I am a rookie re the battery and charging system and have tried to educate myself by reviewing this forum and various battery sites. I still have questions. I can't believe how complex it is to determine your system configuration ie check for factory wiring errors (I think I may this) and then determine if your system components are all working. Boat is a Hunter 340 -2001 with 2 deep cycle Grp 24 automobile flooding batteries. I sail L Ontario and to date I am at shore power every night. Batteries are largely required for fridge, auto pilot, new chart plotter(C-80) and radar (infrequent). This summer may be on the hook at various crusing stops. I purchased from previous owner - batteries of unknown age/condition. I have abused them in the past 2 years by leaving them on the boat overwinter and only charging them up in the spring. Worse I thought they were no maintenance and did not add water regularly. When I did this year the 2 batteries took on a jug of distilled water. Oops. Hydrometer reading are now in the red zone for both batteries. However each individually will start my 3 cyl diesel no problem. I have never had a battery issue but likely have never really drawn on them. I have a Pro Mariner 1230 charger that shows LED lights in trickle mode and batteries show 13.26V currently. Looking at the charger wiring I have a bridge wire going from red terminal 1 to red termnial 2 at the charger - I don't believe this is correct based on forum reads. Correct? Batteries have a dedicated red cable to each positive terminal but are bridged at the ground black terminals. Correct? I plan to carefully check the wiring in the battery switch and the charger, map it out and confirm it is correct. Not sure what it should be though. I also expect to be challenged in mapping the wiring at the main panel as it appears daunitng with all of the wires! Also not sure of the need/value of isolator ie the new switch and isolator package that West Marine promotes to isolate charging battery. Not sure if mine are even isolated now? I think not. Someone suggested I just leave the switch on 'both' and have done so. Also think this is incorrect ie can risk draining both batteries. To test the system I plan to discharge each battery separately under load (any suggestions on how to do this? ie turn on fridge etc and wait for battery to run out?) Plan to recharge it and learn if the batteries, while still working, have minimal reserve as hydrometer would suggest. How do I know what is 'unacceptable or accpetable'? Not sure if I can separately charge each battery? Not sure how to do a equalising charge as suggested every once in a while. Finally I am considering AGM type Optima deep cycle blue tops due to capacity and no maintence required. I notice on the Pro Mariner charger it has only 2 switches for flooded and gel batteries only so emailed mfr. Response was to simply leave it on flooded mode. However thier newer chargers have 3 battery options ie 1 for AGM. What am I mising by using an older charger in the flooded mode. I sent the Optima charging profile to the mfr but they did not reference this in their response. I was not satisfied with the lack of technial content in thier responsee that flooded mode was OK. Finally Optina says to charge at 10 Amps maximum yet the full feature chargers are all 20 amps or more. Will this be a problem? I am thinking of a Xantrex TruPower 20 if I require a new charger. Thoughts? Thanks all! Help! Te real experts are on this Forum.
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By yourself 2 new deep cycle batteries.
or four new golf cart batteries. This will buy you two or three years of reliable battery service and give you time to gain an understanding of batteries and your boats electrical system. I suggest you read a few books on boat electrical systems and batteries in general.
or four new golf cart batteries. This will buy you two or three years of reliable battery service and give you time to gain an understanding of batteries and your boats electrical system. I suggest you read a few books on boat electrical systems and batteries in general.
second Landsend's suggestion
Don't bother testing your existing batteries. As they dried out, lost charge over the winter and are the wrong type anyway, just get rid of them. There is no such thing as "deep cycle automobile batteries" - that is a contradiction in terms as no auto battery is deep cycle design. Do an energy analysis of how much power you would typically use away from the dock, multiply by two (as you never want to discharge below 50% capacity) and buy deep cycle or golf cart batteries to provide that capacity. The concept of having a separate, isolated start battery dedicated solely to the engine is a good approach and ensures you can always run the engine regardless of how abused your house bank gets.
