How Much Draw Is Too Much Draw?

[l008com]

So I plan on re-doing all the electrical in my boat. I'm going to replace the nav lights with super bright LEDs, I may put small LED lights on the floor, I'll eventually add a radio with two speakers, a spotlight/headlight, fix up the bilge pump, and and a depth gauge. I'm not worried about any of this at all.

The point of this thread is that I was also looking at some small 12V coolers to keep drinks cold while I'm out. That would be nice to have when I'm out for 3 hours or more. However I have no idea of my boat can handle that much power drain, without sucking the battery dry even while the motor is running? My motor is a 3cyl 1989 90HP mercury. One cooler I found listed 60 watts as it's draw. What do you think?

 

[wire2]

Re: How Much Draw Is Too Much Draw?

60 watts is ~5 amps, same as 1 headlight. You will probably be ok with the Merc running, but stopped, will pull the battery down.
A safe solution is a 2nd battery for just the cooler. A small garden tractor size will give several hours of cooling, then bring it ashore to charge.

 

[l008com]

Re: How Much Draw Is Too Much Draw?

Is it possible to upgrade the alternators in these motors so they put out more power? Or is that not possible/easy to do?

 

[JoLin]

Re: How Much Draw Is Too Much Draw?

You can upgrade the alternator, but it's expensive and usually of limited benefit unless you actually run the motor for hours at a time.

Good energy management practices help, and a second battery on a switch will, too. Personally, I'd use an ice cooler rather then a 12v. You really need that drain for a few hours on the water?

I'm also in the process of upgrading to LED's as I have some cash. I changed over the 3 lights in the cabin and head. Next up will be the v-berth reading lamps and the stern/anchor light. Finally the courtesy lights in the cockpit. We usually use a battery-operated camping lantern there anyway. I'm not going to bother at all with the bow nav light- that one's only used when the boat is underway and charging anyway. LED there is an unnecessary expense.

My .02

 

[l008com]

Re: How Much Draw Is Too Much Draw?

I'm LED'ing my NAV lights because I want bright, vivid NAV lights, not dim, faded NAV lights. My boat is ooooold. And still, even under way, why waste the energy.

 

[JoLin]

Re: How Much Draw Is Too Much Draw?

I'm LED'ing my NAV lights because I want bright, vivid NAV lights, not dim, faded NAV lights. My boat is ooooold. And still, even under way, why waste the energy.

Hey, do what you want. Just providing a different viewpoint.

Nav lights are nav lights. Our sized boats require CG-approved, 2-mile visibility nav lights. What are you planning to replace the incandescents with, that'll give you more light than that? A brighter LED 'bulb' probably won't fit in the housing, and if you replace the whole unit, you're (hopefully) going to get a CG-approved LED unit instead... and it'll have the same light output.

My .02

 

[l008com]

Re: How Much Draw Is Too Much Draw?

I'm replacing the whole unit. The light would probably be on par with what i have now if I replaced the bulb and the colored shield. But for $35, I'd rather just replace the whole thing with an LED. Nice vivid color, no heat, no electric draw, no replacing bulbs. I likey.

 

[JoLin]

Re: How Much Draw Is Too Much Draw?

Enjoy!