Both batteries can safely be replaced. One is for the clock, so all you'll lose is the time of day. The other backs up any stored readings you've made. All the cal constants are stored in the NVRAM. On 05/10/2012 08:00 AM, volt-nuts-request at febo.com wrote: > New Solartron 7081 -- Bill Ezell ---------- They said 'Windows or better' so I used Linux.