Need Help Charging AGM Battery From Home AC Power

[Sunking]

What you are falling for is Marketing. There is nothing magic about battery chargers. They all do the exact same thing, supply current. Pb batteries are pure chemical reactions with known properties.

All I have been telling you is AGM is different than FLA batteries. They do not use a liquid electrolyte. What little moisture in a AGM battery has to be recombined, and to do that require a minimum current to recombine Hydrogen and Oxygen. Sure a manufacture can say it will charge up to a 125 AH battery with 4 amps. At face value is true if time is of no concern, and a minimum charge current is not required. But that charger does not know what size battery is connected to and what the requirements are. Well expensive ones do because you tell it and then it knows how much current the battery needs.

It is up to the buyer to size the charger correctly. All Pb batteries have maximum and minimum charge rate limits. It is just a characteristic of the chemistry in order to have needed chemical reactions. FLA is universal of a minimum of C/12, and maximum of C/8. AGM and Gel although are Pb, are under pressure and have slightly different requirements in charge rate. Gel must be charged slowly, AGM, or most AGM's need to be charged at higher rates. Example if you have a 100 AH AGM and manufacture minimum charge rate is C/10 and Maximum is C/2 means you charger must be at least 10 amps and no greater than 50 amps. 4 amps will not work no natter what the charger manufacture says.

Will your AGM fully recombine with only 4 amps. I cannot answer that, but I have doubts if it is a 100 AH battery because 4 amps on a 100 AH battery is C/25 which is extremely slow for a battery charger. C/25 is what is called a Trickle Charger to maintain fully charged batteries, not intended to charge a battery.

What I can tell you and anyone following along is a C/10 charger will work for 95% of the time for any battery type or chemistry. Makes life real easy.

[Logan005]

I am glad you are listening. if you haven’t already, disconnect that refrigerator and put the battery on that 1amp maintainer and see if it recovers.

[PowerNS]

I really don't know what to say. ha, call emm, you haven’t listened to any advice given here. I expect better luck for them, as they are trying to sell you, will tell you what you want to hear. Again read the Stickys.

That's not true, I've totally listened to your advice, and I appreciate it. There is a difference between not listening, and questioning, aren't I allowed to question what is being told to me? If YOU had 2 conflicting bits of information coming from 2 different places, wouldn't you want something to back those claims up?
Especially when one of the sources of info is a legitimate long standing company with a good reputation.


I'm sure your right, the 10A charger is probably the better way to go.

[Sunking]

I guess if that happens, I'll upgrade to the 10A charger.

By the time you notice will be too late.

[Logan005]

I really don't know what to say. ha, call emm, you haven’t listened to any advice given here. I expect better luck for them, as they are trying to sell you, will tell you what you want to hear. Again read the Stickys.

[PowerNS]

I never rely on that inverter voltage level display, or the alarm that sounds like a sick and dying criscket...lol.
I have a panel voltage meter wired directly across the +/- poles of the battery, and am watching it like a hawk.
I just sent an email to the manufacturer of the charger, asking them WHY they advertise the 4A charger is good for a 100Ah batter if it is not.
It will be interesting to hear what they have to say.

[Logan005]

that invoice will include a 10amp charger, a new battery and a Low level disconnect. your inverter will only audibly notify you when your voltage drops to 11 volts, most that do auto shutdown don't do so till 10 to 10.5 volts, long after battery is fatally damaged. your currently running PSW and refrigerator, I hope you are monitoring the voltage level. I would not allow it to drop below 12.2 volts.

[PowerNS]

I guess if that happens, I'll upgrade to the 10A charger.

[Logan005]

you are currently discharging a battery you do not have the ability to completely recharge. good luck with it.

[PowerNS]

I'm looking at the specs of this charger, it says that it "repairs" batteries that have been too deeply discharged, if it's supposed to have a feature to repair batteries, how could it be bad for a battery, even if the charging amps are too low??
From the specs:

• Brings batteries back to life; an advanced recovery mode repairs damaged areas of the battery to provide longer, healthier battery performance. Recovers deeply discharged and sulfated batteries with pulse charging.
• Rapid Charging Technology; charges batteries 2X faster than traditional battery chargers, and a lightweight, compact design
• The GEN Mini interactively diagnoses, recovers, and charges wet, gel, MF and AGM batteries from 20-120 ampere hour and maintains all battery sizes.
• Recovery Applies a high-voltage pulse charge when low-voltage, sulfation or lost capacity is detected
  
  

[PowerNS]

The most likely conclusion to draw from what you describe is that one of three things has happened.
1. Your "fully charged" indication is not valid.
2. The battery was only very slightly discharged in the first place, or, most probably
3. Your battery has almost no capacity left at this point and so has reached a "full charge" point which is not very far from the "fully discharged" point.

It looks like my battery was not that discharged to begin with, which is pretty amazing since it's been sitting inside since last May without being charged, but it has been in a room temp environment.

I connected a 1000W pure sine inverter, and have been running a fridge off of the battery for many hours now, and still it has not dipped below the low mark.

I'm guessing the battery is OK, and has the usual capacity as it always had, and it actually was fully charged after connecting it to the new charger.

[Logan005]

maintenance and bulk charges are different. you need to reread all the stickys on battery's and charging stages.

[inetdog]

I understand what you are saying, don't get me wrong, I just don't understand why the manufacturer of the charger says that it is good for batteries up to 120aH if in actuality it is not, and could harm your battery.
Ironically, my battery is now fully charged after only 1/2 hour connected to the charger.
Surprising.

The most likely conclusion to draw from what you describe is that one of three things has happened.
1. Your "fully charged" indication is not valid.
2. The battery was only very slightly discharged in the first place, or, most probably
3. Your battery has almost no capacity left at this point and so has reached a "full charge" point which is not very far from the "fully discharged" point.

[PowerNS]

I understand what you are saying, don't get me wrong, I just don't understand why the manufacturer of the charger says that it is good for batteries up to 120aH if in actuality it is not, and could harm your battery.
Ironically, my battery is now fully charged after only 1/2 hour connected to the charger.
Surprising.

[Sunking]

I guess our definition of "damage" differs quite a bit, to me, damage means the battery will FRY, and a possible smoke show will ensue.

That is only one side of the double edge sword, Over charging, and only occurs in less than 2% of battery failures.

The side of the sword you are ignoring is where 98% of all battery failures occur with Sulfated batteries caused by chronic Under Charging.

So the charger you have cannot possible over charge the battery and fry it, so no worries there you got that covered. It is what you are ignoring that will destroy the battery. I am OK with it so have at it.