Luisafernandes
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I read somewhere, someone saying that AGM "something" were top notch batteries. Now I can't remember the name of the brand or manufacturer. I think it started with an "F" or "M", maybe somebody here knows?
AGM BATTERIES
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mockturtle
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I have Optima but some like Lifeline. Never heard of any F or Ms.
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I have Full River AGM golf carts. So far they have been great. They come with an outstanding warranty which is mainly why I bought them. I think they are 2 1/2 years old and working like new.
I bought them in Quartzsite, AZ.
Bob
I bought them in Quartzsite, AZ.
Bob
Luisafernandes
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Thanks Bob, I'll look them up.
Mockturtle, that's it! Lifeline. I believe someone mentioned that Lifeline are very good and reliable.
Mockturtle, that's it! Lifeline. I believe someone mentioned that Lifeline are very good and reliable.
mockturtle
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I've had my Optima AGMs for five years and they are good as new.
SternWake
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Odyssey
Northstar
Fullriver
Lifeline
are the top of the line AGM.
People tend to lump all AGMs together as to what their charging requirements are.
BUt they actually vary fairly considerably.
Lifeline recommends as much charging current as you can muster, keeping the voltage under 14.4v.
Odyssey recommends 40% of the 20 hour AH rate until 14.7 is reached. Then hold 14.7v for 4 hours and then float at 13.6v
Other AGM's will say not to exceed 30% of the 20 hour AH rate.
Best to meet the manufacturer recommendations.
Northstar
Fullriver
Lifeline
are the top of the line AGM.
People tend to lump all AGMs together as to what their charging requirements are.
BUt they actually vary fairly considerably.
Lifeline recommends as much charging current as you can muster, keeping the voltage under 14.4v.
Odyssey recommends 40% of the 20 hour AH rate until 14.7 is reached. Then hold 14.7v for 4 hours and then float at 13.6v
Other AGM's will say not to exceed 30% of the 20 hour AH rate.
Best to meet the manufacturer recommendations.
Luisafernandes
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Thanks SternWake, great info.
blars
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While different manufacturers have different charging recomendations, I suspect much of it is more different compromises rather than true differences in the batteries. (Optima excepted, they do have a significantly different construction than the others.)
SternWake
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True,
It is not as if the battery will fall flat instantly if not recharged to the manufacturer recommendations.
I spoke at length with an An Odyssey engineer and he said that in cyclic service, the battery will not perform as claimed, when cycled deeply, when the 40% rate at 14.7v is not met. Anything less was going to compromise longevity, without exception. To what degree is the variable.
I ruled out Odyssey as my solar battery, as my solar can barely do 10% of the recommended 40% recharge rate.
Many people on other forums expect the $$$.$$ AGM battery to perform exceptionally on charging systems that come nowhere near close to the specs, and then badmouth a battery for not lasting to their expensive expectations.
Flooded batteries are generally more tolerant of charging currents yet people destroy these time and again by chronic undercharging too.
Since this thread is within in the Going Green subforum, then one should hope to get the most out of any battery, rather than just hope the warranty is honored if premature failure does occur.
I hope to never have to use any warranty on any product, and will do what I can to avoid doing so.
With a Battery costing 2 to 3x as much, one should do what the manufacturer recommends, as close as feasible, and if choosing a charger, should try to find one which comes close. If one already has the charger, then find the battery which comes closest to its abilities.
In general the less expensive AGM's are limited as to their maximum bulk rate. Exceeding their recommendation can pop the Vents, releasing some gas and reducing the lifespan of the battery on each event where the Vents open.
But the limited bulk current might be a sign they will do better on a low and slow solar system compared to the High $$$ AGM which spec a Minimum 40% or In the case of Lifeline, as much as you can possibly feed it.
Bulk rates and voltages vary amongst manufacturers. Hard to say how much one can vary from them and still get good performance and longevity. It hurts more when AGM's fail.
Lifeline has a tech page that is very detailed, very informative.
Choose wisely.
It is not as if the battery will fall flat instantly if not recharged to the manufacturer recommendations.
I spoke at length with an An Odyssey engineer and he said that in cyclic service, the battery will not perform as claimed, when cycled deeply, when the 40% rate at 14.7v is not met. Anything less was going to compromise longevity, without exception. To what degree is the variable.
I ruled out Odyssey as my solar battery, as my solar can barely do 10% of the recommended 40% recharge rate.
Many people on other forums expect the $$$.$$ AGM battery to perform exceptionally on charging systems that come nowhere near close to the specs, and then badmouth a battery for not lasting to their expensive expectations.
Flooded batteries are generally more tolerant of charging currents yet people destroy these time and again by chronic undercharging too.
