Newsletter Archive

How much Power?

Each month, we'll look at one appliance/gadget that is a bit tricky or interesting in terms of power requirements. This month, we'll briefly look at three 220 litre fridges:

12V, 230V and LP gas. This project was part of a contract carried out for the NSW Sustainable Energy Development Authority. It was found that the gas fridge used about 1/2 kg/day of LP (propane) gas. A 45 kg bottle lasts about 3 months. Our test 230V fridge (including inverter losses) used between 1.3 and 2.4 kWh/day while an identical fridge, but converted with a 12V compressor, used between 0.5 and 0.9kWh/day. Predicting power consumption for a fridge is difficult at the best of times. It not only depends on the efficiency of the compressor, insulation thickness and general design but also how it is used. Power consumption will increase not only in higher ambient temperatures but will increase by about 5% for every degree C colder the inside temperature is kept.

New Products

DC/DC ADAPTER
We now have a cigarette lighter type plug adapter which converts from 24V down to 12, 9, 7.5, 6, 4.5 and 3 volts. It is regulated and can handle a current of 1200 mA.

NiCad CHARGER
We now have a NiCad charger which works from a 12V cigarette lighter socket. It charges 1 - 4 batteries AAA, AA, C and D sizes as well as a single 9V battery.

TRAINING COURSES
We offer a range of training courses from 2 days to 4 weeks. These are designed for a range of students from homeowners to system designers.