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When I first bought my boat (single engine, though) and had all of the stock equipment in it and didn't listen to music unless the engine was running even after driving around a bunch it still never charged my battery (single at the time). I eventually started getting the low battery alarm and then realized that was the case and bought an on board charger.
Battery was nearly new. The stator just isn't really powerful enough beyond maintaining a charge and maybe a little charging capacity unless I'm really missing something.
I too had 2 new batteries put in the boat last year but one of them would not last long after being wet slipped. We would cruise a lot to help charge it but it wouldn't stay charged very long. Ended up load testing it and it tested bad. Replaced with another new one and have had no problems since. Just because you put new batteries in doesn't mean that they are good. I deal with this issue at work with multiple brands. Occasionally a battery goes bad shortly after install. Put a different one in and all is good for years.
When I first bought my boat (single engine, though) and had all of the stock equipment in it and didn't listen to music unless the engine was running even after driving around a bunch it still never charged my battery (single at the time). I eventually started getting the low battery alarm and then realized that was the case and bought an on board charger.
Battery was nearly new. The stator just isn't really powerful enough beyond maintaining a charge and maybe a little charging capacity unless I'm really missing something.
Yes, something is not right. Each engine when running should output plenty of power to add charge to the battery. Voltage should read above 14.5v When you are moving, and the boat should output around 20 amps per engine. Usually the home charger outputs between 5 and 10 Amps.
This is a problem and will reduce the life of any battery. A regular starting battery isn't designed to be fully discharged and it will reduce it's life doing so, and the longer it's discharged it will further reduce it's life. This is any battery, any brand, any type. A deep cycle batter is designed to be discharged and recharged many times, but it's life is also reduced when it stays discharged, or partially discharged for periods of time. This is why you need to keep batteries fully charged at all times. An onboard charger is your best bet and if you don't have access to power and a charger then you it is what it is. You will have issues with all batteries eventually, regardless of brand, type, or cost. These engines have stators, not an alternator, they can keep a battery topped off while running, and charge it but not enough to charge a depleted battery.
Have that house battery tested. What are you doing for those 30-60 minutes? Sounds like the battery has lost capacity. If you run the boat long enough it will recharge any battery.
usually we sit at the sandbars and have the stereo playing I would guess around 50-75% volume for 3-4 hours then usually do a good hour wake board session. This past weekend the voltage dropped below 10 and everything shut off. I wouldn’t be shocked if I killed that battery. I just bought this battery a few minutes ago. Now trying to decide which charger to go with. Looking at the Noco Gen2or the Promariner 44012. I can get the promariner today. I have to have the Noco shipped to me.
These engines have stators, not an alternator, they can keep a battery topped off while running, and charge it but not enough to charge a depleted battery.
Maybe we are not far off...but I don't agree with this statement. A decent group 24 deep cycle battery, such as Duracell has 75Amp/Hours of capacity. If you draw 60% (more you risk reduced life...) That's only 45 Amps. 60 minutes of boat run time will bring it to 80%+. It will take another hour or two to get it to 100% because the last 20% has some resistance, but that is true for all batteries.
My point is that the stator has plenty of power to refill any 12V battery given long enough. it is not true that the boat can't recharge a battery with a low state of charge, and if the boat is moving at reasonable speed, it will recharge 3X faster than most wall powered chargers, it just happens the boat has to be running on some power for the charge to happen, while the wall charger has unlimited time to complete the task.
FWIW, I have been using my boat for three years with the two lead acid batteries that came with it. I have never recharged them with anything other than the boat's engine. While I do not run a stereo, I typically run the Garmin chart plotter/sonar all the time - including at anchor (watching the tide). We often fish or float in an area for hours, and the run to that area is usually about 30 minutes. I am sure the Garmin does not draw the power of a custom stereo, but the boat's system can recharge and maintain batteries indefinitely unless you deeply discharge them.
I have two AGM batteries for my trolling motor (which we use all of the time to anchor us with spot lock), and they have to be charged by shore power using the installed battery charger. I recharge them every 3-4 outings.
