Are you using your engine's Aux charging capability?

[TheShortAnswer]

I have a single engine (2006 f250) boat with 2 factory installed batteries. My windlass is direct wired to batt 2. Battery selector switch is the standard 1, 2, both, or off. Many guys like to run in "both" so that both batteries receive a charge from the alternator while running. I like to keep my batteries separate and either run in "1" or "2", that way I know I have a fresh battery available regardless if the other battery has a malfunction or is drained.

I have in the past practiced the advice of running out on "1" and back in on "2" but sometimes forget. On a recent trip I did forget and ruined battery 2 with the windlass. They were due to be replaced anyway......no biggie.

On the boat I have now, I never got around to using the Aux charging wire coming of the alternator. It is a capped plug-in that sits on the engine pan under the engine fuel filter. You simply pull the cap off and plug in the charging wire. Run the charging wire through the cable/wire chase that goes from the engine to the transom, then hook the positive (red) to the desired battery. In my case it was battery 2 which has the windlass direct wired.

By using the Aux charging wire, both batteries charge at all times while the engine is running regardless of selector switch position, and keeps the batts isolated from each other. One cool thing is the windlass (because it is DC) runs even faster because of the charging wire.........very cool. No more forgetting to change the batt switch.

You can buy the Yamaha charging wire (see my pic), or you can actually make one using the protective plug-in cap that you remove.

[OReely]

Is it fused at both ends? It should be.

[TheShortAnswer]

Is it fused at both ends? It should be.

with no piece of electronic equipment needing protection, i see no need for fuses. the aux charging wire acts the same as the battery cables which are the "wires" that normally charge the batts.

[triumphrick]

Actually, on my last motor, Yamaha 150 2 stroke that aux charging plug was coming off a 30A fused connector. Plugging in to it provided me with an entirely seperate charging circuit for the second battery. I understand they can be found on most all larger Yamahas.

[bly]

On my f225 yam formula project boat this is my next project after years of being one of those I just switch the selector on the trip in guys. No more, Im going to do it the right way for once?

[OReely]

with no piece of electronic equipment needing protection, i see no need for fuses. the aux charging wire acts the same as the battery cables which are the "wires" that normally charge the batts.

Actually, the cables that go from the battery to the engine are there primarily to start the engine. Charging is a side benefit exploited by the outboard manufacturers. ABYC makes an exception for fusing starting cables. They do, however, require all other power sources to be protected. The fusing of this wire has nothing to do with protecting ancillary equipment, it is for fire safety.

The aux charge lead should be fused at both ends. The reasoning is that it could be considered a source from either end, that is to say, in a shorting situation the wire could get power from the battery or the engine.

You certainly don't have to follow ABYC standards but they have been well thought out over many years by some of the best in the business. Their primary purpose is to make boating as safe as possible.

[TheShortAnswer]

Actually, the cables that go from the battery to the engine are there primarily to start the engine. Charging is a side benefit exploited by the outboard manufacturers. ABYC makes an exception for fusing starting cables. They do, however, require all other power sources to be protected. The fusing of this wire has nothing to do with protecting ancillary equipment, it is for fire safety.

The aux charge lead should be fused at both ends. The reasoning is that it could be considered a source from either end, that is to say, in a shorting situation the wire could get power from the battery or the engine.

You certainly don't have to follow ABYC standards but they have been well thought out over many years by some of the best in the business. Their primary purpose is to make boating as safe as possible.

i defer to your knowledge and ABYC...........the cable in the pic comes from Yamaha and plugs right in out of the package. i think i will keep it simple. as said in a previous post ......probably fused prior to the plug in.

[BRIANM333]

I use the lead to charge my house battery. It is fused at the engine and I connected it to the house battery on the switched side so when I shut my switch off there is no power going through the rigging tubr to the motor.

A question about being fused at both ends. Battery charger leads are only fused at the charger, so if a short caused the fuse to trip wouldnt there be voltage from the battery to short out on something and not be protected?

[OReely]

Mango,

Like I said, that's up to you. Probably nothing bad will ever happen, but you never know.

Brian,

What happens if there is a short while the switch is on? Lets say the wire chafes through at the point where it passes through the cowling. you now have a live wire inside the cowling. If it hits grounded metal, the fuse on the engine end will pop but the battery end is still live. There is nothing to stop it from dumping a whole lot of amperage into that metal. It could easily start a fire within the cowling or somewhere along the length of the wire. That could ruin your day.

Now, change the scenario to include fuses at both ends. The fuses pop and the worst thing that happens is your battery doesn't charge.

As far as the charger goes, ABYC says "each ungrounded conductor connected to a battery charger.... shall be provided with overcurrent protection within 7 inches of the connection point".

Exception 1) If the conductor is connected directly to the battery terminal AND is contained within a sheath or enclosure....overcurrent protection shall be as close as practicable to the battery, but not to exceed 72 inches.

Exception 2) If the conductor is connected to a source of power other than the battery terminal and is contained...., but not to exceed 40 inches.

So, to answer your question, yes, the terminal end of the battery charger leads need to be fused. If the charger wiring meets the one of the exceptions as listed above, then the supplied fuses are all you need.

I know the above is kind of doom and gloom, but most of the standards are written based on practical experience. An accident happens and the ABYC committee involved in that area looks for ways to solve the problem so it doesn't happen in the future. Some of the standards are written on a proactive basis, an issue is recognized and worked on before it becomes a problem.

ABYC standards are recommendations based on in-depth knowledge of the subject. You can use or ignore them as you wish.

[TheShortAnswer]

Mango,

Like I said, that's up to you. Probably nothing bad will ever happen, but you never know.

Brian,

What happens if there is a short while the switch is on? Lets say the wire chafes through at the point where it passes through the cowling. you now have a live wire inside the cowling. If it hits grounded metal, the fuse on the engine end will pop but the battery end is still live. There is nothing to stop it from dumping a whole lot of amperage into that metal. It could easily start a fire within the cowling or somewhere along the length of the wire. That could ruin your day.

Now, change the scenario to include fuses at both ends. The fuses pop and the worst thing that happens is your battery doesn't charge.

As far as the charger goes, ABYC says "each ungrounded conductor connected to a battery charger.... shall be provided with overcurrent protection within 7 inches of the connection point".

Exception 1) If the conductor is connected directly to the battery terminal AND is contained within a sheath or enclosure....overcurrent protection shall be as close as practicable to the battery, but not to exceed 72 inches.

Exception 2) If the conductor is connected to a source of power other than the battery terminal and is contained...., but not to exceed 40 inches.

So, to answer your question, yes, the terminal end of the battery charger leads need to be fused. If the charger wiring meets the one of the exceptions as listed above, then the supplied fuses are all you need.

I know the above is kind of doom and gloom, but most of the standards are written based on practical experience. An accident happens and the ABYC committee involved in that area looks for ways to solve the problem so it doesn't happen in the future. Some of the standards are written on a proactive basis, an issue is recognized and worked on before it becomes a problem.

ABYC standards are recommendations based on in-depth knowledge of the subject. You can use or ignore them as you wish.

sounds interesting. i was wondering why the wire was inside a sheath (exception 1).