Hi Guys, I have a small start battery and a group 27 house battery. However, anchoring over night the house battery will not last. I'm trying to decide how to increase the house battery. Get a large Gel, ASM, or deep cycle. Also, a option would to run multiple group 27 batteries in parallel. I'm open to any ideas. Thanks Jim
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david lewis
Battery Performance
Any battery you use that is subject to continuous cycles of discharging and re-charging should be deep cycle batteries. These are specially made for this purpose. If you use a regular car type battery (starting battery) for this it will fail very quickly. If you are just using an anchor light your battery should last a lot longer than one night!!! Also depending on where you're anchored you may not be required to use an anchor light but may do so. I use liquid cell deep cycle batteries from Sears and Roebucks, cost about 65 bucks and I can go a week no problem on vacation with good electrical mangement without plugging in to charge them. Obviously they get charged when the engine is running but my engine usage is pretty minimal (15 gals of diesel all year). dave
Any battery you use that is subject to continuous cycles of discharging and re-charging should be deep cycle batteries. These are specially made for this purpose. If you use a regular car type battery (starting battery) for this it will fail very quickly. If you are just using an anchor light your battery should last a lot longer than one night!!! Also depending on where you're anchored you may not be required to use an anchor light but may do so. I use liquid cell deep cycle batteries from Sears and Roebucks, cost about 65 bucks and I can go a week no problem on vacation with good electrical mangement without plugging in to charge them. Obviously they get charged when the engine is running but my engine usage is pretty minimal (15 gals of diesel all year). dave
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Melody Miller
A twelve and two sixes
Hi Jim: The folks at two separate West Marine stores, Annapolis and Alexandria, both counseled me to upgrade to a single 12 volt start battery and two sixes in parallel for the house. (The sixes are the West Marine's Seavolt 215 amp.) Previously I had two 12 volt 27's. I've been very happy with this arrangement. No shortage of power and minimal extra space required for increased capacity. Good luck, Melody
Hi Jim: The folks at two separate West Marine stores, Annapolis and Alexandria, both counseled me to upgrade to a single 12 volt start battery and two sixes in parallel for the house. (The sixes are the West Marine's Seavolt 215 amp.) Previously I had two 12 volt 27's. I've been very happy with this arrangement. No shortage of power and minimal extra space required for increased capacity. Good luck, Melody
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david lewis
In Parallel or in Series?
Batteries in Parallel do not add the same as batteries in series! Think of it this way, the little batteries you put in radios are always placed end to end. These 1.5 volt batteries add up to the summ of 1.5 times the number of batteries in series for the total voltage. Thus 2 six volt batteries in series will be 12 volts but 2 six volt batteries in parallel will be something I'm not sure of since I never tried that. My guess is you will fry the batteries. Any EE's out there care to comment? dave
Batteries in Parallel do not add the same as batteries in series! Think of it this way, the little batteries you put in radios are always placed end to end. These 1.5 volt batteries add up to the summ of 1.5 times the number of batteries in series for the total voltage. Thus 2 six volt batteries in series will be 12 volts but 2 six volt batteries in parallel will be something I'm not sure of since I never tried that. My guess is you will fry the batteries. Any EE's out there care to comment? dave
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Keith
two 6s = 6 in parallel
When you hook up two 6 volt batteries in series it will equal 12 volts. When you hook up two 6 volt batteries in parallel, you get 6 volts, but double the amperage. (the sum of the two batteries) That is why many people use two 12 volt batteries hooked in PARALLEL for their house batteries, it will last longer than one.
When you hook up two 6 volt batteries in series it will equal 12 volts. When you hook up two 6 volt batteries in parallel, you get 6 volts, but double the amperage. (the sum of the two batteries) That is why many people use two 12 volt batteries hooked in PARALLEL for their house batteries, it will last longer than one.
