Grove - 2-Coil Latching Relay

Hi, I have a project that needs to work in a remote location with battery power. I need to install the system, have it switch on 11-V power once after a 2-month wait, and preferably switch the power off after another 4 months. That’s all I need to do, but it must be very reliable and as small as possible.

What I have set up is a PICAXE 08M2 controller (on their “starter kit”), a Grove DS1307 RTC, and a Grove MOSFET. This combination works, but I can’t figure out the power consumption–so I know how long it’ll last. I am also not clear on whether the MOSFET will continue to operate as the battery voltage drops. The battery pack that powers the PICAXE is 3 alkaline AAs.

Someone has suggested that I use a latching relay to save power. I see that the Grove 2-Coil Latching Relay advertises low power consumption. But it also says that its minimum operating voltage is 4.7 V, which I think is too low for the AAs. So may this won’t work unless I figure out a separate battery for the relay. But at 5 V, the battery option doesn’t look easy.

If the MOSFET power consumption is low enough maybe I can keep that. But I don’t know what that is. If anyone can help I’ll appreciate it! Also if anyone knows how low the voltage can go for the MOSFET to operate. Thank you!


Designing for low power consumption requires proper design and testing / measurement of components used before. The Grove modules that you have mentioned are designed to work at 5V.

Make a current consumption measurement using DMM (i.e micro ammeter) for all the components in different states (switched on / stand by state). Use this information to estimate power consumption.

Thanks and Warm Regards