Since this thread is within in the Going Green subforum, then one should hope to get the most out of any battery, rather than just hope the warranty is honored if premature failure does occur.
I hope to never have to use any warranty on any product, and will do what I can to avoid doing so.
With a Battery costing 2 to 3x as much, one should do what the manufacturer recommends, as close as feasible, and if choosing a charger, should try to find one which comes close. If one already has the charger, then find the battery which comes closest to its abilities.
In general the less expensive AGM's are limited as to their maximum bulk rate. Exceeding their recommendation can pop the Vents, releasing some gas and reducing the lifespan of the battery on each event where the Vents open.
But the limited bulk current might be a sign they will do better on a low and slow solar system compared to the High $$$ AGM which spec a Minimum 40% or In the case of Lifeline, as much as you can possibly feed it.
Bulk rates and voltages vary amongst manufacturers. Hard to say how much one can vary from them and still get good performance and longevity. It hurts more when AGM's fail.
Lifeline has a tech page that is very detailed, very informative.
Choose wisely.
Luisafernandes
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SternWake said:
SternWake
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Hello Luisa.
Sorry for the delay.
I tried to respond on my Phone earlier but it was not responding to my Login.
Basically when a battery is discharged below 80%, and you feed it charging current, it can gobble up as much charging current as you can feed it.
As it gobbles up the recharging current, the battery voltage rises.
Voltage is basically electrical 'pressure'
When the battery is discharged low, it is very receptive to accepting charging current. If the batteries resting voltage is 12.2v, about 50%, it is very hungry, thirsty, and can accept large amounts of charging current.
The More charging current you can supply, when the battery is thirsty, this Bulk charging stage, well, this is when the battery is most able to accept every amp of current it is fed, and it is eager to be recharged.
AGM batteries have less resistance( than regular flooded batteries) to accepting this current.
Basically, charging sources are just current providing voltage regulators. The goal being to feed the battery, but not allow the 'pressure' to get too high.
Some batteries say no more than 14.2v, others 14.7v, and some others, mostly flooded batteries, say after a few hours at 14.8v, allow them to go upto 15.3v, for the 'finishing' stage. Then after the battery is truly and obviously fully charged, then allow float voltages, which only require very small current to counteract self discharge , and are to to keep the battery at 13.06v to 13.6 volts, depending on what the manufacturer recommends for their particular battery.
Lifeline says you can feed their AGM batteries hundreds of amps, when they are depleted/ hungry/thirsty. When fed hundreds of amps, a Single medium size battery reading 12.2v, will rise up to 14.4 volts fairly quickly. Perhaps within a minute. It depends on the size and health of the battery. A flooded battery's voltage will rise much faster and an AGM.
Lifeline says this is Awesome, desirable, do it! We command you!! Blast their depleted battery with as much amperage as your charging sources can feed them, until the battery rises to 14.4v, and the battery will be like a swine in feces. Super happy. Feed the same depleted AGM battery the low and slow "trickle charge" after a deeper cycle, and the battery will NEVER, regain full energy density, until it is discharged again and recharged at, the minimum recommended bulk current.
The Odyssey engineer I spoke at length with said that it would take at least 2 cycles to 50% depth of discharge and a 40% recharging rate until 14.7v was achieved and held for 4 hours, before the chronically undercharged Odyssey battery could be restored to its maximum remaining( yet still compromised to some degree) energy density. Odyssey also states that there is basically no upper amperage limit during the bulk stage. Their hundred amp hour battery will easily accept 300 amps. The hard part is actually achieving 300 amps of charging current. That number is huge. Basically it is more than 3 standard 15 amp 115Vac outlets in a normal stick and brick could supply, or nearly so, if they were all on different circuits.
Imagine that for a second. Most people on this forum Would not max out a regular 115Vac 15amp household receptacle with every load turned on in their Van, yet a single High $$$ depleted AGM could Max out three of them, and would love the opportunity to do so.
Let me state that very few charging sources can actually produce in excess of 50 amps DC. The shiniest chromed super high rated alternator can only do so for a very short while, and only at high rpm, and before it heats up, and it will heat up quick when asked to make anything near its claimed rating. This is Info that many not want to hear, nor believe, and will gain me no friends. So it goes. Put A clamp on Ammeter on your cables after 5 minutes before you call me out on it.
Our vehicles have these pesky alternator limiting devices called voltage regulators. The voltage regulator allows the alternator to make as much current as it can at a given rpm, until the pressure/ voltage, rises to a certain amount. somewhere in the 14.5v range.
