# DEKA vs. Lifeline AGM Batteries?



## luv4sailin (Jul 3, 2006)

DEKAs are significantly less expensive. Any thoughts on the difference?


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## christian.hess (Sep 18, 2013)

we have dekas down here...I plan on getting some soon for my boat...2 31´s

wish I knew more about them...

dont know the lifeline agms

sorry


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## Maine Sail (Jan 6, 2003)

luv4sailin said:


> DEKAs are significantly less expensive. Any thoughts on the difference?


Lifeline & Odyssey are the two "premium" AGM's. Lifelines can be equalized Deka and Odyssey can not. Conditioning or equalizing charges can greatly extend the life of Lifeline AGM batteries beyond the competition.

Deka makes great GEL batteries that will outlast even the best of the AGM's. Keep in mind that Deka rates their own AGM at HALF the cycle life of their own GEL's...

For a starting AGM the Deka is not bad but for cycling I would go with Lifeline or Odyssey.

Keep in mind that AGM batteries cost more, tax alternators and belts harder, need to get back to 100% SOC as often as is humanly possible, and generally have a shorter cycle life (in the real world) than deep cycle flooded batteries or GEL batteries.

This is exactly how AGM's were originally marketed to US boat buyers in order to justify the cost difference:

*AGM Pro's: better cycling and depth of dischager over the wet or gell batteries. While most wet batteries are supposed to only go to about 50% depth of discharge, the AGM's are able to go to about 20% depth of discharge without harming them PROVIDED that you don't overcharge them at too high a voltage on their return. *

This is what is so frustrating about the internet, that poor information, is trumpeted as truth when it is simply not..

That statement was exactly how AGM batteries marketed and launched themselves into the marine market. Those far fetched promises of longer cycle life and more usable capacity than deep cycle flooded batteries was soon ousted as a mistruth in the "real world" of PSOC use where battery cycle life really matters.. These far fetched marketing attempts really bit the AGM makers in the ARSE because cycle life at 80% DOD really sucked and still does for most AGM products, the only exception being the Firefly....

Today nearly every maker of AGM batteries, (except for Firefly) Lifeline, Deka/East Penn (and all their private labels), Trojan, Rolls etc. etc. all recommend a 50% DOD not 80% DOD for _optimal cycling life_.

Odyssey still _sells_ on 80% DOD but they readily admit that at 80% DOD you only get 400 cycles (in the lab). One should keep in mind that this 400 cycles is in a laboratory with white glove treatment and not at all reflective of what happens in the real world in a PSOC environment.

Remember that to even attempt to come close to 400 cycles at 80% DOD with Odyssey batteries you'll need a minimum of 40% of capacity in charging current. So a 400Ah bank needs a charge source capable of maintaining 160A even when hot. If this is an alternator you'd need a cold rating of about 200A to have 160A when hot.... How many boaters can do that or expend all that money just to hope they "might" get 400 lab cycles.

The fact is that AGM's don't always offer longer life or deeper cycling and this has been proven time and time again in the "real world" under PSOC cycling.

I find this to be an interesting quote by Trojan Battery. When AGM's first came out the claims were BETTER cycle life than wets as that web site still seems to claim.. Trojan makes GEL, AGM and flooded batteries.



Trojan Battery said:


> *Generally, gel and AGM batteries have about 20% less capacity, cost about two times more, and have a shorter cycle life than comparable flooded lead acid batteries.* However, Gel and AGM batteries do not need watering, are safer (no acid spilling out), can be placed in a variety of positions, have a slower self-discharge characteristic, and are more efficient in charging and discharging than flooded batteries (see table below). *Gel batteries are more suitable for deep cycling applications whereas AGM batteries are more for light cycling and engine-starting applications.*


*Disclaimer:* Keep in mind that ALL of those numbers are LAB DERIVED where temperature, charge rate and charge/discharge cycles are done very methodically and repeatably. Those numbers are NOT at all indicative of what you'll see in the real world. If you want real world numbers chop 40-70% right off the top and now you're in the ball park..

Still Lifeline, Firefly, Northstar and Odyssey are about the best AGM's you can get. Flooded deep cycle lead acid batteries still represent a significantly value on many parameters....

There are pro's & cons to every battery type and batteries should be chosen based on your order of importance for features, benefits and negatives...


