Plan of attack for keeping my marine battery topped off

[WagoneerSX4]

I recently bought a Salter heavy-duty sport 360 12' inflatable boat and a 55lb of thrust trolling motor for putting around lakes that don't allow gas engines. I plan to get a 20hp four-stroke someday but for now I'm sticking with the trolling motor as my main means of propulsion. I plan to use it for remote camping trips that are going to be about a week long and I'd like to be able to spend a couple hours on the water fishing without worrying about having to row back to camp. I'm playing around with the idea of using two small marine batteries to double the amp hours instead of one big one but for simplicity sake lets say it's just one 120 amp hour battery. The motor uses about 55 amps per hour at full throttle, so technically I should be able to get a full 2hrs at full throttle out of the battery. At a top speed of maybe 6-8km/h that should be able to get me a pretty good distance if need-be.

I'm thinking of running a waterproof 15W solar panel on the boat (size restrictions makes 15W the max I want to bring along) and just always having it hooked up to the battery so it slowly charges while I'm fishing. In real-world situations I'm thinking it'll charge at about 1amp per hour. Will I see any extended range in the real-world with that setup or is it not worth it? With the math, even spending 3hrs fishing I'll only see 3amps of added power which nets me just a couple minutes of power, probably not worth the extra gear on the boat.

I'm also planning on getting a kit from solarblvd (or any other suggestions on a better place to buy one would be nice) that's 160W, foldable with carry bag, and comes with the charge controller as well. Anything above that the prices just sky rocket it seems. Again, in the real-world that'll probably get me 10amps per hour so it could probably keep my battery topped up every day as long as I don't completely discharge it. I think in perfect conditions it SHOULD do 14amps an hour but in Canada even in the peak of summer I don't think I'll ever see that. Will I be happy with this setup to keep the battery topped up or am I cutting it too close? My brother just purchased a small generator but I think my trailer is going to be as full as I'm going to want it with the addition of my boat packed in there.

Any suggestions or real-world experiences with this sort of thing would be muchly appreciated! TIA

 

[pugslyyy]

I would check the specs on whatever battery you get - the AH rating is different based on how rapidly you draw the power out. Also, don't forget that fully/deeply discharging a battery will greatly reduce it's life.

For your application, I'm not sure that either solar option would be that helpful.

Instead of a generator, what about just installing some high amp connectors and charging off your alternator?

This might be a buy cheap / flog / replace often scenario.

 

[WagoneerSX4]

This is exactly why I'm wondering about real-world experience because I don't want to just go off theoretical data and end up being disappointed. The performance of ever solar panel seems to be greatly exagerated.

As far as deep cycling the battery, my brother just has a cheap 100 amp hour marine battery to run his sleep apnea machine and he completely discharges it after 3 nights and he's had the same battery for 4 or 5 seasons now and it still lasts the same length. I think as long as you keep the water topped up and trickle charge it back to life they seem to last pretty long. But then again my dad runs two marine batteries in parallel on his fishing boat to run his bow mounted trolling motor and he seems to be going through batteries every other year. I think it really matters at the rate you discharge it as much as the rate that you charge it. He has 22' boat with a big trolling motor and sucks a lot of juice.

I don't think I was clear in my usage. I don't plan on discharging the battery every time I go out, I mean I plan on discharging it to a safe amount every time I go out and top it back off for the rest of the day. Completely discharging it will be a rare occurance (or rather i'm going to try to keep it rare).

Hooking it up the car would probably be a better idea than lugging the generator along. I guess I could always keep that idea as a back up.

 

[pugslyyy]

Hooking it up the car would probably be a better idea than lugging the generator along. I guess I could always keep that idea as a back up.

Yeah, generators are a good way of making AC. Your car already makes DC and at no extra cost to you (maybe a few cables/connectors if you want to get fancy)!

 

[WagoneerSX4]

I just found a few threads were people have installed plugs in the grille of their vehicle so you can just plug the battery in and start the car and voila. I really like that idea, doesn't get much easier. Thanks for bringing that idea up, that might be a way cheaper option. I have an SX4 with a little 4cyl so keeping it idling for a bit it uses next to zero gas, it's also very quiet. Definitely going to look into this option a little more instead of dropping $300 on a solar panel setup.

 

[pugslyyy]

Yeah, get some Anderson SB50 connectors and have at it - serves dual purpose making it easier to hook up jumper cables as well.

 

[WagoneerSX4]

Any links to a full kit? Fleabay just seems to be filled with DIY stuff.

 

[pugslyyy]

I just roll my own with these - http://smile.amazon.com/gp/product/B004KNFTI6

You can buy it already set up - http://smile.amazon.com/WARN-72886-48-battery-lead/dp/B000OV7EDG

Search "battery quick connect" for more options.

 

[WagoneerSX4]

Oh nice, I didn't know they were the same types used for winches. That should help with finding one, thanks again!

 

[WagoneerSX4]

http://www.amazon.com/Battery-Tende...sconnect/dp/B000NCOKZQ/ref=pd_bxgy_auto_img_y

Wondering if something like that would suffice with the other end having aligator clips? Doesn't specify the gauge of wire though. That typs of connector has a few other options as far as charging other things as well. Might be a bit more versatile with the sacrifice or not charging as quickly because of the smaller gauge.

 

[pugslyyy]

Oh nice, I didn't know they were the same types used for winches. That should help with finding one, thanks again!

I'm pretty sure that no matter how they are branded, they are Anderson connectors - http://www.powerwerx.com/anderson-powerpoles/powerpole-sets/sb50-sb-series-50-amp.html

They are available in a bunch of different configurations (Amperage, wire size, etc) - I like the SB50 (50 Amp) for charging / jumper cables but you can buy much larger ones. (If I were rigging a winch it would be a beefier one).

 

[pugslyyy]

http://www.amazon.com/Battery-Tende...sconnect/dp/B000NCOKZQ/ref=pd_bxgy_auto_img_y

Wondering if something like that would suffice with the other end having aligator clips? Doesn't specify the gauge of wire though. That typs of connector has a few other options as far as charging other things as well. Might be a bit more versatile with the sacrifice or not charging as quickly because of the smaller gauge.

That's for a very low-draw maintainer (think motorcycle or ride-on lawn mower) - not a bulk charger like you need.

 

[WagoneerSX4]

Yeah similar ones are listed as 14 and even 16gauge wire, WAY too small.

 

[Jeremy P.]

The 15 watt solar panel would not have enough output to be worthwhile, but the 160 watt setup would work nicely. I purchased the solarblvd 160 watt setup a few weeks ago and have been pleased with it so far. Replacing the charge controller that is on it with a MPPT charge controller would allow you to utilize even more of the output. Then you could use your vehicle as a backup charging source.

 

[wirenut]

If you draw 55 amps from a 120 Ah battery I doubt it would last 1/2 hour. That's a huge draw. There's a lot more math involved than just amps x time. You can google Peukert effect if you really want to read about it.
Most solar panels watt rating is based on 18v or so. That means a 15 watt panel is capable of .8 amps at best. That's not worth dragging it along. The best deal on solar panel is in the 220 to 270 watt range. They can be found for less than $1 per watt. They are a higher voltage panel, about 30v, so you will need a MPPT charge controller to work with your 12v battery.