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Alex
deep cycle only -for house batt
I installed on my 29.5 two 6V/215amp Trojan deep cycle 6+ years ago , and they are still going fine ( with the help of multi-stage AC charger ).I wouldn't go for anything less than deep cycle of good quality ( not less than 600 cycles ).
I installed on my 29.5 two 6V/215amp Trojan deep cycle 6+ years ago , and they are still going fine ( with the help of multi-stage AC charger ).I wouldn't go for anything less than deep cycle of good quality ( not less than 600 cycles ).
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Dennis Cesari
4- Sixes
If you have refrigeration and the space for batteries, I recommmend 4 six-volt batteries. I have two banks of six-volt batteries in parallel and can cove out all weekend and keep the refrigeration going. I also have a 12V starter battery but never need it.
If you have refrigeration and the space for batteries, I recommmend 4 six-volt batteries. I have two banks of six-volt batteries in parallel and can cove out all weekend and keep the refrigeration going. I also have a 12V starter battery but never need it.
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Thomas Ehmke
battery upgrade
Jim, I've been having battery problems for a couple of years and late last season discovered what was happening. Perhaps we share the same problem. In the beginning (a long time ago in a galaxy far, far away) I bought two deep cycle batteries. However, over the years, one of the two would go south on a regular basis. The problem got worse when I chose a new slip w/o shore power. It seemed as though I could never get the batteries up to a full charge and hold it for any length of time. I began to worry that I might get caught out on the water and not have enough battery power to start the engine or use my barebones electronics. I am a member of USPS and this Fall I enrolled in the Marine Electronics course which was taught by an old-time TV-Radio technician. He gave me some great advice, the first suggestion being to shut off the battery switch whenever I left the boat. I had always left the switch in the "both" position. Then, after I had both batteries tested at a battery store, I replaced the one (yet another!) which had a bad cell. The teacher explained that leaving the switch in the "both" position caused the good battery to discharge because of the draw of current by the battery with the bad cell which eventually discharged both batteries. By shutting the battery switch off, the draw from the good battery was stopped, and I had at least one good battery which would hold a charge. I then did some research on my own and found an interesting article on "Creating a Reliable Battery System" in the WM 2000 Catalog. I decided to set up my system using the three on/off switch system described in the article. I replaced the "gone south" battery with a marine grade starter battery,as suggested in the article,and am using a one-year old Gp 27 deep cycle as my house battery. Currently the DC charging current is supplied by a 35Amp Mitsubishi alternator which is original equipment on my O272. I have had a WM Battery Combiner on board for three years. This little piece of equipment will do all the monitoring of the charging system for you as it electronically senses which battery needs charging and directs the alternator or AC battery charger (if you have one)to charge the batteries without your having to throw the battery switch back and forth.The three switch system works well, and when I want a little extra umph to start the engine, I can parallel the batteries for more powerful starting amperage. I have not had to use that feature yet, but the time may come... All of us who use battery power have opinions about the size and type of battery to use in a marine electrical system,and those of us who give it some thought will have different ideas because of different kinds and amounts of on board usage on our boats. I own a small boat and because I follow the KISS philosophy, a Gp 27 battery suits me fine, but others with different usage needs will make other recommendations. Let this be a spring board for your own investigation of what your system does or what you would like it to do and get busy!!! Sure beats freezin' to death with nothin' to do this winter!!
