Aquarium DIY Project - need help identifying a component

[StevenC]

Hi all. I'm working on a solution to keep my aquarium pumps running during a power outage using a 12V deep cycle battery and DC/AC inverter.

I need some some sort of relay so I can have two 12V power inputs (main, and battery backup), and have a single 12V output. While I have main power, the relay should only use that source, but automatically switch over to the battery during a power outage. I'm not sure what exactly I can use to accomplish this? Attached is a simplifed diagram diagram of the design plan.

I found this on Amazon, but I'm not sure if this is what I need? The power load on the inverter will be fairly low, maybe about 50W or less.

Thanks.

 

[Tha fios agaibh]

I'd just use an ac relay and do something like this

 

[Tha fios agaibh]

You need it to have contacts that are capable of handling the inverter ratings even if you are only using a few watts. The Ac to aquarium past the relay and the Ac out of the inverter can be bridged together as one but run a neutral (grounded conductor) along with it.
The push button latches the relay to start it and if power is lost it will use battery power.

 

[StevenC]

You need it to have contacts that are capable of handling the inverter ratings even if you are only using a few watts.

Lol, I wish I could say I understood your diagram. Sorry, electronics not my thing. Does this solution involve me to manually do anything? The idea is that the failover is automatic, with zero intervention from me.

 

[Tha fios agaibh]

Yes, automatic.
Basically household 120v powers the relay coil. The coil magnetic field pulls the normally open contacts closed to deliver power out to pump during normal use.
Once power is lost, the coils magnetic field collapses and a spring pulls contacts back to the normally closed position and the normal power out shuts off. There are separate contacts that also return to normally closed position that can be wired to battery power.

 

[StevenC]

Yes, automatic.
Basically household 120v powers the relay coil. The coil magnetic field pulls the normally open contacts closed to deliver power out to pump during normal use.
Once power is lost, the coils magnetic field collapses and a spring pulls contacts back to the normally closed position and the normal power out shuts off. There are separate contacts that also return to normally closed position that can be wired to battery power.

I see, sounds like what I need. You mind sharing a link to one so I know what to look for? I wouldn't want to get something wrong.

 

[Tha fios agaibh]

Something like this should work.
https://www.amazon.com/gp/aw/d/B00J...+with+base&dpPl=1&dpID=41551PKk-pL&ref=plSrch

 

[StevenC]

Something like this should work.
https://www.amazon.com/gp/aw/d/B00J...+with+base&dpPl=1&dpID=41551PKk-pL&ref=plSrch

Thanks. I really appreciate the info!