12 volt power supplies

Just wondering what folks use for powering a fish finder.  Surely someone has a slick new battery set-up or something? 

There are several options including gel-cell batteries or a set of rechargable AA's.    The trick is you want enough voltage (usually between 10 and 14 volts) and enough amp hours to keep your fish finder running.    A normal fish finder runs at about 150-200 mA, so a battery like a gel cell rated at 3 amp hours will run a normal fish finder for 15-20 hours.
A battery set up using enough AA's to get 12 volts and are rated at 1200 miliamp hours will run the fish finder for 6-8 hours.

Both are plenty of power for a day's fishing.  I'm sure someone could rig up a solar panel to do on the water charging of the battery and get a longer life out of a lower Ah batter if you wanted something really slick.

You could also look into smaller batteries used for running RC cars and planes, but they tend to be expensive relative to larger batteries.

Brian

Yeah man, what B said.

A few links.
http://www.all-battery.com/index.asp?PageAction=VIEWPROD&ProdID=1590
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2160
http://www.thomas-distributing.com/maha_2700_rechargeable_batteries.php

Z

I'd have to interject that what FF you are running makes a difference.  I am able to run my Cuda 168 (basic B&W FF) off 8 AA batteries for about 7 outings (~7hrs/outing).  The whole setup ran me something like $5 and works like a champ.  I even use cheapo Rayovac batteries.

I may switch to a gel cell brick depending on what GPS system I end up getting (a must w/ the Lowrance XOG or Nuvi 500)

I'd have to interject that what FF you are running makes a difference. 

Very true.
NorCal's Fishshim broke it down like this.

Look up your Fishfinders "Current Draw", example Humminbird model 717= 250 mA.

Multiply the current draw by the hours of use you want,ie 10hours x 250mA=2500mA or 2.5Ah.

Or take a known battery size 3.4ah(3400mah)and divide by current draw 250mah=hours of use. ie 3400mA divided by 250mA =approx. 13.6 hours of use.

Examples of size-weight-cost

The least expensive is a sealed lead-acid battery.     12volt- 3.4aH, 2.87lbs., $21

Next up the list would be a NIMH battery pack.         12volt-3.8aH, 1lb.6oz., $39.95

Cutting edge but muy expensive LiFePo4 pack.          12volt-3.0aH  .95lbs.,  $75.50

 The LiFePo4 is supposed to have a much longer lifespan.

Wow!  Thanks for all the info guys.  My ff is the Cuda 250 w/ gps and the current draw is 250 ma with all the lights on.  Somewhere I had it in my head I needed a 7 amp battery, but I like the price of the first one Z listed at 3.4 aH.  Lighter load too.  This will be a fun project to get done and use.  Thanks for the help everybody.

Check you FFs.  Some run well in excess of 12V ... sometimes up to 18V.  If you are using the AA battery pack, you can chain more of them in series, get a higher starting voltage, which will result in longer run times.

-Allen

OK folks.  Another question.  Got my power supply up and the ff / gps works, but I left out the positive side fuse.  Is the fuse critical for an application where the power supply is a 12 volt 7 amp battery?

OK folks.  Another question.  Got my power supply up and the ff / gps works, but I left out the positive side fuse.  Is the fuse critical for an application where the power supply is a 12 volt 7 amp battery?

not critical...cuda 250 can take up to 17 volts.  The only thing it will do is make you feel better. You'd be hard pressed to find anyone that had there finder ruined from the snall batteries we use.


Note: I am not recomending you don't use one, just not critical that you do.......

Regarding fuses ... if you already messed up something enough in your FF that the fuse would blow, then the FF is already messed up.  I think the fuses are good for a larger electrical system like you would find in a bigger boat as they would prevent you from messing up anything else in the system.

I don't use a fuse.  I've never had my FF blow up because I didn't use one (I've never had one blow up for any other reason either).

-Allen

Thanks guys.  Confirms my suspicions.  Last thing I need is to ruin the thing before I can use it.

inline fuses are usually put in place (along with circuit breakers) to protect the wiring rather than the load...that being said the amount of wiring you are using and the small possibility of a direct short between the 2 makes it pretty unlikely you would have any problems...but if you got a fuse laying around and you got five minutes might as well put it in right? put it as close to the positive terminal as possible

at least you have less chance of a battery explosion in the event that you do get wires shorting together

Here's another suggestion if anyone wants it...
This is the setup we used at the kayak shop in San Diego I worked at(sorry, plug alert...)

http://www.kayakfishingsupplies.com/servlet/the-Batteries-and-Battery-Boxes/Categories

I use this setup to power a cuda 168, pump for live well and fish sprayer, and guys also used it to power deck lights.
It requires a battery charger (Home Depot usually has something that will work) and a electrical marine plug fitting(included in the package).
It's completely waterproof and built to last. It is a bit heavier that some of the other suggestions but it does have a nice carrying handle since it is a Pelican Case.
Hope this helps!
Cheers!

This is what I went with.  Something like $36 including shipping.  More than enough power for my Cuda 250 and probably a few accessories if ever the need arises. 


http://www.cabelas.com/cabelas/en/templates/links/link.jsp?id=0036388018049a&type=product&cmCat=SEARCHFEAT_all&returnPage=search-results1.jsp&Ntk=Products&QueryText=battery&sort=all&Go.y=0&_D%3AhasJS=+&N=0&Nty=1&hasJS=true&Go.x=0&_DARGS=%2Fcabelas%2Fen%2Fcommon%2Fsearch%2Fsearch-box.jsp.form23&_dyncharset=ISO-8859-1

You don't need it to protect the FF, you need it to protect against a short circuit. Even 8 AA batteries that are shorted will create a RED HOT cutting wire, melting thru your hull! Inline fuse holders cost about 2 bucks and take less than 5 minutes to rig up. It takes longer to get the beer needed for a proper installation!