MinnKota Gas Generator no-battery System

[zoe_lithoi]

Not being a big fan of batteries (having to keep them charged, they need replacing every 2 years) and having had to paddle back to camp before because the battery ran out of juice;
I decided to look into using a gas generator to run the DC powered Endura C2, 30 ft-lb thrust trolling motor.

MinnKota provided the following information to one of our colleagues here in this forum.

SPEED AMPS THRUST
1 8 4
2 10 6
3 14 10
4 20 15
5 30 30

MinnKota also specifies a Max Current of 50amps ---- presumably needed upon initial starting of the trolling motor.

My gas generator from Harbor Freight cost $89 on sale:
StormCat 60338 900 Peak/700 Running Watts, 2 HP (63cc) 2 Cycle Gas Generator EPA/CARB

For $85, is a DF 1767 Universal AC to 13.8V DC Converter Max 30 Amp.

https://voltage-converter-transform...universal-ac-to-13-8v-dc-converter-max-30-amp

Since 30amp is the 'max' output, it might not run the trolling motor very well in 5th speed (which requires 30amps); but you could always run it in 4th speed.

You would not ---need--- a battery.

There are positive reasons for using a battery.

There might be an issue with the trolling motor startup current which is 50amps max.

The gas generator is noisy (which may scare the fish and ducks away), so you 'could' start the day by using a fully charged battery to run the trolling motor, to quietly take you to your fishing or hunting destination. Then, at the end of the day, when you are ready to leave, hook up the Gas Generator and AC TO DC converter to the battery and now run the trolling motor.

How big of a battery would you need?

Suppose, though, that our trip their and back takes an hour each way, to just run off the battery. So we will need:

2 hours x 30 amps = 60 amp-hours

I --believe-- this is like a motorcycle battery.

What do you all think?

Toby

 

[ondarvr]

The HF generator is a low cost, intermittent use, probably short lived, loud and stinky choice for a generator, if you were serious on running the motor for long periods of time you would need to upgrade to something that is designed for that type of use.

Are you using the boat in places that don't allow gas motors? If not, use a small kicker, it will be a much better option.

 

[Scott Danforth]

Not to mention the inefficiency of generator. And the inverter. The inverter would not live long with a constant max load, and neither will the harbor freight genny at max.

A 2hp kicker would give you about twice the propulsion than your battery-less system you describe with better fuel economy, less weight, and the ultimate simplicity

 

[zoe_lithoi]

Hi Guys thanks for your response.
The reviewers of the gas generator claim they ran the motor for 4 or 5 hours straight.
I intend to run it for 1 hour straight getting to the destination and 1 hour back.
If we run the 800W Gas Generator at half max, we will output 400Watts = 120V * 3.3amps

Suppose the ac to dc converter, which outputs 13.5Vdc at 30amps max, is 50% efficient, then we will get:
0.5 x 120 x 3.3 / 13.5V = 15amps

15amps is 1/2 of the max output of the ac to dc converter.
15amps is 1/2 of the max power needed to drive the 30ft-lb MinnKota motor, ie, we will run it in 4th gear (which draws 15amps), instead of 5th gear (which draws 30amps).

So I think that addresses all your concerns except for the noise.
Toby

 

[ondarvr]

Report back on how it works, it may help others doing the same thing.