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## christian.hess (Sep 18, 2013)

the place I bought my solar regulator sold trojans too...they were smaller though about $200 a peice...how do those compare these days?


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## Irunbird (Aug 10, 2008)

Sorry to resurrect an old thread, but a salesman at Batteries Plus is telling me that the group 31 x2 power AGM batteries (a rebranded Deka, right?) will charge back up 5x faster than a flooded cell of similar capacity, and discharge 3x slower. Is that a bunch of hogwash? I need to replace my aging batteries, and was really just wanting two 105ah basic old lead acid batteries. If his stats aren't just a bunch of hot air, that might be appealing... slower discharge, faster recharge.


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## Maine Sail (Jan 6, 2003)

Irunbird said:


> Sorry to resurrect an old thread, but a salesman at Batteries Plus is telling me that the group 31 x2 power AGM batteries (a rebranded Deka, right?) will charge back up 5x faster than a flooded cell of similar capacity, and discharge 3x slower. Is that a bunch of hogwash? I need to replace my aging batteries, and was really just wanting two 105ah basic old lead acid batteries. If his stats aren't just a bunch of hot air, that might be appealing... slower discharge, faster recharge.


Yep hogwash.... They will recharge faster, when new, but not 5X faster.. Deka's can take about 30-40% of capacity when new and floodeds can take about 25%.

A 100Ah true deep cycle flooded battery (not a G-24, 27 or 31) at a 5A load will discharge at exactly the same speed as a 100Ah AGM only you will quite often get more cycles out of the deep cycle flooded battery, and pay less. Unless you are using the AGM benefits the cost may not be worth it.


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## jdazey (Jan 16, 2016)

*Rats*

A timely thread.

I have two banks of 400ah AGMs. Last Summer the stbd side failed (sudden, drastic overheating). I replaced the two 4Ds with Lifelines. This week the same thing happened to the port side bank (Deka Intimidators). I was on the verge of ordering another set of Lifelines when I see Mainesail saying the FLAs are a better way to go.

Sitting here at the dock, the batteries are charged by a Trace U2512SB inverter/charger. I've got 6 very old 75w solar panels that will be replaced by 100w Renogys going to 2 pwm controllers.

I don't think I can mix the AGM and FLA batteries. So do I buy another $1100 set of AGMs, ditch the AGMs and get FLAs, or bite the financial bullet and go to LiFePo?

The LiFePo option is appealing for the weight savings as well as more capacity, but I've been concerned about how much other stuff I'd have to replace. The price of the batteries alone is quite sobering.


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## Maine Sail (Jan 6, 2003)

jdazey said:


> A timely thread.


If by _timely_ you mean 2014...... (wink)



jdazey said:


> I have two banks of 400ah AGMs. Last Summer the stbd side failed (sudden, drastic overheating). I replaced the two 4Ds with Lifelines. This week the same thing happened to the port side bank (Deka Intimidators). I was on the verge of ordering another set of Lifelines when I see Mainesail saying the FLAs are a better way to go.


*#1* Why do you have two house banks? That is likely issue number one.. One large banks is better for many reasons,

*#2* Flooded are not "better" but for many boaters they do often represent a "better value" and yield similar cycling lives for a lot less money. Deep cycle batteries such as golf cart batteries in either GC2 6V or GC-12 12V are a good long cycling option. AGM's require significant cost to charge them _properly,_ and if not charged "properly" meaning temp compensation, minimum charge currents and regular 100% SOC recharges, you can destroy them far sooner than they should be and the cost will be higher to you when they are destroyed..

*#3 *What you are experiencing is likely an internal failure/short if the batteries is heating that badly. This usually stems from abuse and not tracking battery state of health on a regular basis.

*#4* The East Penn AGM is NOT the quality of the Lifeline batteries so they can't really be directly compared.

In testing specific to sailboat cycling type use they do not handle PSOC cycling very well and are not a true _deep cycle_ design. For more info on this see the *May 2015* and *August 2015* issues of Practical Sailor.

If you want to spend money on an AGM, for deep cycling house bank use, you'll want a premium branded AGM, your Lifelines are a premium AGM. That said the East Penn/Deka GEL batteries are tremendous deep cycling batteries. Deka rates (lab cycle life) their GEL product at 1000 cycles and their AGM at just 300-350 cycles.

