Simple Battery Question:
Advanced
Joined: Aug 2010
Posts: 50
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From: San Diego, CA
Actually the battery in question is not a gel-cell, its an absorbed gas mat (AGM) battery. Of the three common types of batteries (wet-cell, gel-cell and AGM) the AGM is the better option, also usually more expensive. The AGM combines the "best" traits of batteries, high cranking amps and deep cycle use. Usually AGM batteries do not require an initial charge when installed; install the battery then start and ride the bike for awhile to make sure all is good.
Additionally: If by chance you do get a gel-cell battery make sure your charger is for gell cell batteries. Gel-cell batteries require a lower charging voltage than wet-cell and AGM batteries. If you charge a gel-cell with a charger that is not rated for gel-cell batteries you will damage the battery.
If y'all are wondering, I've been an electrician for going on 27 years.
Additionally: If by chance you do get a gel-cell battery make sure your charger is for gell cell batteries. Gel-cell batteries require a lower charging voltage than wet-cell and AGM batteries. If you charge a gel-cell with a charger that is not rated for gel-cell batteries you will damage the battery.
If y'all are wondering, I've been an electrician for going on 27 years.
Road Captain
Joined: Sep 2010
Posts: 535
Likes: 0
From: Huntington Beach
Of course putting it on the Battery Tender won't hurt. However if the open circuit voltage is over 12.6 volts on a new battery, you will be close to a full charge. If the new battery is over 12.7 volts, its almost guaranteed to at or near full charge. These values are for a battery that has been off charge for a minimum of 12 hours.
You should always check the battery voltage out of the box. AGM batteries have an exceptionally good shelf life, self-discharge is very low. If a new battery is low, take it back and get another, chances are its been sitting for a very long time and there could be some sulfation that has already occurred. If its not an old battery, then you still dont want it, it means that the battery has a high resistance short and is self-discharging. Id be a little suspicious of anything below 12.5, and certainly not below 12.4.
The motorcycle charging system is designed to charge and maintain the battery just fine. The back EMF of the battery will dictate the rate of charge current. It would be different if the Battery that had been completely discharged, then you would want to current limit the rate of charge.
You should always check the battery voltage out of the box. AGM batteries have an exceptionally good shelf life, self-discharge is very low. If a new battery is low, take it back and get another, chances are its been sitting for a very long time and there could be some sulfation that has already occurred. If its not an old battery, then you still dont want it, it means that the battery has a high resistance short and is self-discharging. Id be a little suspicious of anything below 12.5, and certainly not below 12.4.
The motorcycle charging system is designed to charge and maintain the battery just fine. The back EMF of the battery will dictate the rate of charge current. It would be different if the Battery that had been completely discharged, then you would want to current limit the rate of charge.
Club Member
Joined: Mar 2009
Posts: 66,126
Likes: 51,446
From: Niles Canyon Ca.
Actually the battery in question is not a gel-cell, its an absorbed gas mat (AGM) battery. Of the three common types of batteries (wet-cell, gel-cell and AGM) the AGM is the better option, also usually more expensive. The AGM combines the "best" traits of batteries, high cranking amps and deep cycle use. Usually AGM batteries do not require an initial charge when installed; install the battery then start and ride the bike for awhile to make sure all is good.
Additionally: If by chance you do get a gel-cell battery make sure your charger is for gell cell batteries. Gel-cell batteries require a lower charging voltage than wet-cell and AGM batteries. If you charge a gel-cell with a charger that is not rated for gel-cell batteries you will damage the battery.
If y'all are wondering, I've been an electrician for going on 27 years.
Additionally: If by chance you do get a gel-cell battery make sure your charger is for gell cell batteries. Gel-cell batteries require a lower charging voltage than wet-cell and AGM batteries. If you charge a gel-cell with a charger that is not rated for gel-cell batteries you will damage the battery.
If y'all are wondering, I've been an electrician for going on 27 years.
I would do a little google research on AGM batteries , they are not the same animal as gel cells or the old sealed wet acid batteries and they do have a bit different handling & charging characteristics . Just an FYI before you cut the life of the battery by doing something wrong .
Road Captain
Joined: Sep 2010
Posts: 535
Likes: 0
From: Huntington Beach
The gel battery is very similar to the AGM as far as charging. I have seen a couple of info sites that claim different but it isn't so. Also, may have been a typo but AGM is absorbed glass mat, glass meaning the separator material is a fiberglass mat that absorbs the electrolyte.
I come from the battery industry back in the 80's and 90's, I was the plant engineer for Power Sonic corporation. We were originally a gel battery manufacturer and then eventually moved into the AGM market as the technology evolved. I designed the high voltage charging facility while there and we built our own in house chargers for our own process. We worked with consumer charger manufacturers to get them to start designing chargers for consumers that were more specific to the sealed lead acid battery.
