Monitoring batteries

At night the whole base hangs on the batteries. How much longer will that last? The first question for that is: how full are they?

What a battery reports#

A station battery (StructureBattery) holds 3.6 MJ, the large one (StructureBatteryLarge) a good 9 MJ. One MJ is a million joules.

Charge in percent#

Ratio already is the share. On a display in Percent mode it turns straight into a percentage:

lbn share BATTERY HASH("Akku") Ratio Average
sbn DISPLAY HASH("Ladestand") Setting share    # Mode Percent

Several batteries: divide the sums#

If batteries of the same size are connected, the average of the shares works. With different sizes it does not: a half-full small one (1.8 of 3.6 MJ) and a full large one (9 of 9 MJ) average out at 75 %. In fact 10.8 of 12.6 MJ are stored – almost 86 %.

The right way: sum all charges, sum all capacities, then divide. Here Sum is the right batch mode, because energy really does add up.

lbn charge BATTERY HASH("Akku") Charge Sum
lbn full BATTERY HASH("Akku") Maximum Sum
div share charge full

Showing energy#

The display has no mode of its own for joules. Divide by a million and show MJ as a bare number in Default mode – “12.6” reads better than “12600000”.

Batteries lose charge by themselves#

According to the game code a station battery discharges even without a load: 10 J per tick (20 W) as long as the air around it has more than 6.3 kPa and is warmer than 0 °C. In vacuum it is 50 J per tick, in cold below 0 °C up to 50 J depending on the temperature. The energy goes into the air as heat. So a full battery without consumers slowly gets emptier – least of all in a heated room with air.