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What you need to know about Optima AGM batteries.
An AGM battery is not like a typical lead/acid flooded battery. As we all know they can be mounted in any orientation you want. We also know they are a better battery than a typical lead/acid battery. What I didn't know until a week ago about them makes them even more special.
If you have a typical lead/acid battery and it dips below 10 volts, most people that specialize in batteries will suggest that you replace it saying irreversible damage has happened, or the battery will no longer have it's stated capacity.
Not wanting to run an extension cord out my garage out into the snow over the winter, my Optima red top in my car got forgotten about. A mistake I assumed cost me ~$160-180 for a new one. I've made this assumption before and traded in a dead Optima years ago. After doing some homework on the internet I found out just how special AGM cell batteries are. I found out they can be subject to a much deeper discharge (similar to deep cycle) than the norm of 10 volts of a lead acid battery and still be fine. So, having a couple chargers on hand, I put mine to the test.
Fact: AGM batteries don't really care for fast charging rates of typical fast chargers.
My charger has 2 amp, 10 amp, and 20 amp charging settings along with a 250 amp setting for engine starting. You may want your battery charged faster, but resist the urge. After arming myself with what I read about Optimas I set my charger for 2 amp charging. I was kind of skeptical if this battery would even function again after this because when I had measured it, it was down around 1.5 volts. My big honking battery was putting out nothing more voltage wise than a typical AA battery.
I originally made the mistake of putting it on the 40 amp setting when I brought it into the garage, but in a days time it only made it up to about 3.5 volts when I made the discovery online about charging rates and such. As soon as I read multiple reports of success on a slower rate, I made my way to the garage and flipped the charger down to 2 amps around late afternoon. That evening I checked on it to see if the battery was getting hot and to check the state of charge. It was now up over 7 volts. The next day I checked it on the way to work and it was up to about 10-11 volts. Today I checked it after leaving the charger off for over a day to make sure I wasn't reading a surface charge and it read around 12.5 volts. Not too long ago I put the battery back in the car and it fired up the first try with a nice healthy charged battery sound. I don't expect that it will have 100% of its original capacity, but at least it's not going to cost me almost $200 to get a new one right now.
That said, if you find your Optima dead as a doornail, what do you have to lose with trying a trickle charge first?
An AGM battery is not like a typical lead/acid flooded battery. As we all know they can be mounted in any orientation you want. We also know they are a better battery than a typical lead/acid battery. What I didn't know until a week ago about them makes them even more special.
If you have a typical lead/acid battery and it dips below 10 volts, most people that specialize in batteries will suggest that you replace it saying irreversible damage has happened, or the battery will no longer have it's stated capacity.
Not wanting to run an extension cord out my garage out into the snow over the winter, my Optima red top in my car got forgotten about. A mistake I assumed cost me ~$160-180 for a new one. I've made this assumption before and traded in a dead Optima years ago. After doing some homework on the internet I found out just how special AGM cell batteries are. I found out they can be subject to a much deeper discharge (similar to deep cycle) than the norm of 10 volts of a lead acid battery and still be fine. So, having a couple chargers on hand, I put mine to the test.
Fact: AGM batteries don't really care for fast charging rates of typical fast chargers.
My charger has 2 amp, 10 amp, and 20 amp charging settings along with a 250 amp setting for engine starting. You may want your battery charged faster, but resist the urge. After arming myself with what I read about Optimas I set my charger for 2 amp charging. I was kind of skeptical if this battery would even function again after this because when I had measured it, it was down around 1.5 volts. My big honking battery was putting out nothing more voltage wise than a typical AA battery.
I originally made the mistake of putting it on the 40 amp setting when I brought it into the garage, but in a days time it only made it up to about 3.5 volts when I made the discovery online about charging rates and such. As soon as I read multiple reports of success on a slower rate, I made my way to the garage and flipped the charger down to 2 amps around late afternoon. That evening I checked on it to see if the battery was getting hot and to check the state of charge. It was now up over 7 volts. The next day I checked it on the way to work and it was up to about 10-11 volts. Today I checked it after leaving the charger off for over a day to make sure I wasn't reading a surface charge and it read around 12.5 volts. Not too long ago I put the battery back in the car and it fired up the first try with a nice healthy charged battery sound. I don't expect that it will have 100% of its original capacity, but at least it's not going to cost me almost $200 to get a new one right now.
That said, if you find your Optima dead as a doornail, what do you have to lose with trying a trickle charge first?
I didn't realize slower was better all across the board for all types of battery and didn't even think of boiling the acid dry.
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