Operating fish finder using lithium battery

[Bugeyes]

I have always had my fish finders attached to my starting battery.  When I am vertically jigging, trolling or fligging I like to leave the fish finder on.  If I leave the fish finder on longer than ~3 hours I get concerned about running the battery down too low to start the outboard, so I usually switch off the fish finder.  I always carry jumper cables and a jump-start battery, so I am well protected, but I still prefer to not take any chances.  I am going to begin using a separate lithium battery to power my fish finder.    I currently have a Humminbird HELIX 9 Chirp MSI GPS G3N fish finder.  I'm not sure how powerful of a battery that I need to install.  I realize how bright I have the screen has a major impact on power draw, so I try not to have the screen any brighter than necessary.   Does anyone have any experience in how long a 50 Ah would power my Humminbird?

Your max draw with that setup is 2.9 ah. You'll have 45 usable amp hours in a 50 ah battery. You'd have 15.5 hours of run time in a worst case scenario. Real world you'll never use it all in a day. Lithium is awesome! Enjoy!

[wiperhunter2]

Wiperhunter,  Why not take the Li batteries to a battery store and have them tested?  It might be that one is bad and is draining the other one.  Or both might be bad (having been put on an improper charger prior to you buying your boat.  Something isn't right.  That set up should last at minimum a LONG day (8+hours) or even two days.  You need to get the batteries load-tested.  Voltage might be fine, but under a load they could be bad.  Also I looked up your brand of Li battery and that company went out of business in Jan 2025 according to their Facebook page.

Thanks Scott, so can any store that sell batteries test them, like Auto Zone? Not good, them going out of business.

[Mildog]

The one losing charge is concerning should not lose much if no load on it. I’m having the same issue with one of my newer batteries. I did all the things suggested and nothing changed, customer service says they will replace battery. I didn’t want to wait for back and forth to get replacement so I have new one in the way. And then will return bad one. Customer service said they would refund when mine is returned?
It was draining without any load read 23% when other was 63% after long day of use , then it dropped to 20% the other still remains at 63%. I wanted to drain it, then it read 99% without charging it?? Not possible voltage said otherwise. I wanted to drain it to return (safer) put a lamp on it drawing about 8.5 amps , said it would take 12.5 hours to use the charge up. It was steadily reducing capacity, got down to reading 55% after about 4 hours then it just died and read zero!! Something messed up with it. Hope replacement and other battery remain good?? Time will tell. So far customer service and warranty seem good!

[wiperhunter2]

The one losing charge is concerning should not lose much if no load on it. I’m having the same issue with one of my newer batteries. I did all the things suggested and nothing changed, customer service says they will replace battery. I didn’t want to wait for back and forth to get replacement so I have new one in the way. And then will return bad one. Customer service said they would refund when mine is returned?
It was draining without any load read 23% when other was 63% after long day of use , then it dropped to 20% the other still remains at 63%. I wanted to drain it, then it read 99% without charging it?? Not possible voltage said otherwise. I wanted to drain it to return (safer) put a lamp on it drawing about 8.5 amps , said it would take 12.5 hours to use the charge up. It was steadily reducing capacity, got down to reading 55% after about 4 hours then it just died and read zero!! Something messed up with it. Hope replacement and other battery remain good?? Time will tell. So far customer service and warranty seem good!

Glad I'm not the only one having problems like this but what a painful way to learn about this new tech.

[talyn]

I have always had my fish finders attached to my starting battery.  When I am vertically jigging, trolling or fligging I like to leave the fish finder on.  If I leave the fish finder on longer than ~3 hours I get concerned about running the battery down too low to start the outboard, so I usually switch off the fish finder.  I always carry jumper cables and a jump-start battery, so I am well protected, but I still prefer to not take any chances.  I am going to begin using a separate lithium battery to power my fish finder.    I currently have a Humminbird HELIX 9 Chirp MSI GPS G3N fish finder.  I'm not sure how powerful of a battery that I need to install.  I realize how bright I have the screen has a major impact on power draw, so I try not to have the screen any brighter than necessary.   Does anyone have any experience in how long a 50 Ah would power my Humminbird?

