I have a 4000W Coleman generator, a MTD lawn tractor, and a John Deere Gator that are all in their 20's in age. When new battery time comes, is there a downside (or an upside) to getting AGM batteries? I've read that standard lead-acid chargers will damage AGM batteries; true? Any tips appreciated. I guess the claim is that AGM batteries last longer; is it worth it?
What's the deal with AGM batteries?
- Thread starter RobLewis
- Start date
I have a Diehard AGM in my daily driver for 18mths now. I tried 3 optima red tops about 20yrs ago. They were crap for general automotive applications.
I just retired from a marine mechanic job next to dry stack storage facility. Some of the bigger boats had multiple batteries. Some of the expensive AGMs, and Optima blue tops would get zapped to lower single digit volts on some boats. The standard Interstates seemed to be able to handle being charged up and testing OK.
The Blue Tops, and other AGMs approaching $500 range per battery did not seem to come back from that very easily. This is contradictory to what I’ve read about AGMs. Go figure.........
I just retired from a marine mechanic job next to dry stack storage facility. Some of the bigger boats had multiple batteries. Some of the expensive AGMs, and Optima blue tops would get zapped to lower single digit volts on some boats. The standard Interstates seemed to be able to handle being charged up and testing OK.
The Blue Tops, and other AGMs approaching $500 range per battery did not seem to come back from that very easily. This is contradictory to what I’ve read about AGMs. Go figure.........
I have this for almost 10 years in a Honda-powered tractor used for summer and winter. It costs more but is worth it.
I replaced the original AGM battery in my 2009 BMW two years ago (date code of 01/2009). The battery never officially died, but it was cranking over slow on really cold mornings so I replaced it before there was an issue.
I have AGM batteries in the Ford F-150, the Corvette and had one in the Jeep which I sold a couple weeks ago. I really like the AGM batteries and they do last much longer.
AGM are commonly used in motorbikes because they can be mounted in a non upright poristion.
They have a slightly better CCA and also perhaps protect the plates a little better against vibration.
Normal chargers will not harm them. Their resting voltage is also a little higher than regular led acid
They have a slightly better CCA and also perhaps protect the plates a little better against vibration.
Normal chargers will not harm them. Their resting voltage is also a little higher than regular led acid
Not that I've heard. I've used a standard charger/maintainer on an AGM battery for years without issue. In fact, several of the popular Battery Tender brand chargers/maintainers are switchable for battery type - Lithium (LiFePO4) on one side and AGM/Lead Acid on the other.
I thought about getting an AGM battery for the riding lawn mower. But instead, I got a mulching adapter to mulch my leaves, so I'm using the mower more often off season, which reduced the number of times I put it on a battery tender enough to make it tolerable.
Interstate Battery says
"This is also why an AGM battery needs special charging.
Regular battery charging can break AGM batteries. Regular batteries need 15-17 volts to get the same amps. However, voltage greater than 15 volts can overheat an AGM and generate enough pressure to pop its safety valve. That one-way valve is supposed to relieve excess pressure from the harmless gases that come when a battery’s charging. Too much voltage becomes too much pressure, and pop. Without an airtight seal, an AGM will dry out in hours.
Then you’re in the market for a new AGM battery."
www.interstatebatteries.com
"This is also why an AGM battery needs special charging.
Regular battery charging can break AGM batteries. Regular batteries need 15-17 volts to get the same amps. However, voltage greater than 15 volts can overheat an AGM and generate enough pressure to pop its safety valve. That one-way valve is supposed to relieve excess pressure from the harmless gases that come when a battery’s charging. Too much voltage becomes too much pressure, and pop. Without an airtight seal, an AGM will dry out in hours.
Then you’re in the market for a new AGM battery."
Here’s How to Charge an AGM Battery and Why It’s Different | Interstate Batteries
Absorbed glass-mat batteries offer incredible performance, but you could ruin them with them with the wrong battery charger.
www.interstatebatteries.com
My original 2018 Motorcraft AGM rated at under 700 CCA still tests over 800 CCA. I have a light parasitic draw and I honestly thought it was the battery until I tested it the country way - by disconnecting the battery and seeing if it lost any juice over 12 hours. I've had it tested at 6-8 different places over the last 3 weekends and everywhere I had it tested shows consistently over 800 CCA - so I next went to parasitic draw. Winner winner chicken dinner. I think I know where it is too (sensor in my shifter) - just need to find the time to confirm.
I use a plain old tender on it (low amp, let it go 12 hours) about once a month to bring it all the way up as Ford thinks it's necessary to only charge the darn thing through BMS to 80%. With the draw I'm experiencing now, I put the tender on it every night.
I turned BMS off through ForScan and it still rarely charges it to over 12.3-4
4-5 amp chargers are good for AGM batteries if I'm not mistaken. There are some people that really know their stuff on battery chargers, one of them will probably be along shortly to correct me or confirm me.
I use a plain old tender on it (low amp, let it go 12 hours) about once a month to bring it all the way up as Ford thinks it's necessary to only charge the darn thing through BMS to 80%. With the draw I'm experiencing now, I put the tender on it every night.
I turned BMS off through ForScan and it still rarely charges it to over 12.3-4
4-5 amp chargers are good for AGM batteries if I'm not mistaken. There are some people that really know their stuff on battery chargers, one of them will probably be along shortly to correct me or confirm me.
AGM batteries need a voltage regulated charge, excessive voltage will cause them to vent which is bad for them. Many battery chargers for regular batteries have historically not been voltage regulated, because applying 15V or 16V to a regular battery won't generally hurt them, they have lots of liquid electrolyte so if some of it gets turned into oxygen and hydrogen and vented, no big deal.
That will definitely cause the AGM battery to vent. You can actually hear them vent in a very quiet room. Kinda sounds like the noise that Rice Krispies make when you pour milk on them, but much quieter.
My 2013 BMW came from the factory with an AGM battery. But it has a battery current flow monitoring system that tracks all the coulombs in and out of the battery, and I understand the charging system never charges the battery to 100%. Yes, in an application designed for an AGM battery, it can last al long, long time.
But just slap one in place of a lead acid battery, so long as it fits in the space? Your mileage may vary.
But just slap one in place of a lead acid battery, so long as it fits in the space? Your mileage may vary.
Recently replaced my wife’s Nissan Sentra flooded cell battery with an AGM. From what I read they do better with start/stop technology and all the advanced electronics that newer autos have. O’Reillys had the AGM battery same price as advanced auto for a flooded cell well O’Reilly had a mail and rebate, so it was actually cheaper for the better battery.
If the battery is not vented and if there is no place to add water then to the best of my knowledge it is some form of an AGM.
AGM's are the "norm" today except if special applications. Both cost wise and sometimes purpose wise will turn flooded cell batteries be used..
Its not possible to have a straight "flooded" standard battery without a way to add water.
AGM's are the "norm" today except if special applications. Both cost wise and sometimes purpose wise will turn flooded cell batteries be used..
Its not possible to have a straight "flooded" standard battery without a way to add water.