Usually this voltage is reduced to mid 13's all too quickly, as it is safer to under charge a battery, and lawyers and Bean counters have already decided what is acceptable, and are not concerned about maximizing battery life, and certainly not for those of us who want to quench thirsty batteries until the batteries cry uncle, and flooded Deep cycle batteries, cycled deeply would love to cry uncle each and every recharge cycle. High $$$ Am batteries will laugh at what would make a flooded battery cry 'uncle'. Low$$$ AGm batteries would commiserate with the Ashamed flooded battery which cried uncle. Very possible the flooded battery might laugh at the sentimental low $$$ AGM which blew its caps when fed more than it could handle.
Basically when the battery is low, and being fed with charging current, until it rises in the mid 14 volt range, can accept as much current as you can feed it. Commonly called the constant current stage. This "Bulk" stage which maxes out any particular charger. Once 14.xx volts is reached, the current required to hold 14.xx volts diminishes, and keeps diminishing with more time. Once current to hold the battery at 14.xx volts starts declining significantly, the bulk stage is over, and the acceptance/ Absorption / Constant voltage stage begins.
Lifeline wants Huge initial recharging currents. They do not care how soon the current begins tapering, the important part is to Quench the battery when it is most thirsty. Tell a Lifeline battery that Grandpa said a Slow trickle charge is always best for any battery, and the Lifeline battery will come back from the grave, (probably after a still respectable lifespan) and Haunt you.
the second "stage" among the common '3 stage' charger of today is the acceptance/ absorption stage. The constant voltage stage. The charging source limits the maximum voltage, and the amperage to hold this voltage keep diminishing as the battery resists the pressure. The only way to force the battery to accept more current in this stage would be with higher pressure/voltage, but doing so is very hard on the battery, and voltages above 15 or so, can be dangerous to Electronics still connected to the battery. 3 way fridges( propane) are a notorious device damaged by excessive voltage. If there is a load on the battery when a charging source is applying 15,5 volts, and that load shuts off, the voltage can skyrocket up into the 16 or 17's, briefly, but that might be more than certain devices can handle.
Most charging sources will either claim that either a certain amount of time has passed in the acceptance stage, or the current to hold 14.xx volts has dwindled below a certain threshhold and declare the battery is fully charged, and revert to the so called third Stage, float, or sometimes Maintenance charging.
However, automatic battery charging sources today are more concerned with not Overcharging a battery. They are not really concerned with truly full charging a battery. The overcharged battery might possibly be dangerous, and if an AGM, might be damaged irreparably by a single significant overcharge,and then the lawyers start circling like vultures.
Some also believe that having a battery in maintenance mode for a week will indeed fully charge a battery. Some others state that unless that battery is held in the mid 14's for a certain amount of time, then a full charge is all but impossible.
This is highly debated and no doubt is different for each and every battery, even those of the same make/ age/ type/ and coming off the same assembly line.
My opinion is that flooded batteries will never reach a true 100% at 13.6v, no matter how long they are plugged in to a charging source. But that is opinion, worth what you paid me for it. I've read claims from others who have old Magnatec " battery boiler" converters that are feeding AGM's well into their 10th year, and once again the owner claims they are good as new, which is impossible.
Honestly, the charger manufacturers are screwed either way. The soothing green light that indicates a full charge, really means little.
With AGM batteries, one cannot stick a Hydrometer into the electrolyte and read the specific gravity of each individual cell., and this is the single best battery measuring tool, so confining oneself to AGM means one can only remain ignorant as to true state of charge.
The owner of An AGm basically needs to have an Amp hour counter, or needs to monitor when the charging current required to hold 14.4x volts, diminishes below , ie, 0.5 amps, before the battery can be considered in the 95%+ range, and even then it is just a guess, albeit a well educated one, perhaps.
So when Lifeline say there is no Limit on Bulk charging amps they are saying dunk the dehydrated person in a fresh water spring, untill 14.4v is met.
Odyssey says dunk that dehydrated person deep enough so that they will drink a minimum 40% of their body weight (battery capacity (a/h) measured at the standard 20 hour rate), until 14.7v is reached. They don t list a maximum current. Pretty much not feasible to provide more than a hundred amps anyway, as most high end converter are maxed out in this range anyway.
100 amps of Solar at 14.4v is 1440 Watts of Solar panels on their best day in full sun on a cool day.
Basically the High$$ AGM can take more charging current than most anybody could hope to provide, and will thrive on that excessive charging current, So lifeline says, do your worst( best)
The Lesser $$$ AGM say to limit charging current or the battery might be damaged.
The AGM battery which has no limits on current has less resistance to accepting charging current.
The AGM battery which say to limit current is worried that too much pressure' voltage' and too much amperage will pop the vents.
