Has anybody had any experience with AGM batteries? How do they compare with deep cycle in the trailer sailer situation? We have to replace our deep cycle and have been advised that AGM is the way to go. Bing
Absorbed Glass Mat Batteries
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Deep cycle, Gel, AGM/Glass uses.
Bing, I'll keep this simple and you can ask more as needed. Deep cycle batteries are a type of battery that allows itself to be drawn down deeply and then be recharged repeatedly vs. car batteries that won't allow the repeated deep draw down and recharge cycles. That said, there main types of deep cycle batteries, 1. Lead acid deep cycle. These are the "wet" type battery that contain sulphuric acid. They must remain upright and require the water/acid level to be maintained at all times. (monthly) They are the cheapest and can be quickly recharged. 2. Gel batteries. These are a newer type deep cycle battery and use a gel rather that a "wet" acid and therfore can be laid on their sides without acid running out, although "I" wouldn't do this for an extended period. They require a "smart, or 3 step type battery charger". Over charging will greatly shorten their life. The recharge cycle is longer that a wet battery. They require no maintance other than cleanleness. They cost more to start with but stand up very well. I use this type of battery. 3. AGM or "glass mat" batteries are the top of the line and use a glass/gel construction and are dry. They can be used upside down if needed. The plus side of these batteries is that they can be rapidly recharged like wet batteries but also must not be over charged. They have no maintance and cost the most. The newer battery charges(like those sold at Wal-Mart) are 3 step chargers and are available starting about $40. If you charge your battery from an outboard it probably won't keep up with your demand. A solar charger of any size(75 amp +) would need a 3 step regulator to not over charge. For a trailered boat I would use a "Gel" battery. Look in the West Marine catolog for a very good explanation of batteries. Ray
Bing, I'll keep this simple and you can ask more as needed. Deep cycle batteries are a type of battery that allows itself to be drawn down deeply and then be recharged repeatedly vs. car batteries that won't allow the repeated deep draw down and recharge cycles. That said, there main types of deep cycle batteries, 1. Lead acid deep cycle. These are the "wet" type battery that contain sulphuric acid. They must remain upright and require the water/acid level to be maintained at all times. (monthly) They are the cheapest and can be quickly recharged. 2. Gel batteries. These are a newer type deep cycle battery and use a gel rather that a "wet" acid and therfore can be laid on their sides without acid running out, although "I" wouldn't do this for an extended period. They require a "smart, or 3 step type battery charger". Over charging will greatly shorten their life. The recharge cycle is longer that a wet battery. They require no maintance other than cleanleness. They cost more to start with but stand up very well. I use this type of battery. 3. AGM or "glass mat" batteries are the top of the line and use a glass/gel construction and are dry. They can be used upside down if needed. The plus side of these batteries is that they can be rapidly recharged like wet batteries but also must not be over charged. They have no maintance and cost the most. The newer battery charges(like those sold at Wal-Mart) are 3 step chargers and are available starting about $40. If you charge your battery from an outboard it probably won't keep up with your demand. A solar charger of any size(75 amp +) would need a 3 step regulator to not over charge. For a trailered boat I would use a "Gel" battery. Look in the West Marine catolog for a very good explanation of batteries. Ray
Okay, Another Question
Thanks for that, Ray. Now another question you may be able to answer. Someone has told me that two 6 volt batteries joined together are better than one 12 volt battery. What are your thoughts? Regards Bing
Thanks for that, Ray. Now another question you may be able to answer. Someone has told me that two 6 volt batteries joined together are better than one 12 volt battery. What are your thoughts? Regards Bing
Cost Basically
You can purchase golf-cart type six volt batteries at a price often well less per amp than a single 12 volt of the same total capasity. Also, and important to many, is the fact that you can lift them alone (mostly). Rick D.
You can purchase golf-cart type six volt batteries at a price often well less per amp than a single 12 volt of the same total capasity. Also, and important to many, is the fact that you can lift them alone (mostly). Rick D.
Bing, the answer lies in your charger.
Without knowing your electrical needs and use it is hard to say which battery is best. The method you recharge your batteries with is a bigger hitter. If you use quite a bit of juice for a stereo, reading lamps and overnight campouts then you need expanded capacity which means large or multipule batteries. If you day sail only and just run the stereo then a single 100 amp hr battery will do. If you can plug in to 110 v power to recharge and use a "3 step" charger between trips then a smaller battery will do. When we cruised on our 38' boat we had 800 hrs worth of batteries with 3 large solar panels and a wind generator. Overkill? No, just comfort and a hell of a lot of cost. Rick is right about amp capacity cost using 6 volt batteries but for trailer sailing I think the mess and maintanance requirements for wet batteries is too much hassle. Get or copy the battery and charging info in the West Marine catalog as it is a very good explanation and answer to your question. Ray
Without knowing your electrical needs and use it is hard to say which battery is best. The method you recharge your batteries with is a bigger hitter. If you use quite a bit of juice for a stereo, reading lamps and overnight campouts then you need expanded capacity which means large or multipule batteries. If you day sail only and just run the stereo then a single 100 amp hr battery will do. If you can plug in to 110 v power to recharge and use a "3 step" charger between trips then a smaller battery will do. When we cruised on our 38' boat we had 800 hrs worth of batteries with 3 large solar panels and a wind generator. Overkill? No, just comfort and a hell of a lot of cost. Rick is right about amp capacity cost using 6 volt batteries but for trailer sailing I think the mess and maintanance requirements for wet batteries is too much hassle. Get or copy the battery and charging info in the West Marine catalog as it is a very good explanation and answer to your question. Ray
What can i expect then?
