Replacement deep cycle batteries

One last quote from Rod aka Maine Sail about AGM vs FLA batteries. Exactly to the main (no pun intended) point I've been trying to make.

While many folks do buy them for the right reasons, many don't. AGM's definitely have some great benefits but are expensive and are, as we've learned over the last 17+ years in the marine market place, arguably a bit less tolerant of abuse than deep cycle flooded batteries.
 

No experience with them but they are marketed as a very high quality battery. I ruled them out on cost grounds and doesn't seem to have changed.

Tayna prices delivered:
4 x T105 £519.80 (450Ah@12V), £1.16/Ah

Es-Store price
4x 6FS220 £849.60 (440Ah@12V), £1.93/Ah

The Rolls would need a lifespan of 166% vs. the T105s in similar service to just break even. There's also a much greater financial risk in event of failure over the longer break even time. I can't see any advantage over T105s in normal use.

Rolls might win if I was going to remote areas and wanted to install the most robust build quality I could buy. However, I seem to remember posts from a few years ago where Rolls batteries failed very quickly and the warranty was useless. I think that the batteries needed to be returned to UK in order to claim. It was several years ago and I can't remember the details but it was enough to allow me to drop Rolls from consideration.
 
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One last quote from Rod aka Maine Sail about AGM vs FLA batteries. Exactly to the main (no pun intended) point I've been trying to make.

While many folks do buy them for the right reasons, many don't. AGM's definitely have some great benefits but are expensive and are, as we've learned over the last 17+ years in the marine market place, arguably a bit less tolerant of abuse than deep cycle flooded batteries.

Yes I agree with everything MaineSail says - I've have already said that in my replies - but you are just picking sentences which suit your opinions.

I agree AGMs are "arguably a bit less tolerant of abuse than deep cycle flooded batteries." -but MaineSail also says its because most of them can't be equalised. Lifeline and Full River can be. The most important point he also makes is that not all AGMs are the same!!!!!

Any battery - especially sealed batteries - that can't be equalised should not be on a cruising boat.

This is not really a cruising Forum so why don't you keep your opinions for the US Cruisers Forum?

Since you have never used AGMs your opinions are just that.
 
This is not really a cruising Forum so why don't you keep your opinions for the US Cruisers Forum?

Since you have never used AGMs your opinions are just that.


That's you told skipmac ;) ;)

You're only allowed to cut and paste google results about AGM's if your boat has some.

n63m82.jpg
 
Yes I agree with everything MaineSail says - I've have already said that in my replies - but you are just picking sentences which suit your opinions.

I agree AGMs are "arguably a bit less tolerant of abuse than deep cycle flooded batteries." -but MaineSail also says its because most of them can't be equalised. Lifeline and Full River can be. The most important point he also makes is that not all AGMs are the same!!!!!

Any battery - especially sealed batteries - that can't be equalised should not be on a cruising boat.

This is not really a cruising Forum so why don't you keep your opinions for the US Cruisers Forum?

Since you have never used AGMs your opinions are just that.

Sorry, have not seen any rules on this forum that prohibit cruising related discussions. I do believe Yachting and Boating would cover cruising as part of the definition of yachting and boating, and I do believe I am allowed my opinions as much as anyone. I have tried to keep this discussion on a polite basis and supply facts and quotes to support my position. Seems like when I provide evidence that refutes your opinions, with no other recourse you have to resort to rudeness. Congratulations.

I pick quotes that specifically support my opinions that you continuously claim are wrong. I see you ignore those same quotes when they do not support your opinions.

By the way, I have used AGM batteries in several applications and highly recommend them...... in the proper context.

I see no benefit in further discussion so you are very welcome to the last word, whatever that may be.

Bye.
 
...I see no benefit in further discussion so you are very welcome to the last word, whatever that may be.

Bye.
I agree further "discussion" is pointless.

A pity because a lot of people are following this thread - I do hope they all fully read the excellent article which you linked to, which I agree with in total.

My last quote is a simple repeat from that MainSail article which refutes MOST of your arguments:

FACT: All lead acid batteries sulfate regardless of AGM, GEL or Flooded.
FACT: All batteries require proper charging
FACT: PSOC use will shorten the life of all lead acid batteries not just AGM

NOT ALL AGMs ARE CREATED EQUAL.
- is also one of the most important points to remember. Like leisure batteries some are starter only, some are deep cycle, but many cheaper ones are for Telecom and Solar standby - not built and designed for regularly falling off 2 metre waves, nor daily 50% deep discharges. These points are just something else for potential users to understand which hasn't been covered in this thread.

