fuse

[tony silveira]

Where my onboard charger connects to battery there are in line fuses to both pos and neg. The one on positive has blown a couple times lately. Got on water today with dead batterys. All wires are clean and good. Any ideas?

 

[steven evans]

TJ this could be a number of different things. But here are a few simple ones to check.

Is the charger actually charging?

How old are the batteries?

Are the batteries good and will they hold a charge?

Make sure you don't have a radio or light staying on somewhere.

Did you replace the blown fuse with the same size and not a larger fuse? If you replace a smaller fuse with a larger one you run several risks. #1 being the larger fuse is likely to allow to much current to pass and not "protect" the wire or the components in the circuit (also could cause a fire). If you do have a short somewhere that is quickly blowing a small fuse it may not blow a larger fuse and the short itself will drain your batteries.



Another thing about a charger is does it have indicator lights on it? If it quits charging there is the possibility that the indicator lights on the charger will stay on and would actually be drawing current from your batteries instead of the charger charging the batteries.

 

[tony silveira]

I'm definitely due for some new batterys but they still hold charge. Trying to get all I can out of them. I didn't think that would blow fuse I run 24 volt it only blows fuse on one battery.

 

[steven evans]

No an old battery "shouldn't" cause a fuse to blow. I was just giving reasons as to why your batts may have been dead. I do have a question though. Is the fuse that's blowing in-line between the charger and the battery? There are 2 main reasons why a fuse will blow - a shorted circuit or to much current (amps) flowing through the circuit.

 

[Scott Hammer TOXIC]

are your batteries wired correctly?

 

[tony silveira]

Yes Steven it is in line between charger and battery. Don't think its a short cause it would blow right away as soon as plug it in. I wonder if I'm running to small of fuse it is a 20 amp. Yea toxic they are wired right. Never had any problem till fuse blew a couple monthes ago. Then did it again last week. I hope the charger isn't going bad.

 

[Dyno6942]

TJ, I would switch the charger leads from battery one to battery two, and vice- versa, and see if the problem persists.My onboard 3 bank only has fuses on the battery side, 20 amp. I have more problems keeping the charging cord connected, than anything else (Hubble Inlet).

 

[steven evans]

What gauge is the wire? That will help to determine what size fuse you need. It is likely #12 awg which is only rated for about 20 amps. If it is #12 AWG then the 20 amp fuse is the largest you should use. Honestly though TJ I think you may have a charger issue.

 

[Major Mark]

Don't know if you have a MG or MK motor, but as far as wiring goes, MK requires between 10ga to 4ga wiring and either a 50 or 60amp circuit breaker for all their motors 40# thru 101#. The variant is dependent on which particular motor you have and how long of a wire run you have. The only model MK sells that could get by with wire as small as 12ga is their 30#/12v unit, and then only if the wire run is 10 feet or less. I would start with verifying the wire & breaker are proper size for application. After that as it's just one battery feed having a new issue, I'd double check all wire connections for decay or corrosion, check that a wire route didn't get damaged by a pinch or kink. I for sure would not put in a larger then specified fuse. That would possibly lead to an on board fire or damage to expensive gear/equipment.

I do have a pdf file MK sent to me before I purchased my Terrova last summer & was wiring my new boat for it. I'd be happy to email it to whomever would like it for reference.

 

[steven evans]

Major Mark is exactly correct and has given some really good things to check. But the way TJ is explaining it is, these fuses are on the charger side of the battery. Not the "load" side feeding the troller. These fuses would only be protecting the charger circuit and wouldn't require a large conductor or fuse/breaker. There would be no current passing through these wires or fuses while the troller or other equipment is operating. Yes there should definitely be a much heavier conductor with a much higher amp rating breaker/fuse protection from the batts to the troller.



TJ- a few more questions. Does the fuse blow while it's charging? Or does it blow while you are operating the troller and other equipment from the batteries? Is this a 2 bank charger?



As I said earlier. You may have a short (and not know it). It could be somewhere that you don't realize and it may only show up when you have some certain switch in the 'on' position while you're charging and it will blow the fuse, or you could have a shorted battery cell. You also may be having charger issues. If it's a 2 bank onboard charger make sure that you have it connected correctly. If you don't have the correct negatives hooked to the correct battery and the same with the positives it will cause you an issue.



The first thing I would do (JMO) is I would remove the batteries and have them tested. Make sure none of them have a dead or shorted cell. Once you are satisfied that it isn't the batteries I would re-install them but only hook up the charger wires . Charge them up and if the fuse doesn't blow during charging then you have a good idea that you have a different issue. Clean all connections and wiring as oil/water/dirt will conduct and will set up ground paths causing headaches. Also like Major Mark said look for kinks, cuts, etc. Sorry I'm rambling but trying to throw you some more ideas out there.



Another thing to check is how much current (amps) the charger is putting out. If you have a clamp on amp meter then check that.

 

[Ralph Hayden]

Is there a possibility that the in-line fuse holder is shot? It's probably a long shot but they're cheap enough to replace if all else fails.