battery charger question

[SkunkedAgain]

I have never had a gas motor battery go dead from running accessories while fishing.

I have had this happen a few times (the most recent time was on Saturday, while sturgeon fishing).  Understand, that I am often anchored up, vertically jigging, or casting and fishing the bottom, for several hours and sometimes for an entire day, with a powerful fish finder running off of my starter battery.  This can also become an issue as the battery ages.  I always carry jumper cables on my boat and I also carry a "Micro-Start XP-10 Jump Starter Personal Power Supply".  With the jumper cables I can jump-start by using one of my trolling batteries (assuming they are not run down from using my Minn-Kota) or I can easily jump-start mine or someone else's boat.  The same goes for the Micro-Start (this is a high-end light-weight charger (can jump-start a diesel engine).

There are several possibilities that would cause that Kent.  Battery age would be one.  Amp hour rating of the battery would be another.  Weak output from boat motors alternator.  You may have a parasitic drain from an automatic bilge pump, radio, GPS, etc., that may all be operating without the engine running, or parasitic loads caused by a short in the electrical system.  In my 18 years of big boat ownership, that has never happened to me.

The best answer to eliminate that possibility would be go to a battery with a significant increase in amp hour rating.  There are a few available AGM batteries that run in the 250 AH range and cost $500 plus.  But you wouldn't need the jumper cables any longer.  

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This sounds like a good post to ask this question due to other comments, I am adding an additional ff this year, it's a Helix 9 with SI... I was planning on running it on my smaller ice fishing batteries, they are 10 amp hour... Will that be enough juice to run the day fishing?  I have made the mistake of running my finders on my other batteries  before and drained them between the electric motor and finder and had to hand start the motor to get back.. So I like to keep my main motor battery isolated so I have juice and also so I don't get motor interference into the electronics... Anyway I haven't run the SI before does it take more power than the regular 2D finders?  If so any guesses how much more?  2X, 3X just a guess is fine, don't need exact numbers just curious what to plan on... Thanks Jeff

Since the Helix 9 w/ SI is spec'd at a 1 amp draw, the 10 AH battery should technically run the unit for 10 hours.  It doesn't appear that this unit uses a touch screen to select functions, so you should be okay.  My Elite has a touch screen and the touch wouldn't work without me touching the negative battery terminal while touching the screen or I was hooked to a 12 AH or greater battery.

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As mentioned by KENTOFNSL I have heard of issues with Battery being drained by use of newer, multiple and or "high powered" electronics.  Many of the fishing professionals are using a dedicated battery now to power their electronic ONLY, finders, gps and 360 degree scanners. Often they only run the main motor to get to a spot and then fish ALL day using an electric motor. So the big motor is not charging it enough to cover what they have depleted. Also I have heard that a separate battery can help eliminate any potential interference that can occur when hooked to the same battery as your running motor?

Sorry; didn't mean to imply that it COULDN'T happen.  I'm sure it can and does happen.  But it doesn't have to happen with a good selection of components coupled with a technically sound design.  Buy a battery with enough AH rating and you won't need a separate battery to run the electronics.  A friends Ranger bass boat will run for 3 to 4 days off one charge of his 3 batteries used to power his 36 vdc electric motor.  He selected huge AH rated batteries throughout his boat and runs 3 sonars/gps units off the motor crank battery all day with the motor shut down most of the day and has never drained the crank battery to where it wouldn't start his 250 HP engine.  Use big enough batteries and you won't have problems.

Thanks Bob.... Sounds great... Jeff