Fish finder battery question

Have you guys noticed any differnce in brands? Is there one with a longer useable life?

I run the 9ah sla

I am waiting on my maxx life battery.  22 bucks from amazon.  Ita 9ah. And is a AGM battery.  Im not sure what the fish finder needs.  But i think it can run as low as 5amps.  Many buy 7amps and last all day.  So i figure the difference in price and weight is minimal.  9amps should last me all day and then some.  Is your battery not lasting all day?   If it last a year.  Im ok with it.  A hassle but i spend 20 bucks on other nonsense. :/

I think I've typed this up here before but here it goes again.

To find the right battery for YOUR particular setup you simply need to know your total electronics current draw (in aH).

Something important to note about these 12v Deep Cycle AGM SLA batteries is that for them to stand the test of time you shouldn't discharge them past 50% of their rated capacity.  Doing so will lead to the battery not accepting a full charge and will eventually kill the battery all together.

For instance, my Humminbird 587ci HD DI has a max current draw of .55 amps per hour.  I wanted the fish finder to be able to last me a full 16 hours on the water without dying.  Therefore:

16 hours multiplied by .55 amps per hours equals = a total use of 8.8 amps for a full day of fishing.  Sticking to the 50% charge rule means I need a battery with at least a 17.6aH rating in order to provide the power I need and not kill my battery or decrease its life span.  I currently run a 22aH battery in my Pro Angler and have had the same battery for the last 4.5 years.

Also, to further see that I always have power when needed over multi day trips I purchased a Deltran 1.25amp Battery Tender instead of using the little cheap chargers that are often sold in big box stores with the batteries.  Those little chargers are generally rated for charging at 500MaH.  That would take 22hrs to charge my battery back to full if I had drained it to the 50% point.  My Deltran Battery Tender can charge my battery back to 100% in only 8.8hrs which to me equals a good nights sleep in between long fishing days!! LOL
 

  Or spend the $$$ and go lithium.       

Ive heard horror stories about lithium

So at 12w  (.9A @ 13vDC) i need an 18aH battery? For 10hours

My preference is LiFePO4

This is what I run on my Elite 4...
http://www.frys.com/product/6703015?site=sr:SEARCH:MAIN_RSLT_PG

Another good option is...
http://www.batteryspace.com/lifepo4-battery-12v-9ah-108wh-18a-rate-with-led-indicator-replace-sla-12v-7ah-lighter-weight-and-higher-capacity----un38-3-passed.aspx


Like Baitman said $$$

So at 12w  (.9A @ 13vDC) i need an 18aH battery? For 10hours

If it's 0.9ah, then 10 hours will take 9 amps. Am I missing something?

Ive heard horror stories about lithium

Rumors spread by noobs who don't take care of their batteries. There are Pros and Cons on any battery, but with care, lithium's benefits far out weight SLA.

  Or spend the $$$ and go lithium.       

I just picked up this unit for $59 on Amazon.

RAVPower 15000mAh Portable Power Bank Pack.

Mike

I just picked up this unit for $59 on Amazon.

RAVPower 15000mAh Portable Power Bank Pack.

Mike

How does this help for a fish finder battery? It only has 5v USB outlets from what I can see.

Yep, your math looks about right.  Many people will tell you it's not needed and that you can use the little 9aH batteries.  Those small ones will work for a bit but you'll have to replace them before long b/c they just aren't meant for that kind of work.

So at 12w  (.9A @ 13vDC) i need an 18aH battery? For 10hours

If it's 0.9ah, then 10 hours will take 9 amps. Am I missing something?

Ive heard horror stories about lithium

SLA AGM Deep cycle batteries aren't meant to be discharged below 50% of their rated capacity.  They'll perform for a bit but if you do this continually you'll kill the battery to the point that it will start not lasting a day on the water and then it will eventually stop accepting a charge.  So if your fish finder needs 9aH for a full day of fishing then you need to double that amount when searching for a battery to run it in order to not discharge it past 50%.

Oh. I see why 18ah. I agree you should discharge SLA to more than 50%. Well, no such problem with lithium. The absolute no-no is never discharge a single cell lithium to 2.5v (from 4.2v max). You get roughly 2% capacity left when the cell reaches 3.0v. I use almost all of my pack's rated capacity without any damage or memory issues with my Lipo packs. I do that a lot, and I've been testing my lithium batteries for years. The deterioration rate for lithium is nothing like lead acid. You'll be lucky to get 70% of the rated capacity from an SLA after 6 months of use or in storage. AGM is slightly better, but still deteriorates much faster than lithium.

I'm not trying to promote lithium batteries. Like I said, each type of battery has its Pros and Cons. I carried a fully charged AGM battery to the Islander trip two years ago. When I tried to use it the next day, it was dead. That battery was less than a year old. Needless to say that was the last time I used an SLA.

I'm about to replace mine just for good measure but as I mentioned that battery is 4.5 years old and has been used HARD!!!  Also, the Deltran Battery Tender I use goes into a maintenance mode once the battery is fully charged.  This keeps the battery from being "burned out" by overcharging it.  Since I'm picking up a second Pro Angler I'm thinking of trying the Deltran 2 Bank Battery Tender and will use my current charger as a backup.

Lithium ion batteries definitely seem to be where the future of batteries are going.  I love the lighter weight and smaller foot print but I would sure like the price to come down some as well as I dislike the expense of having to replace all my current chargers since the lithium ion batteries require a special charger.

Just FYI. My IMAX B6AC smart charger costs $43. It can charge anything. My 5ah 4S Lipo battery costs $35 on sale at HobbyKing. That's not much more than SLA if any. 5ah not enough, get one more. You can fully discharge these cells with no damage and no memory effect. Good luck.