Jim, I've been having battery problems for a couple of years and late last season discovered what was happening. Perhaps we share the same problem. In the beginning (a long time ago in a galaxy far, far away) I bought two deep cycle batteries. However, over the years, one of the two would go south on a regular basis. The problem got worse when I chose a new slip w/o shore power. It seemed as though I could never get the batteries up to a full charge and hold it for any length of time. I began to worry that I might get caught out on the water and not have enough battery power to start the engine or use my barebones electronics. I am a member of USPS and this Fall I enrolled in the Marine Electronics course which was taught by an old-time TV-Radio technician. He gave me some great advice, the first suggestion being to shut off the battery switch whenever I left the boat. I had always left the switch in the "both" position. Then, after I had both batteries tested at a battery store, I replaced the one (yet another!) which had a bad cell. The teacher explained that leaving the switch in the "both" position caused the good battery to discharge because of the draw of current by the battery with the bad cell which eventually discharged both batteries. By shutting the battery switch off, the draw from the good battery was stopped, and I had at least one good battery which would hold a charge. I then did some research on my own and found an interesting article on "Creating a Reliable Battery System" in the WM 2000 Catalog. I decided to set up my system using the three on/off switch system described in the article. I replaced the "gone south" battery with a marine grade starter battery,as suggested in the article,and am using a one-year old Gp 27 deep cycle as my house battery. Currently the DC charging current is supplied by a 35Amp Mitsubishi alternator which is original equipment on my O272. I have had a WM Battery Combiner on board for three years. This little piece of equipment will do all the monitoring of the charging system for you as it electronically senses which battery needs charging and directs the alternator or AC battery charger (if you have one)to charge the batteries without your having to throw the battery switch back and forth.The three switch system works well, and when I want a little extra umph to start the engine, I can parallel the batteries for more powerful starting amperage. I have not had to use that feature yet, but the time may come... All of us who use battery power have opinions about the size and type of battery to use in a marine electrical system,and those of us who give it some thought will have different ideas because of different kinds and amounts of on board usage on our boats. I own a small boat and because I follow the KISS philosophy, a Gp 27 battery suits me fine, but others with different usage needs will make other recommendations. Let this be a spring board for your own investigation of what your system does or what you would like it to do and get busy!!! Sure beats freezin' to death with nothin' to do this winter!!
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Debra B
Stick to one technology (Gel, AGM or Flooded)
There are plenty of books on the subject of 12 volt systems. One thing seems clear, if you have flooded batteries, then upgrading to Gel (I'm not sure about AGM) probably means a new regulator for the alternator, and a new battery charger. Gel batteries cook at anything above 14.1 volts, while flooded need 14.3 volts to just get started on a charge. Battery chargers that can be set to handle gel or flooded cannot handle a different technology on different banks, so all banks need to be the same (gel or flooded or AGM I suppose). I can't find enough info on the AGM batteries to know if they need special chargers as well. What size you need will really depends on how long you are away from shore power, and what you need to run during that time, and how you charge -- wind, alternator, solar. There are some huge (8D) flooded cells rated at 900+ cycles. They are large, heavy, and expensive, but tempting. BTW a good source for this type of information is Practical Sailor.
There are plenty of books on the subject of 12 volt systems. One thing seems clear, if you have flooded batteries, then upgrading to Gel (I'm not sure about AGM) probably means a new regulator for the alternator, and a new battery charger. Gel batteries cook at anything above 14.1 volts, while flooded need 14.3 volts to just get started on a charge. Battery chargers that can be set to handle gel or flooded cannot handle a different technology on different banks, so all banks need to be the same (gel or flooded or AGM I suppose). I can't find enough info on the AGM batteries to know if they need special chargers as well. What size you need will really depends on how long you are away from shore power, and what you need to run during that time, and how you charge -- wind, alternator, solar. There are some huge (8D) flooded cells rated at 900+ cycles. They are large, heavy, and expensive, but tempting. BTW a good source for this type of information is Practical Sailor.
