AGM Batteries In Equipment

[Mr. Wrench]

I was wondering what you guys could teach me about AGM batteries in equipment. It seems like I'm seeing more of them. A couple of examples, T880 trucks and recently a Bell haul truck. In the T880 it must be because they are in the cab under the passenger seat. Safer, can't spill, won't gas, though they do have vent hoses that hook to the battery and go out the floor. Someone said that you have to charge them with a special charger, one that is for AGM batteries. It seems like when they go died that they can be hard to charge back up. What is special about an AGM battery charger? In my experience it is easier to kill them and cost alot more to replace AGM batteries. Is there a special way you should charge them? Why are they in equipment more? In my opinion the best battery ever made is a DEKA group 31 with threaded top post.

 

[Bootheal]

I’m having similar questions on a smaller scale. How does a vehicle with original lead acid battery charge the AGM properly at higher required voltage?

 

[Coaldust]

A dumb, constant-current charger will chronically over-charge an ATM. They require the constant voltage 14.4-15v. So, a digital controlled charger is needed. Some vehicle alternators don’t work so well
With AGMs.

AGMs don’t handle abuse or deep cycling very well.

They don’t gas, so they work good in the cab. They can be shipped by airplane, so that’s nice when I have to ship batteries to the bush.

 

[Shimmy1]

A dumb, constant-current charger will chronically over-charge an ATM.

I'm not sure the bank will be impressed if you try and charge their ATM...

 

[Welder Dave]

I've wondered the same thing. I charged the AGM in my F150 with an old 6 amp charger with no ill effects. It's all I had after the battery went dead when I was in the hospital. I just changed that battery because it was getting a little weak and the cold and snow was coming. Being 10 years old I can't complain. I had a deep cycle RV battery explode and spray battery acid all over. If I keep the 5th wheel, I'll put in an AGM.

 

[mg2361]

AGM vs Flooded Lead Acid video

	AGM (Absorbent Glass Mat)	Flooded Lead-Acid
Construction	Sealed with fiberglass mats absorbing the electrolyte	Vented with liquid electrolyte, which can be topped up with distilled water
Maintenance	Maintenance-free	Requires regular checks and additions of distilled water
Vibration Resistance	High	Low, more susceptible to damage from shock
Spill-Proof	Yes, can be mounted in various positions (except inverted)	No, must be kept upright to prevent spills
Recharge Rate	Up to 30% faster	Slower
Cost	Higher initial cost	Lower initial cost
Lifespan	Typically 4-7 years or more	Typically 3-5 years
Deep Cycling	Can handle deeper discharges (up to 80%) better	Lower deep cycle ability (around 50%)
Safety	Safer, sealed design minimizes gassing and risk of spills	Vents produce hydrogen gas

 

[AllDodge]

I like AGM and have used for years in Truck/Boat with no issues. Haven't tried my equipment yet but might do it next time. The issue is I'm using Odyssey and Lifeline Bats which are on the higher end side, not like Duracell, Interstate and such. They last years longer then LA

 

[Coaldust]

Seems to me, very unscientific, the AGMs are more sensitive to freezing damage that flooded lead acid. Which, goes against the inherent nature of AGM’s. I can rescue a cold, discharged, old fashioned battery where the AGMs just don’t bounce back. But, IDK?

Swapping those passenger side, under-seat batteries on a K-Dub sucks. And the voltage drop from the batteries to the starter is well above SAE spec. On a brand new rig.

And PACCAR installs an inaccessible battery cable quick connection under the cab. Which then corrodes. Molded connections, and not enough extra rope to make a repair. But, a complete cable assembly is unbelievably expensive and prohibitively unavailable. No way to even access with the air reservoirs, transmission, exhaust system in the way. Best you can do is patch and cobble.

 

[Truck Shop]

A better battery when running a mass of emergency/rotating light systems.

 

[Truck Shop]

Best you can do is patch and cobble.

Heavy on the cobbler-peach by chance?

 

[AllDodge]

Seems to me, very unscientific, the AGMs are more sensitive to freezing damage that flooded lead acid. Which, goes against the inherent nature of AGM’s. I can rescue a cold, discharged, old fashioned battery where the AGMs just don’t bounce back. But, IDK?

Where do you see that with analysis?

 

[Coaldust]

Where do you see that with analysis?

A decade of maintenance expense tracking with a fleet of 80 power units. And my NAPA Pro-link account. About 1/3 of the fleet uses AGM batts, but they account for the majority (60%) of battery replacements.

It’s not scientific by any stretch, just a casual
observation with many variables. IMO, the Mexican made Clarios red tops are junk. The Missouri EnerSys ODYSSEY are decent, but over-priced. The Deka AGM from Pennsylvania is my favorite and 1/2 cost of a ODYSSEY.

