Batteries....

[spareparts]

every time i turn around someone is having battery problems, most of the time its the type of battery or size. Engine manufactures post a minimum spec for cranking batteries for the engine they manufacture. Any thing with a computer on it needs at least 750 CCA(900 MCA), Any of your bigger I/O engines need the same whether they are computer controlled or carbed. Yamaha seems to be the most conservative with their requiremnts, but I run into more bad battery cables( factory supplied) on Yamaha's than other brands. Check the engine manufactures for minimum battery cable size for the lenght of cable, 75% of the used boats I work on won't even come close. Make sure your battery switch is up to the rating of the battery also, theres no sense in putting a hot battery in behind a cheap switch. But probably the biggest problem I run into is finding deep cycle batteries for starting batteries, engine manufactures strickly forbid this, for good reason. Most deep cycle battereis rarely meet the minimum CCA/MCA requirements, deep cycle batteries are designed to be "cycled" meaning run down and charged back up( at a slow rate), not cycleing the battery will result in a loss of performance, futher degrading its abillaty to perform as needed. If you are using an on board charger, they charge at a different rate than regular batteries( if you charge them fast, they will degrade as well). I've seen plenty of people get by with deep cycle batteries to start their outboard, but when its replaced by a proper starting battery, its a night and day difference in starting. I've been thru this with battery suppliers more than once, never use a deep cycle on anything other than trolling motors or depleteting house batteries( set up with their own charger and isolated system). AS afar as dual purpose batteries go, they do neither job well, they don't cycle as good as deep cycle, and they don't start as good as starting, they also don't respond as well to high output charging systems(late model EFI motors) like deepcycles. I've installed dozens of West Marine( or Deka) maintanance free 1000 MCA group 24 batteries with a single failure, I've also used Interstate 24XHD, 27XHD wet cell with simular performance. I haven't had a lot of experiance with gel, or AGM's but the ones I've seen rarely outlast a standard wet cell if properly maintaned, I have seen several that were cooked due to over charging, Gel and AGM require slower charging rates simular to deep cycle, they sometime require turning down the charging rate on altenators