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Equalizing AGM batteries

74K views 25 replies 15 participants last post by  SRQJohnson 
#1 ·
I have two Lifeline AGM batteries and two West Marine (East Penn) AGM batteries on my IP37. They have not been holding their charge recently. I spoke with the Lifeline people, and they said my batteries should be equalized. When I spoke with the people from East Penn they said that their AGM batteries should never be equalized. Trying to equalize them would make them worse.

Question: Has anyone successfuly equalized their AGM batteries?
If so, a description of your technique would be very helpful.

Shel IP37-55 SEAS THE DAY
 
#2 ·
It's not a good idea

AGM's may not go dead very easilly, but if they do, you have to have the capability of "equalizing" them to get them back. When AGM's go dead, they will charge back up under normal charge parameters just like they normally do, slightly faster maybe, but they will not hold that charge. I.E., their true capacity will be greatly diminished. If you find that the batteries reach 13.1 volts and yet as soon as a load is put on them they start dropping down much faster than normal you need equalization. Oh, yes, equalizing a sealed battery is not a good thing to do, but Lifeline will heartilly recommend it as soon as they hear what you have to say the problem is.
15.5V for 3 hours is an AGM's equalization parameter. If you have a newer Link 2000 with an AGM battery selection (#3), then it "may" have this parameter in it. Some do, some don't. If not, set it for Lead Acid (#1) and raise the ambient temp to max... 120? and let it run for 3 hours. That will do 15.75V which is ok. This is of course, AFTER you have charged them normally and they "show" full charge. Now, with the Link 2000 and Heart Inverter/Charger, and access to shore power, this is easy. Since cruisers "often" run batteries dead, accidentally of course, and do not always have access to shore power, you should consider having the capability of putting out that 15.5V off your alternator so you could accomplish this if you needed to away from the dock.

Fair Winds

Cap'n Dave
 
#3 ·
NO! Stop!

NEVER, NEVER, NEVER equalize these batteries against the manufactures advice. AGM batteries are known in the industry as VRLA (valve regulated lead acid). These batteries have a stringent charge requirement to prevent a condition known as thermal runaway at high temperatures and to maintain full charge at low temperatures. Without the proper charger, these batteries have been known to explode. Admittedly, these explosions have happened, as far as I know, only in industrial settings. However, some of those that did where in controlled environments, i.e. air conditioning. Most have happened in huts without adequate air temperature control (ever been in your boat in the sun while it's in the slip). I have never heard of one happening on a boat, but there is always a first time. I have yet to see a marine charger with temperature compensation (lowering the float or charging voltage at high temperature and raising it at low temperature). They may be out there, if so, if you insist on having AGM batteries or sealed batteries you should invest in one.

Sealed batteries use to be the craze in the early 90s with the maintenance free battery for your car. When is the last time you have seen a new car with a maintenance free battery as standard equipment? Now granted, auto batteries are not deep cycle, but the chemistry is the same.

Replace your batteries. Do NOT try and revive them. I have been designing chargers for the telecommunications industry for over 20 years (mostly VRLA batteries) and will NOT have them on my boat. A good set of wet cells (notice good, i.e. deep cycle, thick plates. Etc.) will outlast VRLA every time if maintained properly.
 
#4 ·
Dave, I agree

However Xantrex makes a charger with temp compensation. What I am not sure of the voltage limits in the equalize mode. The new ones do, the problem being, one wont know unless one has the operating manual.

Regular lead acid wet cell batteries are way better and more bang for the buck.

Fair winds

Cap'n Dave
 
#5 ·
We installed a commercial marine temperature compensated charger on our last boat in 1998. The present owner just wrote me (among other topics) to say the batteries continue to deliver full performance.

What ever you do in this situation it is a good idea to back up and ask why you are having to do it. AGM batteries are very sensitive to charging regimen. Done properly they will deliver excellent service for 10-15 years. Charged improperly they will fail to deliver even half the expected amp hours.

First, these batteries were designed around three stage charging.
Second, the voltages (and temp comp) for charge, absorb, and float phases are critical.
Third, they must be recharged 100% on every cycle.

