Off Grid Solar Setup

In the summer of 2014, Brecht designed and implemented an off grid solar system in the middle of Detroit city. As odd as it may sound, many people in Detroit are living off-grid right now. This is due to the fact that many of them can no longer pay their bills and the electrical company comes and takes the electrical meter. Therefore pushing them into either illegally reconnecting their house to grid power or living without electricity.

The goals of this project were:

Prove the feasibility of solar power for smal families in Detroit city (Proof of concept)
Analyse and asses the current electrical installation in the house
Design an off grid solar system that works well for Detroit weather
In the design, use as much as possible reclaimed materials, so it blends well into the house
Offer free education for detroit inhabitants after the implementation is done

Design Drivers

Total cost for the off grid installation is max. $3500 (including solar panels, batteries, inverter, low voltage circuit breakers)
Total cost for rewiring and adapting the house to the solar off grid installation is max. $500
The system has to be able to automatically run a dumpload in winter (for melting water or heating the room)
The entire installation needs to be visually appealing
The entire installation needs to be able to be replicated easily
Minimum lifetime of 20 years, this means a yearly cost of $200 or monthly cost of $16

Analysis of current situation

The house received 2 x 110V and 1 Neutral. The solar system will give 1 x 110V and 1 neutral.

The house has two meters, of which one was still connected to the grid but no longer to the house and the other one had been taken. The wiring in the house was partly gone and partly corroded. The cables that were still in the house were old and not usable. The entire house has to be rewired.

Some electrical outlets and switches can be reused as well as the junction boxes from the basement. The electrical distribution board cannot be reused due to heavy corossion.

The old location of the electrical distribution board was in the basement, however, a more optimal location would be in the heart of the house. This will reduce the runs with electrical cable a lot.

The old grounding for the system was to the water pipes, remnants have been found but most of the pipes have been stolen and therefore no good ground exists anymore. The new system will need a new ground rod as well as a connetion to the remaining water pipes.

Greg and Maina consume approximately 1 kWh on a daily basis.

Design

Components

4 x Trojan L16ReB / 6V 370Ah batteries
Outback FM60 MPPT Charge Controller
1 x 1000W 24V Samlex Inverter
2 x Midnite 15 Amp Breakers
2 x Midnite 30 Amp Breakers
2 x Midnite 63 Amp Breakers
1 x Midnite Solar Ground Fault Protector 63 Amp / 500 mA
4 x 250 Wp Solar Panels
Cable
Electrical distribution board
6 x 110V breakers

Implementation

The DC breakers, charge controller and inverter were all built into an old television that was found in the house. Old analogue amp meters were ordered on-line and show the consumption on the outside of the television. In the television, a display with the battery voltage was added and a light that can be turned on and off by flipping a switch on the outside. The batteries were fitted in an old suitcase that was found in the house. To make the wiring look more attractive, the wall behind the installation was covered in reclaimed wood. It is from this wall, that the wiring runs to the house. There is a special disconnect for the solar panels due to their high voltage. A ground was added and connected to the house wiring as well as to the solar panels’ casing.

On a sunny day, the solar panels produce approximately 8 kWh and the batteries have a total storage capacity of 8,88 KWh. Of which 25% is usable, which equals to 2,2 kWh. This means that the system can provide enough power for 2 – 3 days with no sun at all if that were ever necessary.

The oak boards on the wall were cut with a 1000 Watt skill saw, all running of solar power!

Education

After the installation was finished and the whole house was re-wired, we invited local permaculture groups and people from the area to come and take a “radical electrical empowerment workshop”. About 30 people showed up from very different backgrounds. Some were actually doing electrical repair works in their detroit homes, others were just interested to see how all of a sudden, the house that hadn’t had lights for 15 years, now has christmas lights burning and a stereo playing, and a lot of people came out to see the installation we had all been talking about for so long.

The workshop was split into 5 parts:

The fundamentals of electricity. The difference between voltage, wattage and amps.
The different possible solar setups
Different components of an off grid solar system and how to calculate their sizes (panels / charge controller / batteries / wire)
Basic wiring skills
Presentation of the solar setup

A journalist of MichiganNow.org came and wrote an article about the workshop, more info here: http://www.michigannow.org/2014/09/07/perma-culture-house/
You can find the audio recording of the interview by clicking here: