Re: Battery condition question- interstate starting battery
I believe this is generally good practice for vehicles, too -- if it gets weak enough to require a jumpstart, bench charge it at your next opportunity. You might not be doing enough driving to bring it back up to 100%, putting it in a state of chronic undercharge and shortening its useful life.
This is correct.
Battery type isn't as critical on a vehicle as an outboard because typically a vehicle is driven every day (or most every day of the week), thus it remains at its optimum charge via the alternator trickle-charging it on a regular basis.
Most outboards are not used every day, thus the battery has a lot of down time, giving it time to discharge. If the end user does not trickle-charge it off a battery charger before its next use, it's left up to the stator (alternator) to attempt to charge it to full capacity. And again...a stator is not designed to charge a weak or dead battery. When this happens, the weakest link in the circuit is placed in high risk of failure. That weak link(s) are the diodes in a regulator/rectifier. When they fail, the stator can no longer charge the battery.
This is why it's imperative to use a battery charger to trickle-charge the battery overnight before each & every use of the boat.
If the boat is used every day or at bottoms, every week of the year, then a battery charger isn't required. In this case, the trickle-charge that a stator gives the battery while in use is usually enough to keep the battery charged during an outboard's down time.
However, most folks do not use their boat each week of the year. Some folks do use their boat each week (or even every day) during the warm months or just Summer, but it's the off-season (late Fall-early Spring) when a battery sits for months with no charge applied that is a failed regulator/rectifier in waiting come next Spring.
March & April are BY FAR, the two months in which we receive the most calls for charging issues...when folks are just getting their boats going again. They've neglected to charge their battery off a battery charger before the first use of the season. They believe that an outboard's charging system is fully capable of charging a weak battery. Sometimes they get lucky if the battery hasn't discharged too much. But when it does discharge too much, they are usually left with a blown regulator/rectifier.
And even some of those folks replace their regulator/rectifier, but omit replacing the battery. Guess what happens to the new regulator/rectifier?
This is exactly why it's imperative to use the proper type battery that will stand up to the abuse (constant discharging & charging) that an outboard goes through. That way, if the end user happens to forget to charge his battery after extensive down time, they may be fortunate that they have not blown their regulator/rectifier.
