Another generator question

[StandUpGuy]

I am no electronics Guru so I have a question. The question is not about a trailer per se but it could be. It is actually about a generator used on a boat. If one had a boat with an electric trolling motor and you also had on the boat a generator, could you if the battery ran out, connect up a 12v transformer to a gas powered generator and inturn run the trolling motor off of it? Or would on in this case simply charge the battery and run the motor off of that battery while it was being charged?

[SubaruDave]

It's Similar to the alternator in a car, It runs all the electrical and charges the battery (while using the battery to minimize voltage spikes)

So I guess the answer to your question is, it will run the trolling motor and charge the battery at the same time. (as long as the generator puts out more watts/amps than the motor pulls)

[StandUpGuy]

It's Similar to the alternator in a car, It runs all the electrical and charges the battery (while using the battery to minimize voltage spikes)

So I guess the answer to your question is, it will run the trolling motor and charge the battery at the same time. (as long as the generator puts out more watts/amps than the motor pulls)

That makes sense.

So if a generator is rated say 800 watts and a motor draws 40 amps then how long does it take the driver in car A to reach Saint Louis?

[eamarquardt]

I don't think it's quite that simple. I have a Honda 1000 watt generator but the specs say that its DC output is only about 8 amps and the generator says "Battery Charging Only" at the DC output terminal.

I also have a Coleman generator (both generators are garage sale items) and it also says "battery charging only" on the DC output.

Poking around on the net it seems that trolling motors draw about 30-40 amps at full power.

So, the DC output on a typical generator isn't going to put out enough current to run the motor.

If you get a converter that will put out the DC amps required by your motor (with some margin for error), power the converter with your generator (assuming the generator is powerful enough), and then use the converter to run your motor and charge your battery it will work.

A small outboard would be simpler and perhaps more reliable.

Cheers,

Gus

[StandUpGuy]

It would be a sailboat with an electric trolling motor for alternative propultion. The plan is to have the ability of simply charging a second battery for an extended trip in the boat. I was simply wondering about what if both batteries were discharged and I had emergency need for electric motor propultion. Perhaps easiest of all is simply to always run the generator to charge one discharged battery so I am never without charge.

[eamarquardt]

It would be a sailboat with an electric trolling motor for alternative propultion. The plan is to have the ability of simply charging a second battery for an extended trip in the boat. I was simply wondering about what if both batteries were discharged and I had emergency need for electric motor propultion. Perhaps easiest of all is simply to always run the generator to charge one of the batteries so I am never without charge.

An outboard would be far less complicated. I have a nice British Seagull available.

Cheers,

Gus

[StandUpGuy]

It would be a sailboat with an electric trolling motor for alternative propultion. The plan is to have the ability of simply charging a second battery for an extended trip in the boat. I was simply wondering about what if both batteries were discharged and I had emergency need for electric motor propultion. Perhaps easiest of all is simply to always run the generator to charge one of the batteries so I am never without charge.

An outboard would be far less complicated. I have a nice British Seagull available.

Cheers,

Gus

I don't have the boat so it is all planning at this point.I had an old Evenrude 9 hp on an old sailboat a while back and it was a fabulous motor. Those little outboards are great.

[eamarquardt]

I got a Johnson 6hp (1974 model) for $100 at a garage sale. I pulled the lower end off to check the water pump impeller and there was virtually no wear. The upper end also looks like new. It starts and runs perfect. I have a 10' Archilles (used to be the tender for our 38' sloop) and plan on going fishing this next summer.

I also have a late model British Seagull but it's noisy and slow but it is funky/old time looking!!!!

Cheers,

Gus

[BPFox]

If you don't mind the sound of that gas engine, why not make your own 12 volt generator using a old lawnmower engine hooked up to used alternator from the auto salvage yard. That way you can troll all day and never worry about running down the battery.

[bdosborn]

I thought about going the DIY route but went with a Yamaha instead to keep the noise down. Then I added PV panels and I don't run the generator. Still, I think it would be a fun project.