While not a true analogy, consider the1 /2 inch diameter garden hose, but attached to a fire hydrant source. Turn the Spigot all the way up. Aim it into a 55 gallon drum and eventually the bucket will fill up @ 14.xx volts, and no matter how you aim the hose, a certain percentage more is going to do nothing extra.
Now consider Hooking a 4 inch diameter firehose to the hydrant and aiming it at the 55 gallon drum at the same pressure/ voltage.
It will fill up much more rapidly, and this is what Lifeline, Odyssey, Northstar, Lifeline, and other high Dollar AGM manufacturers say is best for their batteries when they are cycled deeply, and are thirsty like Viking in the desert. These are the lowest resistance AGM batteries.
The less expensive AGMs say that you will burst the balloon if you try the firehose tactics. Do not burst the balloon. Limit bulk current to no more than 30 percent the Amp hour capacity, or no more than 30 amps for a 100 amp hour battery on these more economic AGM's.
And this is not necessarily a bad thing. Lesser AGM's could very well do better on a solar System which cannot hope to meet minimum bulk currents. But these Lesser AGM;s might not perform any better than regular Flooded batteries in the same environment, but one does not have to worry about watering them or dealing with terminal corrosion or dealing with offgassing in an enclosed space.
Also the Bragging rights one has when one owns an AGM. I'll Admit it. I Have a high$$ AGM I mostly use as an engine starting battery. The thing can start my engine so quickly it is almost scary. It Spanks My flooded battery, which is rated at 40 more amp hours, in terms of voltage held for amp hour removed, and also in the engine starting comparison. The AGM is Impressive in this matter, the fully charged larger flooded...... Eh. it works.
My high Dollar 90 amp hour Northstar AGM also obviously loves being recharged at a high rate. I can recharge it low and slow on the solar daily, and it still outperforms the flooded battery, but if I take it to 50% and then feed it 25+ Schumacher plus some solar provided amps, until the Schumacher quits, then the violence and quickness in which it starts my engine thereafter, or the surprisingly high voltages it will hold as a House battery after such a high amp recharge, is truly impressive. I really cant state this enough at this stage in the AGM's life. It is A monster. An Impressive monster at any task I have asked of it, but when solar is it's main recharging source after a week of Cycles, less so. Still better than the flooded though.
I just do not know the longevity of this AGM in such Usage. Also what does it matter if it takes .25 seconds to start my engine vs .75 seconds.
And if it holds 12.45v where as my flooded battery will drop to 12.19v under the same usage, what does it matter? I am not running an Inverter in the morning to run a coffee pot or hairdryer, where the higher voltage will make a difference. I don;t know what the low voltage alarm on my inverter sounds like, yet.
It is Just a high $$ bragging rights AGM. But a Confidence inspiring one, and I love not having to worry about checking its water levels.
I just bought a gallon of Distilled water for my flooded battery, and after I top it up, I can expect overnight voltages to fall more than they do now. Inconsequential in my usage, but what other way is there to gauge battery performance? For most it works until it does not.
My amp hour counter is another tool entirely, an eye opening one.
I am always amused when I see claims of 5 year old batteries performing just as good as day one. A 5 year old battery held on a maintenance charger for its whole life cannot have the same capacity as day one. Much less a regularly cycled one.
A more accurate description is that a 5 year old battery might still have enough capacity to meet the owner's needs, perhaps with room to spare. But a 5 year old battery which still does so, was also obviously not cycled 365 days a year either.
There is a huge difference. Cycle life vs age can be opposite ends of the spectrum, especially when daily cycles are half the equation.
Daily cyclers hoping to get max longevity should yearn to meet manufacturer recharging specs. Minimum bulk current and Acceptance voltage. Float voltage is only really important on batteries which were not cycled the night before, and if this is the case, then 2+ hours at 14.XX volts in unnecessary too.
Weekend warriors can brag about how many years they can get, but it means nothing to those of us who cycle them each and every night. Apples and oranges, or more like Apples, and anteaters.
Not comparable.
Sorry for the delay.
I tried to respond on my Phone earlier but it was not responding to my Login.
Basically when a battery is discharged below 80%, and you feed it charging current, it can gobble up as much charging current as you can feed it.
As it gobbles up the recharging current, the battery voltage rises.
Voltage is basically electrical 'pressure'
When the battery is discharged low, it is very receptive to accepting charging current. If the batteries resting voltage is 12.2v, about 50%, it is very hungry, thirsty, and can accept large amounts of charging current.
The More charging current you can supply, when the battery is thirsty, this Bulk charging stage, well, this is when the battery is most able to accept every amp of current it is fed, and it is eager to be recharged.
AGM batteries have less resistance( than regular flooded batteries) to accepting this current.
Basically, charging sources are just current providing voltage regulators. The goal being to feed the battery, but not allow the 'pressure' to get too high.
