Will my Vista 20P alarm panel overcharge a Yuasa NP4-12 backup battery?

No, your NP4-12 backup battery will not be overcharged by a Vista 20P alarm panel, or any Honeywell Alarm Panel for that matter.

Alarm panels are designed to float charge your battery. That means it provides just enough new charge to counteract the battery's natural rate of discharge, constantly keeping your battery at full capacity. The reasons for this are two fold -- to prevent your battery from descending into a deep discharge and to make sure your battery is at full capacity when a power outage occurs.

When using a charger...
It is possible to overcharge your battery. Doing so can have a negative impact on battery performance and drastically shorten battery life.

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