7

LTC1042

1042fa

APPLICATIO S I FOR ATIO

Wind Powered Battery Charger

A simple wind powered battery charger can be

constructed using the new LTC1042, a 12V DC permanent

magnet motor, and low cost power FET transistor.

The DC motor is used as a generator with the voltage

output being proportional to its RPM. The LTC1042

monitors the voltage output and provides the following

control functions:

1) If generator voltage output is below 13.8V, the control

circuit is active and the NiCad battery is charging

through the LM334 current source. The lead acid

battery is not being charged.

2) If the generator voltage output is between 13.8V and

15.1V, the 12V lead acid battery is being charged at

about a 1A/hour rate (limited by the power FET).

3) If generator voltage exceeds 15.1V (a condition caused

by excessive wind speed or 12V battery being fully

charged) then a fixed load is connected thus limiting

the generator RPM to prevent damage.

This charger can be used as a remote source of power

where wind energy is plentiful, such as on sailboats or

remote radio repeater sites. Unlike solar powered panels,

this system will function in bad weather and at night.

LTC1042 • A105

8

7

6

5

1

2

3

4

LTC1042

12V

GENERATOR

WIND

LM334

4.5V

NiCAD

BATTERY

215k

10k

0.1µF

MTP8N05

36Ω

5W

1N4001

MTP8N05

12V

LEAD ACID

0.1µF

0.1µF

107k

10M

WITHIN

WINDOW

13.8V TO 15.1V

OVER VOLTAGE

(>15.1V)

100k

10k

68Ω

LT1004-1.2

+

+

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.

However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-

tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.