Uninterruptable Power Supply

[rthorntn]

Hi,

May I just say what a bunch of extremely helpful people you are

I got to thinking about home security and specifically thieves just switching your power off before they rob you because no doubt a lot of the more basic security systems out there don't have a battery backup, my fuse box is unlocked and on the outside of the house.

I would like to keep the security system active for a period of time without spending a fortune on an expensive UPS.

I have 4KW of solar panels with two strings feeding in to an Aurora inverter, it would be cool to somehow be charging a big battery with that to power the security system.

Does anybody have any ideas or thoughts about the best way to do this, I could probably get to a situation where all of the security stuff was running off 12v?

Thanks for looking.

Cheers
Richard

[alxnik]

1st order of the day. Lock your fuse box.

You can supply anything from 12v if the batteries are beefy enough, but if you security system runs off mains voltage then you will need an inverter so basically a UPS. Also, charging your batteries straight from the panels is tricky too, it depends on the max voltage of each panel and the way they are connected. You will need a specific voltage regulator - which exists in your inverter.

[johansen]

4kw of solar implies you should have a 48 volt battery bank but i digress.
fieldlines.com would be a better place to ask your question.

there is a trade off between cost and reliability vs warranty.
you can get a 20 year warranty on 98+% efficient hardware if you're willing to pay for it.

[G7PSK]

All security systems I have seen have a 12 volt back up battery in them, I have a friend who installs and services them, he always has a supply of cheap second hand SLA batteries removed from security systems that have been serviced as they are changed every 2 years as a matter of routine to ensure that there is no battery failure in the systems, so there must be a place in your system for a back up battery.

[SeanB]

Never met a security system without a backup battery. Generally this also powers the siren as well, as then you can get by with only a 1A trickle charger, which cuts cost and standby power use a lot. If yours dies with the mains the battery is dead, deceased, probably bloated and most likely cracked and leaking acid over the case it is in. Replace with another and nothing else is needed. Even alarms from the early 1970's had a battery, and often those alarms had absolutely nothing electronic in them aside from the diodes in the battery charge circuit.