That last item is critical. No deep cycle battery should ever be discharged more than 50%. Many people with a wet cell background have become accustomed to considering a battery charged enough at 85% -- about the point reached when the long absorb/float process begins. Wet cells tolerate this reasonably well. AGMs do not.

AGMs treated this way will recover less and less of their performance on each charge cycle. It starts slowly, but within a season or two, a 600amp hour bank can be delivering less than 100 amp hours before reaching a discharged voltage state.

For this reason if the engine hasn't brought the batts back for us when we shut down, the generator is fired up until all the amphours are returned (Via Xantrex).

I recommend Steve D'Antonio's AGM article published in Ocean Navigator for a fuller description.
 
#6 ·
Amen to Dynameme's post...but the problem remainns...what to do about AGM's that have not been holdinng a charge if you don't have a fancy system that has the built in circuitry to do it. I recently read of a "pulse" conditioner that "vibrates" the scale off the battery plates so you don't have to put in an equalizing charge. Any one know about this or have in use experience with one?
 
#7 ·
DynaMeme,

Excellent post and the advice goes for any battery system you install, wet cells as well as AGM or gel-cells.

Camaraderie,

Most of the pulse chargers will work for a short time, but they may not address the real problem of VRLA (AGM and gel-cell) batteries. These batteries will tend to dry out when they are cycled too deeply, charged with too high of voltage, kept at a high temperature and charged, i.e. everyday life on a boat. And since they are sealed there is no way to add the water back. As pressure increases within the battery with excessive charging and/or high temperature, the valve (Valve Regulated Lead Acid) will vent the pressure, i.e. hydrogen, to prevent damage (this is the way it’s suppose to work). With the hydrogen vented it’s eliminated from the battery environment and so cannot combine with the oxygen (via a catalyst) within the battery to maintain the water level. Hence, dry batteries, dead batteries.

None of my customers (telecom companies) use a pulse charger. They have tried them and concluded they don’t work. They just replace the batteries after fiver to ten years (and that is on 20 year batteries), more often if they are in harsh environments.

A dead AGM battery is a dead battery and should be replaced.
 
#9 ·
"15.5V for 3 hours is an AGM's equalization parameter. " I don't know what LifeLine quotes but the AGMs I have from other makers will start to cook and boil off electrolyte WAY BEFORE 15.5V. If you can get them up that high, you will definitely harm them by boiling off electrolyte, even if you don't melt anything internal.

Since there are several different technologies and chemistries being used, and an AGM maker can set the blow-off valve to different pressures, I'd second the recommendation to never exceed the manufacturer's ratings.
 
#10 ·
Equalizing with Link 2000

This may be an old topic, but I thought I'd share my equalizing attempts with the Link 2000(R). This is specifically in regards to Lifeline AGMs--which Lifeline says should be equalized at 15.5v x 8 hours as follows:
---------------------
Charge with voltage-regulated (Constant voltage) charger.

Charge1 @ 15.5 volts for 8 hours.

¹ Avoid overcharging. All batteries must be adequately vented during charging to avoid accumulations of explosive hydrogen gases. Never install or charge in a sealed container or sealed room.

Equalizing should only be done when the battery is showing symptoms of capacity loss or from inadvertent deep discharges. In the event equalization is necessary, make sure to go through the normal charge cycle. Once the battery is fully charged, begin equalizing.
---------------------------
The above is from Lifeline's website. So, I tried to equalize following the Link 2000 instructions. The Link 2000 will keep the voltage at the battery's acceptance level according to the manual. With battery type selected as type 3 (AGM) and normal tempurature setup (80), when in equalization mode the voltage only goes to 14.3 @ 2-4amps (batteries fully charged before trying equalization). This is obviously not a true equalization voltage, so I decided to override the battery setting to Type 0. Now, equalizing sends the voltage to 15.8v at 60amps. Needless to say, I chickened out and immediately shut off the charger.

So, the alternative is "equalizing" in AGM-mode which basically keeps the voltage in acceptance mode (14.3) rather than dropping down to float (13.3) for 8 hours. Will this help a sulfated AGM battery just to keep the voltage at 14.2-14.4? Probably not but if anyone else has done this let me know.

