In even the most basic renewable energy system it is essential to monitor the charge in the battery bank, the voltage and current coming from the generator, and the current being drawn by the power inverter or other loads. In this article we will cover moving coil meters – the cheapest and simplest devices for displaying current and voltage in a system.
Moving Coil Voltmeters
The simplest way of monitoring the voltage of the battery bank is a moving coil voltmeter. These are available from around £5-10 each and can simply be wired to the positive and negative outputs of the battery bank. They do not need their own battery power since they take a tiny current from the batteries.
Pictured above is a 8-16 Volt DC Analogue Voltmeter which is perfect for measuring the voltage of a 12V battery or 12V battery bank.
NEW We have an excellent top-quality 0-30VDC moving coil voltmeter for sale in the REUK Shop.
Moving Coil Ammeters
Ammeters, used to measure the current flowing into or out of the battery bank, are also available for a wide range of different applications from micro-Amps (e.g. in solar cell experimentation) to hundreds of Amps (e.g. in large wind turbines). Pictured below is a 0-20A moving coil ammeter.
Since the current flows into and out of the battery bank as the batteries are charged or discharged, the most suitable renewable energy system ammeters are centred on zero – a positive reading indicates that the batteries are being charged by the generator, and a negative reading indicates the batteries are being discharged.
Above is a photograph of an automotive analogue ammeter which shows currents from -200 to +200 Amps. This would have limited use in most domestic renewable energy systems except with very large wind turbine generators and multi-kW hydroelectric generators since the current range is so large – however there are many smaller range ammeters available – e.g. -20A to +20A which would be perfect for a small domestic wind turbine generator or solar installation.