Battery Charger concerns...

[Duty Free]

I have a 1996 Marlin 30’ with a Dytek Battery charger for the 4 batteries on board. My concern is if I leave the charger on while docked for long periods of time, say 24/7 through the week, will it “cook” the batteries or will it drop down to a trickle charge ?? Again, the unit is a 96’ so not sure of the advanced technology.
Just worried that I am doing more harm by plugging in the charger for an hour or so each day, rather than leaving it on all the time.
Does anyone have feedback as to the best way to handle this matter.
I should say that the batteries are brand new as of July 4th. and although new, the 2 house batteries seem low to me when checking lights and radio, etc.
As soon as I plug the dock power in, everything gets brighter… Okay, I will be quiet now and wait for your comments.. Thx, :bang

 

[BobP]

Good question !

Expect several different responses.

Seems you are concerned the Dytek may ruin the batteries (?)

Another issue for some is just leaving the shore power on all the time and battery charger irrespective of need or not, just to be on safe side or can't be bothered.

More depends on how you use the batteries and how often you are at the boat.
ie. an hour will do little to get the house battery back after a day of running a LW pump continuously or the halogen floods all nite long, etc.

Perhaps start with a new charger, if not you will have to measure voltage at battery terminals to be sure it backs down when it goes thru it's 2 or 3 step cycle to a maintenance level, and if you don't have sealed batts, how often adding water is a big telltale.

Overcharging wrecks the batts, but that means overvoltage for too long, not that the battery charger is on too long. Been there done that and wrecks several batts with a fautly charger in one season, did see adding water several times in season, now not at all - all season.

A discharged battery for too long wrecks it too, at least conventional battery designs.

You may want to begin anew with a new charger, and if you keep any DC load on (for long periods of time) while the charger is on the battery charger may be tricked believing the battery is not charged and continue with it's higher output mode - check with manufacturer of new charger if you select one.

I picked up a marine/RV battery booklet at the Interstate distributor by me, very informative, you may want to look for it on their website. Gives figures on how long it takes to recharge batteries given what load is on it and other info.
I have nothing to do with Interstate, but use 27 and 29 series Interstate Marine Deeps rated both start and deep cycle.

For my own boat, I never leave the charger on when gone for the week, but will overnite on weekend stays. It's a 3 output 20A total output charger.

Good luck.

 

[Duty Free]

Thanks for getting back to me on this issue... I think my first step is to measure the voltage on each battery to ensure what the actual process is going on. I hate to have to replace the charger if it is ok afterall.
Seems that I can leave my car sitting for weeks and the battery remains strong. If I let the boat sit for just a couple of days, the batteries show evidence that they are getting very low...
Again, thanks for taking the time to help out.. I will let you know my progress.

 

[uncljohn]

depends if its a "battery charger" or a "maintanence/trickle charger" A maintanence charger will charge the battery, then when battery is full it swicthes off. A normal battery charger that your dad used to slap on the old Ford will fry your battery if left on for long periods b/c it doesn't turn off.

 

[BobP]

You are welcome -

No reason for your batteries getting low, should be same as car, unless sump pump(s) are running. Some electronics have memory circuits, inverters, galvanic isolators have indicator/alarm circuits, etc.

Shut these all off when leaving boat (Sump Pumps are configured for direct fused power from batts since they never should be depowered.)

When battery switches are off, everything else should be dead.

Clean all terminals at rear of batt switches and mounting surface behind, and the tops of batts.

If your pump (s) are running other than after rain or the like, you have a leak and have to find it. Transom service doors may let some SW washdown in, but a boat static at the dock should never see pumps run w/o rain.
Some A/C drain condensate into bilge.

You have to do some troubleshooting to find out if there is circuit leakage, or the batteries are not being fully charged.
I recall a time a float swicth was leaking, sooner or later especially being under water, it can happen.

A wet cell can be tested for charge percentage with a hydrometer, pick up a cheap one at parts store. No other way to verify it.

You want to be sure batteries get fully charged otherwise not much power will be available.

You can mount a digital VM to the instrument panel, I installed a NEWMAR LCD 3 input model, works great. Then look at it and become familar how it responds when turning on the charger and as time proceeds see it lower down.
See the rise when motors are running, etc.