battery question

[SandySteel]

My buddy's boat has a 45 jet on it with the standard electric start. He hasn't used it much and it has largely sat in storage for almost two years. It gets out on occasion and recently he started experiencing problems with the battery.
It will hold a charge for only a short length of time (an overnight charge for the next morning and it works fine) and then the next time we take it out the battery is dead again, even within two weeks. We took it to Schucks to have it tested and it came up with replace on all of their tests. So my buddy bought a new battery.
Is it better to get an onboard charger that keeps the battery topped off? Will this extend the life of the new battery? It is really the pits when you go to put in only to discover that you have to pull out the rope in the cowling and do a hand start.

Eric

[Killertraylor]

Before you go and spend a ton of cash on an on board charger, spend $20 and hook up a Perko battery switch so he can turn everything off when the battery isn't in use (assuming he doesn't have one already). My batteries hold a charge for months as long as there is no current drawing from them. Maybe he's got something drawing the power out?

[Pilar]

Killertraylor, good suggestion. There is more to it though. There are 2 sure fire ways to kill a boat battery. Ignore it for long periods of time or let it run low on water.

If you have a standard battery charger, plan on using it once a month over night. If you discharge the boat battery (all day on anchor with the radio blaring) on any given day, charge it that night.

Even behind an open battery switch, a battery will internally discharge to dead in 6 weeks or so. This varies by age and condition but plan on overnight on the charger once a month.

Never store a battery unless it is fully charged and use a hydrometer to check the charge level if you know how.

Good luck.

[ 08-13-2002, 01:50 PM: Message edited by: Pilar ]

[AngleThis]

I have a better idea... Instead of buying an on board battery charger, buy a second battery and wire it up to the above suggested Perko switch. That will provide for great realiability. Also, for a few bucks more he can get a solar trickle charger to keep the batts "topped off". Of course, this is only useful in the summer, but it sounds like he doesn't use his boat much in the winter anyway.

[Artwo]

Eric,
When I had my sled and I wasn't going to be using it for a month or two I would simply disconnect the negative terminal from the battery. When I decided to use it again I would put the battery charger on it over night the night before and it would operate just fine. I would also have my battery checked about every six months or so for its overall condition. I do like the idea of the portable charger/jumper boxes, you can also use them for other vehicles if you need to as well.

JK

[Small Fry]

If he has the room go with the dual batterys and the perko switch. It ain't worth your life to get caught with a dead battery in a pinch.

just my 2 bit's

[Herring Impaired]

I use those Battery Chargers they sell at Harbor Freight ($15-$20, unless you find them on sale). More like a trickle charger, but they claim to keep your battery active so they don't get sulfated up. If I don't plan on using the boat for a week or more, I hook this bad boy up and have never had a problem with the battery at the boat launch.

Also a good idea to replace the battery every three years or so as well.

[Clackman]

went exclusivly to gel cell batts all problems gone period

[rebell]

On board chargers are worth there weight in gold! So are battery isolater switches. Plain and simple, the worst thing you can do to a battery is let it get below 50% discharge. A good on board charger will maintain your batteries, and keep them fully charged. I have a Pro Mariner 15-3 charger on my boat and leave it plugged in 24-7-365. The only time my charger is not hooked up is when I am fishing. But be carefull, not all on board chargers allow you to do this. Some will over charge your battery if left hooked up. Also, stay away from trickle chargers, if left hooked up to long they will boil your battery, and when you need a quick charge, they wont get the job done. Spend the money, its worth every penny. If you have any more questions log on to semarine.com. They are out of Scappoose and have forgoton more about battery technoligy then most peaple know.
By the way, Im on my 6th year on a set of Rolls batteries from these guys and they are still going 100%.

[fishonksm]

Eric, A couple of quwetions.
1.)what type of battery are you using?
2.)does the motor have a charging circuit?

I've recently found out that you should not be using a deep cycle battery if you motor has a charging circuit. It was recomended that i use a marine starting battery as the charging circuit would over time ruin the deep cycle battery as deep cycles are made to be complety discharged then recharged fully.

On the other hand the marine starting provides ample starting amps plus reserve power to run acceoriesss.

A battery charger hooked up for long periods to either type is fine only if the charger is an auotmatic shut off type, anything else will cook your battery. and be sure to watch the water level and keep it toped off. :cheers: