Charging the ol' battery....

Philster

Captain
Joined
Sep 15, 2009
Messages
3,342
Scarab has been laid up and well-covered since November when she last ran. I did not remove the battery.

All the accessories work and the hatch has been up/down a number of times since March, but I decided to charge the battery, since I didn't all winter. (Yes, I know I ran a risk of a depleted battery being vulnerable to a freeze).

Well, she is currently charging at 4 amps. My charger will automatically charge from 2-10 amps and the meter is reading 4 amps.

I have to admit ignorance here. What is a good reading, and best way to test the battery? I am trying to be more budget conscious, instead of just replacing stuff whether it needs it or not.
 

This_lil_fishy

Master Chief Petty Officer
Joined
Jul 23, 2008
Messages
841
Re: Charging the ol' battery....

The needle should drop to almost zero if the battery takes a full charge. Do yerself a favor and get a good quality marine charger. The newer electronic ones with trickle charging can really bring a marginal battery back to useable levels. I find most of the old automotive ones really don't charge very well.

Ian
 

Boatist

Rear Admiral
Joined
Apr 22, 2002
Messages
4,552
Re: Charging the ol' battery....

How Low your battery charger output should go to really depends on the type of charger you have.
A Smart or Automatic charger should drop to near zero amps.
A Manual charger may never drop to near zero and can badly over charge your battery.
If you have a voltmeter then normal charge levels are in the 13.8 to 15 volt range.
If it goes much higher than that then your should monitor closely and when climbs over 15 volts shut it off.
Check again the next day with your volt meter. If it is fully charged and in the 70 to 80 degrees range then should measure 12.6 volts.

The reason you should charge your battery in the off season is all batteries self discharge.
A discharged battery will be damaged by sulfation .
General rule is to charge once a month in hot weather if not used and every couple of month in the cold season.

Best thing you can do is make it very easy to charge your battery in the boat.
Install a Marine smart charger and make it easy to get power to it.
Most of these charger are three stage charger and will bulk charge pretty quickly then switch to a float or absorption mode and then shut off.
They are not the cheapest but they make it easy to care for you battery.
I personaly would not buy a charger under 10 amps per battery so you can fully charge ever large batteries is less than 24 hours.
A cheap float charger is another way to go. They put out about 13.2 volts and will not over charge but take a very long time to charge a discharged battery.
Really more of a maintainer than a charger.
 

john from md

Commander
Joined
Apr 13, 2008
Messages
2,184
Re: Charging the ol' battery....

If you don't have power where your boat is stored, you need to take the battery out. Even if it doesn't freeze, the plates start sulfating and shorten the life of t he battery. Keeping a battery tender on a battery when not in use will usually extend the life of the battery by a couple of years.

John
 

ziggy

Admiral
Joined
Jun 30, 2004
Messages
7,473
Re: Charging the ol' battery....

along with what others are saying.
after i think i'm all charged up, i like to take my batt. over to my local napa store before the season starts. they'll load test your batt. for you. my napa does this for free.

only problem with my notion is that this year i took it over to them and they wanted to use the electronic tester on it. i knew they had an old style tester in back so ask them to use that. well, the batt. failed the old style tester (it has heating elements in it that really put the load to it). bummer for me mine failed. so i ask them to try the electronic tester on it. it came back with flying colors on that test. this is the first year i've got conflicting info on my batt. leaves me wondering which test was right.
anyways. i still think it's a good idea to have it load tested prior to use...

in my case, i'm takin my chance. 3 year old batt. that has been maintained over the lay up. i've also added a jump pack to my basic onboard items list too, just in case.. ;)
 

fat fanny

Lieutenant Commander
Joined
Feb 9, 2006
Messages
1,935
Re: Charging the ol' battery....

I have always maintained the charge on my battery throughout the winter but this year after6 years it was low on fluid and charge was depleated bought the fluid @ napa refilled and charging raned between 12 to 13 volts I leave it sit for a day or 2 and check it periodically not moving to much. I may have to replace it for reliability purposes but will see it's almost 8yrs old 1st yr with any problems.
 

john from md

Commander
Joined
Apr 13, 2008
Messages
2,184
Re: Charging the ol' battery....

8 years is a good life on any battery. If you go outside with that boat, I would change the battery just to be on the safe side.


BTW, you can buy a High Rate Discharge Tester (100 amp draw) from Harbor Freight for $19.95 when on sale. I have one and, along with voltmeter, hydrometer and battery tenders, I manage to get long life out of all of my batteries including those for back up sump pumps and generators.

John
 
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