Don't bother testing your existing batteries. As they dried out, lost charge over the winter and are the wrong type anyway, just get rid of them. There is no such thing as "deep cycle automobile batteries" - that is a contradiction in terms as no auto battery is deep cycle design. Do an energy analysis of how much power you would typically use away from the dock, multiply by two (as you never want to discharge below 50% capacity) and buy deep cycle or golf cart batteries to provide that capacity. The concept of having a separate, isolated start battery dedicated solely to the engine is a good approach and ensures you can always run the engine regardless of how abused your house bank gets.
I'll "Third" the suggestions. Replace what you have with
2 true deep cycle flooded batteries - group 27 or 31 and use the next 2-3 years to get up to speed on battery systems and alternatives. I have seen charger manufacturers recommend the use of "Flooded" setting for AGM's. It may be adequate but not ideal. Sounds like your batteries are wired in the old standard way; two identical batteries wired to a 1-Both-2-Off battery switch. Works OK but again, not ideal.
2 true deep cycle flooded batteries - group 27 or 31 and use the next 2-3 years to get up to speed on battery systems and alternatives. I have seen charger manufacturers recommend the use of "Flooded" setting for AGM's. It may be adequate but not ideal. Sounds like your batteries are wired in the old standard way; two identical batteries wired to a 1-Both-2-Off battery switch. Works OK but again, not ideal.
Charger wires
The charger has three circuits that can provide a total of (guessing here, whatever the max capacity of the charger is) 20 amps. Since you only have 2 battery banks you have an extra + wire. It is common to use two of the wires on the house and the other one on the engine battery by "shorting" two together. Watch total amps and wire size and length. I'm not a fan of all the fancy electric switches and diods that do what the 3-way switch does. As long as you know which bank is numbered #1 and #2 you only have to manage those to keep the engine battery charged. Both at the dock so they all get charged, Both when motoring for the same reason, #1 (house) when under sail and #2 (engine) to get the engine started when #1 is dead otherwise use #1 to start the engine and after a few minutes of charge switch to both. You want to avoid draining one bank and then switching to both as the good bank will start to charge the dead one and you could overload your wiring. So if you have a dead battery bank give it some charging alone BEFORE you switch to both. The fancy switches do all this for you but at a cost. They don't charge rapidly due to ~1 volt being subtracted for the control diodes to do their job. Left for a week it does not matter and from the way you use your system you could get buy with it. Course when they crap out you will get NO warning. I personaly have NEVER heard of a 3-way switch failing! The three different types of batteries all have different voltages for charging, float, bulk.....resting. All are close in numeric value but charging at the wrong (too high) voltage can damage them. The "fancyer" the battery the more easily they are damaged by over voltage charging. So if you can set your battery charger for that type great, don't forget to set your alternaltor voltage regulator also. Setting the regulator is probably only possable for a VERY expensive regulator and then you have to turn a screw and read a volt meter which requires you to know what voltage you are looking for. As you probably guessed I'm not a fan of "fancy" batteries either. Good old flooded cell cheap deep cycle batteries are the best bang for the buck. Yea you have to check them EVERY time you go out but that is the price for a robust system that cost minimal $$$ and will not leave you calling for a jump start on Sunday morning. If you are interested, I have an excel spread sheet that can help you determine your electrical loads and size your battery bank. Just drop me an email at william-roosa@us.army.mil OH BTW, you are asking all the right questions.
