One of the issues I face as a 100% QRP operator is looking after my battery power, especially while operating portable. SLA batteries don’t come cheap.
I read about a neat little piece of gear called the battery saver in Silicone Chip magazine back in September 2013 and finally got a chance to purchase the kit and build it over the Christmas holidays.
The kit went together nicely in no time at all, thanks to the small parts count. The settings are adjustable, depending on your requirements. Basically this is to set the cut out voltage that suits your particular type of battery. Mine being 12V SLAs I set it to cut out at 11.5V.
I then mounted the small PCB in a rather large metal enclosure, the only one I had handy at the time.
It seems to work rather well. But now I need to purchase a new 12V SLA battery as the ones I am using are a bit long in the tooth and shut down frequently.
The only problem I have encountered is that the 1M Ohm trimpot doesn’t adjust the until it clicks as mentioned in the article. Mine turns and turns and turns … I also found it very difficult to get Mosfet Q1 to turn off and on.