FF Battery Issues

Help!  I continue to have issues with my Garmin 400C color fish finder.  I'm using a Werker 12 volt 8 AMH battery that I bought from a battery store in Dublin.  I thought I was having a problem with the FF but it has become clear that this is a battery issue.  After using it for about 5 hours yesterday, the display froze up and started displaying weird messages.  This is the third time I have had this issue and have even had the FF replaced by Garmin.  The battery I'm using is just like the ones Cabelas sells that many of you use.  I checked the battery with a volt meter this morning and it was down to 10.3 volts after yesterday's use. I'm pretty sure that's why the FF is acting up since it requires 12 volts.  I'm wondering if the battery is bad or if I'm just expecting too much from a battery of this size and should "trade up" to an 18 AMH battery.  I'm also wondering if my charger might be the problem.  It's an old automatic automotive battery charger.  I can see the gauge drop to almost zero after the battery has charged for a while.  I have been leaving the battery connected to the charger to maintain.  I would really like to continue to utilize an 8 AMH battery due to its size and weight versus the 18 AMH but I don't want to buy a new one and have the same problem.  Has anybody else experienced this issue?  I don't think I could ever go back to a black and white screen after getting used to the view from this one but I need a better power solution for sure.  Any suggestions???

Almost assuredly your battery is going bad.

What is the charge rate on that automotive charger you are using?  How much current does it supply? I'm going to guess you are charging to fast with it and that has caused your battery to go bad.

-Allen

Sounds to me like you might have a bad cell in the battery.  Also, that battery is so small, it will not require a great deal of charging current to charge it and overcharging with high amperage will hurt the battery.  Make sure you sharger has a "trickle" mode or "maint" mode that only allows like .8-1.2 amps of charge during this mode.  Even that is quite high for a battery of that size.  I try to charge mine using a battery maintainer as the charger.  Applying too much amperage will cause batterries to heat during a charging cycle.  Being a sealed battery, damage can happen. 

i use that little chap trickle/float charger from harbor freight. I even replaced the clamp on leads it comes with and use the female connectors that fit the battery....never had an issue and I have left it on the charger for days at a time.

 http://www.harborfreight.com/automatic-battery-float-charger-42292.html

Thanks guys.  I just ordered a new battery and a small trickle charger that's designed for the battery. 

Martin

Still curious as to what kind of charger you were using.  Can you provide a make/model number?  I'll look up the specs and give feedback on what may have gone wrong.

-Allen

According to the manual:

http://static.garmincdn.com/pumac/Fishfinder400C_ENOwnersManual.pdf

the Garmin 400C draws 21W max at 12V, so that is a 1.75A current draw. Your 12V 8Ah battery is only rated to support that load for 4.57 hours. During which time its voltage will steadily decrease until the fish finder craps out at around 10V.

According to the manual:

http://static.garmincdn.com/pumac/Fishfinder400C_ENOwnersManual.pdf

the Garmin 400C draws 21W max at 12V, so that is a 1.75A current draw. Your 12V 8Ah battery is only rated to support that load for 4.57 hours. During which time its voltage will steadily decrease until the fish finder craps out at around 10V.

Interesting.  I didn't know any FF drew that much current.  Even high end ones with lots of bells and whistles from other manufacturers barely draw 1/2 that.  I'm going to have to start bringing an ammeter to events and taking some real world measurements on various FF's.

-Allen

My color lowrance draws about 17x less power!  U sure that's a Garmin, not Gremlin?

~Bill

Damn!  I guess I'll cancel the battery and trade up to an 18AMH.  The Garmin FF has lots of features that I don't use that may be the "power hog" issue.  I know it can be interfaced with various other marine electronics and there are a ton of wires that don't get connected to anything when just the basic FF is used.  Can I expect to get about twice the time from an 18AMH battery?  If not, is there a better solution?  Thanks for all of the input.

Allan:  The charger is a Schauer 0132-02 BR 312.  I think I bought it at least 25 years ago.

Allan:  The charger is a Schauer 0132-02 BR 312.  I think I bought it at least 25 years ago.

Yeah, like I'm going to be able to find a datasheet on that.   

-Allen

Damn!  I guess I'll cancel the battery and trade up to an 18AMH.  The Garmin FF has lots of features that I don't use that may be the "power hog" issue.  I know it can be interfaced with various other marine electronics and there are a ton of wires that don't get connected to anything when just the basic FF is used.  Can I expect to get about twice the time from an 18AMH battery?  If not, is there a better solution?  Thanks for all of the input.

Allan:  The charger is a Schauer 0132-02 BR 312.  I think I bought it at least 25 years ago.

A 18Ah battery is rated to support that load for 10.29 hours, so a little more than twice your current running time.

1.75a sounds like a lot. My Humminbird 597 dual scan draws .5-.7a.
Martin, you should test the draw to confirm, then you can decide what capacity you'd need base on how long you need it to last.
Please also note that batteries are over rated. If your battery holds 80% or more of the rated capacity, they're considered good, especially true for small batteries.
Nowadays you have many battery options. Lead acid don't hold the charge very well, and has large voltage sag. I've been using a 5ah Lithium Polymer battery for my ff. It lasts me 9-10 hrs.
Anyhow, there are pros and cons for every type of battery. If you're interested in testing your battery/ff/charger, I'll be happy to help you check them out and give you some suggestions. I play with batteries quite a bit.

ernest

Damn!  I guess I'll cancel the battery and trade up to an 18AMH.  The Garmin FF has lots of features that I don't use that may be the "power hog" issue.  I know it can be interfaced with various other marine electronics and there are a ton of wires that don't get connected to anything when just the basic FF is used.  Can I expect to get about twice the time from an 18AMH battery?  If not, is there a better solution?  Thanks for all of the input.

Allan:  The charger is a Schauer 0132-02 BR 312.  I think I bought it at least 25 years ago.

A 18Ah battery is rated to support that load for 10.29 hours, so a little more than twice your current running time.

Not exactly.  It's not a linear equation.  You can't just do 18/1.75.  Batteries are rated (and optimistically at that) according to what current they can supply for 20 hours.  So an 18Ah battery can supply a 0.9A load for 20 hours.  But that doesn't mean that it can supply a 1.8A load (twice 0.9A) for 10 hours (half of 20).  It will in fact last less than 10 hours, maybe 9-9.5 hours.

And as Ernest points out, most battery ratings are over rated.

I'm still really curious about the 1.75A load.  It really doesn't strike me as correct.  Perhaps a call to Garmin is in order.

-Allen

I looked up the Garmin 400c ,21watt power draw-1.75amps!
What a power Hog, color does draw more but that is a lot.