Power, supplies and batteries

At home

Most transceivers want 13.8 V DC. A 100 W HF radio draws roughly 20–25 A on peaks, so buy a 30 A supply minimum.

• Switching supplies are light and cheap but can generate RF hash; buy one marketed for amateur

use.

• Linear supplies are heavy, expensive and electrically quiet.

Fuse both the positive and negative leads, and use Anderson Powerpole connectors — they are the de facto amateur standard and make field interoperability trivial.

In the field

• LiFePO4 is now standard: light, flat discharge curve, thousands of cycles, safe chemistry.

A 6 Ah pack runs a QRP station all day and a 100 W radio for a couple of hours of casual use.

• Sealed lead acid is cheap and heavy, and dies if deeply discharged.
• Charge LiFePO4 with a charger designed for it — an SLA charger will not fully charge it and may

damage it.

Solar

A 100 W folding panel and a charge controller keep a portable station running indefinitely. Use MPPT if you want the panel's rated output; PWM controllers are cheaper and lose 20–30%.

Emergency power

For emergency operations, plan for 24 hours of operation without mains power, and test it once a year on a weekend rather than discovering the gaps during an activation.