Converting a lawn mower into a generator

Bruce

[glenpinpat]

We use a generator on our boat. It runs flood lights for our bow hunting setup. We have it hooked to also to a battery charger that has a fast charge system it will not run an electric trolling motor but it will charge a second battery in about 3hrs, letting us bow hunt all night if we choose. We have 2 deep cycle marine batteries that we can switch. Patrick

[StandUpGuy]

We use a generator on our boat. It runs flood lights for our bow hunting setup. We have it hooked to also to a battery charger that has a fast charge system it will not run an electric trolling motor but it will charge a second battery in about 3hrs, letting us bow hunt all night if we choose. We have 2 deep cycle marine batteries that we can switch. Patrick

This is exactly what I was thinking. thanks for that. My logic is that on a small sailboat I do not want the high weight of an outboard motor up high on the transom. an electric trolling motor is light weight and the two heavy batteries can be built in low on the boat bottom thereby lowering the center of gravity. So with your set up of two batteries and a generator I can (in an emergency situation) run the engine on one battery and charge the other at the same time. Maybe in a year or so I can build such a boat.

[eamarquardt]

We use a generator on our boat. It runs flood lights for our bow hunting setup. We have it hooked to also to a battery charger that has a fast charge system it will not run an electric trolling motor but it will charge a second battery in about 3hrs, letting us bow hunt all night if we choose. We have 2 deep cycle marine batteries that we can switch. Patrick

This is exactly what I was thinking. thanks for that. My logic is that on a small sailboat I do not want the high weight of an outboard motor up high on the transom. an electric trolling motor is light weight and the two heavy batteries can be built in low on the boat bottom thereby lowering the center of gravity. So with your set up of two batteries and a generator I can (in an emergency situation) run the engine on one battery and charge the other at the same time. Maybe in a year or so I can build such a boat.

Your logic escapes me. Two deep cycle batteries, a generator, battery charger, and a trolling motor versus a 2 or so hp outboard and your concern is weight? Even if you were considering something as small as a Sabot, I think a 2 hp 2 cycle engine would give you far better sailing and motoring performance, better reliability (water and electricity sometimes don't play well together), and far less complexity and maintenance.

I had a 38 foot sloop in the Santa Barbara Channel (windy lane to locals, hurricane gulch to non locals) so I'm familiar with sailing and boats.

We used to sail a Hobie cat off the beach. Our "alternate propulsion" system was a paddle.

Cheers,

Gus

[StandUpGuy]

In a flat bottom sailboat often ballast is added on the floor of the boat to lower the center of gravity. Instead of adding lead I would add two marine batteries. This is good weight in a sailboat. Weight added to one end of the boat and up high as in an outboard is bad weight.

We use a generator on our boat. It runs flood lights for our bow hunting setup. We have it hooked to also to a battery charger that has a fast charge system it will not run an electric trolling motor but it will charge a second battery in about 3hrs, letting us bow hunt all night if we choose. We have 2 deep cycle marine batteries that we can switch. Patrick

This is exactly what I was thinking. thanks for that. My logic is that on a small sailboat I do not want the high weight of an outboard motor up high on the transom. an electric trolling motor is light weight and the two heavy batteries can be built in low on the boat bottom thereby lowering the center of gravity. So with your set up of two batteries and a generator I can (in an emergency situation) run the engine on one battery and charge the other at the same time. Maybe in a year or so I can build such a boat.

Your logic escapes me. Two deep cycle batteries, a generator, battery charger, and a trolling motor versus a 2 or so hp outboard and your concern is weight? Even if you were considering something as small as a Sabot, I think a 2 hp 2 cycle engine would give you far better sailing and motoring performance, better reliability (water and electricity sometimes don't play well together), and far less complexity and maintenance.

I had a 38 foot sloop in the Santa Barbara Channel (windy lane to locals, hurricane gulch to non locals) so I'm familiar with sailing and boats.

We used to sail a Hobie cat off the beach. Our "alternate propulsion" system was a paddle.

Cheers,

Gus

[eamarquardt]

In a flat bottom sailboat often ballast is added on the floor of the boat to lower the center of gravity. Instead of adding lead I would add two marine batteries. This is good weight in a sailboat. Weight added to one end of the boat and up high as in an outboard is bad weight.

You, again, seem to have made up your mind before you asked the question. Flat bottom boats derive most of their stability from their form, not ballast. All the added weight will degrade sailing performance and will be lost should you ever swamp the boat (it happens). Some sailboats use "funny" shaped keels so that they can have the same righting moment but minimize the weight. I can't envision a 25 pound outboard on the transom being worse than 150 pounds (or more) of batteries, generator, and charger in the bottom of a flat bottomed boat.

Two batteries, a generator, a battery charger, and a trolling motor are not in keeping with the KISS principle.

In all fairness though, my boat had 6,600 pounds of lead bolted to the bottom. I was very careful when I unbolted it and lifted the boat off to reseal it as the factory's job left a bit to be desired. It leaked!

To each his own.

Cheers,

Gus