Some batteries say no more than 14.2v, others 14.7v, and some others, mostly flooded batteries, say after a few hours at 14.8v, allow them to go upto 15.3v, for the 'finishing' stage. Then after the battery is truly and obviously fully charged, then allow float voltages, which only require very small current to counteract self discharge , and are to to keep the battery at 13.06v to 13.6 volts, depending on what the manufacturer recommends for their particular battery.
Lifeline says you can feed their AGM batteries hundreds of amps, when they are depleted/ hungry/thirsty. When fed hundreds of amps, a Single medium size battery reading 12.2v, will rise up to 14.4 volts fairly quickly. Perhaps within a minute. It depends on the size and health of the battery. A flooded battery's voltage will rise much faster and an AGM.
Lifeline says this is Awesome, desirable, do it! We command you!! Blast their depleted battery with as much amperage as your charging sources can feed them, until the battery rises to 14.4v, and the battery will be like a swine in feces. Super happy. Feed the same depleted AGM battery the low and slow "trickle charge" after a deeper cycle, and the battery will NEVER, regain full energy density, until it is discharged again and recharged at, the minimum recommended bulk current.
The Odyssey engineer I spoke at length with said that it would take at least 2 cycles to 50% depth of discharge and a 40% recharging rate until 14.7v was achieved and held for 4 hours, before the chronically undercharged Odyssey battery could be restored to its maximum remaining( yet still compromised to some degree) energy density. Odyssey also states that there is basically no upper amperage limit during the bulk stage. Their hundred amp hour battery will easily accept 300 amps. The hard part is actually achieving 300 amps of charging current. That number is huge. Basically it is more than 3 standard 15 amp 115Vac outlets in a normal stick and brick could supply, or nearly so, if they were all on different circuits.
Imagine that for a second. Most people on this forum Would not max out a regular 115Vac 15amp household receptacle with every load turned on in their Van, yet a single High $$$ depleted AGM could Max out three of them, and would love the opportunity to do so.
Let me state that very few charging sources can actually produce in excess of 50 amps DC. The shiniest chromed super high rated alternator can only do so for a very short while, and only at high rpm, and before it heats up, and it will heat up quick when asked to make anything near its claimed rating. This is Info that many not want to hear, nor believe, and will gain me no friends. So it goes. Put A clamp on Ammeter on your cables after 5 minutes before you call me out on it.
Our vehicles have these pesky alternator limiting devices called voltage regulators. The voltage regulator allows the alternator to make as much current as it can at a given rpm, until the pressure/ voltage, rises to a certain amount. somewhere in the 14.5v range.
Usually this voltage is reduced to mid 13's all too quickly, as it is safer to under charge a battery, and lawyers and Bean counters have already decided what is acceptable, and are not concerned about maximizing battery life, and certainly not for those of us who want to quench thirsty batteries until the batteries cry uncle, and flooded Deep cycle batteries, cycled deeply would love to cry uncle each and every recharge cycle. High $$$ Am batteries will laugh at what would make a flooded battery cry 'uncle'. Low$$$ AGm batteries would commiserate with the Ashamed flooded battery which cried uncle. Very possible the flooded battery might laugh at the sentimental low $$$ AGM which blew its caps when fed more than it could handle.
Basically when the battery is low, and being fed with charging current, until it rises in the mid 14 volt range, can accept as much current as you can feed it. Commonly called the constant current stage. This "Bulk" stage which maxes out any particular charger. Once 14.xx volts is reached, the current required to hold 14.xx volts diminishes, and keeps diminishing with more time. Once current to hold the battery at 14.xx volts starts declining significantly, the bulk stage is over, and the acceptance/ Absorption / Constant voltage stage begins.
Lifeline wants Huge initial recharging currents. They do not care how soon the current begins tapering, the important part is to Quench the battery when it is most thirsty. Tell a Lifeline battery that Grandpa said a Slow trickle charge is always best for any battery, and the Lifeline battery will come back from the grave, (probably after a still respectable lifespan) and Haunt you.
the second "stage" among the common '3 stage' charger of today is the acceptance/ absorption stage. The constant voltage stage. The charging source limits the maximum voltage, and the amperage to hold this voltage keep diminishing as the battery resists the pressure. The only way to force the battery to accept more current in this stage would be with higher pressure/voltage, but doing so is very hard on the battery, and voltages above 15 or so, can be dangerous to Electronics still connected to the battery. 3 way fridges( propane) are a notorious device damaged by excessive voltage. If there is a load on the battery when a charging source is applying 15,5 volts, and that load shuts off, the voltage can skyrocket up into the 16 or 17's, briefly, but that might be more than certain devices can handle.
