battery charger question

[r2u2]

I plan to purchase an onboard 3 bank charger. I use 3 12 volt batteries. One for the engine one for the depth finder the other for the trolling motor. What do you suggest, 15 amp or 30 amp. What has been your experience with brands?

Would it be cheaper to go back to the Bannana Boat?

Thanks,
RJ

[dubob]

@r2u2

I plan to purchase an onboard 3 bank charger. I use 3 12 volt batteries. One for the engine one for the depth finder the other for the trolling motor. What do you suggest, 15 amp or 30 amp. What has been your experience with brands?

Would it be cheaper to go back to the Bannana Boat?

Thanks,
RJ

That is an unusual battery configuration IMHO. I have 2 engines (drive motor & kicker motor) and both have their own battery. However, I use a BLUE SEA SYSTEMS SELECTOR MARINE BATTERY SWITCH like this:

It is always left in the 1+2 position so that both batteries are being charged if either motor is running. My sonar runs off this power source, not its own battery. While fishing, my kicker motor is always running and driving the boat forward in a straight line. There is no need to charge my motor batteries when the boat is out of the water.

I have a 24 volt electric motor up front that is used every fishing trip to steer the boat. I have a 2-bank charger that is plugged in and charging after every day of fishing. My 24-volt system will run for anywhere from 6 to 8 hours depending on the winds on any given day.

I guess I’m questioning why you have a separate battery for just your sonar instead of hooking the sonar to the boats power buss fed by your drive motors battery like every other boat accessory like boat lights, bilge pump, live well pump, downriggers, etc. A typical sonar will draw about 1 amp at 13 vdc and a Gp 24 battery (75Ah) will keep it going for at least 75 hours. Even if you don’t run the gas motor for fishing, you aren’t going to run the sonar 75 hours and make your gas motor battery dead for cranking the gas motor. I have never had a gas motor battery go dead from running accessories while fishing.

I would recommend you run the sonar off the gas motor accessory buss in the boat and buy a 1-bank charger for the electric trolling motor. Whatever current rating you buy will fully charge the battery overnight. If you really want to leave the sonar on its own battery, then buy a 2-bank. I can’t imagine you would be running a gas motor that doesn’t re-charge the crank battery while the gas motor is running. There is no reason I know of that would dictate charging the crank battery at home.

Even if you’re running a mudd motor type boat and don’t run the mudd motor to fish, you would still be okay to run the sonar off the crank battery. You never completely drain the crank battery. If your really feel uncomfortable doing that, then buy a 2-bank charger and charge the electric motor battery & crank battery after each fishing trip.

[Therapist]

What brand charger are you looking at? What is the cost? What type of batteries are you using? Questions you need to ask. An alternate method that a buddy came up with was to buy 3 Schumer 8 amp chargers at Wal Mart. Coupled with a
power strip, he built a charging system for under a $125 . Works like a charm, the chargers are smart chargers w/ auto shut off and maintain features which allow you to set it up and leave it on. Worth checking out!

[RockyRaab2]

I agree with dubob that having a separate battery for the ffinder is unnecessary - both for need and excess weight. The only time you might need to top off the cranking battery is during winter storage, and a cheap trickle charger would do that. For the trolling motor battery, a one-bank smart charger of 10 or 15 amps ought to be plenty.

[wiperhunter2]

@dubob

That is an unusual battery configuration IMHO. I have 2 engines (drive motor & kicker motor) and both have their own battery.
It is always left in the 1+2 position so that both batteries are being charged if either motor is running. My sonar runs off this power source, not its own battery. While fishing, my kicker motor is always running and driving the boat forward in a straight line. There is no need to charge my motor batteries when the boat is out of the water.

I have a 24 volt electric motor up front that is used every fishing trip to steer the boat. I have a 2-bank charger that is plugged in and charging after every day of fishing. My 24-volt system will run for anywhere from 6 to 8 hours depending on the winds on any given day.

I guess I’m questioning why you have a separate battery for just your sonar instead of hooking the sonar to the boats power buss fed by your drive motors battery like every other boat accessory like boat lights, bilge pump, live well pump, downriggers, etc. A typical sonar will draw about 1 amp at 13 vdc and a Gp 24 battery (75Ah) will keep it going for at least 75 hours. Even if you don’t run the gas motor for fishing, you aren’t going to run the sonar 75 hours and make your gas motor battery dead for cranking the gas motor. I have never had a gas motor battery go dead from running accessories while fishing.

I would recommend you run the sonar off the gas motor accessory buss in the boat and buy a 1-bank charger for the electric trolling motor. Whatever current rating you buy will fully charge the battery overnight. If you really want to leave the sonar on its own battery, then buy a 2-bank. I can’t imagine you would be running a gas motor that doesn’t re-charge the crank battery while the gas motor is running. There is no reason I know of that would dictate charging the crank battery at home.

Even if you’re running a mudd motor type boat and don’t run the mudd motor to fish, you would still be okay to run the sonar off the crank battery. You never completely drain the crank battery. If your really feel uncomfortable doing that, then buy a 2-bank charger and charge the electric motor battery & crank battery after each fishing trip.

