Solar charging batteries two fold question

[timo5150]

I am doing a winter project building a 12 foot Sevylor raft. I plan on my wife, daughter, and myself being able to fish from it. I am putting in a floor, front, middle and rear deck for seats. Most of our fishing will be in lakes but they often have a fair amount of wind. I am looking at the Minn Kota 45 to 50 lbs. thrust motors. 1st question will this thrust range be enough for these conditions? I have a 15 watt solar panel that I was thinking about mounting on the back of the boat. It charges via a 12 volt cigarette lighter attachment which I can plug into the Minn Kota battery box I have. 2nd question can I charge the battery with the solar at the same time I am running the motor? Sorry 3rd question is there any danger of harming the motor doing this. Thanks in advance for any help with this, I am new to trolling motors.

 

[NYBo]

Re: Solar charging batteries two fold question

Welcome to iboats!

It's going to be awfully crowded with three in that boat; fishing is going to be very tough.

If you want to stay with a 12v motor, 55# is the maximum you can get, IIRC. Any larger will require 2 batteries. With an inflatable, you want he most you can get, so a 50# would be the least I would go with in the wind.

If you think that small solar panel will extend your running time to any measurable degree, forget it. It doesn't put out enough juice to make a difference. It's also a bad choice for recharging the battery after use; it would take days of good sunlight if you've used the trolling motor for any length of time. No, there is no danger using the solar panel while running the motor, but it would be a waste of time.

 

[Silvertip]

Re: Solar charging batteries two fold question

Let's look at some numbers. 15 watts = 1.19 amps (15/12.6 volts). 1.19 amps will not light a bulb on your trailer tail light so it cannot possibly add to run time. A 45 - 50# trolling motor draws about 40 - 45 amps worst case. So to put this in perspective, for each hour you run the motor at worst case it would take over 40 hours of full sunlight to replace that power. At that output level, the panel could never fully charge the battery. And by "never" I really mean that! The panel cannot provide the output necessary to fully charge the battery. This is simply not a workable solution. You won't damage anything if you wish to try this but I can assure you, it is a wasted effort.