Trickle charge?

I'm looking into buying a battery for my fishfinder (finally). What battery do you all use and would you recommend it? Also, I've read a little about providing trickle charges to batteries. What exactly does this mean? Does it keep enough power while out on the water, then once home you can charge the rest of the way?

I saw this at REI and was wondering if you think it would do the job...

http://www.rei.com/outlet/product/793401

I think I understand your trickly charge question.  No need to charge while out on the water.

Trickle charge means don't use a car battery charger on full for a charge if  you're using Sealed Lead Acid  batteries.  Use a charger than is <1A.  And make sure it has auto shutoff.

-Allen

Trickle charge is just a slow, continous charge.

Definition =  An electric charge supplied to a storage battery at a continuous low rate to keep it fully charged.

I have been happy as a clam at high tide with this one:



Its a "float charger" just to confuse the discussion a bit more 

Its designed for: 
    * Use on 12 volt batteries while in storage or during cold weather
    * Floating circuit maintains a full charge without overcharging
    * Automatic safety shutoff

(If you didn't already know it, that's a copy and paste from their page)

Is it the "right" one? I dunno But I've been putting my 7 amp-hour gel cell alarm/ups/deer feeder/ FF/GPS battery on it for the last 5 years or so after fishing and its magically recharged a day or two later. The best part is its $8.

   http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=42292

Now that there is a bargain ... why doesn't it surprise me that Wali is all over that.

-Allen