Solar

The Ultimate Guide To DIY Off Grid Solar Power (youtube) | Tin Hat Ranch

4 panels for over 1100W

1000W transformer (for 900W max load)

4 6V duracell SLIGC125 golf cart batteries from batteries plus

Golf cart batteries are designed deliver a lower amount of power over a longer amount of time and then recharge quickly (compared to car batteries)

Results in 12V 470AH (5640 watt hours)

4800 watt hours after only 85% inverter efficiency

Lead acid:

• Never discharge below 50% capacity, or you will severely limit the life of the batteries
• Less you cycle the batteries, the longer they last

Due to 50% discharge limit, you only have 2400 watt hours

When sizing battery capacity, use a minimum of 2 days, but not more than 5 days, so your solar cells can routinely fill the batteries to capacity.

Build frames out of unistrut, available at any home improvement store, usually in electrical section. For tilting mechanism, screw hooks and gauge straps.

Use a Voltage Drop Calculator to determine voltage drop from wires.

SolarReviews.com

Off Grid example BOM

Grounding

DIY Solar Forum - FAQ - Grounding PV

• Photovoltaic System Grounding
• Grounding Photovoltaic Modules: Issues and Recommendations
• The Ground-Fault Protection Blind Spot: Safety Concern for Larger PV Systems in the U.S.
• Grounding Photovoltaic Modules: The Lay of the Land

Photovoltaic System Grounding 2012 study report (pdf)

• When is Ground Fault Protection (GFP) needed? The available fault current may not be enough to enable the OCPD to function under some conditions, such as during cloudy weather or in the early morning or late afternoon. To address this issue, PV systems have ground-fault detection requirements that account for the potentially low fault current. (page 10)
• The sizing requirement for overcurrent devices in PV DC source and DC output circuits is 1.56 times the Isc. (page 12)
• During the operation of a single-phase inverter in the stand-alone inverting mode (either an off-grid system or a utility-interactive system with battery backup), the DC current between the batteries and the inverter may have 120 hertz (Hz) ripple currents that are in excess of the average DC currents. These ripple currents interact with ferrous enclosures in the same manner as AC currents, indicating that the EGCs should be routed with the DC circuit conductors. The allowance in the NEC (250.134[B]EX2) that the EGCs in DC systems may be run separately from the circuit conductors should not be followed in PV systems with battery backups. (page 12)
• Color Codes. The DC grounded conductor must have insulation colored white or gray or have three white stripes if it is 6 AWG (American wire gauge) or smaller. Larger size conductors must be marked with these colors at their termination points. Grounded PV source and PV output conductors 6 AWG and smaller are allowed to be marked in the same manner as larger conductors, in order to allow the use of the durable, black-insulated USE-2 and PV cable/PV wire in exposed locations within the PV array (NEC 200.6).

Glossary

EGC - equipment grounding conductors

Suppliers

altE store (Grid Tie with Battery Back-Up 1.8 kW Solar Home System)

Solacity - In Canada, but ships everywhere. (recommended: Steve_S)

Offgrid Wholesalers - a wholesale membership club (recommended: Off Grid Circuits)

IMO Solar - Fire Raptor, Isolators, Connectors, Terminal Blocks and other PV connectivity and devices.

Blue Pacific Solar

DIY Solar Forum discussion on locally supplied breakers