If you have been beach or water hunting a long time, you should know how important it is to have your metal detector batteries charged. Nothing is worse than arriving at a beach to see excellent beach or water hunting conditions, but you cannot take advantage of them because you neglected to make sure you have enough juice for your metal detector.
Traveling long distances to detect and having battery problems is the ultimate downer.Nine times out of ten, if your main battery pack is not charged your back up battery pack is going to be in just the same state.
You should always make sure your main and spare battery packs are charged and ready to go, especially if you seldom use the spare battery pack.
I make a point of alternating battery packs so I can guarantee my spare battery pack is good to go if my main battery pack is drained.
Any battery pack I use is charged after every beach or water hunt, I use Nimh battery packs that have very little charge memory.
Although I have only ever had one battery problem spoil a metal detecting trip many years ago, I vowed it will never happen again and it has not.
Two rechargable battery packs, an alkaline pack and spare batteries for the alkaline pack, all leave the house with me when I go to the beach to metal detect.
My thermo nuclear option detecting battery kit, insure that if I need to stay and take advantage of excellent conditions I can.
The back up battery pack to me is the important thing to remember, especially if you do not use it very often.
People have a bad habit of keeping the back up battery pack in their vehicle for many weeks or months, sometimes in very hot vehicles which can damage the batteries or battery pack.
Damaged terminals can render the battery pack useless, but unfortunately you do not find that out until you really need and want to use it.
I do not recommend you leave AA batteries in your spare alkaline battery pack for long periods, just in case they do corrode and ruin the battery pack.
When I do put batteries in a pack, I write the date the batteries were installed on a piece of blue painters tape.
I do the same thing on my rechargable packs if recharging after a hunt is not possible, so I can keep track of the hours I have used the pack.
As a rule I like to use fresh batteries, more juice equals more detection depth and better target IDs on many metal detectors.
Battery packs and batteries may seem like a boring subject, until you are are faced with excellent treasure hunting conditions and have to leave the beach because your metal detector will not power on.