For the last three years I have been running my Helix 10 Mega SI DI G2N on a LiFePO4 12.8V 20Ah when icefishing. I set the unit to ice fishing mode and after 8hrs on the ice the battery indicator on the fish finder still shows a full battery. I have never had a problem running 8 hrs on the 20 Ah battery so 50 Ah will last all day.

[Bduck]

I'm in the learning stages of using a LI battery. I installed a 24V battery to operate the new Minnekota bow mount. I added a battery monitor to watch for power drawdown. I've yet to get this new setup on the water and won't anytime soon. The link provided is the monitor installed. 

Amazon.com: Renogy 500A Battery Monitor with Shunt, High and Low Voltage Programmable Alarm, Range 10V-120V up to 500A, 20ft Shielded Cable, Compatible 12V Lithium Sealed, Gel, Flooded Batteries,Black : Automotive

[wiperhunter2]

I'm in the learning stages of using a LI battery. I installed a 24V battery to operate the new Minnekota bow mount. I added a battery monitor to watch for power drawdown. I've yet to get this new setup on the water and won't anytime soon. The link provided is the monitor installed. 

Amazon.com: Renogy 500A Battery Monitor with Shunt, High and Low Voltage Programmable Alarm, Range 10V-120V up to 500A, 20ft Shielded Cable, Compatible 12V Lithium Sealed, Gel, Flooded Batteries,Black : Automotive

That looks interesting Roger, do you know how it connects to your batteries? Is it a direct connection or wireless?

[wiperhunter2]

I just got back from having my batteries checked at Auto Zone and sure enough, one of them was bad. Now from what was said here, I need to buy two more to have a matching set, is that correct? What if I buy the exact battery from the same company? Hopefully that is why the on board charger wasn't working on one of the batteries.

[Bduck]

I'm in the learning stages of using a LI battery. I installed a 24V battery to operate the new Minnekota bow mount. I added a battery monitor to watch for power drawdown. I've yet to get this new setup on the water and won't anytime soon. The link provided is the monitor installed. 

Amazon.com: Renogy 500A Battery Monitor with Shunt, High and Low Voltage Programmable Alarm, Range 10V-120V up to 500A, 20ft Shielded Cable, Compatible 12V Lithium Sealed, Gel, Flooded Batteries,Black : Automotive

That looks interesting Roger, do you know how it connects to your batteries? Is it a direct connection or wireless?

It connects directly to the battery Curt, Easy Peasy. I had to manufacture a small bracket using a double backing tape to mount in place so I wouldn't have to drill any holes. 

[gmwahl]

It appears to have Bluetooth monitoring?
A buddy bought a battery thinking it had Bluetooth monitoring from  wording on ad online. He couldn’t get it to work. Called the factory, turned out he purchased a non smart battery!! No Bluetooth monitoring!

It says right on the battery that it has bluetooth but I'll try calling them to make sure, maybe they can give me an idea why it isn't working. After charging both batteries individually, I now have it hooked up in parallel. After charging them separately, I rechecked the first one again and the voltage had dropped from 13.46 to 12.36. I'm not sure if charging them for 24 hrs was enough but it worries me that it drop at all.

 12.36 volts after charging, assuming that it is not under ANY load, would indicate a possible faulty cell.  It is normal for LiFePo4 batteries to go from 13.6ish down to 13.2 or SLIGHTLY lower, but 12.3 is not normal.  Is the other battery holding between 13.0 and 13.2 volts after you balanced them in parallel?

LiFePo4 batteries will have a very flat discharge curve and won't tip you off to being discharged (by being weak) until you are at the point of damage usually, and that is usually around 2-2.5 volts per cell.  A lead acid battery will discharge in a constant downward slope and you will know when you are getting close to discharge because the battery will get gradually weaker.  If you let a LiFePo4 battery go until it just stops, you may have damaged cells.  

Because those are smart technology,  I suspect that the battery BMS won't allow it to be either overcharged or drawn down too low and will have a cutoff, but it is still possible.  That may be why your battery is acting the way that it is.

Mike

[wiperhunter2]

It appears to have Bluetooth monitoring?
A buddy bought a battery thinking it had Bluetooth monitoring from  wording on ad online. He couldn’t get it to work. Called the factory, turned out he purchased a non smart battery!! No Bluetooth monitoring!