Bob, I guess you have not got into fligging or fishing without running your two gas motors. I do that in the Spring and Fall most every year now, so I can understand what Richard is doing plus I sometime run up to three finders off one battery, one for a stand alone GPS and one for fish finder from the transom and the third from the bow for side scan, on my electric trolling motor. Two units running at the same time is bad enough but adding a third unit really draws the juice, so for that reason alone, having one battery for just my finders makes sense. That way I’ll never get stranded. This isn’t a problem if I run my kicker but it seems more and more I’m fligging, so this setup makes sense for my needs.
I have a two bank charger for my two electric trolling motor batteries, can’t remember the brand name for sure but it could be from Cabela’s. I run a second, single bank charger that I bought from Harbor Freight that is just for the fish finder battery. This setup works for me but my forth battery is just for my main motor and like you said, it charges that battery, so I don’t usually have to charge it.

[Tin-Can]

I only have 1 battery in my current boat. It charges off the motor when the motor is running, and during the winter I have a trickle charger (very inexpensive at Harbor Freight) hooked up to the battery.

My first boat (2004 Lund 1700 ProSport) had the main cranking battery of course, and storage spaces up front for 2 aux batteries that were pre wired to the electric trolling motor plug in the bow. That would have been great for a 24 volt trolling motor. But I had a 12 volt trolling motor, so I separated that circuit thru a Perco switch (much like the one dubob showed). I wired a 2 circuit volt meter so I could watch the charge in both aux batteries. I wired from the cranking battery to the console Perco switch and from the aux batteries in such a way that when running the big 115 HP motor I could select ALL on the switch, and the motor would charge all 3 batteries at once.
When using just the trolling motor, I would select Battery 2 or 3 individually and when one got down to about 8 volts, I would switch to the other one. That set up would give me about 4 to 6 hours of electric trolling in calm water. Then when I would start up the main motor, turn the Perco switch to 1+2, it would charge my 2 aux batteries while running. Never took long to top them right back up, so I never invested in a plug in charger bank .

[BearLakeFishGuy]

I run a NOCO Genius charger. I think a 15amp is plenty (5 amps/bank) for the three batteries. I keep mine plugged in all winter and it only kicks on when it is needed. I’ve never had any issues with this charger and for the cost, it was a lot cheaper than a Minn Kota or other big name charger. A NOCO 5amp x 3 battery charger was about $175. Whereas a 10amp x 3 battery was nearly double that cost. Unless you want your batteries charged quickly and have lots of money to spare, then the 5x3 is plenty.

[nofish2]

@r2u2

I plan to purchase an onboard 3 bank charger. I use 3 12 volt batteries. One for the engine one for the depth finder the other for the trolling motor. What do you suggest, 15 amp or 30 amp. What has been your experience with brands?

Would it be cheaper to go back to the Bannana Boat?

Thanks,
RJ

I run a Minn kota three bank charger. I really like it just plug it in at the end of the day and you are good to go in the morning. When the battery is fully charged it will switch to a trickle to maintain it.

I am not sure but I think my will change amp output depending on the charge needed. I gave $100 for it and have had it two years. I found it on ksl and it was new.

[Kent]

@dubob

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).

[dubob]

@wiperhunter2

Bob, I guess you have not got into fligging or fishing without running your two gas motors. I do that in the Spring and Fall most every year now, so I can understand what Richard is doing plus I sometime run up to three finders off one battery, one for a stand alone GPS and one for fish finder from the transom and the third from the bow for side scan, on my electric trolling motor. Two units running at the same time is bad enough but adding a third unit really draws the juice, so for that reason alone, having one battery for just my finders makes sense. That way I’ll never get stranded. This isn’t a problem if I run my kicker but it seems more and more I’m fligging, so this setup makes sense for my needs.
I have a two bank charger for my two electric trolling motor batteries, can’t remember the brand name for sure but it could be from Cabela’s. I run a second, single bank charger that I bought from Harbor Freight that is just for the fish finder battery. This setup works for me but my forth battery is just for my main motor and like you said, it charges that battery, so I don’t usually have to charge it.

Your correct Curt, I hardly ever still fish anymore. But let me provide a little more information on lead acid batteries (same holds true for Gel Cell or AGM batteries as well). Lets assume you are running a Gp 27 marine, deep cycle battery with a rating of 100 amp hours (AH). That rating is based on a standard that assumes a draw time of 20 hours will consume all 100 amps, or 5 amps per hour. Lets also assume that all three of your sonar/gps units will draw something less than 5 amps total. I’m going to guess between 3 and 4 amps would be about right. Since the draw is slightly less than 5 amps, then it stands to reason that the time it would take to consume the 100 amps the battery is rated at will be slightly longer than 20 hours.

