Eurochron EFWS 301 Mode D'emploi page 37

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Always exchange the entire set of batteries/accumulators, only use batteries/
accumulators of the same type and by the same manufacturer with the same
charge status (do not mix full with semi-full or empty batteries/accumulators).
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Never mix normal batteries with rechargeable ones. Use either batteries or
rechargeable batteries.
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Regarding environmentally compatible disposal of batteries and rechargeable
batteries, please read the chapter on "Disposal".
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