Most charging sources will either claim that either a certain amount of time has passed in the acceptance stage, or the current to hold 14.xx volts has dwindled below a certain threshhold and declare the battery is fully charged, and revert to the so called third Stage, float, or sometimes Maintenance charging.
However, automatic battery charging sources today are more concerned with not Overcharging a battery. They are not really concerned with truly full charging a battery. The overcharged battery might possibly be dangerous, and if an AGM, might be damaged irreparably by a single significant overcharge,and then the lawyers start circling like vultures.
Some also believe that having a battery in maintenance mode for a week will indeed fully charge a battery. Some others state that unless that battery is held in the mid 14's for a certain amount of time, then a full charge is all but impossible.
This is highly debated and no doubt is different for each and every battery, even those of the same make/ age/ type/ and coming off the same assembly line.
My opinion is that flooded batteries will never reach a true 100% at 13.6v, no matter how long they are plugged in to a charging source. But that is opinion, worth what you paid me for it. I've read claims from others who have old Magnatec " battery boiler" converters that are feeding AGM's well into their 10th year, and once again the owner claims they are good as new, which is impossible.
Honestly, the charger manufacturers are screwed either way. The soothing green light that indicates a full charge, really means little.
With AGM batteries, one cannot stick a Hydrometer into the electrolyte and read the specific gravity of each individual cell., and this is the single best battery measuring tool, so confining oneself to AGM means one can only remain ignorant as to true state of charge.
The owner of An AGm basically needs to have an Amp hour counter, or needs to monitor when the charging current required to hold 14.4x volts, diminishes below , ie, 0.5 amps, before the battery can be considered in the 95%+ range, and even then it is just a guess, albeit a well educated one, perhaps.
So when Lifeline say there is no Limit on Bulk charging amps they are saying dunk the dehydrated person in a fresh water spring, untill 14.4v is met.
Odyssey says dunk that dehydrated person deep enough so that they will drink a minimum 40% of their body weight (battery capacity (a/h) measured at the standard 20 hour rate), until 14.7v is reached. They don t list a maximum current. Pretty much not feasible to provide more than a hundred amps anyway, as most high end converter are maxed out in this range anyway.
100 amps of Solar at 14.4v is 1440 Watts of Solar panels on their best day in full sun on a cool day.
Basically the High$$ AGM can take more charging current than most anybody could hope to provide, and will thrive on that excessive charging current, So lifeline says, do your worst( best)
The Lesser $$$ AGM say to limit charging current or the battery might be damaged.
The AGM battery which has no limits on current has less resistance to accepting charging current.
The AGM battery which say to limit current is worried that too much pressure' voltage' and too much amperage will pop the vents.
While not a true analogy, consider the1 /2 inch diameter garden hose, but attached to a fire hydrant source. Turn the Spigot all the way up. Aim it into a 55 gallon drum and eventually the bucket will fill up @ 14.xx volts, and no matter how you aim the hose, a certain percentage more is going to do nothing extra.
Now consider Hooking a 4 inch diameter firehose to the hydrant and aiming it at the 55 gallon drum at the same pressure/ voltage.
It will fill up much more rapidly, and this is what Lifeline, Odyssey, Northstar, Lifeline, and other high Dollar AGM manufacturers say is best for their batteries when they are cycled deeply, and are thirsty like Viking in the desert. These are the lowest resistance AGM batteries.
The less expensive AGMs say that you will burst the balloon if you try the firehose tactics. Do not burst the balloon. Limit bulk current to no more than 30 percent the Amp hour capacity, or no more than 30 amps for a 100 amp hour battery on these more economic AGM's.
And this is not necessarily a bad thing. Lesser AGM's could very well do better on a solar System which cannot hope to meet minimum bulk currents. But these Lesser AGM;s might not perform any better than regular Flooded batteries in the same environment, but one does not have to worry about watering them or dealing with terminal corrosion or dealing with offgassing in an enclosed space.
Also the Bragging rights one has when one owns an AGM. I'll Admit it. I Have a high$$ AGM I mostly use as an engine starting battery. The thing can start my engine so quickly it is almost scary. It Spanks My flooded battery, which is rated at 40 more amp hours, in terms of voltage held for amp hour removed, and also in the engine starting comparison. The AGM is Impressive in this matter, the fully charged larger flooded...... Eh. it works.
My high Dollar 90 amp hour Northstar AGM also obviously loves being recharged at a high rate. I can recharge it low and slow on the solar daily, and it still outperforms the flooded battery, but if I take it to 50% and then feed it 25+ Schumacher plus some solar provided amps, until the Schumacher quits, then the violence and quickness in which it starts my engine thereafter, or the surprisingly high voltages it will hold as a House battery after such a high amp recharge, is truly impressive. I really cant state this enough at this stage in the AGM's life. It is A monster. An Impressive monster at any task I have asked of it, but when solar is it's main recharging source after a week of Cycles, less so. Still better than the flooded though.