 

[AllDodge]

Thanks
I'm in a area where lowest temps are maybe -10F and they don't stay that way for long. Your area probably gets colder

My LA boat Bats would last 3 years on average. The lifeline and Odyssey weight more and last on average 7 years. My watercraft last 9 years and reg LA last 2 yrs.

Truck is at 3 yrs for LA and 6 for AGM Odyssey. Going to do a real test this time. Had 2021 Ram diesel and just bought Odyssey Bats because cold weather was having issues. Installed then removed because I bought a 2025 Ram diesel so swapped Bats and traded. Have Bats in the barn and keep them topped off. Hope they last, otherwise and lot of wasted money

 

[Welder Dave]

Not having to top them up is a big bonus of AGM's. I've had LA batteries last 7-13 years in machines I don't use regularly but 10 years for the AGM in my daily driver that has gone dead a few times from sitting a couple month's is impressive. It wasn't completely dead but the cranking speed was a little slower so I changed it before it got in the -20'sC. My truck also has auto start/stop which I think tests a battery more. I didn't mind paying the extra $$ for a new AGM.

 

[Mr. Wrench]

Seems to me, very unscientific, the AGMs are more sensitive to freezing damage that flooded lead acid. Which, goes against the inherent nature of AGM’s. I can rescue a cold, discharged, old fashioned battery where the AGMs just don’t bounce back. But, IDK?

Swapping those passenger side, under-seat batteries on a K-Dub sucks. And the voltage drop from the batteries to the starter is well above SAE spec. On a brand new rig.

And PACCAR installs an inaccessible battery cable quick connection under the cab. Which then corrodes. Molded connections, and not enough extra rope to make a repair. But, a complete cable assembly is unbelievably expensive and prohibitively unavailable. No way to even access with the air reservoirs, transmission, exhaust system in the way. Best you can do is patch and cobble.

I agree with you on the PACCAR deal. Nice truck to drive but a real pain to work on their batteries and cable system. All special components, nothing off the shelf, and all expensive. No just crimping a new end on in the field.

 

[Mr. Wrench]

It seems like my little experience is that they take longer to bring back when they are dead. Not sure if they last longer or not yet. Part of the problem may be that I know how lead acids act and AGMs act different and so I just need to learn how they act better.

 

[CStracker]

A decade of maintenance expense tracking with a fleet of 80 power units. And my NAPA Pro-link account. About 1/3 of the fleet uses AGM batts, but they account for the majority (60%) of battery replacements.

It’s not scientific by any stretch, just a casual
observation with many variables. IMO, the Mexican made Clarios red tops are junk. The Missouri EnerSys ODYSSEY are decent, but over-priced. The Deka AGM from Pennsylvania is my favorite and 1/2 cost of a ODYSSEY.

In my business we have a large fleet of F150s with the AGMs from the factory and we're replacing them very often. Not sure if it stems from poor charging, extreme temperature fluctuations, or parasitic drain. It's not brand related either...the ones from the factory lasted no longer than the NAPA Legends that we replace them with. We usually see around 2 years lifespan.
I love AGMs and have had great success in the past. My old Bronco using the winch would fry a lead acid battery quickly but the Deka AGM seemed indestructible. So I'm certainly not anti-AGM. But there must be some situation that they thrive in and some situations that they perform poorly in. I think sitting out in the elements in extreme temperature fluctuations without getting a charge often enough may be one of those situations where they don't seem to last. There's probably some real nerdy battery folks out there somewhere on the www that could shed more light on the subject.

 

[Welder Dave]

I got 10 years out of the AGM in my 2015 F150 and it wasn't completely bad. I changed it for winter because it wasn't cranking over quite as fast. I put an OEM back in because I was impressed with the original. It had even gone dead a couple times when I was in the hospital but charged it up and it was fine.

 

[LCA078]

The US military has been using AGMs across it's fleet since the early 2000's. Some of the main reasons cited from switching from sealed lead acid battery (SLAB) to AGM were lower maintenance, less off-gassing, and less spillage during "operational use". That means that battery acid doesn't go everywhere when the battery gets hit by a bullet or shrapnel or when the vehicle gets flipped over by IEDs. Are they better than SLABs? I feel like they are but like said above, they have their downsides. Personally, I think most batteries die from either crappy manufacturing designs/standards to cut costs or from poorly regulated charging profiles. The next wave of batteries being introduced in the military are li-ion batts so vehicles will have much longer ability to work off the batt without idling the engines.

I can only imagine what a military 6T Li-ion will cost....

 

[Tyler d4c]

You knwo wgat really seems to help (Im calling out all the farmers and lazy/cheap owners here) Battery hold downs if thw poor thinks are bouncing around like a rabbit one redbull they arnt going to last. They need to be held good. When stuff shows up to me they get either fixed or atleast a nice 1 inch strap around to hold them. Seems every machine i touch for the first time has them gone