12VDC Low-Loss Power Gate

One of the problems with my scheme to have a 12V SLA battery wired in parallel with the station 13.8V power supply is that I have to disconnect the battery when the power supply is switched off.  Otherwise the battery back-feeds the power supply and keeps its power indicator and cooling fan running.  Eventually the battery would discharge to a flat, unrecoverable level.

To remedy this and also to give me an integral 12V distribution panel I purchased KI0BK‘s Low Loss PWRgate box for $50 from Flint Hills Radio.


The power gate acts as an interconnect controller and buffer between the battery, DC power supply and the loads (mostly radios) via three Powerpole output connectors.  By using MOSFET switches there is very little voltage drop through the power gate, up to 25A.



It’s smaller than I envisioned from the maker’s photo.


Installed in my shack an seems to work well.  Now I don’t have to disconnect the battery when I shut down the power supply.



From the manufacturer website:  Low Loss PWRgate transfers up to 25 amperes at up to 16 volts DC continuously. It is a safe way to connect both a battery and a power supply to a load, while electrically isolating both from each other. Whenever your 13.8 volt power supply is on, the supply feeds the load while also charging the battery, keeping the battery healthy and ready for use. When the power supply is off, or loses power, the battery feeds the load.

2 thoughts on “12VDC Low-Loss Power Gate

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s