See if you are doing that, then it's time too to synch controller+inverter with the other sources as well, with hybrid car type strategies like use as much battery as possible first vs as little as possible/charge battery...etc. Really a hybrid car control strategy model coupled to a genset instead of wheels has a lot of the right capability.

I like the supercap because it can suck in large amounts of electricity. No worries about pulsing or the right tenths of a volt, just shove the juice in the cap at or below its ratings. Then, on the other side of the cap, a smart charger can take its own sweet time charging, desulfating, balancing, and other battery tasks, even when the sun is down, as the cap would still have plenty of juice left.

I also wouldn't mind seeing a smart meta-controller. That way, you can have an EFOY fuel cell, solar, wind, shore power, generator, and engine alternator, and the controller can deal with all those power sources at once to ensure the batteries are charged as optimally as possible.

Maybe even have an RFID chip on the batteries with some sensors built in, so the controller would know the age, type, amount of acid (if flooded), plate status, etc. I know that modern BMWs do something like this, where if the car battery is pulled, the vehicle won't start until the dealer re-inputs these parameters into the car's computer, so the vehicle knows exactly what voltage the battery will make and its expected life.

Then, the last piece of the puzzle would be a smart EMS. If the batteries go below 50%, shed everything but vital circuits. If below 25%, shed everything but the e-brakes. Better the EMS cutting off current than having a dead fridge or furnace due to undervoltage burnouts.

Of course with all these controllers come cool tricks, such as turning on the fuel cell when the solar cells stop giving enough useful energy, turning the generator on if batteries are rapidly discharging, allowing the A/C or microwave to take its locked rotor amps from the batteries, then firing up the generator to handle the constant load, etc.

Me too so it could still adjust the voltage up and down on the solar panels to maximize watts out. Really the cap could just be on a 3rd set of terminals as well doing an energy buffer function.

You could make a poor man's version with a medium sized battery as well. Either the cap or a secondary battery would let you continue trickle charging until sun up the next morning. If MPPT were one of the few with boost AND buck converter functionality built in, you could use a single (below 80% capacity, old mostly used up) 6v golf cart battery as the buffer.

Actually this could be the basis of a smart controller like that by adding a bit of circuitry to be able to switch around where the charge goes to, and where it comes from...

Jim

Call me crazy, but I wish supercap tech would get to a point where I could put one between the MPPT controller and the batteries. It would then act as a buffer, where the MPPT controller can be far less precise getting current into the cap because of the ability for capacitors to accept lots of amps in a short time, and the charger using the cap's electricity can be fairly simple, not having to be concerned about the individual panel voltages and watt outputs.