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Old 25-05-2012, 11:26   #76
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Re: AGM vs Sealed Lead Acid Battery

No, you're absolutely right!

I didn't even look, having been replacing batteries in UPS units for over 20 years. Never noticed the switch, but I'm told by Batteries Plus that the one I bought is an AGM (I've already installed it so can't easily check), and they say that AGMs have been used in small UPS units for many years.

They put their lifespan at "3-5 years".

The world turns, and some of us don't even notice :-(

Thanks for the catch.

Have a good weekend.

Bill

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Originally Posted by hellosailor View Post
billt-
I'm sure you're sure, but are you sure your UPS batteries were gel? In the typical "computer" UPS boxes the batteries quietly switched to AGM a decade ago, and while they batteries look the same--they're usually AGM these days.
Coincidentally, with a maximum 4-year life being normal for the way they are built.

As it was explained to me, UPS batteries are expected to lose 25% of their capacity per year, and another 25% per ten degrees Farenheit over room temperature, so on the typical hot summer day when they are needed...you can be down 50% before they are two years old in a hot room.

Some of the utility companies here routinely replace their larger AGM backup batteries every 2 years because of this (large "car" sized) and they've been using AGM, not gel, for whatever reasons. (The batteries often go to ham radio groups, who then stretch out whatever life is left in them.)

What this says about deep cycle AGMs versus what the battery makers say about their longevity...ahem.<G>

But unless you've got some special UPSes (as I suspect you might<G>) those sound like typical consumer units, typical battery life, apparently by design. Eveready gives away flashlights, Gillette gives away razors...those UPS companies get a sweet price for replacing batteries!
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Old 25-05-2012, 11:30   #77
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Re: AGM vs Sealed Lead Acid Battery

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Originally Posted by Capitain Mike View Post
Hi Bill thanks for your reply om this old thread.

"maintenance-free" wet cell batteries...the worst of all types for a boat.
I think I have these because there is nothing to unscrew to top up. So what do you recommend? Flooded Lead Acid that can be topped up? instead of the non top up??
What you want for the house bank are real deep-cycle batteries. Flooded deep cycle 6V golf-cart size batteries, in series to make 12V, are often the best choice, both for price and for robust construction and longevity.

Avoid "maintenance-free" and "dual purpose" batteries, unless of course they're deep-cycle AGMs or gels.

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Old 25-05-2012, 14:30   #78
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Re: AGM vs Sealed Lead Acid Battery

bill-
Sneaky, ain't they? <G>

The stories I've been solemnly told by a number of vendors (especially APC) over the years, make boat brokers sound like mass candidates for sainthood. For a while, APC sold replacement batteries. Then they refused to sell their special "cartridges" because, you know, there could be high voltage in there. You had to send their units out to one of two (east coast, west coast) GenYouWhineAuthorized vendors to have the batteries swapped out and the units recalibrated. Oh yes, terribly dangerous if they aren't recalibrated when the batteries are changed. [sic]
But the 25% per year business, makes laptops and tablets incredibly more competitive. Even with the (cough, cough) incredible price of laptop batteries. Kinda make lithium boat batteries look like a bargain, don't they?!
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Old 09-02-2013, 20:13   #79
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Re: AGM vs Sealed Lead Acid Battery

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Originally Posted by goboatingnow View Post
AGMs, really dont offer any benefits to boaters, unless you can use their high charge acceptance. Otherwise they are easily damaged. Buy good quality open wet cells.

Dave

Interesting enough, one benefit of AGM's has been suggested by Farrier Marine relating to use in catamarans is that in the event of a capsize, you wouldn't need to worry about the possibility of having to deal with spilled acid inside a partially submerged upside down cat. Although that does seem like a fatalistic design constraint, it is stated as a true safety argument for using AGM's with cats.