It says right on the battery that it has bluetooth but I'll try calling them to make sure, maybe they can give me an idea why it isn't working. After charging both batteries individually, I now have it hooked up in parallel. After charging them separately, I rechecked the first one again and the voltage had dropped from 13.46 to 12.36. I'm not sure if charging them for 24 hrs was enough but it worries me that it drop at all.

 12.36 volts after charging, assuming that it is not under ANY load, would indicate a possible faulty cell.  It is normal for LiFePo4 batteries to go from 13.6ish down to 13.2 or SLIGHTLY lower, but 12.3 is not normal.  Is the other battery holding between 13.0 and 13.2 volts after you balanced them in parallel?

LiFePo4 batteries will have a very flat discharge curve and won't tip you off to being discharged (by being weak) until you are at the point of damage usually, and that is usually around 2-2.5 volts per cell.  A lead acid battery will discharge in a constant downward slope and you will know when you are getting close to discharge because the battery will get gradually weaker.  If you let a LiFePo4 battery go until it just stops, you may have damaged cells.  

Because those are smart technology,  I suspect that the battery BMS won't allow it to be either overcharged or drawn down too low and will have a cutoff, but it is still possible.  That may be why your battery is acting the way that it is.

Mike

Thanks Mike. When I took it in to be tested they said the one battery was toast, the other one was good but can I even buy one battery to replace the bad one or do I need to buy two at a time for my 24 v system? From everything I'm reading on this thread, I'm guessing I should buy two but that will cost over $600, so I'm looking for a deal and so far, I'm finding nothing less than that.

[Mildog]

Don’t know anything about these brands Walmart and Amazon usually stand behind stuff??
about 300 Bucks for 2 with coupon, Amazon has 10$ off coupon on that one.

[wiperhunter2]

The top one I'm looking at, here is a link to the ones that look the best:
https://www.amazon.com/Lifepo4-Battery-L...9tdGY&th=1

https://www.amazon.com/TCBWORTH-Recharge...to_dp&th=1

[BearLakeFishGuy]

All those Li batteries are probably made in the same factory and have different labels or outside cases. If I were to switch to Li, I would buy the cheapest one from a reputable store or on-line store, so you can return them. Wal-Mart is my go-to since they are pretty hassle free when it comes to returns on just about anything. I saw several Li batteries on line for about $179/each for 100aHr or better.

[wiperhunter2]

Of the two brand names I'm looking at, the first one has the best rating and cost $338 total, for two 12 v, 100 ah Lifepo4 battery, with built-in smart BMS, lithium battery. The second one, cost $146 for each 12v lithium battery, same 100 ah Lifepo4 with BMS or a 24 v for $332.99 but in addition to the BMS it also has the bluetooth tech. both the 12 v or the 24v are the same brand name but has a slightly lower rating. I'm thinking the 24 v is better because of the bluetooth but I'm not sure. Both are from Amazon.

Edit: Just measured my battery compartment, it is 19" long at the most, and the 24 v battery is over 20" long, so it won't fit.

[gmwahl]

It appears to have Bluetooth monitoring?
A buddy bought a battery thinking it had Bluetooth monitoring from  wording on ad online. He couldn’t get it to work. Called the factory, turned out he purchased a non smart battery!! No Bluetooth monitoring!

It says right on the battery that it has bluetooth but I'll try calling them to make sure, maybe they can give me an idea why it isn't working. After charging both batteries individually, I now have it hooked up in parallel. After charging them separately, I rechecked the first one again and the voltage had dropped from 13.46 to 12.36. I'm not sure if charging them for 24 hrs was enough but it worries me that it drop at all.

 12.36 volts after charging, assuming that it is not under ANY load, would indicate a possible faulty cell.  It is normal for LiFePo4 batteries to go from 13.6ish down to 13.2 or SLIGHTLY lower, but 12.3 is not normal.  Is the other battery holding between 13.0 and 13.2 volts after you balanced them in parallel?

