On-board charger

[SweeperForce]

I got a battery charger you mount to the boat. Water and salt proof with 120 volts input and 14.1 output using 14 gauge wire. It has two outputs, one for each battery. The one set is for the starting battery, it has a 10amp in-line fuse on the positive lead. That makes sense. Now the second set is for the accessories, it has a 10 amp fuse on both the positive and the negative leads. That doesn't make sense. Can you shed some light on why its like this?

The leads out of the charger are only five feet. I need fifteen feet. They sell extension cables that are fifteen feet, that will give me plenty. Now the extension also have a fuse on the both leads. So that will be two fuses on the pos and two fuses on the neg for a 20 foot run, isn't that a bit excessive. The extension sells for $40 per set and I need two. So what I did is order 50 feet of duplex 14 gauge from my wire guy at half the price. This is tinned wire made for marine applications. Do I really need all these fuses?



Tom

 

[Capt Sully]

Re: On-board charger

I would think you would mount the charger close to the batteries to keep the cables short. Then use a heavy duty long power cord to power the charger. Thats what I did and it's worked over the years just fine.

 

[Silvertip]

Re: On-board charger

So what's the problem. The fuses are there and it hurts nothing. I also agree that the charger doesn't need to be 20 feet away from the batteries. Why there is a fuse in a ground lead is not a mystery. You can fuse either the positive or negative or both leads. Fusing the positive is the current philosophy. Fusing only the negative means that a short or current draw in excess of the fuse rating in the positive lead would not blow the fuse if that short occurred before the fuse. Fusing the negative lead will also shut down charging of the battery in the same manner that a fuse in the positive lead. Since you have a charger that has two fully independent chargers in one package, there may be a potential issue with the isolated ground circuitry where fusing one of the negative leads is desired. Some chargers, although designed with fully isolated grounds that allow use in a 24 volt system, also have circuitry that allows one charger to assist the other when its battery is topped off. That means there is internal switching that removes that ground and applies it to the other output hence the possible need for a fuse in the ground lead.

 

[BoatDrinksQ5]

Re: On-board charger

Typically NO you can't use your own cabling due to there being temperature sensors in the leads near battery to sense or control an overheating battery. I don't know about your particular charger - but seems pretty standard these days.