# fish finder battery



## smithgh (Mar 29, 2010)

Hey Everyone,

I'm a long time reader of the forum this is the first time I've posted anything though. I have a 14' lonestar, I think it's a commander model. Don't know much about the boat, it came with little to no documentation, the title listed the manufacturer and model as unknown. No one that's seen it can tell me more than that they "think" it's a lonestar. I'm assuming commander is the model because it says commander on a plate on one of the seats.

Anyway, I could use some help understanding what size battery I can use to run my humminbird 587ci. I have a normal deep cycle marine battery in the bow of my boat that runs my trolling motor. The fish finder is near the stern, I could run some wire up to the bow battery but I'd rather not, the boat is unfinished so there's no good place to secure the wiring. Also I've heard that the TM may cause some interference with the FF. I tried running the fish finder off an old 12v security system battery that I had lying around. It's sealed and really small, seemed like a good option. The space is especially important to me, I don't want another full size marine battery. They're expensive, heavy, and take up space that I don't really have. The security system battery worked great for about 5 minutes then the FF shut off. I started the FF again and it only stayed on for 2 minutes. After that about 20 seconds. I'm assuming it drained the battery (or the FF was pulling more than it could handle). This doesn't really make sense to me because the FF only requires a 3amp fuse so it can't be pulling too much. Does anyone know where I can find a small, relatively inexpensive battery that could run this fish finder for at least 3 or 4 hours without harming the FF or going dead?

I think my dad has a battery that was used in some capacity on an air compressor, I might try that next. Just wondering if there are any battery experts out there than can help me understand what I need to look for in a battery to make sure that it will actually run the FF. I'd like to get out of the trial and error approach.

Thanks!


edit: Forgot to mention that I've read on here that some people use tractor and/or motorcycle batteries. I was thinking of that as an option also. Can anyone tell me how well they work with the color FF with GPS?


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## RivRunR (Mar 29, 2010)

Here's the thread when I asked just about the same question... https://www.tinboats.net/forum/viewtopic.php?f=5&t=12200

And following their advice, I now use a lawnmower battery for my H-bird 141c and it works great. Used it on about 5 trips now, and still haven't had to recharge it. If you've got a riding mower, just rob the battery for your next trip as a trial-run and see how it does, but I expect it'll work just fine.


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## redbug (Mar 29, 2010)

the lawn mower battery is the way to go. you could also use 2 6v lantern batteries in series to power it.
Rivrunr Remember if you don't charge the battery in between trips it may get a memory and not take a full charge. 
You always want to charge your batteries before storage


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## RivRunR (Mar 30, 2010)

redbug said:


> the lawn mower battery is the way to go. you could also use 2 6v lantern batteries in series to power it.
> Rivrunr Remember if you don't charge the battery in between trips it may get a memory and not take a full charge.
> You always want to charge your batteries before storage




I have my TM and cranking battery on a 2-bank charger...you think I should take my cranking battery off the charger and put the lawnmower battery for the front FF on the charger instead?


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## redbug (Mar 30, 2010)

i wouldn't go that far.. if you have a portable charger i would hook it up for a few hours 
it shouldn't take very long to charge it


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## RivRunR (Mar 30, 2010)

redbug said:


> i wouldn't go that far.. if you have a portable charger i would hook it up for a few hours
> it shouldn't take very long to charge it



ahhh, ok...thanks!


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## smithgh (Mar 30, 2010)

I did some additional research, figured I'd share what I learned. Most batteries have an ah (amp hour) rating. This is how long a battery will provide X amps of power for 1 hour. The old compressor battery that my dad had lying around is a 12v 7.5ah battery. Given that the installation for my humminbird 587ci suggested that I put a 3 amp in-line fuse between the battery and the powerhead it's pretty obvious that the device can't pull more than 3 amps. My suspicion is that it actually pulls less than 2.5 amps under normal circumstances. That way you're not too close to the ceiling when the device requires peak power. if my logic is correct and the 7.5ah battery is still in good enough shape to actually deliver 7.5ah, then my FF should run for at least 3 hours before it goes dead. I won't be able to take this thing to the lake and test it for a couple weeks. I'll let everyone know whether it works as expected or not. I'm hoping it will because the compressor battery is free. If it doesn't work I'll get a tractor battery because we know that will work.

Thanks a lot for the help!


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## redbug (Mar 30, 2010)

You can test it in the garage... you wont hurt your depth finder having it on and out of water.. it should be fine 
I know that with 2 6v lantern batteries you can run a depth finder for several trips without replacing the batteries
good luck


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