Display

The measurement module with the top part unclipped.
There are two options for linking the display module to the measurement module. You can use the included USB cable to connect it directly to the measurement module, or you can use the built-in wireless connection. A wireless connection is established automatically if the USB connection is not available. You can use several modules at the same time – according to the manufacturer, up to 26 channels are possible simultaneously. With a wireless connection, the display module must be provided with its own supply voltage. This can be done via the micro USB port (5 V) or via a two-way JST connector (8–16 V), for which a matching cable is included.

The display measures approximately 3 × 2.5 cm and is very bright, so it is easy to read even under high ambient light conditions. There are three touch-sensitive buttons next to the display. By default the display shows the measured voltage and current, along with the time at the start of the measurement cycle. A battery icon can be displayed on the left to indicate the remaining battery capacity after you enter the nominal battery capacity. The connection mode, relay state and measured temperature are shown at the top of the screen.

Even more information appears when you touch one of the buttons. Then the supplied or consumed power is shown beneath the voltage and current. In a smaller area below that you can see how many ampere-hours the power source or battery has supplied, the number of watt-hours and the elapsed usage time. On the right there is a list with a number of menu items that you can scroll through with the up and down keys. We have more to say about some of these later on.

Potential applications

The load on the output can be replaced by a battery charger,
with measurements made in both directions.
This set of display and measurement modules can be used for various purposes. For example, you can measure the current suppled to a load by a power source. If the power source is a battery (primary or rechargeable), you can use this to keep track of how many ampere-hours it has supplied. You can also work in the opposite direction, with the load replaced by a battery charger. Then you can measure how much energy has been loaded into the battery.

There are a number of menu settings that are especially interesting for use with rechargeable batteries. In particular, you can set upper and lower limits for switching off the relay. This can be used to avoid deep discharging the battery when it is powering the load, or overcharging when it is being charged. You can also set a maximum positive current (from the power source to the load) and a maximum negative current (from the charger to the battery) for switching the relay. With this combination, you can also easily keep track of how much power a connected circuit uses or how much energy was stored in a battery during charging, without having to use a calculator. The battery icon can also be hidden if you do not need it in a particular application.