The Fluke-805 and Fluke-805 FC use 2 AA Lithium-Ion non-rechargeable batteries and also an internal coin cell battery for real time clock backup. If the unit shows a coin cell error, and/or the date and time setting must be reset often, it indicates that the internal coin cell battery needs to be replaced. As this is not a user-replaceable part, we recommend you contact the Service Center.
Request a quote for a Performance Test, and inform the Service Center that the internal coin cell battery needs to be replaced. The Service Center will quote pricing and lead time for the RMA.