You know, I don't think you have to equalize fuel cells :D .
 
#11 ·
Mkf-
When in doubt...email or call Lifeline, ask them about your equipment and situation. Since they are pretty much alone in recommending equalization for AGMs, maybe they can tell you what's special for their batteries at the same time. (And wouldn't it be interesting if they just said "don't".<G>)
 
#12 ·
Lifeline Needs a Jump Start

I have a set of four Lifeline AGM's on Eventyr and have experienced a marked loss of performance. I contacted Lifeline a year ago and was instructed to equalize them at 15.5 volts. I did this with my Xantrex TrueCharge 40+ on the wet cell setting. I regained some capacity, but only temporarily.

In my situation, I'm living on the hook almost 24/7/365. I have solar and wind charging, but most days, I do not get back to a full charge. I run the generator on occasion but only for an hour or two a day. When it's running, I have two 40 amp chargers putting it back into the bank, but not to a full charge. Doing that would require five or six hours of gen running time.

I'm seriously thinking of switching to wet cell deep cycle batteries. It seems the value is there as well as the performance.

I contacted Lifeline on a warranty issue recently and they weren't much help. I had a casing failure and obvious leakage around one of the posts. I sent photos and a detailed explanation to them and had several conversations on the phone with the warranty rep. He basically told me that, yeah, it is a problem and we can send you a replacement for that battery. The problem with this, as I told him, is that one new cell in a bank of three older cells won't work. Further, I would be responsible for shipping the thing from California to St. Maarten. I was completely unsatisfied with this arrangement, but that was the end of our discussions.

Lifeline advertises as a premium manufacturer. Be aware that premium manufacturer and premium cost does not equate to premium customer service.

-Dan Forter
S/V Eventyr
IP40-129
www.ipphotos.com/eventyr
 
#13 ·
Dan.. I went the other way...from wet to AGM after experiencing the SAME performance you are describing from the wet cells so I'm not sure that switching is the answer you are looking for. So far the AGM's are doing well for me but I've only had them a bit over a year. I am beginning to believe that with every day use, the important thing is to really cycle the batteries down to 50% and then give the a FULL charge up with the generator at least once every couple of weeks. The constant "mini" charging from solar/wind and minor generator runs seems to gradually deteriorate the batteries ability to take a charge. I have no technical foundation for this but a couple of long term cruisers suggested the new routine to me and as I said, it is working so far. I really lie the AGM's from the maintenance aspect since it is a pain to access them in my boat but I do NOT have "Lifeline" so can't comment on them specifically. Down island, you are facing a hell of an expense to replace them so I understand the wet cell attractiveness. Have you tried deeply discharging your current ones and then bringing them back to full charge dockside with the charger?
Good luck!
 
#14 ·
Good Day All. Reading the thread on AGMs and discovering that 'mini charges' (with solar panels etc) will degrade them is bad news, and also that equalization is sometimes necessary makes it worse. The reason I use them is because maintaining acid batteries is a bore. I had gels before and had good results with them, but AGMs came along, I thought all my problems were over. I thought that my 80 watts of solar power was well enough to top up a pair of 8Ds (and two G27s for the diesel) but if not going to full charge is not good?! That wasn’t in the advertizing! I upped the alternator to 200 amps; installed a Balmar Max Charge and a PV7D regulator for the solar panels and battery combiners, all on the quote from West Marine that ‘batteries don’t die, they’re murdered’. So now I’m guilty of involuntary man slaughter. Usually the batteries are all showing at least 13.2 volts when I go aboard, now it’s 12.8. I will do a ‘full charge’ with the engine and see what happens; wish me luck.
CKS
 
#17 ·
Ip32120

As AGMs are "sealed" they should not be subjected to the "equalizing" conditions. Flooded lead acid can take the overcharging conditions that the equalizing subjects them to as they can vent. The AGMs venting are safety valves. Lead acid batteries should be equalized as the plates will build up scale and this reduces capacity. The AGM while "starved" is a lead acid but cannot be equalized. I have had AGMs and now use gel which because of a different electrolyte are so slow to sulfate that you don't even have to think about it.
 
