digital ammeter I bought from Amazon a short while ago - the display unit is definitely faulty. I checked the voltage across the shunt with my DVM and obtained sensible readings. Incidentally, connecting or disconnecting the inverter negative lead from the battery bank made no difference, so all the charging current is via the shunt; so is all the discharging current apart from the inverter.
I connected my centre-zero moving coil voltmeter across the shunt to allow me to monitor the charging. The scale is marked 10 - 0 - 10 (volts). Full scale deflection would correspond to 114A; with this in mind I was interested to see that, when I fired up the engine again from cold, the charge current measured just 5A. Within seconds the alternator body was almost too hot to touch; the internal fan was blasting out hot air and that strange smell. Cooking enamel insulation?
Other relevant facts: the outputs of the engine and domestic alternators are combined in a Sterling Alternator to Battery Charge Controller stuck to the steel wall of the engine room. When we got to the boat on Sunday the engine room was thick with condensation - all over the engine, the walls and the Sterling ABC. Had this water got inside the device and affected it? When I checked the ABC before switching the engine off after the run yesterday I saw a warning LED glowing, corresponding to "HIGH ALT TEMP, STOP". (There are temperature sensors on each alternator and one of the batteries.) If nothing else, this shows that the temperature sensor on the domestic alternator works, and that the ABC is recognising this. Everything else on the ABC seemed to be working normally.
What I would really like to know is ...
- Is there an easy test to see if the alternator is working properly?
- Is there an easy test to see if the Sterling ABC is working properly?
- If the Sterling ABC is faulty is this what has caused the demise of the alternator?
- Is the alternator definitely dead?
- Is there an easy way to bypass the Sterling ABC?