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Mk4 HR Series Battery Replacement 

The Mk4 version of the HR series of loggers has a user 

replaceable battery. No soldering or sealant is required. 

Earlier versions of the HR logger had a factory or  

technician replaceable battery. This required  

soldering and using sealant. 

 

How do I know if my HR logger is a Mk4 version? 

 

Battery voltage is 7.2 volts (not 3.6 volts). 

 

There is a small "4" in a triangle shape on the loggers label. 

 

The battery enclosure at the back of the logger is 77mm long (not 55mm). 

 

The replacement battery kit for the HR Mk4 logger includes: 

 

Replacement battery. 

 

Replacement label. 

 

Instruction sheet. 

 

Extra Parts for HR Mk4 logger 

 

 

If needed (any coloured wires), the 

Stainless steel Mk4 tube 

(battery enclosure). 

 

2 16x1mm O rings (

battery enclosure

). 

 

1 014EPR O ring (

communications socket

). 

 

Instructions for changing a HR series MK4 Battery 

 

Remove the label. 

 

Gently unscrew the battery pack from the logger. Only one and a half turns are  

required (see fig 1). 

 

Look at the wires inside the logger. If they are all grey you do not need to  

replace the stainless steel battery enclosure. 

If they are red, black, orange and  

yellow the battery enclosure will need to be replaced with the Stainless Mk4 

tube (battery enclosure) 

(see fig 2). 

 

Disconnect the 2pin white plug connected to the battery wires from the logger 

printed circuit board. Squeeze and withdraw (see fig 3). 

 

Withdraw the battery from the battery enclosure (see fig 4). 

 

If you need to replace the battery enclosure, disconnect the 3pin white plug  

connected to the battery enclosure and connect the new battery enclosure  

(with grey wires). 

 

Note that both the 2pin and 3pin connectors have a small keyway on one side so 

that they can only be connected the correct way around (see fig 5 and 6). 

 

Check that the two O rings on the battery enclosure thread for damage and  

replace if necessary. 

 

Slide the new battery into the battery enclosure being very careful not to damage 

or squash the thin grey communications wires. 

 

Connect the plug from the new battery to the logger printed circuit board. 

It will only connect the correct way around.  

 

 

 

 

 

 

>>> 

Trutrack Loggers—Mk4 HR Series Battery Replacement 

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