All comments partially true. Our stators put out 20-25 amps depending who you credit with the info. That said, you do NOT get all of that possible charging power as some of it goes to run the engine, electronics etc. and this can greatly reduce the available amperage to charge. Add-in a stereo, even under way, and you might be charging your batteries far less than you thought. If you stop and anchor you will further deplete your batteries (house in this case). Big NOTE: different battery chemistries accept charges at GREATLY different rates. If you are using the least technologically advanced batteries (Flooded Cell) it it quite possible that you never recharge them to the proper level during a boating trip. This is where it gets interesting - if you are trailering that boat home and putting it on a charger, fine - the correct charger will properly charge your batteries without damaging them, however, if you wet slip your boat (I do) in a non-powered slip you have a whole new problem. If you keep returning the boat to your wet slip with its battery/batteries under charged you will slowly (or not so slowly) kill your battery/batteries by continually diminishing the charge acceptance rate and amp hour capacity. THAT is where AGM TPPL can come to your rescue because they re-charge so much faster with less required charge amperage and lose their charge so much slower that your boat can now charge its batteries after more use, faster therefore requiring less of a run at speed on the way home. There is no easy or one size fits all answer to this complex problem.
I have 2 lead acid batteries, and I was testing my added ACR... it took several minutes for the system voltage to drop below 13v after power off. I've returned after a week to find a battery at 12.7. I think it's changing all the way up.
(snip)...THAT is where AGM TPPL can come to your rescue because they re-charge so much faster with less required charge amperage and lose their charge so much slower that your boat can now charge its batteries after more use, faster therefore requiring less of a run at speed on the way home. There is no easy or one size fits all answer to this complex problem.
I think the greatest advantage of AGM is the greater capacity. The other factors you mention are all true, but I think the effect is not that great if the batteries are in good health. If the boat is used frequently discharge rate is not a huge factor, and charging resistance does not have a significant effect on charge time I don't think (maybe consumes 10% of the load to bring the battery from 40 to 90%?)
I agree there is no magic answer, but flooded batteries for the price are still a pretty decent deal if you can live with their limitations. ($75 group24 at Costco, not a bad deal)
I have 2 lead acid batteries, and I was testing my added ACR... it took several minutes for the system voltage to drop below 13v after power off. I've returned after a week to find a battery at 12.7. I think it's changing all the way up.
I think the greatest advantage of AGM is the greater capacity. The other factors you mention are all true, but I think the effect is not that great if the batteries are in good health. If the boat is used frequently discharge rate is not a huge factor, and charging resistance does not have a significant effect on charge time I don't think (maybe consumes 10% of the load to bring the battery from 40 to 90%?)
I agree there is no magic answer, but flooded batteries for the price are still a pretty decent deal if you can live with their limitations. ($75 group24 at Costco, not a bad deal)
@Beachbummer using the HD Flooded that came with my 2020 SX195 the charge at return to dock was never over 80% and that was with only limited use of the stereo and at least a 10 minute run home at 5500 RPM. At that rate I figured I had about a week before failure. Swapped for a Northstar TPPL and have not had a problem in 12 weeks. So far (knock on wood) returning fully charged, charging much, much faster and drawing down much, much slower.
usually we sit at the sandbars and have the stereo playing I would guess around 50-75% volume for 3-4 hours then usually do a good hour wake board session. This past weekend the voltage dropped below 10 and everything shut off. I wouldn’t be shocked if I killed that battery. I just bought this battery a few minutes ago. Now trying to decide which charger to go with. Looking at the Noco Gen2or the Promariner 44012. I can get the promariner today. I have to have the Noco shipped to me.
I just got finished speaking with support at Noco to confirm a couple things. Then I purchased the Gen3 from amazon. That's a hell of a price. I am going to go over kill with two of the Northstar AGMs wired parallel for my house bank. The start battery i have is more than sufficient so i will leave it be. The marina will let me leave my boat in a service rack over night once a week on a weekday so I can hook it up to the charger for 12-14 hours but once every two weeks will probably be sufficient. All these combined should be more than sufficient even after i do stereo upgrades later this year.
I just got finished speaking with support at Noco to confirm a couple things. Then I purchased the Gen3 from amazon. That's a hell of a price. I am going to go over kill with two of the Northstar AGMs wired parallel for my house bank. The start battery i have is more than sufficient so i will leave it be. The marina will let me leave my boat in a service rack over night once a week on a weekday so I can hook it up to the charger for 12-14 hours but once every two weeks will probably be sufficient. All these combined should be more than sufficient even after i do stereo upgrades later this year.
i have 2 regular lead acid batteries in my current boat, 232. during the season it is wet slipped and no power so batteries are never charged with anything other than the engine. typically i am only running 10-20 min each way. i will use the stereo 3-5 hrs. not much else drawing power other than the bilge pump which is on 24/7. that kicks on every 5 min to test for water. i have a digital voltmeter in my dash and the power has never dropped below 12.3v even if the boat sits for 2 weeks of no use. while running its usually around 14-3-14.7. never an issue. our engines should be able to do a decent charge on the batteries without them running for hours. sure it might not get them 100% with a 20 min run but enough to keep them at prob 80 or better. with that said, when my new 275 comes in, it will have a pair of odyssey or northstar batteries put in it. expensive @ $400 a piece but no point in even messing around with anything else imo.