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Jim Wharton
upgrade thanks
Guys, Thanks for the input. I also looked in Nigel Calder book {"Boatowners Mech & Electrical Manual") Boy this book is great. Nigel covers all aspect of battery systems and configurations. I'm going to review this and other info more. Thanks Jim
Guys, Thanks for the input. I also looked in Nigel Calder book {"Boatowners Mech & Electrical Manual") Boy this book is great. Nigel covers all aspect of battery systems and configurations. I'm going to review this and other info more. Thanks Jim
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R.W.Landau
Good Advice
Wow, Lots of good advice. Putting it together , The industry is tending toward two 6 volts batteries in series ( positive to negitive and negitive to positive, creating twelve volts).This theory is played out in golf carts. Very severe usage and recharging has proved this system very goodor they would use two 12 volt batteries. Two 12 volt batteries in parallel ( positive to positive, Leaving the voltage 12 volts) is also affective. Part of the theory behind this is that a larger cell works less than a small cell. Each cell produces 2.12 volts +/-( Full charged battery 12.72 volts+/-, 50% discharge a bit above 12 volts). There is chemical reaction that creates the current flow. This reaction creates heat. A cooler a battery remains the more efficent. The chemical reaction is also important. A starting battery has thin plates to allow a quick reaction. The deep cycle is a thicker plate with a slower reaction but a longer power ability.( p.s. a deep cycle starting battery is not a true deep cycle) That is why the golf carts use the large celled 6 volt batteries. They get more power for a longer period with better cycle charging. One more point is that if the batteries are not of equal potential, the lesser will discharge the other. I would not put more than two batteries on a bank because of this. It is best to buy two batteries of equal output and age for a bank of batteries. Hope this works for you r.w.landau
Wow, Lots of good advice. Putting it together , The industry is tending toward two 6 volts batteries in series ( positive to negitive and negitive to positive, creating twelve volts).This theory is played out in golf carts. Very severe usage and recharging has proved this system very goodor they would use two 12 volt batteries. Two 12 volt batteries in parallel ( positive to positive, Leaving the voltage 12 volts) is also affective. Part of the theory behind this is that a larger cell works less than a small cell. Each cell produces 2.12 volts +/-( Full charged battery 12.72 volts+/-, 50% discharge a bit above 12 volts). There is chemical reaction that creates the current flow. This reaction creates heat. A cooler a battery remains the more efficent. The chemical reaction is also important. A starting battery has thin plates to allow a quick reaction. The deep cycle is a thicker plate with a slower reaction but a longer power ability.( p.s. a deep cycle starting battery is not a true deep cycle) That is why the golf carts use the large celled 6 volt batteries. They get more power for a longer period with better cycle charging. One more point is that if the batteries are not of equal potential, the lesser will discharge the other. I would not put more than two batteries on a bank because of this. It is best to buy two batteries of equal output and age for a bank of batteries. Hope this works for you r.w.landau
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Trevor
Battery advice needed
I'm hoping someone can steer me in the right direction here. A few questions: How does one determine the Ah (amp hours) of a given battery? I currently have 2 group 27 deep cycle batteries (new). I use 1 for starting and the other for house, which isn't enough to run stereo, lights, fan for heater overnight on the hook. I happened upon a free 4D battery... will it be useful to add this 4D battery to the house Group 27? Am I inviting problems? Also, is a deep cycle battery needed for the start battery? I always thought a simple car battery would suffice for this since it only required periodic high output without long drains. So maybe running both 27s (with the 4D?) for the house and another battery for starting? Looking forward to some advice... thanks! Trevor
I'm hoping someone can steer me in the right direction here. A few questions: How does one determine the Ah (amp hours) of a given battery? I currently have 2 group 27 deep cycle batteries (new). I use 1 for starting and the other for house, which isn't enough to run stereo, lights, fan for heater overnight on the hook. I happened upon a free 4D battery... will it be useful to add this 4D battery to the house Group 27? Am I inviting problems? Also, is a deep cycle battery needed for the start battery? I always thought a simple car battery would suffice for this since it only required periodic high output without long drains. So maybe running both 27s (with the 4D?) for the house and another battery for starting? Looking forward to some advice... thanks! Trevor