#18 · (Edited)
As AGMs are "sealed" they should not be subjected to the "equalizing" conditions. Flooded lead acid can take the overcharging conditions that the equalizing subjects them to as they can vent. The AGMs venting are safety valves. Lead acid batteries should be equalized as the plates will build up scale and this reduces capacity. The AGM while "starved" is a lead acid but cannot be equalized. I have had AGMs and now use gel which because of a different electrolyte are so slow to sulfate that you don't even have to think about it.
Before making factually worded statements, as above, please freshen up your knowledge on the subject. Posting incorrect information does not help answer the question posed.

Considering this thread was originally, back in 2006, about Lifeline & Deka/East Penn batteries, and Lifeline says equalizing is okay to do if the batteries are showing diminished capacity, and Deka says no then your broad based statement above is an unreliable choice of presented information.

In a worst case scenario bad information might cause someone with Lifeline batteries to buy new batteries per-maturely, which could be an expensive mistake, before trying and equalizing / conditioning charge.

This is a DIRECT quote from Lifeline:


"Conditioning/Equalizing Charge: 15.5 volts for 8 hours
Conditioning/equalizing should only be done when the battery is showing symptoms of capacity loss. If conditioning/equalizing is necessary, first go through the normal charge cycle. Once the battery is as fully charged as possible, start the conditioning/equalizing charge.

To apply a conditioning charge, first go through the normal charge cycle to bring the battery to full charge. The conditioning charge should then be applied by charging for 8 hours. At 77°F (25°C), the conditioning voltage should be set at 2.58 VPC (15.5 volts for a 12 volt battery). The conditioning voltage at other temperatures is shown in Table 5-2. By using the temperature compensated conditioning voltage, batteries that are not in controlled temperature environments may be conditioned without bringing them to room temperature. If temperature compensation is not available, it is best to bring the battery as close to room temperature as possible before applying the conditioning charge.

For maximum battery life, a battery must be recharged to 100% capacity. Recharging to less than 100% may result in premature battery failure. Lifeline batteries are not covered under warranty if they are not recharged properly. For more information, please refer to our warranty policy."


A more accurate statement would have been to say that some manufacturers say it is okay to equalize AGM's and some or many others prefer that you don't. As always read the manual or check with your manufacturer before equalizing AGM batteries.


Because each manufacturer has specific requirements for their own AGM's, a blanket statement can not be made on the topic of equalizing AGM batteries..

Here is Trojan's statement on equalizing AGM's.

Direct quote from Trojan Battery:

WARNING: Do not equalize gel or AGM batteries.
 
#19 ·
"As AGMs are "sealed" they should not be subjected to the "equalizing" conditions."
As Maine says, Lifeline is BUILT TO BE EQUALIZED. East Penn IS NOT. Saying all AGM batteries are the same, or should be treaeted the same, is like saying it's OK to drink the orange Windex because it looks just like Fanta and Nehi.

Could be they are different products under that pretty box, huh? For the price LifeLine charges, they can afford to build a stronger case that can take the strains of equalizing. Maybe it is better, maybe it is not, but it definitely is not the same product.
 
#22 · (Edited)
Again, SOME AGM batteries CAN be equalized and considering the short lives this type of battery has had in the marine market many Lifeline owners are darn happy Lifeline designed their batteries to withstand an equalizing or conditioning charge..

I will post this again:

This is a DIRECT quote from Lifeline Battery:


"Conditioning/Equalizing Charge: 15.5 volts for 8 hours. Conditioning/equalizing should only be done when the battery is showing symptoms of capacity loss. If conditioning/equalizing is necessary, first go through the normal charge cycle. Once the battery is as fully charged as possible, start the conditioning/equalizing charge.

To apply a conditioning charge, first go through the normal charge cycle to bring the battery to full charge. The conditioning charge should then be applied by charging for 8 hours. At 77°F (25°C), the conditioning voltage should be set at 2.58 VPC (15.5 volts for a 12 volt battery). The conditioning voltage at other temperatures is shown in Table 5-2. By using the temperature compensated conditioning voltage, batteries that are not in controlled temperature environments may be conditioned without bringing them to room temperature. If temperature compensation is not available, it is best to bring the battery as close to room temperature as possible before applying the conditioning charge.

