Fishfinder battery voltage dropping quickly

[mi327]

I have had a Lowrance Elite 5 HDI in my yak for a few years and for the past couple months I have noticed a big voltage drop on the fish finder as it is used. Using a 12V 10AH SLA battery the battery reads 12.4 - 12.5V when I first power on the fish finder. It used to be during a at the end of a typical 2-4 hour trip the battery would read around 11.5 -12V. Now I can watch the battery drop as I am fishing and it goes below 10V by the end, even worse I was at about 8.7 at the end of a 3 hour trip on sunday. From what I read that should indicate a fully drained battery if the voltage is that low. I have not changed any settings on the fish finder and I am using the modes I always use.

So far here is all the testing I have done.

I verified with a multi-meter that the voltage displayed on the fish finder matches the voltage at the battery terminals. This eliminates any issue with the wiring going from the fishfinder to the battery, since there would be a difference in voltage or no power if the wiring had an issue. To be sure I replaced the battery connectors as well. This also eliminates an issue with the fish finder not displaying the correct voltage.

I replaced the battery with a brand new one and the same issue occurs, and made sure the charger is properly working.

The only thing I can think of is the fish finder is now drawing more current for some reason and running down the battery quickly. The battery is rated at 1A discharge so it would make sense. Though I would assume if it was drawing too much power it would blow the 5A inline fuse. Any one have any experience with an issue like this, I think I have it narrowed down to the unit but want to be sure.

[J.A. Veil]

I had some of those symptoms several years ago. It turned out my battery was wearing out and could not hold its full charge for very long any more. I could watch the voltage drop until eventually the unit would shut off. Once I replaced it with a new battery, the symptoms stopped.

But your post indicates that you replaced the old battery with a new one. My only suggestion (and it is just a guess) is to try a battery rated for more amp-hours than the one you are using. That may give you a longer time before the voltage drops. Rather than buying a new one, maybe you can borrow one in order to try a test. Good luck.

[mi327]

I had some of those symptoms several years ago. It turned out my battery was wearing out and could not hold its full charge for very long any more. I could watch the voltage drop until eventually the unit would shut off. Once I replaced it with a new battery, the symptoms stopped.

But your post indicates that you replaced the old battery with a new one. My only suggestion (and it is just a guess) is to try a battery rated for more amp-hours than the one you are using. That may give you a longer time before the voltage drops. Rather than buying a new one, maybe you can borrow one in order to try a test. Good luck.

Thanks, I am wondering if the newer battery is the issue now, I did a test in the garage running the Fishfinder for 30 mins with the old battery, and the voltage only dropped from 12.5 to 12.3 volts which is closer to normal. I may still see if I can barrow a friends battery as well, though my battery is rated at 3amps draw which should be more then enough to provide the 1.1A max current draw stated in the manual.

If that doesn't work, I will track down a better multimeter (mine is only rated to measure up to 300mah) or ammeter and see what the actual current draw is and go from there.

[Steve6902]

A fully charged 12 VDC battery should be around 13.4-13.6 Volts. If you can only get the charge up to 12.5 than you have a bad cell. Time for a new battery. They only have a life expectancy of 3-5 years.
When you say that you replaced the battery with a new one, is it one that you just purchased or was it one that was laying around?? Also have you tried a different charger??

[ronaultmtd]

(Fre shipping) I bought two AGM 12v9ahr batteries and swap one of them out after trip...recharge after every use...two years, no problems...798 Hummingbird side imaging combo...paid $20 apiece on EBay...and plan to replace when I upgrade to a 7 inch unit this year...and figure that replacing them every two years is a very economical way to go...the Alternative Lithium batteries are so expensive, you could buy five years of the AGM batteries for the starting price of the Lithium...and how long will the Lithium battery last? More than five years?

[Oldbayrunner]

Your unit without changing any of the factory settings draws around 1 amp so it is drawing what the battery discharge rating is. The problem is with lead acid the more times you run it past 60% capacity the shorter the battery life. The alternative; either buy a bigger battery which also be bigger and will weigh more or although more expensive buy a lifepo4 lithium, The voltage unlike a lead acid's voltage drop holds a constant 13.1 voltage until almost depletion, they are much lighter in weight and have significantly more recharge life. Not to be confused with lithium ion's bad rap of building heat, fire or explosive in water lifepo4 battery are much safer in that regard.

