Saturday, March 23, 2013

Information and control

When I first installed the solar electric system in the house I was excited by all the automatic controls on the inverter. It seemed there was an almost infinite number of settings. I don't know how much time I wasted playing with those. One thing I couldn't quite seem to get right was the automatic charging system. The inverter could be set to charge when the battery dropped to a certain voltage.

It would seem to make sense. Grid power was available. Discharging batteries too low can damage them. Why not set it at a certain voltage and let the automatic stuff handle everything? In the real world, it didn't work very well for me. It seemed no matter how I tweaked the settings, there would be a condition when the automatic stuff didn't work well.

For example: the charging system would often kick on just before sunrise. By the time the sun came up, the batteries were mostly charged up from the grid. Most of the day's sunlight was wasted as there was no more room in the batteries. Worse, that grid power cost money.

In the end most of the automatic stuff was disabled. I installed a simple battery gage and switch right in my kitchen. If the batteries get too discharged a simple flick of the switch charges them up. It was a cheap and simple solution.

Just knowing the exact charge of the batteries is a huge help. If they are bit low, but it's supposed to be sunny later, I'll plan heavy power usage for later in the day. There are times when I see the batteries are fully charged and it's still early in the day so I'll run a load of laundry. If there's going to be a storm that might take down the grid, I'll top off the batteries just in case.

The gage and switch arrange illustrate how I think. The gage shows me what's going on. I like to have information. The switch lets me do something to change things. Information and control. I don't trust things running on autopilot.



  1. The more complicated a system is, the more things can go wrong.

  2. Being in control is why a person puts in a solar system.Most self reliant folks dont tust others or equipment to provide for their needs.I would lay a large wager you almost always insist on driving when you go any where rather than ride shotgun ?Its a state of mind,to be self reliant in all things.

  3. Is most of the stuff in your house run on 12 volts or do you use the converter for 110? You loose a lot when you convert it.

    1. Most things run at 110. There's some loss yet, but nothing I can't live with. 12 volt is more effcient, but it takes heavy gage wire to run it any distance. There's also the problem that my battery bank runs at 24 volts. The reason for that would take more than a few sentences.