# Battery Backup System

Joined Mar 22, 2020
2
I am building a 150 plant hydroponic system and want the piece of mind of a battery backup.

Brand new to an Arduino, but have played quite a bit with a PI. I purchased an Arduino and plan to use it as the smarts of my system/remote monitoring.

1) I have a 110v automation system that I want to switch over to battery/inverter power in the case of a power outage.
2) Ideas or suggestions? I found similar posts on battery/relays, but not for Arduino I am thinking...

-Arduino pulls power directly from battery backup system with fused 12v step down (from ~14.4v battery)
-solar keeps batteries topped off
-Scrounging the parts bin for any 110v transformer with an Arduino friendly input current... this will signal Arduino for power outage event.
-Arduino to cuts signal to NO relay A if power outage >5 minutes...
-Relay cuts 110V power to automation system
-Arduino sends signal to NO relay B after a couple seconds, this kicks on my inverter and sends 110v to my internet modem and automation system.
-Pumps, timers, etc run as usual or until batteries die.
-Arduino monitors for 110v restoration
-Arduino sees 110v is back online
-Arduino kills signal to relay B, Inverter cut off.
-Arduino waits a few seconds and sends signal to relay A, input now routed from grid, power restored to automation system
-Arduino sends me an update that system is back online/health check.
-This would also give me a nice piece of mind if someone killed my power while I wasn't home, and could kick on my security cameras, onto battery power.

Am I overthinking this? Is there an easier way!? What am I not thinking of?

A UPS is too expensive when I can get almost 300AH out of a couple deep cycle batteries for a couple hundred bucks.

#### nsaspook

Joined Aug 27, 2009
8,520
Are you sure your plants are NOT worth the cost of a good UPS?

Joined Mar 22, 2020
2
I live on the top of a mountain, I need days of backup power. Even a $500 ups will be out in hours. Im growing fruits and vegetables, and can build this for$20. I have everything but a dpdt.

#### nsaspook

Joined Aug 27, 2009
8,520
I live on the top of a mountain, I need days of backup power. Even a $500 ups will be out in hours. Im growing fruits and vegetables, and can build this for$20. I have everything but a dpdt.
What are your daily KWH requirements? A standby generator might be more practical depending on the power several days requirements unless you need silence at all times while growing your fruits and vegetables.