*PSOC Testing:* (PSOC = Partial State of Charge Use)

Deka #1 - Lost 30% of initial baseline capacity in PSOC testing
*Deka #2 - Lost 27% of initial baseline capacity in PSOC testing

*Because the results of test #1 were so far off the competitors, a second test on another battery was conducted.

*Premium AGM's:*

Firefly AGM - Only battery in the PSOC cycling testing to not lose any capacity
Odyssey TPPL AGM - Lost 6.7% from initial baseline capacity in PSOC testing
Northstar TPPL AGM - Lost 8.5% from initial baseline capacity in PSOC testing
Lifeline AGM - Lost 11% of initial baseline capacity in PSOC testing



jdazey said:


> Sitting here at the dock, the batteries are charged by a Trace U2512SB inverter/charger. I've got 6 very old 75w solar panels that will be replaced by 100w Renogys going to 2 pwm controllers.


The Trace 2512 was pretty advanced for its day but lacked direct on-battery temp sensing and was very often set up incorrectly by the end user for absorption voltage, float voltage and timer settings. Setting a proper float voltage for dockside charging with AGM's is critical. The _optimal_ charging voltages for Deka are not the same as for Lifeline so one charger is not really the best case for a split bank. This is but one of many reasons why we don't usually _split_ house banks..



jdazey said:


> I don't think I can mix the AGM and FLA batteries. So do I buy another $1100 set of AGMs, ditch the AGMs and get FLAs,


You can certainly mix AGM and flooded _during charging_ PROVIDED they share the same absorption voltage and float voltage, otherwise this is sub optimal and not recommended. You should not discharge flooded and AGM batteries together so running the bank in parallel during discharging is not going to be optimal.



jdazey said:


> or bite the financial bullet and go to LiFePo?


LFP batteries are considerably easier to destroy than lead acid batteries are. I have a guys 10K LFP bank in my shop right now that is a pile of useless scrap because it was not installed, charged and used correctly. This was a factory built system too not a DIY mistake. For a guy like me who specializes in LFP systems these stories are really not all that rare. They are rarer however on the internet, than they should be, because most folks won't admit to destroying thousands of dollars in cells or batteries in a public forum. This is not meant to come off as harsh sounding, but the reality is that if you can't mange lead acid batteries, and get maximum life out of them, then LFP is most likely not a good fit. For Lifeline's you should easily be able to exceed or achieve 7 years + for coastal and 3-5 for full time cruising.



jdazey said:


> The LiFePo option is appealing for the weight savings as well as more capacity, but I've been concerned about how much other stuff I'd have to replace. The price of the batteries alone is quite sobering.


There is really no such thing as "drop in LFP". That said nothing in lead, not even Firefly AGM's, can be compared to the cycle life you will get from a _*properly* installed, charged and discharged_ LFP bank. To do it right, and many refuse to, you will almost always need to start from scratch on everything in your DC charging and discharging _foundation_. This means a charge bus, loads bus and the BMS to protect the bank. A factory made system is the best option for anyone not capable of a DIY LFP system but these are very expensive.. If you are not doing the labor or building the pack yourself (if you are not an EE or highly capable engineering type I would strongly advise against DIY) plan on about 7k -18K for a "_legit_" professionally LFP system. I use LFP on my own vessel so I am not saying this to discourage you, I am saying this to save you money in the long run. Course if you have deep pockets and can afford a multi thousand dollar "oops moment" then absolutely, go for it!

In my experience in this field I believe there are only three "legit" LFP factory made systems currently for marine fractional "C" house bank use and those are Victron, Mastervolt and the *Ocean Planet Energy/Lithionics Li3 System*. In my opinion the OPE-Li3 system is the best engineered for marine use. None of these systems are inexpensive.

Without knowing your daily Ah consumption, even a ball park, charging capabilities, days desired to be engine free, solar capacity, and existing banks Ah capacities there is no way we can make any suggestions other than to say to start with a contiguously wired house bank and get us more info..


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## colemj (Jul 10, 2003)

Sudden drastic overheating is not a normal end of lifetime for batteries unless they were old and very near their end of life and happened to short internally. But I think you would have noticed poor performance long before this.

I would pay attention to finding the cause of that before investing in any new batteries.