The charger has three circuits that can provide a total of (guessing here, whatever the max capacity of the charger is) 20 amps. Since you only have 2 battery banks you have an extra + wire. It is common to use two of the wires on the house and the other one on the engine battery by "shorting" two together. Watch total amps and wire size and length. I'm not a fan of all the fancy electric switches and diods that do what the 3-way switch does. As long as you know which bank is numbered #1 and #2 you only have to manage those to keep the engine battery charged. Both at the dock so they all get charged, Both when motoring for the same reason, #1 (house) when under sail and #2 (engine) to get the engine started when #1 is dead otherwise use #1 to start the engine and after a few minutes of charge switch to both. You want to avoid draining one bank and then switching to both as the good bank will start to charge the dead one and you could overload your wiring. So if you have a dead battery bank give it some charging alone BEFORE you switch to both. The fancy switches do all this for you but at a cost. They don't charge rapidly due to ~1 volt being subtracted for the control diodes to do their job. Left for a week it does not matter and from the way you use your system you could get buy with it. Course when they crap out you will get NO warning. I personaly have NEVER heard of a 3-way switch failing! The three different types of batteries all have different voltages for charging, float, bulk.....resting. All are close in numeric value but charging at the wrong (too high) voltage can damage them. The "fancyer" the battery the more easily they are damaged by over voltage charging. So if you can set your battery charger for that type great, don't forget to set your alternaltor voltage regulator also. Setting the regulator is probably only possable for a VERY expensive regulator and then you have to turn a screw and read a volt meter which requires you to know what voltage you are looking for. As you probably guessed I'm not a fan of "fancy" batteries either. Good old flooded cell cheap deep cycle batteries are the best bang for the buck. Yea you have to check them EVERY time you go out but that is the price for a robust system that cost minimal $$$ and will not leave you calling for a jump start on Sunday morning. If you are interested, I have an excel spread sheet that can help you determine your electrical loads and size your battery bank. Just drop me an email at william-roosa@us.army.mil OH BTW, you are asking all the right questions.
It used to be that C/5 was the optimum charge current.
C/5 is a ratio of battery capacity(Amp Hours)/5 to get the charge current. So if you had a 100 Amp Hour battery, you could safely charge it at 100/5 = 20 Amps. A group 27 battery is slightly less than 100 Amp Hour - so a 20 amp charger would be OK for that battery. The other thing to consider is that the 20 amps out of a charger is shared between two batteries if it is a dual charger. If one battery needs more charge, then it will take more current. So, you could get a situation that a dual 20 amp charger would charge one of the batteries at the full 20 amps.
C/5 is a ratio of battery capacity(Amp Hours)/5 to get the charge current. So if you had a 100 Amp Hour battery, you could safely charge it at 100/5 = 20 Amps. A group 27 battery is slightly less than 100 Amp Hour - so a 20 amp charger would be OK for that battery. The other thing to consider is that the 20 amps out of a charger is shared between two batteries if it is a dual charger. If one battery needs more charge, then it will take more current. So, you could get a situation that a dual 20 amp charger would charge one of the batteries at the full 20 amps.
New charger & new batteries.
Geoff: This is a good time to look at a new charger & new batteries. Xantrex now makes a charger that will allow you to charge multiple battery chemistries off a single charger (flooded, gel & AGM). If you were looking for a large capacity battery bank, I would suggest that you look a bank of 6V flooded golf cart batteries. It does not sound like you need this type of capacity. An Optima makes an excellent starter battery. You can either go with Gel or AGM's for longevity & good capacity with minimal or no maintance. A couple of Group 31's would give you about 200 amps for your housekeeping. I have had Gel's on my last two boats, the last ones lasted for 10.5 years. Cheap by any standards and I never had to touch them.
Geoff: This is a good time to look at a new charger & new batteries. Xantrex now makes a charger that will allow you to charge multiple battery chemistries off a single charger (flooded, gel & AGM). If you were looking for a large capacity battery bank, I would suggest that you look a bank of 6V flooded golf cart batteries. It does not sound like you need this type of capacity. An Optima makes an excellent starter battery. You can either go with Gel or AGM's for longevity & good capacity with minimal or no maintance. A couple of Group 31's would give you about 200 amps for your housekeeping. I have had Gel's on my last two boats, the last ones lasted for 10.5 years. Cheap by any standards and I never had to touch them.
Some good advice here
but a good way to learn what you need is to call Jack rabbit marine. or look them up on the web. They are great to deal with and will give you all the info you need to plan a good system.
but a good way to learn what you need is to call Jack rabbit marine. or look them up on the web. They are great to deal with and will give you all the info you need to plan a good system.
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