Originally Posted by Redbugdave
I would visually check them from time to time. Does the ELT have some sort of voltage monitor or some way of letting you know the batteries are getting low? I always thought ELT's had some sort of special battery. That's interesting.
There's a panel-mounted indicated that tells me if the device is operational, but not the specific battery state (or if they are leaking).
Most ELTs do use a special battery. One of the selling points of this old unit is that it takes regular D cells (which are lots cheaper and generally just as good for this purpose). Anyway, ELTs have changed technology in the last 5 years, and it is time to upgrade mine to the newer 406 MHz unit. The new unit has a lithium battery that is good for 5 years--and costs $130 to replace (I can buy a LOT of D cells for $130).