[Yak Fish]

You may want to check out a lithium battery. They cost more but they last longer. You can also use more of their capacity because their voltage remains nearly constant until the very end where it drops off sharply. Lead Acid drops off continuously from the moment a load is applied.

[mi327]

Thanks for the replies I am now leaning towards the charger causing an issue. The current setup worked perfectly for 3 seasons up to about Aug of this year, and the same issue occurs with a new and old battery so that is the only thing that I haven't tried. I would love to go to LIfePO4 but cost wise it is too high.

Any one know of a good adjustable current 12V charger? Something that could charge at around 2-2.5 amps for the yak battery, but I also want higher current options to charge other batteries.

[ronaultmtd]

Mike- after three years, I would seriously considered replacing the battery...$20 and free shipping on EBay...batteries do lose their function over time...even the expensive, light-weight Lithium batteries...I plan on replacing both of my batteries this season and they are two years old...I fish at least one day every week, sometimes several times a week, so my equipment gets used...I always have a fully-charged battery ready to go...I use a small plug-in charger designed for charging rechargeable lithium batteries that came with a battery I bought several years ago...takes a few hours but works good...

[mi327]

Mike- after three years, I would seriously considered replacing the battery...$20 and free shipping on EBay...batteries do lose their function over time...even the expensive, light-weight Lithium batteries...I plan on replacing both of my batteries this season and they are two years old...I fish at least one day every week, sometimes several times a week, so my equipment gets used...I always have a fully-charged battery ready to go...I use a small plug-in charger designed for charging rechargeable lithium batteries that came with a battery I bought several years ago...takes a few hours but works good...

Yes I did replace the battery in Sept when the symptoms started to appear with an similar battery. Issue occurs with two different batteries, one older and one new. That's what has me baffled is that it happens with a brand new battery the only thing I can think of is either the battery is not getting charged properly or something in the unit itself is drawing excessive current.

[ronaultmtd]

Mike: the question that hasn’t been answered is the new battery one you just purchased or is it one you have had a while just as a spare? If it is a brand new battery you purchased, then it seems the only other answer is your Head unit has picked up an issue internally, maybe corrosion or a component going bad...might be time to call Lowrance customer service...if it is within the five year window, Lowrance will give you significant upgrade credit to purchase a new unit at a real discount...

[mi327]

Mike: the question that hasn’t been answered is the new battery one you just purchased or is it one you have had a while just as a spare? If it is a brand new battery you purchased, then it seems the only other answer is your Head unit has picked up an issue internally, maybe corrosion or a component going bad...might be time to call Lowrance customer service...if it is within the five year window, Lowrance will give you significant upgrade credit to purchase a new unit at a real discount...

The battery was purchased in Sept when I first noticed the voltage drop, unless I happened to get a bad replacement battery as well. I may call Lowrance as well thanks for the advice, I would like to first get a ammeter on it so I can see about what the current draw is. That will allow me to confirm if it is the head unit or the battery before I call, and be able to tell the tech all the steps I took.

[john from md]

I have a color Humminbird and also use a 10AH battery. I find that wearing my polarized sunglasses causes me to increase the screen brightness and really bites into the battery life. My older B&W had less draw than the larger color unit and it is pretty noticeable. I am planning to look into getting a LifePo battery for next season. Providing the rain doesn't rain out the next season.

[NattyBoh74]

I don't know if you're interested but I have a brand new in box Nocqua 10ah battery for sale. I bought a larger battery, so if no one wants this I'll return it. I got it on sale at 112$, so you'll save a few bucks.

[ronaultmtd]

After upgrading Lady Luck by installing a Lowrance Hook2-7TS, and using it twice (love it, by the way) I pulled the trigger on a Dakota Lifepo4 12v 10ah battery...$99.00...looked at the other Lithium batteries, but decided to go with Dakota...I buy made in the USA whenever the quality and price is fairly close to imported merchandise...the Dakota is assembled in the USA from imported components...not quite made in the USA but close...and they have a big following in the kayak fishing community as does the Nocqua, the other battery that I seriously considered. Since I already have a lithium battery charger, I didn’t need to get another one...and make no mistake...do not use a SLA battery charger on lithium batteries...that is a no no...after four hours of full use my regular SLA 12v9 ah battery was dropping voltage but the Hook 2-7 TS was still functioning...I want a full day of power...