Battery Calculator

How to take accurate current readings

Follow this method to measure the panel load safely and correctly. Incorrect meter setup can blow fuses or damage your meter, so please check each step.

⚡ Meter setup (VERY IMPORTANT)

• Set your multimeter to **DC Amps (A or mA)**.
• If your meter has **separate ports**, use:
  • COM = black lead
  • 10A / A port = red lead for currents above ~300mA
  • mA port = red lead for small loads (if unsure, use A port)
• Your meter must be in **series**, NOT across + and – like a voltage check.

🟦 How to connect your meter (series measurement)

You are measuring how much current flows from the battery / PSU into the system.

1. Isolate the **battery negative (-)** from the panel.
2. Put your meter **in series**, like this:
   Panel – (negative) → Meter COM, and Meter A port → Battery –
3. Your meter now becomes the “bridge” carrying the current.
4. Power up the panel and wait 30–60 seconds for it to stabilise.

📘 1. Taking the Standby Current (Quiescent Load)

• Ensure panel is in a **healthy state** (no alarms, no walk-test, all zones closed).
• Communicators should be in **idle** (not dialing).
• Keypads and expanders must be powered as normal.
• Read the current shown on the meter — this is your **standby current (A)**.

📙 2. Taking the Alarm Current

• Trigger a **full alarm condition** (all sounders, strobes, relays, outputs).
• If the system has external sounders: hold the meter tight — current may spike.
• Read the meter value once everything is running — this is your **alarm current (A)**.
• If you cannot safely trigger a real alarm:
  • add up alarm currents from device datasheets
  • or use the PSU test function if the panel supports it

📏 Tips for reliable readings

• Meter leads must be fully pushed into the correct sockets.
• If the meter shows OL / 0 / jumps around → switch to a higher amp range.
• Never put the meter across + and – in A mode — that’s a dead short.
• Galaxy panels often stabilise after 20–40 seconds — wait for it.
• If a communicator is sending data, your current may briefly spike — ignore those moments.

✔ Final values you need for the calculator

• Standby current = current when the system is healthy.
• Alarm current = additional load during alarm.
• The calculator already applies:
  • 12 hours standby
  • 0.5 hours alarm
  • 25% EN50131 safety margin

If readings don’t seem right, repeat the test or check device datasheets for expected consumption.