For maximum battery life, a battery must be recharged to 100% capacity. Recharging to less than 100% may result in premature battery failure. Lifeline batteries are not covered under warranty if they are not recharged properly. For more information, please refer to our warranty policy."


A more accurate statement would have been to say that some manufacturers say it is okay to equalize AGM's and some or many others prefer that you don't. As always and as you said at the end read the manual or check with your manufacturer before equalizing AGM batteries. But some AGM's CAN be equalized!

Because each manufacturer has specific requirements for their own AGM's a blanket statement can not be made for all AGM batteries. Here is Trojan's statement on equalizing AGM's.

Direct quote from Trojan Battery:

WARNING: Do not equalize gel or AGM batteries.

If you had left your statement as; "Read your battery manual 1st" it would have been accurate information.

Clearly blanket statements do not always work as applied to all brands of AGM batteries and seeing as Lifeline is perhaps the #1 AGM maker in terms of marine market volume, here in the US, that means that a lot of boaters can equalize their AGM's to get more life from them....
 
#24 · (Edited)
This is the problem with mixing batteries. Some AGMs can handle equalization while others will just run away; all bad. I would suggest removing the connections to the ones that CAN be equalized (make sure the other batteries are fully charged) and equalize them with a separate battery charger as that will allow you to leave the settings alone on your charger or inverter/charger if you have one. Once equalized, disconnect the external battery charger and reconnect those batteries. This is why I caution most not to equalize any AGM until you read your manufacturers manuals, considering the average boater's electrical/electronic skills.
 
#25 ·
My opinions, use them at your own risk, and research them as you feel the need to before using them until you content you "get it".

AGM batteries are great for quick energy release and ease of charge, but equalizing them like you would a wet cell battery (flooded vs AGM "absorbed glass mat") has been a bad idea the two times I tried it (against my better judgement :)). A little research on my end suggest that 14.7 volts is as high as these batteries should ever be charged, and that should only be with enough current/amperage to get the voltage there, but never more that 0.75 amps on a 6 volt - 3 cell, or 1.5 amps on a 12 volt - 6 cell battery regardless. Like someone else said, fully charge your battery, then maybe even float it at 13.5-13.6 volt and <100 milliamps for a couple of days to really saturate the battery, then equalize it. Never start equalize charging any battery until it has had a full charge done, and never do this inside your home or garage, but only outside or in a well ventilated shop with all the safety precautions that make sense.

The charging algorithms for AGM batteries do not exceed 14.7 in my Midtronics GR-8 charging system I don't believe (a 3000.00 charging system), nor do the voltages go as high in my Schumacher algorithms for AGM's as they do for "wet cell" batteries. That said: LISTEN, - BUT!!!!!, WATER FROM THE BATTERY ELECTROLYTE BEGINS TO SUBSTANTIALLY BE BOILED OFF AT ONLY 14.4 VOLTS, so if you go above this often or FOR A LONG PERIOD OF TIME ON AN AGM, or even on a sealed WET lead acid battery - you will eventually dry out one of the cells, and the battery will be no good, and the dry state could allow the battery to create and electrical arc and result in an explosion; I did not experience this on my AGM's, but I did dry out the cells most likely as both AGM's I tried to equalize a few times, lost ~ 2.1 volts o/v across the battery indicating a killed cell, and the battery sides shrunk in as though negative pressure from lost volume in that cell had been created. Bottom line in my opinion, if you must equalize your AGM, don't go above an average of 0.25 amps per battery cell (0.75 and 1.5 for 6v/3cell and 12v/6cell batteries respectively) and don't even do that unless your going to invest in a battery tester (Harbor Freight Tools sells one that is about $75 bucks that does just fine for measuring internal resistance and open voltage across the terminals (o/v). Use the tester to determine when equalizing is actually helping vs. hurting. If equalizing your battery doesn't decrease the internal resistance of the battery, improve it's resting voltage after a charge is completed and the battery rested for a 12-24 hour period, or for sure if equalizing is increasing your internal resistance, then your not doing your battery any favor by equalizing it unless your trying to put it out of it's misery. It's also great to use to track and assess the general condition of your batteries health and state-of-charge. The ohms resistance (< than 3 is excellent battery condition in my experience, 3-4 is very strong, 4-5 is still really good, 5-7 is starting to suggest the needs to be serviced or replaced, and over 7 is for sure a weak battery ready to let you down when you don't want it to. There's a lot of information and knowledge required to safely equalize a battery, so please be careful, do this at your own risk...(my opinions are mine and are "as is..." without any warranty of safety or efficacy). Battery care can be dangerous, so have eye and skin protection on, never do it without being able to get medical help for yourself, or without being able to access fire control/extinguishers. Just be damn careful. Safe boating!!!

