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. Even if you haven't drained them all the way, it's best practice to charge them up when the pack is not in use or in storage.
The best practice for storing your SLA/AGM battery pack: If you have purchased our maintenance charger, just put your battery on that charger and leave them on that device indefinitely, until duty calls once again. The maintenance chargers we sell are 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 it in an optimal state of health given its age and how many cycles it has endured.
Storage in cold environments such as an unheated garage during the winter (or the like) is not recommended! If you leave your battery pack off of charge and just sitting around in such a situation, it won't be long before the battery fully discharges and ultimately becomes useless due to process of sulphation. When this happens your battery will be incapable of receiving a charge.
If you maintain your SLA/AGM batteries, keeping them mostly or fully charged up while not in use, the batteries should last you for 2-3 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; which is true for all battery chemistries.
Be aware that 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. The key again is to endeavor to keep them charged up as much as possible - that's the main theme here. Why is this the case you ask? Battery electrodes within the pack will go through a process called sulfation when they are depleted. If a battery is left in discharged state for an extended duration of time this chemical process of sulfation can/will ultimately ruin the battery, rendering it incapable of receiving a charge.
If sulfation 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(s) we sell; and then just keep cycling them, taking them on and off over time (unplug and plug the charger back in to reset it's measurement circuit(s)). This can sometimes break up the sulfation, and "wake" the pack up, restoring some capacity. How much, it depends on the maintenance charger charging algorithm, and how much sulfation has set in.
Also, we highly recommend you do not discharge your 12 volt battery pack below 12 volts if you can at all help it. There are fish finders on the market that will accept a wide range input of voltage. Some of these products will run on less than 12 volts; and as a result will keep sourcing power from your 12 volt battery drawing it down below the 12 volt level. What voltage is too low for a 12-volt battery? 12.0 volts or below - At 12.0 volts your battery is considered to be fully discharged or 'flat' and should be recharged as soon as possible. The lifespan of your battery will be severely affected if it remains within this voltage range for even relatively short periods of time.
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. If you have our 800ma charger, that charger will charge a 5ah battery from full depletion in 6.25 hours.
Math: 1amp charger
All of our SLA batteries are nominal12 volts; therefore your charger must charge at 12 volts.
Our SLA 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 :)
Great link to read about caring for, using and storing lithium battery packs (particulartly LiFePo4 chemistry):