Switching
Using inverters is of course a possible solution if DC equipment is not available. However, AC devices are not always
designed with power savings in mind. Furthermore, there will be a power loss in the DC to AC inverter, and another power
loss in the AC to DC power supply. And devices specifically created for DC tend to be less power hungry. Alas, native DC
solutions will be superior post-pole shift. Going for DC instead of AC, taking smaller windmills in consideration, will affect the
whole power supply planning. Examples are:
- Amateur Radio Power Amplifiers like the 1 kW ICOM-PW1 require a minimum of 90-132 V AC at 20 A for 500W
output, 180-264 V AC at 15A for 1 kW. Trying to run this monster on a car battery with an inverter would drain the
battery immediately. Instead, using the built-in 100 W PA which runs on 12 V (13.8 V to be exact) may be sufficient,
since the radio frequencies will be much less crowded than today. At 20 A, this would require 2 * 100 Ah batteries in
parallel.
- One recommendation I've received warns against my system thinking of running 30 kW windmills. Smaller and portable
windmills to charge batteries only can be moved after the shift. My current thinking is to have one battery in each cabin
(maybe the new Rolls 450 Ah model) and a number of surplus batteries that can be charged by the windmills. The
charged batteries will then have to be carried to the cabins etc. For the Amateur Radio equipment, PCs etc., the
batteries will likewise have to be carried to the individual buildings and rooms where the equipment is located.
- Smaller cabins may be wired for DC lamps, fridges etc. Larger buildings may have a DC wiring in place for a later
replacement of the batteries with a source that is powerful enough to overcome the attenuation.
- Instead of using electricity for cooking, wood stoves may be the best short-term solution.
In other words, going for battery supplied DC instead of grid supplied AC will require specialized devices as well as careful
planning.
Offered by Jan.