Voltmeter and temperature guage

A separate project: to adapt a car voltmeter to fit on my Daytona 900. Here's the dash before I started, showing a black lower trim beneath the strip of warning lights:

Pic 1: The dash before adding the voltmeter

Pic 3: Live supply from brown
horn connection

Pic 2: The car voltmeter (top) and two wires
ready for tinning

The voltmeter was an ebay purchase and also has a thermometer function. It is designed to be used inside a car plugged into the cigarette lighter. That made the wiring simple: just chop of the plug, strip the postive and negative wires, tin with solder and the crimp on a couple of connectors. The downside is lack of weather proofing.

I used 'red' spade connectors and heat shrink tube to insulate. The extra two relays visible in the picture are for the air horn compressor and auxiliary/daytime lights I'd fitted. I took power from the redundant horn terminals (brown) because it is live with the main ignition switch in the on position. I had to add an earth - easy to do. 

I hadn't realised the voltage would have dropped by a volt or two compared to a direct feed from the battery. i could test this because the additional relays are fed directly with an additional loom I'd installed a few years ago. I'll fix that some other time.

Pic 5: illuminate voltmeter

Pic 4: voltmeter in place and powered on

 I made up a new instrument mounting trim from 3mm aluminium plate. I cut a clear plastic sheet to size to keep the worst of the rain off the meter, hence the reflection over its face in picture 4. Pics 5  and 6 show the illumination  - seems to match the clocks pretty well. I think it will cope OK like that but not hose pipes or pressure washers. As long as I remember, I'll be OK.

Pic 6: Showing 16.7 C and 11.3 volts - small red light is a warning that the battery is low