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Battery Backup

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I'm busy building a pic based electronic door lock which will operate the lock via a relay. I've been thinking it might be a good idea to include a battery backup incase there's a power failure and i cant get into my house.

Using a lead battery looks like a good solution. My question is on the charging of it - I've read a few posts here about backup batteries, but should i be worried about overcharging the battery. You can charge it with a constant current, but do I need to monitor the voltage/current and shut it off when its been charged. The backup battery will most likely never kick in but want to have it just in case.

Your feedback would be welcome.

Nigel Goodwin

Super Moderator
Most Helpful Member
You simply need to arrange for the battery to be 'trickle charged', this is a low charging current which keeps the battery topped up, but can never overcharge it.
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