wrote:
On Jun 15, 1:23 pm, Salomon Fringe wrote:
...

Yes I actually have the printed version of that doc, but I don't think
there is even a hint of being able to use a AGM for 8+ years while
deep-cycling... ?


Well, I don't think I said that. What I was trying to say is that the
author doesn't seem to have had any trouble coming up with published
data. For instance he notes that deep cycle flooded cells ("semi-
traction") get 350 cycles at 60% DOD (which is deep cycling) while
AGMs get 650-800 depending on construction and chemistry. Service
life depends on how you use them but the AGMs look much better than
the semi-traction batteries for deep cycle use. His service life
numbers suggest that some AGMs will be expected to last 10 years.
AGMs have only been popular in marine use for less than a decade so it
may be hard to get real numbers. My experience has been fantastic.
YMMV... I think some of the very negative responses in the "Dutch
magazine" (if they exist, got a citation?) might have been for gel
cels. AGMs are not gel cells and linking them is bogus (or maybe even
dishonest). AGMs have really good cycling numbers and they are
published and you've even posted a link to them. So the Sterling
guy's conclusion that you should avoid AGMs because they have "poor
cycling numbers" is hard to figure. The rest of his arguments seem to
be based on straw men and thin air, too. Who is this guy?

Although it's a little off topic http://www.proboat-digital.com/proboat/20080203/
is interesting and has some insight into usage issues.

...

Err, I was hoping you would have the links handy... ;-)


I was hoping you'd do your own. If you can't google I'll do it for
you, but last time I looked both Full River and Lifeline (Concord) had
graphs and spec sheets on-line for their AGMs. You may have to plot
data from your favorite flooded deep cycle battery for comparison but
if the flooded guys have nothing to hide their data will be on-line,
too... ;-)

I'm not trying to sell AGMs. There are good reasons that they don't
use them in golf carts, for instance. But the guy at Sterling seems
to have decided that he hates AGMs and then gone off to figure out
why.

--Tom.


Well the author of the Victron article really did a good job and I have
used his info extensively but I did realize that Victron sells gel and
AGM but nothing else in terms of batteries so I assumed a slight nudge
towards their product line in the numbers. Also his pricing info in the
comparison was way off from what I found, e.g. full traction was just
50% of the price he stated.
The amount of active material in any lead acid battery, be it flooded
gel or AGM is what makes the battery survive longer for cycling, and so
comparing the most expensive thick-plate AGM with standard flooded cells
does not make sense. We should compare AGM and flooded batteries that
have equal weight (lead) or, for a different comparison, equal price. I
think that in real life, a flooded cell will hugely outperform the AGM
for cycling use because you can equalize a flooded cell to refresh weak
cells, because you cannot monitor the temperature of each battery (let
alone every cell) while charging which means guaranteed overcharging of
some batteries/cells - destroying your typical AGM cell. Of course it is
cheaper, too.

Returning to the Victron article, even with my suspicions about the
author towards his own product line, what I distilled from the article
was that tubular plate traction batteries are the best deal for serious
cycling, not gel or AGM. I did my research two years ago so things may
have changed but I don't think the numbers can have changed that much.

I would like to know from people who have REALLY deepcycled their AGM's
500 times (anybody counting?) and are still using them. If these exist I
believe that you will find they paid as much for their AGMS as they
would have for equivalent capacity traction - which would last at least
twice as long.

On Jun 16, 12:58 am, Salomon Fringe wrote:
Well the author of the Victron article really did a good job and I have
used his info extensively but I did realize that Victron sells gel and
AGM but nothing else in terms of batteries so I assumed a slight nudge
towards their product line in the numbers. ...

Now wait. You're accusing the guy of lying to sell overpriced
batteries that will fail if they ever get used and you're saying
you've used his "info" extensively? Is this wise?

Also his pricing info in the
comparison was way off from what I found, e.g. full traction was just
50% of the price he stated.

Pricing changes all the time. Still, I think he was testing 24v full
traction batteries which might well explain the difference.

... in real life, a flooded cell will hugely outperform the AGM
for cycling use because you can equalize a flooded cell to refresh weak
cells, because you cannot monitor the temperature of each battery (let
alone every cell) while charging which means guaranteed overcharging of
some batteries/cells - destroying your typical AGM cell. Of course it is
cheaper, too.

