Intro: Getting More Energy From My Solar Panels.
I do love powering my home from the sun. It's wonderful and empowering! My biggest load is my inverter air conditioner and I just made a change to my charge controller settings that allows for more energy to be pulled from the solar panels.
Step 1: The 'big' Load.
Air conditioning for us tropical dwellers is one of the biggest electrical loads in the home. I power one of mine from a 1000 watt pure sine wave inverter.
Step 2: Energy Storage.
Via my outback flexmax 80amp charge controller, energy is stored in my lifepo4 batteries. The thing is, once they are fully charged the controller goes into float mode giving low amperage to my home loads.
During the hot daytime when I run that air conditioning unit off the batteries, I want lots of amps being deposited into the lifepo4 batteries.
Step 3: The Fix!
The outback fm80 has a setting to reenter bulk charging which gives the highest current into the battery bank. The default value is pretty low so by carrying it up to 27.0V I can force the charge controller to pull high amperage from the photovoltaic panels and into the batteries during times when the battery voltage dips low (that is, when the air conditioning is running on solar power).
Since the inverter for the air conditioning uses the majority of these amps, the batteries are not being overcharged. If I switch the air conditioning to utility supply, the charge controller will quickly to into absorption then float mode.
I could go with a higher voltage setting but for now I do not want to risk extended application of absorption mode on my Lithium iron phosphate battery bank. The outback fm80 has a safety timer for absorption however in time I will know if it is valid for rebulking.
Other brands of mppt charge controllers should have an equivalent setting.
I hope this instructable has been helpful!