I just do not know the longevity of this AGM in such Usage. Also what does it matter if it takes .25 seconds to start my engine vs .75 seconds.
And if it holds 12.45v where as my flooded battery will drop to 12.19v under the same usage, what does it matter? I am not running an Inverter in the morning to run a coffee pot or hairdryer, where the higher voltage will make a difference. I don;t know what the low voltage alarm on my inverter sounds like, yet.
It is Just a high $$ bragging rights AGM. But a Confidence inspiring one, and I love not having to worry about checking its water levels.
I just bought a gallon of Distilled water for my flooded battery, and after I top it up, I can expect overnight voltages to fall more than they do now. Inconsequential in my usage, but what other way is there to gauge battery performance? For most it works until it does not.
My amp hour counter is another tool entirely, an eye opening one.
I am always amused when I see claims of 5 year old batteries performing just as good as day one. A 5 year old battery held on a maintenance charger for its whole life cannot have the same capacity as day one. Much less a regularly cycled one.
A more accurate description is that a 5 year old battery might still have enough capacity to meet the owner's needs, perhaps with room to spare. But a 5 year old battery which still does so, was also obviously not cycled 365 days a year either.
There is a huge difference. Cycle life vs age can be opposite ends of the spectrum, especially when daily cycles are half the equation.
Daily cyclers hoping to get max longevity should yearn to meet manufacturer recharging specs. Minimum bulk current and Acceptance voltage. Float voltage is only really important on batteries which were not cycled the night before, and if this is the case, then 2+ hours at 14.XX volts in unnecessary too.
Weekend warriors can brag about how many years they can get, but it means nothing to those of us who cycle them each and every night. Apples and oranges, or more like Apples, and anteaters.
Not comparable.
Luisafernandes
Well-known member
That's all you going to say? I thought I was getting an in depth description on how batteries work?
Wow, just kidding. Very informative. I must say I'll have to read that a few more times to understand it more fully.
In your opinion, would buying a Lifeline be a good choice, or do you have others in mind?
Thanks a bunch!
Wow, just kidding. Very informative. I must say I'll have to read that a few more times to understand it more fully.
In your opinion, would buying a Lifeline be a good choice, or do you have others in mind?
Thanks a bunch!
Zil
Well-known member
Good job SternWake. I have seen opinions for both sides of AGM batteries. The boat people seem to have more problems with AGM than with FLA used as house banks. I think it is the inability to charge the AGM properly. They are not as forgiving as FLA. I would switch from FLA to LiFePo technology before considering AGM. But that is me.
SternWake
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Lifeline has one of the most informative pages on the Internet about Lead acid batteries.
http://www.lifelinebatteries.com/manual.pdf
They say a 100 amp hour battery cycled to below 50% should receive no less than 20 amps, which is half of What Odyssey recommends.
All the top Dog AGM's will be good choices for those that have decided on the AGM path. The Odyssey might last just as long when treated the same as the other AGM's. Who can really say, but they are rather adamant about a 40% recharging current when deeply cycled, and no doubt this will scare away some customers who are aware of it. Yet they still do it, where as the marketing departments of other batteries might scream bloody murder at any published literature requiring extra effort from the user to achieve a full charge.
Batteries Plus, a nationwide chain, Rebadges NorthStar AGM's as X2 Power, and adds another year to the warranty.
Sears Rebadges Odyssey batteries and calls them their Diehard Platinum AGM series, generally they are a good percentage less expensive than the Odyssey. The odyssey engineer I spoke with said they are exactly the same internally. No corners were cut when stuffing the different colored battery case with lead plates.
Sears rebadges Deka Intimidator AGM and calls them Die Hard gold AGM. These are among the most economical AGM's available.
As I stated, I am extremely impressed with my Northstar AGM, but it is only 8 months old at this point, and I am cycling my other Flooded battery 6 to 1 more, so a longevity comparison will mean little.
Whatever AGM you do ultimately decide upon should perform well, if you can meet their recommended recharge regimen to a T, every so often, say every 7 to 14 cycles, and more is better.
While lead acid batteries supposedly have no memory, I find that an occasional deeper discharge and a high recharge rate for an adequate timespan, is like a slap across the face of a lazy battery whether flooded or AGM.
It's all about the recharging. Some put their confidence in the high dollar name and are disappointed at premature failure, some others buy cheap yet recharge the battery promptly and fully and can get thousands of cycles.