Cheap AGMs are just not worth buying.
 
Hi Skipmac
Can I thank you for your contribution to this thread and apologise for the rudeness you have been subjected for daring to confront a view that you did not share. I hope you ignore the advice to feck off, many of us welcome intelligent debate particularly when it is backed up by information pulled from respected sources and find it more illuminating (and entertaining) than uncontested assertions. I certainly would not like to be associated with the AGM faction if they can only defend their position by abuse, but the thread has opened my mind on battery choice.
And if this is not a cruising forum what is it?
 
I agree further "discussion" is pointless.

A pity because a lot of people are following this thread - I do hope they all fully read the excellent article which you linked to, which I agree with in total.

My last quote is a simple repeat from that MainSail article which refutes MOST of your arguments:

FACT: All lead acid batteries sulfate regardless of AGM, GEL or Flooded.
FACT: All batteries require proper charging
FACT: PSOC use will shorten the life of all lead acid batteries not just AGM

NOT ALL AGMs ARE CREATED EQUAL.
- is also one of the most important points to remember. Like leisure batteries some are starter only, some are deep cycle, but many cheaper ones are for Telecom and Solar standby - not built and designed for regularly falling off 2 metre waves, nor daily 50% deep discharges. These points are just something else for potential users to understand which hasn't been covered in this thread.

Cheap AGMs are just not worth buying.

I agree that this is a useful and interesting thread and will be happy to continue if you can keep it civil. Life is too short for me to deal with rudeness.

That being said, I think we are mostly in agreement. If you could take a deep breath, count to 10 and read what I'm saying calmly maybe we can come to some kind of conclusion.

1. AGMs are great batteries, great technology and offer some great advantages. Also it is not worth buying cheap AGMs like the car batteries.

2. To take full advantage of the benefits like faster charging, one needs to have a balanced system with adequate charging capacity. PLEASE NOTE: I am NOT saying AGMs won't work at all with a smaller charging system. I am NOT saying they will die immediately or explode in fireball. I am NOT saying you will realize no benefits. I am only saying that AGMs will give the best results and longest life when charged properly. I am also NOT saying that FLAs don't also benefit from proper charging. ALL BATTERIES will give best results and longest life if properly cared for.

3. To reiterate what I said above, yes ALL batteries need proper care, both in charging, installation, wiring, etc, etc etc. However as I point out and back up with several references, FLA batteries are more tolerant of abuse than AGMs or one might say AGMs need proper care more than FLAs. I and NOT saying that FLAs are immune to abuse. I am NOT saying they don't suffer loss of capacity, loss of life, etc. Only that they are more tolerant of various abuses like storing at partial SOC for long periods, not frequently fully charging, not periodic equalization than AGMs.

4. I don't care to spend more time researching UK prices but I can confirm from buying and researching battery prices in the US that a proper, deep cycle AGM battery is 3-4 times more expensive per amp hour than a similar quality, deep cycle FLA. For my battery bank that means at 660 amp hour bank for USD$600 for FLA vs $2000 for AGMs.

So even if both battery types are identical regarding tolerance of abuse, poor charging, etc one can kill off a $600 set of batteries or a $2000 set of batteries for moderate improvement in charge time. Remember the Mainesail test that showed almost 6 hours to fully charge an AGM from 50% to 100% SOC? How much longer will it take to charge FLAs? Don't have the exact figures at my fingertips but as I recall maybe another hour or so.

If I was better endowed with filthy lucre and could spend boat bucks as I wished I would go for AGMs. Actually with unlimited budget and time I would go for LiFePO batteries to get the maximum usable charge/recharge for the smallest, lightest battery bank. Regrettably that is not the case so I will stick with FLAs for my house bank. Which by the way is six years old, has been off the grid for almost the entire six years so only able to equalize twice, has spent months cycling between 60-90% SOC with a few drops to around 50%, yet still going strong.
 
Hi Skipmac
Can I thank you for your contribution to this thread and apologise for the rudeness you have been subjected for daring to confront a view that you did not share. I hope you ignore the advice to feck off, many of us welcome intelligent debate particularly when it is backed up by information pulled from respected sources and find it more illuminating (and entertaining) than uncontested assertions. I certainly would not like to be associated with the AGM faction if they can only defend their position by abuse, but the thread has opened my mind on battery choice.
And if this is not a cruising forum what is it?