I just need to work out a way to deal with the somewhat onerous charging schedules that they keep.......( they don't like to see a charge voltage higher than 13.8 and they need to be charged to full as much as possible.)
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Old 09-02-2013, 22:23   #80
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Re: AGM vs Sealed Lead Acid Battery

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Originally Posted by btrayfors View Post
Captain Mike,

This thread is a year old!

ALL the batteries talked about in this thread are lead-acid types. Gelled batteries, AGMs, and flooded batteries are all lead-acid. The term, "sealed lead acid" is a generic term which is non-specific. It could mean VRLA batteries (AGMs, gels, etc.) or it could mean "maintenance-free" wet cell batteries...the worst of all types for a boat.

We know a lot more about battery types and their application on boats these days.

Flooded batteries are by far the most economical and will suit many boaters very well. They are relatively more forgiving than are gels and AGMs, and have more cycles than AGMs. But, they require periodic maintenance, sometimes give off noxious gasses, must be mounted in sealed boxes, etc., etc.

Premium flooded batteries, like those from Rolls/Surette, have very long lives, often exceeding 10 years in marine service.

AGMs are very popular these days, but not many boats have enough charging capacity to take advantage of their incredible ability to take a big charge. They also must be fully charged at least once every few weeks or they will sulfate and deteriorate badly. Still, they represent good value for some types of boaters.

Gels are the most expensive of the three types and, used properly, are the longest lasting. Many gels last 8, 10, 12 or more years. I have two in my basement now which are 15 years old and which still perform very well. However, these are the most sensitive to overcharging and the charging voltages must be set properly.

Not all gels are created equally, just as with other types of batteries. I have four UPS units in my home/workshop which are in service 24/7, and which use gelled batteries. I just replaced a gel in one of them which was less than 4 years old, and replaced one in another UPS unit last year which was only 5 years old. These batteries live in an "ideal" environment -- room temperature, always on (proper) float charge, etc., etc.

I use small motorcycle-size 7AH AGMs in my dingy, maintained with a small solar panel. These run an automatic bilge pump, a fathometer, and lights. I'm on my third AGM now; the first two lasted about 3 seasons each.

There are several other types of sealed batteries, including TPPL, spiral wound, etc., each claiming to have an advantage over other types. These tend to be the most expensive types.

Hope this helps a bit,

Bill
This has been a great thread with some real life input from very knowledgeable cruisers.

Unfortunately I have learned that my 4 year old AGM choice was not really an informed one.

So far they are still working fine, but not really being tested under constant cruising conditions, which will happen by the end of this year.

When I switched to AGMís from Flooded it was for these two main reasons:

#1. I found the Flooded 400Ah (24v) system in the tropics needed a lot of make-up distilled water. (Perhaps it was too low a capacity to last 24hrs at anchor with 5 on board and boiled out too quickly on recharging).

#2. My original Batteries being located under the dining floorboards, it was awkward and messy to hydrometer test and blind fill some of the cells with Funnel and hose. Battery acid spills were always a danger and when charging, fumes were definitely noticed.

So I switched to AGM and really upped the amp hours by putting in 8 xFullriver 260Ah-12 AGMs in the same location, but tucked away on both sides as they did not require maintenance.

They have been obviously much nicer to live with, but my reason to go large AGM was flawed when I believed that sulphation was not an issue if you only bulk charged to 80% at anchor using the generator (I can bulk at 120amps @24v via 2 chargers.

Time will tell how the AGMís fair under real cruising conditions with new solar and slowly converting lights to LEDís, but curious what otherís would have chosen in my circumstances?

