BOS…….Balance of SystemWind and Hydro Power

What is the BOS?• DC only system (small

cabin)– Charge controller– Batteries

• Conventional AC system (house)– Charge controller– Batteries– Inverter

Model List Price ($US)

 C35 $119.00

 C40 $159.00

 C60 $199.00

Xantrex “C” Series Charge Controller

•12, 24, 48 VDC•automatically directs extra power to a dedicated load such as an electric water heater and ensures batteries are never over-charged.

•three-stage charging (bulk, absorption, and float)•pulse width modulation (varies the charge current gradually from 0-100%)

Model # is rated DC current

www.xantrex.com

ModelList Price

($US)

MX60 $649

Outback MX60 MPPT Charge Controller

•12, 24, 48 VDC•60 amps•Primarily for PV

“Hydro / Wind Turbine Applications: Consult factory for approved turbines“

Probably not worth paying for the solar MPPT technology for hydro

www.outbackpower.com

The NCHC

• Website says:• Pretty it may not be, but the

NCHC will regulate PV, Wind, or any other current limited charging source with the highest efficiency possible in an alternative energy system charge controller.

www.nwpwr.com/products/Charge_Controllers/nchc.htm

ModelList Price

($US)

NCHC60/24vdc

$259

Diversion Load, aka Dump Load

• Usually a resistive load like a heater

• At least as large as the full turbine output and within the current limit of the charge controller

• Small hydro system = small amounts of heat

• Use waste heat for water heating, air heating…

• Usually not enough heat for domestic use (1kW = 3412 BTU)

Head lights as dump load for wind turbine

Outback Inverters

Xantrex Inverters

Modified Sine Wave/True Sine

• Cheaper• Not good for certain

electronics like printers, audio equipment, microwaves, clocks, cordless tool chargers

• True sine wave provides clean power like the grid

AC Systems

• Larger systems can be AC, no battery

• Davis, p.74:

If the continuous output of a system is high enough to meet your needs for surging capacity, no battery/inverter subsystem is required, and AC can be generated directly.