:encouragement:
 
For anyone considering AGM batteries based primarily on the ability to recharge the batteries much faster than FLA batteries I highly recommend reading this test conducted by Rod Collins aka Maine Sail. Here are his preliminary comments and the reason he wanted to conduct this test.

"I have long known that a higher charge rate, with AGM batteries, does not necessarily translate to *significantly faster charge times from 50% SOC to 100% SOC. For the first part of this test, 50% SOC to 100% SOC, I compared a charge rate of .2C with a charge rate of .4C on the same Lifeline GPL-31T battery.

"Significantly Faster" - Please understand, & take with a grain of salt, what I am comparing "significantly faster" to. I was once told by a self espoused expert on AGM batteries (expert defined here as an owner who had AGM batteries and whom had read the glossy marketing materials) that with his 150A alternator he could recharge his 440Ah bank of AGM batteries from 50% to 100% in less than an hour and a half. While the owner was fully capable of basic math, 1.5 hours times 150A = 225Ah's he failed to take into consideration that his .34C 150A alternator could not put out 150A for 1.5 hours and his bank, at anywhere close to .34C, would hit absorption voltage rapidly and begin limiting alternator current. Even if the alt could run at at a face value of 150A it is simply impossible to return 225Ah's to the bank in 1.5 hours from 50% SOC."


There is absolutely no argument that AGM batteries can take a much higher rate of charge than FLAs. Also AGMs will (depending on the brand and condition of the batteries) accept that charge more efficiently than FLAs. However, AGM batteries are not magic. Like any lead/acid battery, FLA, AGM or gel, the charge acceptance will taper off dramatically as the system exits bulk charge mode. AGMs (like all batteries but AGMs even more so) like to be charged to 100% state of charge on a regular basis to maintain health and offer maximum life. You should seriously consider this and your ability to charge AGMs the way they like to protect what can be a very significant investment in a battery bank. If you have a large budget and can afford to replace the batteries every few years then all this is moot.

A couple of notes and comments. First Rod, as always gives full disclosure on the limitations of the test. The battery he used was not new but also not trashed so the actual time to charge may be more or less depending on the age and condition of one's battery but not by hours, more like fractions of hours. Also he was using equipment that allowed him to set the charging conditions to exact standards and maximize the charging process. In the real world almost no boat will have a charging system optimized the way it can be done under lab conditions resulting in charge times a good bit longer than his test results.

Enjoy.

http://www.pbase.com/mainecruising/effect_of_charge_rate_on_agm_battery
 
I went cheap!
My 4 Jeanneau originals lasted just over 2 years, so I was worried about frequent replacements. My 3 Hankooks at £55 each plus VAT but including delivery have almost matched them and are still looking great. The boat is left in the water without power over winter with an occasional charge every 4 weeks or so. It sits on 12.9 volts output between charges. I hope to get a few more years and will then buy some more at that price.110Ah batteries.jpg
 
I went cheap!
My 4 Jeanneau originals lasted just over 2 years, so I was worried about frequent replacements. My 3 Hankooks at £55 each plus VAT but including delivery have almost matched them and are still looking great. The boat is left in the water without power over winter with an occasional charge every 4 weeks or so. It sits on 12.9 volts output between charges. I hope to get a few more years and will then buy some more at that price.View attachment 63214

Hi Phil,

If your 12 V requirements are modest then there is no real need to invest in expensive batteries. Only if you have 12V refrigeration, extensive autopilot use or other high power requirements on a sailboat does it make sense to add a large, deep cycle battery bank of whatever technology.

If you only run a few lights, small electronics, etc then by all means buy a leisure battery or two. Just understand that a leisure battery is actually a vehicle starting battery, possibly a slightly enhanced starting battery but not a true deep cycle and will not tolerate (there's that word again) deep discharges as well as a deep cycle battery. However, for the cost and as long as it suits your needs, its the cheapest option.
 
The boat is left in the water without power over winter with an occasional charge every 4 weeks or so.

Thread drift, but you could probably fit a temporary solar panel on deck to keep a trickle charging into those batteries and prolong their life. Solar panels and basic controllers are quite cheap these days. You don't have to have an elaborate installation, you could just tie a panel down on deck temporarily.
 
Trojan do a 130AH deep cycle lead acid thats the same physical size as a normal 110AH. That works for me as the battery box is made for the 110AH size, so two of them give me an extra 40 odd AH's .
 
As that old bloke, Quandry said, good thread and valuable info. Good to have the input and the time taken to write the posts. I too will need to replace a domestic bank of three 85AH batteries and was looking at the options. Probably just go with lead acid as the best cost/performance option.
 
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