How to replace Bluelab pen batteries

If you have a Bluelab pH or conductivity pen, use this guide to change the batteries

Bluelab pens are powered with 1 x AAA alkaline battery. Don't use rechargeable batteries. A low battery warning is indicated by a battery symbol appearing on the screen. Only remove the battery cap when it requires changing. Battery life is expected to be 350 hours.  

To change the battery in the Bluelab pH Pen, Soil pH Pen or Conductivity Pen, follow the steps below.  

1: Remove the old battery  

Undo battery cap fasteners with a screwdriver. Remove the battery cap and tip out the old battery.  

Undo the battery cap fasteners on the Bluelab pH Pen with a screwdriver

2. Check for corrosion  

Flat batteries may leak and cause corrosion. Check battery contacts and the battery for signs of corrosion. Battery contacts should be cleaned first if corrosion is found before proceeding to step 3.  

3: Fit new battery  

Insert the new battery positive end (+) down into the body.  

Insert the battery into the pH pen positive end down

4. Ensure waterproof battery cap seal is clean  

The seal will fail if dirt is present or the seal is not properly in place. 

5: Replace battery cap 

Tighten the fasteners on battery cap until there is no space left between the cap and body. This ensures the unit stays 100% waterproof.  


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