Like Nolex, my past experience with Sonnenshein Gel had been great at + 11 years.
Is that what I should consider when it comes time to replace? Donít really want to go back to carrying lots of distilled water or the fumes.
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Old 10-02-2013, 08:49   #81
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Re: AGM vs Sealed Lead Acid Battery

bill-
"I have four UPS units in my home/workshop which are in service 24/7, and which use gelled batteries. I just replaced a gel in one of them which was less than 4 years old,"
Unless those UPSes are commercial telecom type, are your 100% certain they have gel batteries? UPSes used to, but for a decade now almost all of them have quietly switched to AGM. From Panasonic, Yuasa, and a raft of non-name other sources. The batteries look the same as they always did, plain gray or black cases, but they have gone to AGM inside.
And yes, they are designed and built for a 2-to-4-year replacement cycle on the batteries, which derate 25% per year for various reasons.

viento-
Charging AGMs shouldn't be an issue unless you are using an antique charging source. If your charger has an "AGM" setting, it should be able to deal with the math and the charge profile correctly for them. If you are bulk charging from a dumb wind or solar dump charger, that's problematic for any battery type and a smarter regulator is needed. Or, lots more supervision from your end.
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Old 10-02-2013, 17:22   #82
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Re: AGM vs Sealed Lead Acid Battery

Quote:
Originally Posted by hellosailor View Post
bill-
"I have four UPS units in my home/workshop which are in service 24/7, and which use gelled batteries. I just replaced a gel in one of them which was less than 4 years old,"
Unless those UPSes are commercial telecom type, are your 100% certain they have gel batteries? UPSes used to, but for a decade now almost all of them have quietly switched to AGM. From Panasonic, Yuasa, and a raft of non-name other sources. The batteries look the same as they always did, plain gray or black cases, but they have gone to AGM inside.
And yes, they are designed and built for a 2-to-4-year replacement cycle on the batteries, which derate 25% per year for various reasons.

viento-
Charging AGMs shouldn't be an issue unless you are using an antique charging source. If your charger has an "AGM" setting, it should be able to deal with the math and the charge profile correctly for them. If you are bulk charging from a dumb wind or solar dump charger, that's problematic for any battery type and a smarter regulator is needed. Or, lots more supervision from your end.
I agree. I have both Gels for my 12 volt house bank and 8A4D's for my 48 volt propulsion bank. Both are still going strong and I will starting my sixth season with them (assuming the snow from blizzard Nemo ever melts here). I think the reason for this is both banks were ALWAYS charged with devices setup for AGM or Gel charging parameters. That includes my solar controllers, wind generator and AC chargers. Because I use electric propulsion I no longer have an alternator hooked to an engine so the AC chargers where usually connected to the Honda 2000 generator at anchor or more rarely grid power at a dock. I think this is what has allowed them to continue to be reliable in my on board applications.
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Old 11-02-2013, 02:14   #83
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Re: AGM vs Sealed Lead Acid Battery

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Originally Posted by Pelagic View Post
This has been a great thread with some real life input from very knowledgeable cruisers.

Unfortunately I have learned that my 4 year old AGM choice was not really an informed one.

So far they are still working fine, but not really being tested under constant cruising conditions, which will happen by the end of this year.

When I switched to AGMís from Flooded it was for these two main reasons:

#1. I found the Flooded 400Ah (24v) system in the tropics needed a lot of make-up distilled water. (Perhaps it was too low a capacity to last 24hrs at anchor with 5 on board and boiled out too quickly on recharging).

#2. My original Batteries being located under the dining floorboards, it was awkward and messy to hydrometer test and blind fill some of the cells with Funnel and hose. Battery acid spills were always a danger and when charging, fumes were definitely noticed.

So I switched to AGM and really upped the amp hours by putting in 8 xFullriver 260Ah-12 AGMs in the same location, but tucked away on both sides as they did not require maintenance.

They have been obviously much nicer to live with, but my reason to go large AGM was flawed when I believed that sulphation was not an issue if you only bulk charged to 80% at anchor using the generator (I can bulk at 120amps @24v via 2 chargers.

Time will tell how the AGMís fair under real cruising conditions with new solar and slowly converting lights to LEDís, but curious what otherís would have chosen in my circumstances?