Electrochemically, what makes both the AGM and gel batteries different from the traditional wet batteries is that they are made with a calcium lead alloy whereas the wet cell is made with an antimony lead alloy. Both AGM and gel are gas recombinant systems, which allows them to be sealed with a pressure valve rather than a vent as in a wet system. Electrochemically, they are pretty much the same. Electrochemically, they get charged the same and their float requirements are very similar. They are both considered SLA (sealed lead-acid) batteries or VRLA (valve regulated lead-acid) batteries.
Where there may be some misconception is that, apples to apples, the AGM may tolerate an overcharge state a little better than the gel. The gel will actually dry out. Its basically sulfuric with fumed silica to make it jelly-like. But overcharge is detrimental to both in the end, they are not as tolerant as the wet cell batteries. There are not as many gel batteries in the market place anymore, AGM has won out in many markets, the gel is much more difficult and expensive to manufacture.
I don't mean to pick anyones post apart, your word of caution here is very wise. Just trying to lend some industry info.
I come from the battery industry back in the 80's and 90's, I was the plant engineer for Power Sonic corporation. We were originally a gel battery manufacturer and then eventually moved into the AGM market as the technology evolved. I designed the high voltage charging facility while there and we built our own in house chargers for our own process. We worked with consumer charger manufacturers to get them to start designing chargers for consumers that were more specific to the sealed lead acid battery.
Electrochemically, what makes both the AGM and gel batteries different from the traditional wet batteries is that they are made with a calcium lead alloy whereas the wet cell is made with an antimony lead alloy. Both AGM and gel are gas recombinant systems, which allows them to be sealed with a pressure valve rather than a vent as in a wet system. Electrochemically, they are pretty much the same. Electrochemically, they get charged the same and their float requirements are very similar. They are both considered SLA (sealed lead-acid) batteries or VRLA (valve regulated lead-acid) batteries.
Where there may be some misconception is that, apples to apples, the AGM may tolerate an overcharge state a little better than the gel. The gel will actually dry out. Its basically sulfuric with fumed silica to make it jelly-like. But overcharge is detrimental to both in the end, they are not as tolerant as the wet cell batteries. There are not as many gel batteries in the market place anymore, AGM has won out in many markets, the gel is much more difficult and expensive to manufacture.
I don't mean to pick anyones post apart, your word of caution here is very wise. Just trying to lend some industry info.
Club Member
Joined: Mar 2009
Posts: 66,126
Likes: 51,446
From: Niles Canyon Ca.
The gel battery is very similar to the AGM as far as charging. I have seen a couple of info sites that claim different but it isn't so. Also, may have been a typo but AGM is absorbed glass mat, glass meaning the separator material is a fiberglass mat that absorbs the electrolyte.
I come from the battery industry back in the 80's and 90's, I was the plant engineer for Power Sonic corporation. We were originally a gel battery manufacturer and then eventually moved into the AGM market as the technology evolved. I designed the high voltage charging facility while there and we built our own in house chargers for our own process. We worked with consumer charger manufacturers to get them to start designing chargers for consumers that were more specific to the sealed lead acid battery.
Electrochemically, what makes both the AGM and gel batteries different from the traditional wet batteries is that they are made with a calcium lead alloy whereas the wet cell is made with an antimony lead alloy. Both AGM and gel are gas recombinant systems, which allows them to be sealed with a pressure valve rather than a vent as in a wet system. Electrochemically, they are pretty much the same. Electrochemically, they get charged the same and their float requirements are very similar. They are both considered SLA (sealed lead-acid) batteries or VRLA (valve regulated lead-acid) batteries.
Where there may be some misconception is that, apples to apples, the AGM may tolerate an overcharge state a little better than the gel. The gel will actually dry out. It’s basically sulfuric with fumed silica to make it jelly-like. But overcharge is detrimental to both in the end, they are not as tolerant as the wet cell batteries. There are not as many gel batteries in the market place anymore, AGM has won out in many markets, the gel is much more difficult and expensive to manufacture.
I don't mean to pick anyone’s post apart, your word of caution here is very wise. Just trying to lend some industry info.
I come from the battery industry back in the 80's and 90's, I was the plant engineer for Power Sonic corporation. We were originally a gel battery manufacturer and then eventually moved into the AGM market as the technology evolved. I designed the high voltage charging facility while there and we built our own in house chargers for our own process. We worked with consumer charger manufacturers to get them to start designing chargers for consumers that were more specific to the sealed lead acid battery.
Electrochemically, what makes both the AGM and gel batteries different from the traditional wet batteries is that they are made with a calcium lead alloy whereas the wet cell is made with an antimony lead alloy. Both AGM and gel are gas recombinant systems, which allows them to be sealed with a pressure valve rather than a vent as in a wet system. Electrochemically, they are pretty much the same. Electrochemically, they get charged the same and their float requirements are very similar. They are both considered SLA (sealed lead-acid) batteries or VRLA (valve regulated lead-acid) batteries.
