The batteries that come with our powered kits do not like to be sitting around in a state of discharge. It is important to charge them back up as soon as you can, once you have drained them. Even if you haven't drained them all the way.
When storing your battery, make sure you definitely charge them up completely. You may then leave them sitting for a while, but we would recommend no more than 4 months; and then you should again put them on charge; as they naturally discharge on their own when they are sitting around. Even better, if you have purchased our maintenance charger, just put your batteries on that charger and leave them on that device indefinitely and perpetually, until duty calls once again. The maintenance charger we sell is designed to sense that the battery has reached an optimal voltage. Once it senses this is the case, it will go into a float or maintenance mode, applying a very small charge over time, to keep the battery from discharging; and keeping in an optimal state of health given its age and how many cycles it has endured.
Also storing in a cold environment is even more of a faux pas. If you are going to store them sitting around in the cold somewhere, you should charge them up every 2 months to be safe. And of course, we would suggest you don't even do this to be ultra safe.
If you maintain these batteries, keeping them mostly or fully charged up, and ultimately taking this advice, the batteries should last you for 3-4 years under "normal use"; that is unless you use your fish finder every day (who gets to do that? - we're jealous); if this were the case, you will likely need to replace your battery around once a year regardless, as use (cycles) does deplete the batteries capacity no matter the case; and this is a truth for all battery chemistries.
One thing to be aware of, is SLA or AGM chemistry batteries, such as the ones we include in our powered kits don't like to be fully discharged; so again charge them up as soon as you possibly can if you fully discharge them - and yeah, even if you don't fully discharge them. Just try to keep them charged up as much as possible - that's the main theme here. Why is this the case, well what happens is the battery electrodes within the pack will go through a process called sulphation when they are depleted. When this happens, the electrodes within the pack can no longer accept a charge due to the sulphation that has occured.
If sulphation does occur, sometimes you can get lucky, and revive the pack more or less if you put the batteries on a maintenance charger like the one we sell, and then just keep cycling them, taking them on and off over time. This can sometimes break up the sulphation, and "wake" the pack up, restoring some capacity. How much, it depends on the maintenance charger charging algorithm, and how much sulphation has set in.
Lastly a note concerning charging your batteries and charging devices:
A charger that puts out 1 amp of current will charge a 1 amp battery in 1 hour. So if you have our charger that charges at 1.5 amps and you have our 5 amp hour battery; our charger will charge that battery from a full discharge situation in about 3.33 hours.
All of our batteries are 12 volts because this is what fish finders run at - 12 volts - therefore your charger must charge at 12 volts.
Our chargers charge at 12 volts, and have an intelligent maintenance cycle. We always recommend you leave the charger plugged in somewhere, and when you are done using your battery powered mount, as soon as possible connect it back to the charger and leave it on there until you wish to use it again. Do not ever leave your battery sitting around in a state of discharge (did we say that already?).
We sincerely hope this battery care web page helps you get the most from and out of your battery packs you have received when purchasing your fantastic fish finder mounts and accessories from Fish Finder Mounts .com!
From your friends at Fish Finder Mounts .com :)