If You Are Following Along At Home

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The post title is based on the David Lettermen joke which refered to ‘scoring along at home’ during Stupid Pet Tricks’.

I have been mostly running the house off of solar with the exception of a few circuits that don’t use much power and the drier and stove/oven. In fact I don’t use much power that the panels cannot offset. I am still using a bunch of power from the utility if I have cloudy days; primarily because I don’t have the other 4 panels online or the third battery.

To enable the third battery I will have to be off solar for a day or two or three. The two current batteries are sitting on top of the workbench. I have to switch the transfer switch to the grid and shut down the solar controller. Then take each of the 100 pound batteries and set them aside, move the workbench out of the way, put some pallets on the ground and put the new battery rack on them. Then I need to install all three batteries in the rack and tie them together. Hopefully the cables I have will reach from the controller to the new rack which will be nearby. If not I need new cables. The ones I am using I bought on Ebay and are welding-type wire with the lugs already crimped on. I have a crimper and can get lugs if I need to however I prefer ones already made.

The two batteries I have hold a total of 200Ah at 48 volts DC. The third will bring the capacity up to 300Ah. This is because the batteries are in parallel and the current adds. If I was to string the batteries in series the current would be the same but the voltage would triple to become 144 volts DC. The same kind of thing happens with solar panels hooked up in parallel or series. How you configure things depends upon the needs of what hooks to it. In some cases you might have to place some things in series and then parallel another set.

Today I moved things a round in my service panel connected to the grid.This panel is what I sometimes call a breaker box. I routed the clothes drier to run off solar and it pretty much swamped my system. Based upon the chart below, can you tell when I turned on the drier?

The top of the chart is my maximum capacity. That is why I will leave the big loads on the grid for now. They only get used for an hour or so in a given week.

I have the system set that between 3pm and 5pm (when the rate goes up dramatically), if the batteries are low, they can get recharged from the utility grid. Although not ideal it is the cheapest option. I still want to run as much off sunlight as I can.

Adding the third battery will give me 1/3 more capacity which means I can run 1/3 longer with the same load. That will help get through the cloudy dats. Although it was pretty cloudy today and I was receiving quite a bit of power from the panels.

Adding the other 4 panels will double my capacity to draw during the day and will charge the batteries twice as fast.

Just keep in mind that I do have that 6,000 watt limit of the hardware. I could double that and add more panels and batteries and so on but I am trying to keep costs down, not needing to eliminate electric costs fully. I still expect to reduce my usage buy perhaps 2/3 and get that almost $300 monthly elect bill down below $100. Ideally it would be about $40 which I think is the minimum payment I have if I don’t draw anything from the grid.

Certainly at that point I could switch to a propane stove and propane drier. Propane does costs us here but with the on-demand hot water heater I use, I only have to swap out those BBQ sized tanks every few months or more for $22. I know that my electric hot water heater cost a lot more than that. Those electric and gas models constantly heat the water, the water cools and it heats it again. That is not as efficient as an on-demand unit.

When all my wires and devices are in place, I’ll take photos. Since I have been testing the system, it is not yet ready for public viewing 🙂 I am trying to be very careful to ground things, protect the wires and put documentation in place in case I am not around. Luckily the system will run unattended for quite some time and would only need to be tweaked if some conditions changed.

  • In case you have not followed along until now:
  • My house can run completely off the electric grid.
  • It can mostly run when hooked to my solar installation which generated power just like the grid can.
  • The grid can run into my installation and be used t opower most of the house. It also can charge the batteries.
  • Solar panels supply a DC voltage and current into the controller and can be used to charge the batteries and/or run the house.
  • The controller can also use a generator to supply AC to the controller which can run the house or charge the batteries.

So yes it is versatle.

A big expense for me has not been the system, but the shipping to me here in Hawaii. Mainlanders will pay lots less. For example, 1 battery and the cabinet cost $1900. Shipping via ocean cargo ship $1,077. My previous order of 2 batteries and the controller cost $4200  and shipping was $924. As they say, “Your mileage may differ” and it will be lots less. Some suppliers offer flat shipping cost of maybe $300, so buy everything they have 🙂

Anyway, that is the current status.