My steps in synopsis:
1. Charge my battery completely
2. Float it at 13.5 - 13.6 volts for a couple of days
3. Measure the electrolyte specific gravity (can't do this in an AGM or Sealed wet Lead-Acid)
4. Equalize at less than 1.5 amps total on the 12v/ 6cell battery and 2.5 to 2.65 volts per cell (15 - 16 volts on a 12 volt battery) HERE IS WHERE THE VOLTAGE FOR AN AGM OR SEALED BATTERY IS RELAVANT BECAUSE YOU CAN'T REPLACE THE ELECTROLYTE OR MONITOR THE INDIVIDUAL CELLS
5. Recheck electrolyte specific gravity and quit equalizing when no further evidence of improvement is noted or if battery starts getting hot, or electrolyte becomes colored at all.
6. Determine if battery if good after 24 hours of rest following any charge or equalization.

AGAIN.....AT YOUR OWN RISK! THIS REALLY IS ONLY SAFE TO DO IF YOUR AUTOMATIC CHARGER HAS AN EQUALIZATION MODE (genius, xantrax, and progressive dynamics make automatic chargers that equalize) BECAUSE DOING IT MANUALLY WITH A DC POWER SUPPLY REQUIRES SOME KNOWLEGE TO AVOID INJURY, FIRE, EXPLOSION, OR EVEN DEATH!!! I wouldn't even do them on my boat, and I don't have a big boat...just sayin'. Take them out and do the equalization in a controlled environment!!!! Did I say...AT YOUR OWN RISK YET????
 
#26 · (Edited)
Re: Equalizing with Link 2000

I have changed everything I own with a starting - type battery to AGM. I have discovered that around normal boating outdoor temperatures AGMs will show an open circuit voltage around 13 volts.

Around means an older battery will be around 12.8 to 12.9. A new battery will be about 13.1 to 13.3. Higher voltages for newer batteries. I have had occasion to need to equalize or revive a severely discharged battery. I have a squadron of smart chargers and the standard roll around big boy too. A severely discharged battery will show charging, then after the expected time, based on charger capacity and battery size, 'Fully charged'.

But it will not be. The smart chargers will bring battery voltage up in the high 14s or 15s of volts for a while, then trickle back and declare the battery charged. If the battery is allowed to rest about 10 minutes or so, the open circuit voltage will droop to about 12.4, to 12.7 or maybe 12.8.

The battery now is about 2/3 charged. I now put it on a voltage regulated, current regulated lab power supply and set the voltage for 16 volts and 1 amp for small batteries, in the range of 15 to 35 Ahours. IE Jet Skis, lawn equipment, and motorcycles. For 100 AH batteries I set the current limit to 1.5 amps to 2.0 amps. When the pwer suply is powered on it will go to full set current, (1.0 Amps in small battery case) and will current limit at about 13 volts and change. As the battery continues to charge, the current will stay the same, and the voltage will gradually rise, until the voltage reaches the voltage set point. At this time the voltage will not rise, and the current will begin to decrease. At this time I consider the battery as fully charged as practical, and disconnect it.

I have AGM batteries in lawn tractors, Jet Skis, a motorcycle, the tow truck, and a dual setup in a boat. There are other things like gensets, etc with AGMs also, but they do not get the attention the other stuff does.

That's what I do.
 
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