what battery for fishfinder ?

My method is a bit more expensive but is ultra light ...this pack runs my Lowrance DSI 5 color all day with the back light on 8....

http://www.amazon.com/Anker-20000mAh-Aluminum-Multi-Voltage-Technology/dp/B005NGLTZQ/ref=sr_1_11?ie=UTF8&qid=1447592807&sr=8-11&keywords=external+battery&refinements=p_89%3AAnker

I hope you realize that this battery is rated at 20a @ 3.7v only. It contains a single Lipo cell battery. Total power=74watt. Cost = $80. That's $1.08/watt.
This battery is $25. 4 cell Lipo. 14.8v @ 5a... http://www.hobbyking.com/hobbyking/store/__15521__Turnigy_5000mAh_4S1P_14_8v_20C_Hardcase_Pack.html
Total power=74watt. That's $0.33/watt.

Besides cost, if you're running 12v out of the Anker, it has to boost from 3.7v to 12v. Roughly 10% efficiency lost in the boost circuit is typical, meaning you will get ~66.6watt from your battery. Where as, if you're powering the your FF directly from the 4 cell Lipo, all power goes directly to the FF. You lose nothing.

Just saying.

I do not understand  electronics and the money is not important  but I can run my lowrance all day with a batt that is ultra light  that is what i care about .

I got 2 of those LiPos connected in series. http://www.hobbyking.com/hobbyking/store/__15521__Turnigy_5000mAh_4S1P_14_8v_20C_Hardcase_Pack.html
Thanks to you of course   I learned my lesson to stay away from AGM / SLA batteries and cheap chargers.  Ruins a day of fishing when your FF goes dead at around 4 hours.  I own Dragonfly 7 Chirp.

My method is a bit more expensive but is ultra light ...this pack runs my Lowrance DSI 5 color all day with the back light on 8....

http://www.amazon.com/Anker-20000mAh-Aluminum-Multi-Voltage-Technology/dp/B005NGLTZQ/ref=sr_1_11?ie=UTF8&qid=1447592807&sr=8-11&keywords=external+battery&refinements=p_89%3AAnker

I hope you realize that this battery is rated at 20a @ 3.7v only. It contains a single Lipo cell battery. Total power=74watt. Cost = $80. That's $1.08/watt.
This battery is $25. 4 cell Lipo. 14.8v @ 5a... http://www.hobbyking.com/hobbyking/store/__15521__Turnigy_5000mAh_4S1P_14_8v_20C_Hardcase_Pack.html
Total power=74watt. That's $0.33/watt.

Besides cost, if you're running 12v out of the Anker, it has to boost from 3.7v to 12v. Roughly 10% efficiency lost in the boost circuit is typical, meaning you will get ~66.6watt from your battery. Where as, if you're powering the your FF directly from the 4 cell Lipo, all power goes directly to the FF. You lose nothing.

Just saying.

If you go lipo,do your research and be safe.lipos have a reputation for catching fire and or exploding due to over charging

The video shows a lithuim-ion battery not Lipo.  FYI  most modern laptop, tablet, e-book reader, cell phone, MP3 player, cordless screwdriver or drill, etc. –  uses lithium-ion batteries.

LiPo (Lithium Polymer) batteries are widely used by 1000's of Radio Control hobbyist.  As SeaBird said these people are very critical of their batteries.   A custom made RC Helicopter can cost more than a fully rigged kayak.

Yeah I know but the danger is still there,I've got six lipo batteries for two trucks and two quads (drones) some get hot and others don't ,depends on size,capacity and so on.i just don't want to see a "warning post" later on down the line where half of someone's wall got set on fire due to a battery fire that's all.02 cents out

In the video the battery was being overcharged on purpose.  He even had a temperature gauge and knew it was overheating.  Its like constantly blowing air into a balloon till it pops.

For FF applications my Lipo batteries never get hot, in use and charging.  I have charged mine about 25 times. 
Modern chargers that cost about $60 have built in features for programming the adequate current for charging, time limit, measure Internal temperature, cut off temperature setting to prevent over heating.  During the charging process you can see critical information like; battery voltage, elapsed time and charged capacity. etc.  Specifically for LiPos if you put in the wrong settings the charger won't even turn on and forces the user to change his settings.  Some have Wifi so you have control on your cell phone.

My point is it all comes down to user knowledge and not buying cheap products that ships from overseas.  Its really not that complicated.  I figured things out in a couple of charges. My 2 cents.

I just go low-tech with the Remco brand SLA that came with the Lowrance kit. The little plastic shields over the battery posts fell off years ago. I just gooped some GOOP on there and carried on. Still working just fine. No waterproof box needed.

Browsing craigslist and found these batteries for sale in the Santa Rosa area.

https://sfbay.craigslist.org/nby/bpo/5540207575.html

That craigslist post sure looks shady... I hope they weren't stolen.


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Sounds like if you like to tinker the lipo or lithium is cool to play with but the sealed lead acid batteries are simple inexpensive and do the job.  I don't mind the weight if its a couple cool ones or a fish in my cooler.  And if your in a Hobie or similar you probably won't notice the extra 4 or 5 lbs.