The LIFEPAK 500 Rechargeable SLA (sealed lead acid) Battery Pack should be recharged either
monthly or after use, and the replacement shelf life is 2 years or 200 charges. The charger for
this battery (11140-000002) has been discontinued by Physio-Control. If you do not have a
charger, you should purchase the non-rechargeable battery (11141-000158).