A bank of LFP batteries equivalent to 800Ah of lead will cost ~$2,000 - which is the same ballpark as your AGM's. Plus, there is probably a market for 1yr old Lifelines that would pay for part of the cost of converting.

If you are getting new solar controllers anyway, then you can choose ones that are programmable for Li charging regimes.

We used to have your model of Trace inverter/charger and I _think_ I remember the charging voltages/times/rates are all user-settable with potentiometer knobs. If so, you are all set with that, assuming the range of control is within Li specs.

That probably just leaves your alternator to worry about. You don't mention it, but at worse, you may need to buy a ~$300 Balmar 614 that can derate your alternator to run cooler while being highly programmable for LFP charging. If you have a stock alternator with internal regulator, you may be able to easily convert it to external regulation depending on which type it is.

But I would start with figuring out why your batteries are dying suddenly with overheating.

Mark


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## jdazey (Jan 16, 2016)

First, thank you all for the replies.

Timely? Oops, I got here from the murdering batteries thread which is fairly current. Oh well, I guess I won't worry about hijacking the thread.

1. Two banks? Well that's the way the boat came when I bought it a year ago. The two banks are about 25' apart (catamaran). I just checked and discovered that I have:

Port side: Leece Neville 35214610 110 amp alternator going to a Balmar ARS5 regulator. Output goes to a large battery isolator. One leg of the isolator goes to the starting battery and the other to the port house bank.

Stbd side: Yanmar (Hitachi?) 12272N 80 amp w/ internal regulator. I believe the PO had a Balmar 150 amp alternator, and there is another ARS5 that is disconnected. I don't know why he ditched the Balmar. There is another isolator wired the same as the port side.

3. Agreed regarding internal short. Since I've had the boat it's made one trip up the coast from FL to VA and a couple of weekends. Otherwise it's been plugged into shore power.

4. Will replace with Lifelines.

The Trace inverter is indeed programmable, and I believe covering the range required. The doc give figures for NiCad batteries and has an equalization mode that could be used to manually charge batteries at higher voltages. I still have to check how the charger is wired for two banks as it isn't designed for that.

I've followed the LFP threads on another forum. I am not DIY qualified. One of the three packages would be the way I'd have to go. I've been practicing Li battery care with my cell phone. I'd dearly love to save a lot of weight but agree that LFP may well be over my head.

The batteries were new in 2012, used in FL and the Bahamas. Why they died and in this fashion is a good question. I'll have to check the settings on the Trace. The Lifeline doc says they can be eqalized, but only when capacity has dropped off. The Intimidators can not be equalized. The Trace has maintained the SOC at 13.2 to 13.3 according to the Ample Power Energy Monitor II. 

So I have no answer for why the batteries went into thermal meltdown. Any suggestions?


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## Salty Mike (Nov 3, 2015)

So glad I found this thread, my boy is looking into getting me a deal on some Deka seconds through a dealer he knows I was going to have him inquire about the Intmidator (AGM) line but now after reading Mr.Main Sails thoughts I guess I'll just go with their 6v FLA golf cart batteries or maybe I'll have him look into the gel batts if you think they are up to the task. 
I'd like to think I could keep a set of liFePo alive but just starting out in this cruising ligestyle I believe I'll have a whole lot of stuffs to be learning about and trying to manage to be able to keep up with something like that.

Main Sail if we ever meet up remind me that IOU a beer.

And thanks to jdazey for reviving this thread.


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## jdazey (Jan 16, 2016)

On my last boat I used 6V batteries (Trojan), and they were fine. Big thing was a 6V battery weighs a lot less than an 8D. Getting them in place is a lot easier on the back.

Cheers,


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## SD Matthews (Jan 21, 2017)

What a great discussion! Reading the threads I can see most everyone here is educated and presents ideas and thoughts well. With that said I was reading on the Impact Battery blog and came across two articles that offer critical thought to this discussion. The one is titled: What Makes LifeLine Batteries So Great? And the other is titled: The Best AGM Battery No One Knows About.

The second article talks about NorthStar batteries being the best pure lead AGM option vs what most most people believe to be Odyssey. I see some people here mentioned NorthStar and Odyssey as well. From what I can see LifeLine has really built a strong reputation with the military reinforcing the reliability factor. All in all these guys seem to have some really good articles and appear to know a thing or two about batteries. Might be worth a look.


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