Ive got 4 agms 3 on the house and one to start, standard yanmar alternator about 35a and an older 50 amp 3 bank guest charger. What should i expect in service with this set up. Do i really have to change the alternator and charger?
Ive got 4 agms 3 on the house and one to start, standard yanmar alternator about 35a and an older 50 amp 3 bank guest charger. What should i expect in service with this set up. Do i really have to change the alternator and charger?
Expect
Ed, I'm not sure there is anything wrong with your set-up that would shorten battery life, just that you are charging a lot slower than is necessary or possible with the AGM's. You don't say what size the batteries are, but I'm presuming four Group 24 or 27. You will wind up running the engine for much longer periods if you stray away from shore power connections for more than a day. We have two house Group 4D agm's and one Group 27 agm for the starter. We use a Balmar 100 amp alternator and a 100 amp multistage charger. Still takes a fair amount of engine time if that is the only option, but way less than the 55 amp that came with the boat. The Balmar is also hooked through a MC612 regulator. Dan Jonas (S/V Feije II)
Ed, I'm not sure there is anything wrong with your set-up that would shorten battery life, just that you are charging a lot slower than is necessary or possible with the AGM's. You don't say what size the batteries are, but I'm presuming four Group 24 or 27. You will wind up running the engine for much longer periods if you stray away from shore power connections for more than a day. We have two house Group 4D agm's and one Group 27 agm for the starter. We use a Balmar 100 amp alternator and a 100 amp multistage charger. Still takes a fair amount of engine time if that is the only option, but way less than the 55 amp that came with the boat. The Balmar is also hooked through a MC612 regulator. Dan Jonas (S/V Feije II)
Dan, sounds like you have a neat setup!
Mine will have 3 agm group 27,s and one agm 27 to start on. its all i think i have room for. And i think it will be enough for us but time will tell, the budget is holding up my big ideas. Thanks for the info it helps. I was less concerned about overheating the batteries with the engine, but the single stage 50 amp guest has me a little concerned it they had to charge a while.
Mine will have 3 agm group 27,s and one agm 27 to start on. its all i think i have room for. And i think it will be enough for us but time will tell, the budget is holding up my big ideas. Thanks for the info it helps. I was less concerned about overheating the batteries with the engine, but the single stage 50 amp guest has me a little concerned it they had to charge a while.
Charger
Ed, Given your set-up and location in warmer weather, I would probably not leave the charger on when away from the boat for any length of time. A multi-stage charger should probably be a priority item on your wish list. With three group 27 agm's you will have about 300 amps capacity on the house side and about 100 amps usable between the 50% discharge and 85% charged state. 50% represents the lower end of the desired discharge cycle and 85% charged is what you can put back in at a reasonable rate. Anything above 85% will be too slow to offset the expanded engine runtime. Your 35 amp alternator is not going to deliver 35 amps. You will probably be lucky to get 25-28 at the 50% discharge level. That 100 amps will take over 4 hours to replace. If your engine can handle it, you might want to get something up around 70 amps or a little more as a second item on the wish list. Many here don't like the cost of the AGM's, but I like not having to think too much about the fluid level and I leave my charger on all the time when away from the boat. I also like the fact that they take a high charge rate well. Dan Jonas (S/V Feije II)
Ed, Given your set-up and location in warmer weather, I would probably not leave the charger on when away from the boat for any length of time. A multi-stage charger should probably be a priority item on your wish list. With three group 27 agm's you will have about 300 amps capacity on the house side and about 100 amps usable between the 50% discharge and 85% charged state. 50% represents the lower end of the desired discharge cycle and 85% charged is what you can put back in at a reasonable rate. Anything above 85% will be too slow to offset the expanded engine runtime. Your 35 amp alternator is not going to deliver 35 amps. You will probably be lucky to get 25-28 at the 50% discharge level. That 100 amps will take over 4 hours to replace. If your engine can handle it, you might want to get something up around 70 amps or a little more as a second item on the wish list. Many here don't like the cost of the AGM's, but I like not having to think too much about the fluid level and I leave my charger on all the time when away from the boat. I also like the fact that they take a high charge rate well. Dan Jonas (S/V Feije II)
Charger
Ed, Given your set-up and location in warmer weather, I would probably not leave the charger on when away from the boat for any length of time. A multi-stage charger should probably be a priority item on your wish list. With three group 27 agm's you will have about 300 amps capacity on the house side and about 100 amps usable between the 50% discharge and 85% charged state. 50% represents the lower end of the desired discharge cycle and 85% charged is what you can put back in at a reasonable rate. Anything above 85% will be too slow to offset the expanded engine runtime. Your 35 amp alternator is not going to deliver 35 amps. You will probably be lucky to get 25-28 at the 50% discharge level. That 100 amps will take over 4 hours to replace. If your engine can handle it, you might want to get something up around 70 amps or a little more as a second item on the wish list. Many here don't like the cost of the AGM's, but I like not having to think too much about the fluid level and I leave my charger on all the time when away from the boat. I also like the fact that they take a high charge rate well. Dan Jonas (S/V Feije II)