LiFePo4 batteries will have a very flat discharge curve and won't tip you off to being discharged (by being weak) until you are at the point of damage usually, and that is usually around 2-2.5 volts per cell.  A lead acid battery will discharge in a constant downward slope and you will know when you are getting close to discharge because the battery will get gradually weaker.  If you let a LiFePo4 battery go until it just stops, you may have damaged cells.  

Because those are smart technology,  I suspect that the battery BMS won't allow it to be either overcharged or drawn down too low and will have a cutoff, but it is still possible.  That may be why your battery is acting the way that it is.

Mike

Thanks Mike. When I took it in to be tested they said the one battery was toast, the other one was good but can I even buy one battery to replace the bad one or do I need to buy two at a time for my 24 v system? From everything I'm reading on this thread, I'm guessing I should buy two but that will cost over $600, so I'm looking for a deal and so far, I'm finding nothing less than that.

Your "good" battery will be ok with a new one as long as you are at more than 90+% or better of your rated capacity after a full recharge or cycle.  Below that and the old battery will draw on your new one as it attempts to equalize and balance and would accelerate the wear and degradation of the new battery cells.

Example being, if your old battery is rated for 100 amp hours and after draining it down and doing a full, deep recharge, or a series of cycle charges, you only have 90 or less amp hours capacity,  then you wouldn't want to parallel that with your new battery. I don't know if you have a charger that let's you know capacity or not....not too likely with on-board chargers, but a battery company can do a cycle test on it and let you know it's final capacity.

Mike

[wiperhunter2]

Thanks Mike, sounds like you have a lot of firsthand info on this subject. Glad to know I can buy just one instead of two. Is there a battery store that you can recommend that could check out my good battery, so I can find out where it is on it's final capacity?  I know Auto Zone had no clue, when I ask them.

[MrShane]

Of the two brand names I'm looking at, the first one has the best rating and cost $338 total, for two 12 v, 100 ah Lifepo4 battery, with built-in smart BMS, lithium battery. The second one, cost $146 for each 12v lithium battery, same 100 ah Lifepo4 with BMS or a 24 v for $332.99 but in addition to the BMS it also has the bluetooth tech. both the 12 v or the 24v are the same brand name but has a slightly lower rating. I'm thinking the 24 v is better because of the bluetooth but I'm not sure. Both are from Amazon.

Edit: Just measured my battery compartment, it is 19" long at the most, and the 24 v battery is over 20" long, so it won't fit.

Curt,
Not being able to fit the 24v is a mixed blessing.
If your main starter battery dies on you, you cannot simply connect to your trolling motor battery for a quick jump start if it is a single 24v.

[wiperhunter2]

Of the two brand names I'm looking at, the first one has the best rating and cost $338 total, for two 12 v, 100 ah Lifepo4 battery, with built-in smart BMS, lithium battery. The second one, cost $146 for each 12v lithium battery, same 100 ah Lifepo4 with BMS or a 24 v for $332.99 but in addition to the BMS it also has the bluetooth tech. both the 12 v or the 24v are the same brand name but has a slightly lower rating. I'm thinking the 24 v is better because of the bluetooth but I'm not sure. Both are from Amazon.

Edit: Just measured my battery compartment, it is 19" long at the most, and the 24 v battery is over 20" long, so it won't fit.

Curt,
Not being able to fit the 24v is a mixed blessing.
If your main starter battery dies on you, you cannot simply connect to your trolling motor battery for a quick jump start if it is a single 24v.

That's true but lucky for me the previous owner took care of that by installing 2, 12 v batteries in the back battery compartment. One for starting and the other for accessories. Downriggers, fish finders, etc.

[Mildog]

Update on my battery issue li -time asked me to charge and balance my two the try them out, the problem
Persisted, one battery draining much more than other, way out of balance. They said after I did that they would replace battery and send me a return label and replace battery when they get “bad” one back.
I told them I need it fast so I wouldn’t miss fishing time . They said I could order a new one and they would refund it to me when “bad” battery is returned. I got the new battery in 2 days. Printed label they sent me this morning and used box from new one to pack “bad” up, fed ex will pick up tomorrow . They covered return ship.
I got the new battery Friday charged both and balanced all seems to be working fine on first trip out all good. I Will get refund shortly I presume after they receive return. So for what it’s worth, the chat and email with li-time customer service has been very good, and they are honoring warranty!