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Thomas Ehmke
Trevor- a couple of definitions
Amp/Hr.-"the amount of energy that can be taken from a battery between conditions of full charge and discharge. Since the amount of energy that can be drawn from a particular battery depends upon the rate at which current is drawn, a figure established by convention in the industry sets this rate as the maximum current that will fully discharge the battery in 20 hours at a temperature of 72-78 degrees until it drops to 10.5 volts while under load. For example, a battery with a 90 ampere-hour rating would supply 90/20=4.5 amperes for 20 hours, under those conditions. This is known as the 20-hour rate, and is normally given when no other is specified. Reserve minutes are the number of minutes that a battery can power a 25-ampere load until it drops to 10.5 volts under load. CCA (Cold Cranking Amps) is a measure of the current that a battery can deliver for 30 seconds at 0 degrees F without having the voltage drop below 7.2 volts. MCA (Marine Cranking Amps) is similar to CCA, except the temperature used is 32 degrees F. MCA is usually about 20-25% higher than CCA for the same battery." Definitions courtesy of the Marine Electronics Student Manual of the USPS. My thoughts about your battery usage are the common ones. What electrics are you using that discharges the Gp 27 deep cycle battery overnight? What is the amperage of your alternator? Do you use the battery switch to isolate the batteries so that there is no discharge from one battery to another? Even though the batteries are almost new, have you checked for a dead cell in either battery? Do you have a combiner or external regulator that optimizes the charge to both (all) batteries from the alternator? Lots of questions... There is no reason why you shouldn't be able to use two Gp 27's in parallel for a house bank, but make darned sure that you have a quality charging system to keep that bank fully charged along with the starting battery. The equipment is out there to do all of this, but it involves a lot more than using the 1,2,Both,Off battery switch which is universally (almost) used to direct alternator charging. As far as battery combinations are concerned, I would not use a Gp 27 and a 4D in parallel as a house bank. Many of us (including you and me) use a starting battery in one bank and a deep cycle for house loads in the other bank. Others on the site will make other suggestions depending upon what electrical devices are used on board. I am a KISS person, so one battery in the house bank suffices. Hope this helps. Tom
Amp/Hr.-"the amount of energy that can be taken from a battery between conditions of full charge and discharge. Since the amount of energy that can be drawn from a particular battery depends upon the rate at which current is drawn, a figure established by convention in the industry sets this rate as the maximum current that will fully discharge the battery in 20 hours at a temperature of 72-78 degrees until it drops to 10.5 volts while under load. For example, a battery with a 90 ampere-hour rating would supply 90/20=4.5 amperes for 20 hours, under those conditions. This is known as the 20-hour rate, and is normally given when no other is specified. Reserve minutes are the number of minutes that a battery can power a 25-ampere load until it drops to 10.5 volts under load. CCA (Cold Cranking Amps) is a measure of the current that a battery can deliver for 30 seconds at 0 degrees F without having the voltage drop below 7.2 volts. MCA (Marine Cranking Amps) is similar to CCA, except the temperature used is 32 degrees F. MCA is usually about 20-25% higher than CCA for the same battery." Definitions courtesy of the Marine Electronics Student Manual of the USPS. My thoughts about your battery usage are the common ones. What electrics are you using that discharges the Gp 27 deep cycle battery overnight? What is the amperage of your alternator? Do you use the battery switch to isolate the batteries so that there is no discharge from one battery to another? Even though the batteries are almost new, have you checked for a dead cell in either battery? Do you have a combiner or external regulator that optimizes the charge to both (all) batteries from the alternator? Lots of questions... There is no reason why you shouldn't be able to use two Gp 27's in parallel for a house bank, but make darned sure that you have a quality charging system to keep that bank fully charged along with the starting battery. The equipment is out there to do all of this, but it involves a lot more than using the 1,2,Both,Off battery switch which is universally (almost) used to direct alternator charging. As far as battery combinations are concerned, I would not use a Gp 27 and a 4D in parallel as a house bank. Many of us (including you and me) use a starting battery in one bank and a deep cycle for house loads in the other bank. Others on the site will make other suggestions depending upon what electrical devices are used on board. I am a KISS person, so one battery in the house bank suffices. Hope this helps. Tom