@Beachbummer .....yes, we kind of have it a$$ backwards. We leave our slip boat for a couple of hours up and down the river and around islands then anchor in a sandy cove to swim, have lunch/dinner and I put on a scuba mask and wash the hull. That's the Admiral's choice so I'm down with that .....happy wife - you know the rest LOL. Then it's a 10 minute scoot back to the marina so that IS harder on the battery. Form my cruising days I started using AGMs as I didn't like inverters so on the last boat I had 6 AGMs. They were absolute killers - couldn't wear them down. If we anchored I would run everything off the AGMs then when they showed some depletion I'd turn-on the generator to re-charge them. Thing is it didn't take long to pay the difference from flooded to AGM as running a 5KW generator with 91 marine at 7GPH adds-up real fast!
Maybe we are not far off...but I don't agree with this statement. A decent group 24 deep cycle battery, such as Duracell has 75Amp/Hours of capacity. If you draw 60% (more you risk reduced life...) That's only 45 Amps. 60 minutes of boat run time will bring it to 80%+. It will take another hour or two to get it to 100% because the last 20% has some resistance, but that is true for all batteries.
My point is that the stator has plenty of power to refill any 12V battery given long enough. it is not true that the boat can't recharge a battery with a low state of charge, and if the boat is moving at reasonable speed, it will recharge 3X faster than most wall powered chargers, it just happens the boat has to be running on some power for the charge to happen, while the wall charger has unlimited time to complete the task.
Ok agreed. You can drive your boat around for 1,2 3 or more hours to charge the batteries. Not really practical. It also comes down to usage. If you drive the boat around a decent amount of time and not anchored for hours and hours with several amps pounding out tunes then you could potentially balance out use and draw on the batteries. But, if you are currently using the boat and are drawing the batteries down each trip, then there are two potential solutions assuming the batteries aren't defective.....driving around for hours and hours, or charging the batteries each trip.
@Beachbummer .....yes, we kind of have it a$$ backwards. We leave our slip boat for a couple of hours up and down the river and around islands then anchor in a sandy cove to swim, have lunch/dinner and I put on a scuba mask and wash the hull. That's the Admiral's choice so I'm down with that .....happy wife - you know the rest LOL. Then it's a 10 minute scoot back to the marina so that IS harder on the battery. Form my cruising days I started using AGMs as I didn't like inverters so on the last boat I had 6 AGMs. They were absolute killers - couldn't wear them down. If we anchored I would run everything off the AGMs then when they showed some depletion I'd turn-on the generator to re-charge them. Thing is it didn't take long to pay the difference from flooded to AGM as running a 5KW generator with 91 marine at 7GPH adds-up real fast!
i have 2 regular lead acid batteries in my current boat, 232. during the season it is wet slipped and no power so batteries are never charged with anything other than the engine. typically i am only running 10-20 min each way. i will use the stereo 3-5 hrs. not much else drawing power other than the bilge pump which is on 24/7. that kicks on every 5 min to test for water. i have a digital voltmeter in my dash and the power has never dropped below 12.3v even if the boat sits for 2 weeks of no use. while running its usually around 14-3-14.7. never an issue. our engines should be able to do a decent charge on the batteries without them running for hours. sure it might not get them 100% with a 20 min run but enough to keep them at prob 80 or better. with that said, when my new 275 comes in, it will have a pair of odyssey or northstar batteries put in it. expensive @ $400 a piece but no point in even messing around with anything else imo.
@mrcleanr6 .......and respectfully suggest if getting the AGMs get the TPPL. The difference in weight between even a "regular" AGM and a TPPL is noticeable but the main difference is that the lead plates in the TPPL are 99.9% PURE lead (thin plate, pu
@Diybrad yeah, gas hogs. A 5KW marine engine with the water cooling and mufflers is a pretty big rig. Has to be able to run fridges, ice makers, stoves and microwaves and battery chargers.
