Trevor,
Firstly, some info that may be useful for other users:
When we first started testing the set-up in the aeroplane we noticed something rather strange: Every time the PTT button was pressed the amps reading would plummet to -80! We found that an aerial that we had mounted inside the (wooden) fuselage was radiating. We switched to an external aerial and the errant display was gone.
Now however we have a silghtly different problem in that the ammeter doesn't fluctuate from zero even when all consumers are switched on. Upon checking the wiring diagram I see that the shunt is only wired to monitor charging current and not consumer consumption and so the reading will only fluctuate if the battery is low and the alternator is pumping out full volume to compensate. Is this right? I'm not an electrician so some layman's clarity on what I should expect to see would be nice.
Secondly, and not very important in the short term: whilst the engine is running one of my fuel guages fluctuates between 65 & 45 litres. It's very rythmic and so looks like it's picking up a spurious signal from somewhere. Any ideas?
Colin