Onset HoBo® U12-015 series data logger battery replacement and repair

We repair and replace batteries on this type of logger.

Battery life

The battery life is determined in a few ways:

  • Time and frequency that the logger is connected to the USB port of your computer. The logger draws virtually no current when connected and idle but draws, relatively, high current when first connected and when writing/reading the logging parameters to/from the logger.
  • Logging interval. It stands to reason that every time the logger writes the current temperature to the logger some current is drawn and if this is as frequent as every second the battery will not last as long as logging every hour for instance.
  • Shelf life of the battery. The battery has a reasonably long shelf life so if the logger isn’t often used it will still be good in a few years.

Batteries should be replaced when the software indicated battery Voltage falls below 3.5V. In my experience if the battery gets really low the logger will connect to the USB but not to the software. Your data is still intact and can be recovered after the battery has been replaced. Please mention this when sending the logger in so we can recover the data for you (we do test all the logger functions which would over write your valuable data)

Over temperature exposure

Care should be given to these wonderful durable loggers when exposing them to the high end of the temperature specification. If the temperature is a little higher than 125ᶛC for a very short duration that will not cause any damage but higher than 130ᶛC is looking for trouble as the battery can destruct. The battery will also expand slightly and this makes removing the battery and electronics very difficult.

Cap seal

The cap seal is also very important and should be lubricated with the supplied lubricant to prevent the seal from drying out. This also enables the cap to be removed and installed a lot easier and assists in making a very good seal preventing moisture entering the logger.

USB Connection while logging

Do not log while the logger is connected to the USB of your computer. In some cases, but not all, the indicated/logged temperature rises a degree or two causing inaccurate results if performing a calibration for instance.

Used U12-015-02

Used U12-015

U12-015 datasheet

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