IPS Circuit

Here is the circuit diagram of a simple IPS (Instant Power Supply). The circuit is simple low cost and can be even assembled on a veroboard.

IPS Circuit

Instant Power Supply Circuit Diagram

Backup depends on the ampere of your battery and how many machines (fans, lights etc) you are running. It also depends on Watt of IPS. A fan and three energy lights can be run by a 200W of IPS.
To get more backup time you have to increase your battery power. And if you want to run more than one fan or add other machine you also need to increase Watt of IPS. In order to maximize the watt of IPS you must increase the quantity of FET & Transformer value.

See Also: Speed Limit Alarm Circuit