The battery depleter needs to learn how to be a good battery recharger to get a good lifespan. And this starts with the manufacturer recommended regimen. Find a battery which comes closest to the abilities of the charging source, or tailor the charging product to the battery recharge specs.
The best AGM on the planet is still going to be damaged by chronic undercharging.
http://www.lifelinebatteries.com/manual.pdf
They say a 100 amp hour battery cycled to below 50% should receive no less than 20 amps, which is half of What Odyssey recommends.
All the top Dog AGM's will be good choices for those that have decided on the AGM path. The Odyssey might last just as long when treated the same as the other AGM's. Who can really say, but they are rather adamant about a 40% recharging current when deeply cycled, and no doubt this will scare away some customers who are aware of it. Yet they still do it, where as the marketing departments of other batteries might scream bloody murder at any published literature requiring extra effort from the user to achieve a full charge.
Batteries Plus, a nationwide chain, Rebadges NorthStar AGM's as X2 Power, and adds another year to the warranty.
Sears Rebadges Odyssey batteries and calls them their Diehard Platinum AGM series, generally they are a good percentage less expensive than the Odyssey. The odyssey engineer I spoke with said they are exactly the same internally. No corners were cut when stuffing the different colored battery case with lead plates.
Sears rebadges Deka Intimidator AGM and calls them Die Hard gold AGM. These are among the most economical AGM's available.
As I stated, I am extremely impressed with my Northstar AGM, but it is only 8 months old at this point, and I am cycling my other Flooded battery 6 to 1 more, so a longevity comparison will mean little.
Whatever AGM you do ultimately decide upon should perform well, if you can meet their recommended recharge regimen to a T, every so often, say every 7 to 14 cycles, and more is better.
While lead acid batteries supposedly have no memory, I find that an occasional deeper discharge and a high recharge rate for an adequate timespan, is like a slap across the face of a lazy battery whether flooded or AGM.
It's all about the recharging. Some put their confidence in the high dollar name and are disappointed at premature failure, some others buy cheap yet recharge the battery promptly and fully and can get thousands of cycles.
The battery depleter needs to learn how to be a good battery recharger to get a good lifespan. And this starts with the manufacturer recommended regimen. Find a battery which comes closest to the abilities of the charging source, or tailor the charging product to the battery recharge specs.
The best AGM on the planet is still going to be damaged by chronic undercharging.
Luisafernandes
Well-known member
SternWake, great info! Thanks!
Just to confirm that I didn't misread other posts, if I get; 500 watts of solar, do I need exactly 500 amps of battery, or can I get a little less, or do I need a little more? Thanks!
Just to confirm that I didn't misread other posts, if I get; 500 watts of solar, do I need exactly 500 amps of battery, or can I get a little less, or do I need a little more? Thanks!
Where~the~wind~blows
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Sadly I must ask what is an AGM battery?
Luisafernandes
Well-known member
Hi!
I know this one! Well, kinda. I knew what AGM meant but had to look it up to refresh my memory.
"There are two primary types of VRLA batteries, gel cells and AGM. Gel cells add silica dust to the electrolyte, forming a thick putty-like gel. These are sometimes referred to as "silicone batteries". AGM, short for "absorbed glass mat", batteries feature fiberglass mesh between the battery plates which serves to contain the electrolyte. Both designs offer advantages and disadvantages compared to conventional batteries, as well as each other." From Wikipedia.
I know this one! Well, kinda. I knew what AGM meant but had to look it up to refresh my memory.
"There are two primary types of VRLA batteries, gel cells and AGM. Gel cells add silica dust to the electrolyte, forming a thick putty-like gel. These are sometimes referred to as "silicone batteries". AGM, short for "absorbed glass mat", batteries feature fiberglass mesh between the battery plates which serves to contain the electrolyte. Both designs offer advantages and disadvantages compared to conventional batteries, as well as each other." From Wikipedia.
Where~the~wind~blows
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Luisafernandes said:
thanks! didn't think to look it up... duh moment...
Luisafernandes
Well-known member
Where~the~wind~blows said:
: )
No problem.
SternWake
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Luisa, 100 watts of solar to 100 amp hours of battery is a general guideline, and a pretty generous one too.
You can vary the ratio, but more solar for less capacity makes the batteries happier and gives a bigger buffer for bad weather.
In general the roof real estate limits the amount of possible solar wattage. Try to match battery capacity to the wattage on the roof for best results, the best results being happy long lived batteries.
You can vary the ratio, but more solar for less capacity makes the batteries happier and gives a bigger buffer for bad weather.
In general the roof real estate limits the amount of possible solar wattage. Try to match battery capacity to the wattage on the roof for best results, the best results being happy long lived batteries.
