AGM, GEL,SEALED,FLOODED, OPEN, BATTERY QUESTIONS??

[magnetman12003]

I am considering buying a charger for lead acid batteries.  However I see there are many types of lead acid batteries on the market.

My fist question: What is the difference between the sealed lead acid battery and a GEL battery and can a single charger work for both types?

Second question: Will a Absorbent glass mat (AGM) charger work with a sealed lead acid battery?

[thx1138]

I spent some time recently looking into lead acid batteries. They are all base on electrochemistry and each has a specific chemistry and therefore differing charging and discharging regimes.

I'm not exactly sure what you mean by "sealed lead acid battery". That's a type of construction rather than a type of battery. "Sealed" is somewhat of a misnomer because all lead acid batteries must be able to vent or they would explode so they are not totally sealed. There are

If you mean a "maintenance free battery" as used in vehicles the only different between them that I can see is that you can't add water to a "maintenance free battery. Long story, shortI was on vacation one time, pulled in for gasoline, and the car wouldn't start. It had started fine when we left that morning. I had it towed to a garage and apparently that sloshed the electrolyte around some. When they disconnected it from the tow truck it started right up. I put a new battery in it anyway and when I got home I cut open the "maintenance free" battery and that was the only difference I could see. If I could have added water to it, it would have been fine. I haven't bought a  "maintenance free" battery since then.

In general, what we think of as "normal" lead acid battery comes in two versions: a "starting" battery is what is used in cars, boats, etc. It has a fast, strong discharge to run starter motors for a short time and a fast charging regime; and a "deep cycle" battery which discharges more slowly but for a longer period and charges more slowly.

I've used both gel-cell and AGM batteries and I've usually just charged them with a cord from the accessory socket in my truck. That might have shortened their life somewhat but they've always lasted 5 to 7 years for me and that's in outdoor applications where the temperatures vary from around -20F to 105F over the course of a year.

The thing that is important about the charging regime is the point at which the electrolyte starts outgassing. If the voltage is too high it will outgas faster which is basically boiling away electrolyte. In a servere case the battery could explode but even minor over voltages beyond the battery's specs will increase outgassing and thus deplete the electrolyte faster. That's a problem in a sealed battery because you can't replenish the electrolyte.

I learned in my recent research that there is a lot more that goes into the chemistry of a battery than lead and electrolyte. It's an art in itself. It's all about ion transfer.

BTW, lead dioxide which is implanted on one set of the plates will kill you in very small doses if ingested so be careful if you open up any batteries. It is a dark brown color.

You might find a charger that will handle several different types but I haven't looked for one. I'm not sure that the charger itself could detect the different types of lead acid batteries and adjust the charging parameters accordingly like some of the chargers do for NiCd, NMHi, Li, etc. So it would probably have switches or buttons or a display to select the battery type.

There's a world of information about lead acid batteries out on the web. It surprised me how much info is out there about all the different types.

[magnetman12003]

I spent some time recently looking into lead acid batteries. They are all base on electrochemistry and each has a specific chemistry and therefore differing charging and discharging regimes.

I'm not exactly sure what you mean by "sealed lead acid battery". That's a type of construction rather than a type of battery. "Sealed" is somewhat of a misnomer because all lead acid batteries must be able to vent or they would explode so they are not totally sealed. There are

If you mean a "maintenance free battery" as used in vehicles the only different between them that I can see is that you can't add water to a "maintenance free battery. Long story, shortI was on vacation one time, pulled in for gasoline, and the car wouldn't start. It had started fine when we left that morning. I had it towed to a garage and apparently that sloshed the electrolyte around some. When they disconnected it from the tow truck it started right up. I put a new battery in it anyway and when I got home I cut open the "maintenance free" battery and that was the only difference I could see. If I could have added water to it, it would have been fine. I haven't bought a  "maintenance free" battery since then.

In general, what we think of as "normal" lead acid battery comes in two versions: a "starting" battery is what is used in cars, boats, etc. It has a fast, strong discharge to run starter motors for a short time and a fast charging regime; and a "deep cycle" battery which discharges more slowly but for a longer period and charges more slowly.

I've used both gel-cell and AGM batteries and I've usually just charged them with a cord from the accessory socket in my truck. That might have shortened their life somewhat but they've always lasted 5 to 7 years for me and that's in outdoor applications where the temperatures vary from around -20F to 105F over the course of a year.

The thing that is important about the charging regime is the point at which the electrolyte starts outgassing. If the voltage is too high it will outgas faster which is basically boiling away electrolyte. In a servere case the battery could explode but even minor over voltages beyond the battery's specs will increase outgassing and thus deplete the electrolyte faster. That's a problem in a sealed battery because you can't replenish the electrolyte.

I learned in my recent research that there is a lot more that goes into the chemistry of a battery than lead and electrolyte. It's an art in itself. It's all about ion transfer.

BTW, lead dioxide which is implanted on one set of the plates will kill you in very small doses if ingested so be careful if you open up any batteries. It is a dark brown color.

You might find a charger that will handle several different types but I haven't looked for one. I'm not sure that the charger itself could detect the different types of lead acid batteries and adjust the charging parameters accordingly like some of the chargers do for NiCd, NMHi, Li, etc. So it would probably have switches or buttons or a display to select the battery type.

There's a world of information about lead acid batteries out on the web. It surprised me how much info is out there about all the different types.

Thanks for your input on this