Like Nolex, my past experience with Sonnenshein Gel had been great at + 11 years.
Is that what I should consider when it comes time to replace? Donít really want to go back to carrying lots of distilled water or the fumes.
Use an Anti Sulphation Battery charger wont stop it all but helps.
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Old 11-02-2013, 02:24   #84
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Re: AGM vs Sealed Lead Acid Battery

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Originally Posted by vientoman View Post
Interesting enough, one benefit of AGM's has been suggested by Farrier Marine relating to use in catamarans is that in the event of a capsize, you wouldn't need to worry about the possibility of having to deal with spilled acid inside a partially submerged upside down cat. Although that does seem like a fatalistic design constraint, it is stated as a true safety argument for using AGM's with cats.

I just need to work out a way to deal with the somewhat onerous charging schedules that they keep.......( they don't like to see a charge voltage higher than 13.8 and they need to be charged to full as much as possible.)
fit water proof Battery boxes and paint the insides with epoxy RANDOLPH ACID PROOF BATTERY BOX BLACK PAINT #345 from Aircraft Spruce
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Old 11-02-2013, 03:51   #85
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Re: AGM vs Sealed Lead Acid Battery

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Here is the info on the three battery types. Flooded will have about 200 charge/discharge cycles, Gel will have about 1000, AGM will have about 300. In the charge acceptance rate - flooded will be 25% of Ah, gel will be 25% of Ah and agm will be about 40% of Ah. A flooded battery will self discharge at a rate of 6% per month if not on a charger, gel and agm will be about 3% per month. Flooded vents hydrogen gas, gel and agm do not. Price -A flooded dual purpose battery will run about 120, a gel will run about 280 and a agm will run about 190. For longevity a gel cell is best, a agm is a good compromise for saftey. Agm's have a 18 month free replacement - 5 year pro-rated, gel - 18 month free, 5 year pro-rated, flooded - 12 month free, 3 years pro-rated. My agm's have lasted no lest than 6 years on my live-aboard sailboat for the last 11 years.
Those prices... group 31? 4D?
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Old 11-02-2013, 04:11   #86
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Re: AGM vs Sealed Lead Acid Battery

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Originally Posted by Capitain Mike View Post
Use an Anti Sulphation Battery charger wont stop it all but helps.
I also have a Rutland 913 a large solar pan and a Sterling Battery charger with anti sulphation and Multi Type Battery charge. If you are using to much power then someone is taking it for granted it's a boat not a house. Ban the electric toasters and hair driers unless you have shore power But check the shore earthing and remember while you are connected it is eating your anodes,
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Old 11-02-2013, 04:18   #87
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Re: AGM vs Sealed Lead Acid Battery

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Originally Posted by btrayfors View Post
No, you're absolutely right!

I didn't even look, having been replacing batteries in UPS units for over 20 years. Never noticed the switch, but I'm told by Batteries Plus that the one I bought is an AGM (I've already installed it so can't easily check), and they say that AGMs have been used in small UPS units for many years.

They put their lifespan at "3-5 years".

The world turns, and some of us don't even notice :-(

Thanks for the catch.

Have a good weekend.

Bill
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Sterling Power Products: What is the best battery to use for an auxiliary charging system?
Sterling Power Products: How effective is advanced battery charging on a battery and can it damage the battery?

Worth a look!!
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Old 11-02-2013, 04:38   #88
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Re: AGM vs Sealed Lead Acid Battery

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Only if installed improperly. They should be oriented so the cells from + to - or - to + go port to starboard not bow to stern. Many people and builders install wet cells incorrectly and this allows the electrolyte to move 6" + vs. approx 1/2" when heeled.
Really? I always thought they should be aligned fore n aft,not side to side.
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Old 11-02-2013, 04:54   #89
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Re: AGM vs Sealed Lead Acid Battery

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Really? I always thought they should be aligned fore n aft,not side to side.
Pictures may help...

Installation & Orientation of Flooded Batteries
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Old 11-02-2013, 05:59   #90
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Re: AGM vs Sealed Lead Acid Battery

sh*t, I need to stop reading this stuff, now I need to pull my batteries out and check to see if they have been spilling (since I rarel have to water them I think mine are OK)
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