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R.W.Landau
More stuff,
Jim, I have done some more thinking here and realized that my suggestion would work for me. Here is what I mean. Not to be smart, most people do not understand batteries and their needs. Yes, their needs. Deep cycle batteries can give you 2000 cycles of charging, IF THEY ARE TREATED CORRECTLY! If they are not treated correctly you may only get a couple hundred charges out of some very expensive batteries. Many weekend sailors use their batteries for the weekend with a couple of quick charges during the weekend. This is fine because they then go back and plug into their shore power where the charger then does a correct job of charging the batteries. (Provided that their charger has been properly designed for their system.) Another consideration is your charging capacity of your boats alternator. If you go Gel Cell, you have to make sure that the charging voltage does not go above 14.1 volts or you will cook the life out of them. If you have not done anything yet, buy Nigel Calders' "Boatowner's Mechanical and Electrical Manual" or "The 12 Volt Bible". If you have some technical ability these books have alot of information. I have found though that with out my previous engineering background, some of this stuff would go right over my head. If you know someone that is good with these things bring them on your boat and let them check things out and make suggestions. If you lack desire or have problems with technical stuff, buy a couple of Sears marine deep cycles, use them till they quite, then replace them. It will be cheaper in the long run. r.w.landau
Jim, I have done some more thinking here and realized that my suggestion would work for me. Here is what I mean. Not to be smart, most people do not understand batteries and their needs. Yes, their needs. Deep cycle batteries can give you 2000 cycles of charging, IF THEY ARE TREATED CORRECTLY! If they are not treated correctly you may only get a couple hundred charges out of some very expensive batteries. Many weekend sailors use their batteries for the weekend with a couple of quick charges during the weekend. This is fine because they then go back and plug into their shore power where the charger then does a correct job of charging the batteries. (Provided that their charger has been properly designed for their system.) Another consideration is your charging capacity of your boats alternator. If you go Gel Cell, you have to make sure that the charging voltage does not go above 14.1 volts or you will cook the life out of them. If you have not done anything yet, buy Nigel Calders' "Boatowner's Mechanical and Electrical Manual" or "The 12 Volt Bible". If you have some technical ability these books have alot of information. I have found though that with out my previous engineering background, some of this stuff would go right over my head. If you know someone that is good with these things bring them on your boat and let them check things out and make suggestions. If you lack desire or have problems with technical stuff, buy a couple of Sears marine deep cycles, use them till they quite, then replace them. It will be cheaper in the long run. r.w.landau
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Alex
AGM batteries..
.. I have checked this issue recently.. It looks promising..Charging them is like flooded lead ;if multi stage charging, 14.4V bulk and 13.3V float will do. "Lifeline" pronaunce them to last 1000 cycles ( to 50%), which if true is impressive .There are now on market both starting ( the first generation , and still best suited for starting , since they are more 'deep cycle' technology than 'many cycles' ) and later 'deep cycle' for 'house' battery . I would give them a try.. Still , if not sure, go for 2 Trojan 6V golf cart deep cycle 220amp.With carefull mantenance they will last forever..(mine are almost 7 years old and still going..)
.. I have checked this issue recently.. It looks promising..Charging them is like flooded lead ;if multi stage charging, 14.4V bulk and 13.3V float will do. "Lifeline" pronaunce them to last 1000 cycles ( to 50%), which if true is impressive .There are now on market both starting ( the first generation , and still best suited for starting , since they are more 'deep cycle' technology than 'many cycles' ) and later 'deep cycle' for 'house' battery . I would give them a try.. Still , if not sure, go for 2 Trojan 6V golf cart deep cycle 220amp.With carefull mantenance they will last forever..(mine are almost 7 years old and still going..)
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