Ed, Given your set-up and location in warmer weather, I would probably not leave the charger on when away from the boat for any length of time. A multi-stage charger should probably be a priority item on your wish list. With three group 27 agm's you will have about 300 amps capacity on the house side and about 100 amps usable between the 50% discharge and 85% charged state. 50% represents the lower end of the desired discharge cycle and 85% charged is what you can put back in at a reasonable rate. Anything above 85% will be too slow to offset the expanded engine runtime. Your 35 amp alternator is not going to deliver 35 amps. You will probably be lucky to get 25-28 at the 50% discharge level. That 100 amps will take over 4 hours to replace. If your engine can handle it, you might want to get something up around 70 amps or a little more as a second item on the wish list. Many here don't like the cost of the AGM's, but I like not having to think too much about the fluid level and I leave my charger on all the time when away from the boat. I also like the fact that they take a high charge rate well. Dan Jonas (S/V Feije II)
Lead acid AGMs
Hi again The brochure on the AGM I am looking at indicates that it is not a "wet" or "gel" type. And it also says: "As the electrolyte is captured within the microfibre mat, there is a much lower resistance within the battery, allowing a more efficient and faster reaction (acid migration) between the hydrogen from the negative and oxygen from the positive plates. There are also voids designed into the mat, for efficient retention of gas without pressure build-up within the battery during a charge cycle and more stable transformation from gas to water during use". The brand is Powercel. They look good to me. They claim that under normal operating conditions, you can get four or five years service life in stand-by and cycling applications and with the correct charging and care to not continually over-discharge the batteries, even longer life can be expected. Yes, they're more expensive, but if they last that much longer, the cost is comparable. Regards Bing
Hi again The brochure on the AGM I am looking at indicates that it is not a "wet" or "gel" type. And it also says: "As the electrolyte is captured within the microfibre mat, there is a much lower resistance within the battery, allowing a more efficient and faster reaction (acid migration) between the hydrogen from the negative and oxygen from the positive plates. There are also voids designed into the mat, for efficient retention of gas without pressure build-up within the battery during a charge cycle and more stable transformation from gas to water during use". The brand is Powercel. They look good to me. They claim that under normal operating conditions, you can get four or five years service life in stand-by and cycling applications and with the correct charging and care to not continually over-discharge the batteries, even longer life can be expected. Yes, they're more expensive, but if they last that much longer, the cost is comparable. Regards Bing
Lead acid AGMs??
Hi again The brochure on the AGM I am looking at indicates that it is not a "wet" or "gel" type. And it also says: "As the electrolyte is captured within the microfibre mat, there is a much lower resistance within the battery, allowing a more efficient and faster reaction (acid migration) between the hydrogen from the negative and oxygen from the positive plates. There are also voids designed into the mat, for efficient retention of gas without pressure build-up within the battery during a charge cycle and more stable transformation from gas to water during use". The brand is Powercel. They look good to me. They claim that under normal operating conditions, you can get four or five years service life in stand-by and cycling applications and with the correct charging and care to not continually over-discharge the batteries, even longer life can be expected. Yes, they're more expensive, but if they last that much longer, the cost is comparable. Regards Bing
Hi again The brochure on the AGM I am looking at indicates that it is not a "wet" or "gel" type. And it also says: "As the electrolyte is captured within the microfibre mat, there is a much lower resistance within the battery, allowing a more efficient and faster reaction (acid migration) between the hydrogen from the negative and oxygen from the positive plates. There are also voids designed into the mat, for efficient retention of gas without pressure build-up within the battery during a charge cycle and more stable transformation from gas to water during use". The brand is Powercel. They look good to me. They claim that under normal operating conditions, you can get four or five years service life in stand-by and cycling applications and with the correct charging and care to not continually over-discharge the batteries, even longer life can be expected. Yes, they're more expensive, but if they last that much longer, the cost is comparable. Regards Bing
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