1974 Ford F100

12 V, negative ground. It used to carry a second (auxiliary) battery.

Dual battery

Restore the second battery where the old aux sat, following the 4Runner's pattern: dual-battery.md. DC-DC charger from the alternator, a shunt on the house battery, fused at both ends.

Bluetooth audio, in the headliner

• A marine-rated Bluetooth amplifier and flush speakers in the headliner, wiring down an A-pillar.
• Powered from the house battery, switched with the ignition, so music at camp doesn't flatten the starter.

RF direction finding

The shared kit with a magnetic-mount array on the roof; bearings on the phone/tablet layout of the app. See rf-df.md.

Engine monitoring on a CAN bus (later)

See engine-can.md.

Open questions

• Engine and carburettor
• Alternator output (sets how fast the house battery charges)
• Where the old aux battery tray is and what's left of its wiring