TechniSat VIOLA 3 Mode D'emploi page 110

Only operate the device using the battery approved for this device.
Normal batteries may not be recharged. Batteries must not be reactivated by other means, not taken
apart, heated or thrown into an open fire (danger of explosion!).
Clean battery contacts and device contacts before inserting.
If the rechargeable battery is inserted incorrectly, there is a risk of explosion!
Only replace with rechargeable batteries of the correct type and model number.
Caution! Do not expose batteries to extreme conditions.
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