Where there may be some misconception is that, apples to apples, the AGM may tolerate an overcharge state a little better than the gel. The gel will actually dry out. It’s basically sulfuric with fumed silica to make it jelly-like. But overcharge is detrimental to both in the end, they are not as tolerant as the wet cell batteries. There are not as many gel batteries in the market place anymore, AGM has won out in many markets, the gel is much more difficult and expensive to manufacture.
I don't mean to pick anyone’s post apart, your word of caution here is very wise. Just trying to lend some industry info.
Last edited by TwiZted Biker; Jan 14, 2011 at 07:54 PM.
Road Captain
Joined: Sep 2010
Posts: 535
Likes: 0
From: Huntington Beach
Thanks for the tech break down , always looking for a education on things and the supplier I get the AGM batteries from has zero specs other than the standard sale rhetoric about how improved they are . I get questions I can answer intelligently now . Do you have general guidelines for the bike size batteries as far charging / type of charger & amp settings ? I know a couple models out there take a heavy amp ( 10.0+ amps ) charge like deep cycle batteries and never show over 12.75 volts fully up .
Even using a grunt charger that puts out 10 amps, ultimately the battery will determine the current and as the back EMF voltage goes up from the batterys internal resistance, then the current will taper down, providing the charger is a taper type charger. Some of the big grunt quick chargers are of the constant current type, those you really have to be careful with. But with limiting the charge rate at 2 amps, then a discharged battery is absorbing energy without meeting it's internal resistance capacity, resulting in a much more complete charge without overheating the little guy.
If you are going to float the battery, be sure that the charger is specifically designed to float or maintain a sealed lead-acid battery. For occasional charging, a good automotive type 2/4/6 amp selectable taper charger will work fine, just use the lower setting, if you can find one with even more settings on the low side, then better. When your on charge voltage gets up over 14 volts, your current will be almost nil, thats when she be done, take her off charge. 12 hours later, on the bench, you should be 12.7-12.8 (ish) volts, confirming that its fully charged.
Hope that helps.
Stellar HDF Member
Joined: Feb 2010
Posts: 3,396
Likes: 266
From: Southern California
The industry safe current used to be a C/4 rate for maximum, not sure if that has changed over the years but its probably still a good safe guideline to follow. That essentially means capacity divided by 4. Which refers to 'reserve capacity'. So if you have a scooter battery that is rated at 20 amp/hr reserve capacity, then your very most maximum current would be 5 amps (20/4). Again, that would be max. I myself have always preferred the C/10 rate so that same 20 amp/hr battery would get charged at 2 amp. Or if you have the time and want to be real conservative, go with the C/20 rate.
Even using a grunt charger that puts out 10 amps, ultimately the battery will determine the current and as the back EMF voltage goes up from the batterys internal resistance, then the current will taper down, providing the charger is a taper type charger. Some of the big grunt quick chargers are of the constant current type, those you really have to be careful with. But with limiting the charge rate at 2 amps, then a discharged battery is absorbing energy without meeting it's internal resistance capacity, resulting in a much more complete charge without overheating the little guy.
If you are going to float the battery, be sure that the charger is specifically designed to float or maintain a sealed lead-acid battery. For occasional charging, a good automotive type 2/4/6 amp selectable taper charger will work fine, just use the lower setting, if you can find one with even more settings on the low side, then better. When your on charge voltage gets up over 14 volts, your current will be almost nil, thats when she be done, take her off charge. 12 hours later, on the bench, you should be 12.7-12.8 (ish) volts, confirming that its fully charged.
Hope that helps.
Even using a grunt charger that puts out 10 amps, ultimately the battery will determine the current and as the back EMF voltage goes up from the batterys internal resistance, then the current will taper down, providing the charger is a taper type charger. Some of the big grunt quick chargers are of the constant current type, those you really have to be careful with. But with limiting the charge rate at 2 amps, then a discharged battery is absorbing energy without meeting it's internal resistance capacity, resulting in a much more complete charge without overheating the little guy.
If you are going to float the battery, be sure that the charger is specifically designed to float or maintain a sealed lead-acid battery. For occasional charging, a good automotive type 2/4/6 amp selectable taper charger will work fine, just use the lower setting, if you can find one with even more settings on the low side, then better. When your on charge voltage gets up over 14 volts, your current will be almost nil, thats when she be done, take her off charge. 12 hours later, on the bench, you should be 12.7-12.8 (ish) volts, confirming that its fully charged.
Hope that helps.
I worked for an OEM that used the expanded metal Lead/Calcium grid design to provide extended shelf life due to the low self discharge rate that minimizing the antimony in the battery structure provided. Our general rule for a these batteries was then when the battery was 0n the 50%-70% plus State of Charge side of the charging curve; that a charging rate of 1 ampere at 14 volts represented a battery between 98%-100% SOC. You just have to be careful because a discharged battery can give the same voltage and charging rate characteristics.
Club Member
Joined: Feb 2008
Posts: 18,575
Likes: 4
From: Norfolk, VA
If the battery reads less than 12.5V, hit it with a low current charger...If more install it and let it rip!!
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