# Smaller Battery Option?



## Deep V 3654 (Feb 12, 2015)

I'm getting ready to wire my new boat up and I'm planning on using a small (6x4x2.5") Cabelas 12V 8AH battery. I don't use a trolling motor, bought LED nav lights, a single small LED interior light and and older Humminbird Matrix 35 FF. When I fish at night I don't use the lights much bc no one is ever around, so I think it should be fine. Has anyone had experience with using similar smaller size batteries? Think it will do the trick? It will fit nicely in the rear side positive flotation area of the boat which are only about 7 inches deep. I am planning on leaving room for a second identical battery (in parallel) in case capacity becomes an issue.

I'm going a bit overboard and (based on recommendations I read here) am using the Seasense 5 switch panel. The wiring is simple, same as everyone else has done. But I also want to hard wire the charger to the boat. The charger is a small wall wart AC/DC thing. I know I could hook up a sensitive ammeter to check, but does anyone think there would be a small phantom power draw from the wall wart when its not plugged into AC? I have an open switch and could always wire the charger through that in case, but didn't want to do that unless its necessary.

Any and all suggestions are welcome!


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## TNtroller (Feb 13, 2015)

I use a 12v deer feeder battery to power a Lowrance Elite 4 gps/ff on my yak, and it does the trick very well, have never run the battery down but I don't fish all day from the yak either, usually 4-5 hrs is it. Set up you lights and battery and see how long they will burn in test run if you are concerned but led lights are very efficient in terms of using juice.


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## JoshKeller (Feb 13, 2015)

for $25 i would get a lawn tractor battery from tractor supply. They weigh about 10 - 15 pounds, and will last several days running everything.


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## lckstckn2smknbrls (Feb 13, 2015)

JoshKeller said:


> for $25 i would get a lawn tractor battery from tractor supply. They weigh about 10 - 15 pounds, and will last several days running everything.


+1


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## Skiffing (Feb 13, 2015)

The LED lights are nothing - unless you have no battery left to run them.

What does the label say on the Humminbird Matrix 35 FF? It should say something like XX amp @ 12V or XX watts.

[This is not what the ducer produces - but what the unit consumes from the battery]

It probably consumes ~ 1 - 2 amps / hour [but double check]. With an 8 ah battery that gives you two to four hours of operation before you reduce that battery below 50%. If you discharge below 50% often the battery will be DOA very soon.


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## Deep V 3654 (Feb 19, 2015)

Thanks for the info. Couldn't find the current draw for my exact model but it looks like it'll be around 300ma and the LED lights around 250ma or so. That should give me more than 7 hours to 50 percent. I think I'll be good with one battery but will design in space for a second one in case I need it in the future.


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## Deep V 3654 (Mar 5, 2015)

As a follow up, here is the start of my small battery panel/shelf that I plan to mount inside the boat. It will be accessed via a 13x17 hatch. I made room for two batteries if needed and a place for the charger. Since I'm in the salt most of the time, I wanted to go with stainless steel for all the hardware.


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## Skiffing (Mar 6, 2015)

That's nice work!

What kind of boat is it going in?


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## Deep V 3654 (Mar 6, 2015)

Thanks. I've got a 14' MirroCraft Deep Fisherman. This is going to (hopefully) fit inside the narrow port side positive flotation bay, just forward of the rear bench seat as you can see in the photo.

To further complicate things I've recently convinced myself that I need a trolling motor...which I will set up on a separate isolated electrical system in a manner that can be relatively easily removed from the boat when not in use. I'm still suffering from sticker shock on the saltwater trolling motors! Where to begin?


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## cliff58 (Mar 7, 2015)

Deep V 3654 said:


> The charger is a small wall wart AC/DC thing. I know I could hook up a sensitive ammeter to check, but does anyone think there would be a small phantom power draw from the wall wart when its not plugged into AC? I have an open switch and could always wire the charger through that in case, but didn't want to do that unless its necessary.



Some chargers do and some don't, only a multimeter can tell you what yours does. If you have a Harbor Freight store nearby a meter can be had for 6 bucks, I have this one and its worked fine for 4 years now


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## slick (Mar 7, 2015)

In battery chargers there is a diode (I think this is the proper name) inside the charger to prevent backfeed. If there wasn't, when clips are hooked to a battery you would have 120 volts at the wall plug end. You may want to put it on a switch, but when you wanted to recharge you would have to remember to flip the switch AND plug it in. The phantom draw is minimal.


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