100 AH/5 amp/hour draw = 20 hours

100 AH/4 amp/hour draw = 25 hours

100 AH/3 amp/hour draw = 33.33 hours

If you’re using a Gp 24 at a rating of 75 AH, then substitute 75 for 100 above and do the math. I doubt seriously that you would be fligging for that length of time and thus create a dead cranking battery. I’m not sure what outboard you have on your boat, but my Mercury puts out 50 amps which will recharge very fast.

There is a very good read at this link that explains a lot about batteries without a lot of technical jargon if you’re interested.

Battery Basics: A Layman’s Guide to Batteries

One last tip about batteries for use in marine applications. Make sure you use DEEP CYCLE RV/MARINE batteries only. Ordinary car batteries will die an early death when used in applications involving constant deep draw downs.

[SkunkedAgain]

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

[Mildog]

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?
In my boat I run a switch like Dubob showed. I have 2 AGM 12 V deep cycles batteries. I have a Single GPS Lowrance Finder that is hooked up through the switch. When I’m running and or trolling with my 50HP 4 stroke I keep it on both batteries and it charges them while I run or troll. If I am fishing using my electric 55 LB thrust 12 Volt to fish I always use battery 1 or 2 alone. So if I happen to drain one too much I always have a strong starter battery. I can fish for usually at least 3 or 4 days on the water and have good battery life to run everything by charging them from main motor while running and or trolling. I usually never have to worry about charging them. When I get home I set it to Both and charge them in that setting, the batteries are usually so close to fully charged that they are good to go in a few hours. I use an Auto charger that will stop charging and just maintain. I got it at Harbor Freight for about 30 Bucks’ It has worked great for many years with no issues. In the winter I keep them hooked up to a trickle charger (harbor freight under 10 bucks) and they are good to go in the spring. These batteries are about 6 years old and still going strong with lots of use. This is a smaller 17 foot aluminum boat so It might not work for others but this has worked great for me for years.
Mildog out

[dubob]

@kentofnsl

“dubob, post:2, topic:321387” wrote:

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.

---

“SkunkedAgain, post:11, topic:321387” wrote:

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.

---

“Mildog, post:12, topic:321387” wrote:

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.

[Anglinarcher]

I’ll chime in and move out quickly.

I think I understand the request. I use a 24V trolling motor system, 80 # thrust, so I have three batteries, two deep cycle AGM’s and one RV starting.

I had used a Cabela’s three bank charger for years. At the end of the day I just plugged the system in and let it top off each battery. It had an automatic setting. (two lead pairs were for one battery type, the third lead pair was for the starting battery) During the winter it was garaged and left plugged in where it would automatically do maintenance charging on the batteries as needed. The only issue was that the charger would go out about every 5 or so years, but the battery life was excellent.

When my son got my boat he had the charger go out so he bought another brand and I am not sure which one yet. I get my boat back at the end of the month. But, the Minn Kota three bank system does the same thing.

Different batteries do last and charge better if charged differently, i.e. AGMs and standard lead acid and gel cells all have different suggested charging voltage. The amperage is optional to a point, but charging a deep cycle at 50 amps is fast, but super hard on the life of the battery. Charging a starting at 50 amps is great, but doing it at 15 amps will work fine, just slower.

As for running a battery down with a fish finder, YEP, it can happen. I use to run my starting battery down all the time and jumping is fine (especially now that I have the Lithium Ion portable emergency device), but that was not the case 15 years ago. Many people using standard fish finders for ice fishing find that 4 to 8 hours kills the small batteries, but a fully charged and good condition standard sized group 24 or 27 deep cycle battery should last for days. I use to be able to tell how bad my trolling batteries were this way…and it was not fun. Still, with the newer fish finders with live view or panoptics and larger screens, more amperage is required. I bet that Jacob Wheeler (pro Bass Fisherman) could tell us about that because he has three on the front and one at the counsel.

So, if you are using a three battery system like mine, check out the Minn Kota, the Cabela’s, the Bass Pro Shops, etc. If your handy, and are using the right charger(s), and have the battery switch, and … OK, I don’t have that time or ambition at my age anymore.

Smart to ask the question and do the research. Most box Stores won’t have an Outiftter/associate that would know. SOME boat repair shops might. Maybe you should call and ask a couple of them.

And for heaven sakes, once you get it figured out for you, let us know also. I, for one, always want to learn… Now, if only the Lithium Ion boat batteries were not so darned expensive…

[SkunkedAgain]

@dubob

“kentofnsl, post:9, topic:321387” wrote:

“dubob, post:2, topic:321387” wrote:

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.

---

“SkunkedAgain, post:11, topic:321387” wrote:

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.

---

“Mildog, post:12, topic:321387” wrote:

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

[liketrolling]

https://minnkotamotors.johnsonoutdoors.com/battery-chargers?_gl=1*bguyg9*_ga*MTM4OTEwNTI4MS4xNjE1ODU1MjA2*_ga_GTWTGQ93QM*MTYxNTg1NTIwNi4xLjAuMTYxNTg1NTIwNi42MA..&_ga=2.71261136.1952295842.1615855206-1389105281.1615855206

[r2u2]

Thanks everyone, appreciate the help.

rj