Just for the record, you can equalize AGMs periodically without
destroying them. The manufacturers even recommend it. I use a
temperature compensated charging system with my AGMs. I don't
understand what you're saying about not being able to monitor the
temp. Your theory about cycling is interesting and testable but it
goes against the published data. Given that I think the burden of
proof lies with you. Go do some tests that suggest that the
datasheets and experts are wrong and you'll garner a lot of
attention.

....
I would like to know from people who have REALLY deepcycled their AGM's
500 times (anybody counting?) and are still using them. If these exist I
believe that you will find they paid as much for their AGMS as they
would have for equivalent capacity traction - which would last at least
twice as long.

I presume what you're saying here is that my experience of REALLY
sailing three times around the Pacific and REALLY living on my boat
full time and REALLY charging my batteries using my engines is REALLY
not valid because you REALLY don't want to hear it? I'm not claiming
to be a representative sample but my experience suggests to me that
some of your concerns about AGMs are overstated. I cruise extensively
and keep in touch with many who do the same and I haven't heard any
negative feedback about AGMs. Again, that's not a random sampling,
but still, here we are in a widely read newsgroup discussing AGMs.
Where are the voices saying "damn, I put one of those in and smoked it
in a week"? Where are the 500 e-mailers who wrote into the Dutch
magazine to complain about AGMs?

I think Roger is right. The discussion has wandered off a bit. I'm
not trying to get into a ****ing match. I don't sell batteries. When
I bought my AGMs it wasn't a slam-dunk, easy decision. I can
understand why lots of folks choose differently. I've been very happy
with the way my AGMs have worked, but performance was not the only
criteria in my decision. As I type this at my nav station, I have two
8D AGMs just a foot or so away from my toes. Safety and aesthetics
have some value for me, too. AGMs are much more shock resistant than
flooded or gel batteries and that makes them less prone to internal
plate failures and shorts. Reliability is important, too. And so it
goes. In different circumstances I can easily see myself doing things
differently. There's lots of room for discussion of the pros and cons
of various systems. My only serious beef with the discussion so far
is with some of the arguments and assertions in your first link which
are, to be kind, bogus.

--Tom.

On Jun 17, 12:02 am, Salomon Fringe wrote:
... Everybody I have spoken to has different (sometimes radically different)
AGM/gel experiences than yours, so I figure there must be something special
in your situation that makes these batteries really shine. I would like to
know what it is.

I wish you wouldn't lump AGMs and gels together. I've heard some
horror stories about gels and am still waiting to hear any about
AGMs. They are very different things.

My house bank is 2 Lifeline 8DL's that live in a well vented
compartment in the living area of the boat. For charging I have two
105 amp alternators and four 85 watt solar panels and a 25 amp, three
stage plug in battery charger set to flooded battery mode. I use an
Ample Power Energy Monitor/Controller. The solar is set to cut off at
13.5 volts. Normally the batteries simply live on the solar and every
once in a while when the voltage gets low (3-5 days typically in port
or daily on passage) I charge them up until their acceptance rate is
~1 amp when using the charger and ~13 amps when using the
alternators. They also get charged when we motor for an extended
period. That's it.

...
I have a 24v setup and when I listened around and did the math two years
ago, I settled for Hawker full traction at half the price mentioned in the
Victron article. My second choice would have been semi traction based on
price and power. ...

Cool. How's it been working for you? What's your set-up and what
kind of service have you put them to?

--Tom.

wrote:

On Jun 17, 12:02 am, Salomon Fringe wrote:

... Everybody I have spoken to has different (sometimes radically different)
AGM/gel experiences than yours, so I figure there must be something special
in your situation that makes these batteries really shine. I would like to
know what it is.


I wish you wouldn't lump AGMs and gels together. I've heard some
horror stories about gels and am still waiting to hear any about
AGMs. They are very different things.

My house bank is 2 Lifeline 8DL's that live in a well vented
compartment in the living area of the boat. For charging I have two
105 amp alternators and four 85 watt solar panels and a 25 amp, three
stage plug in battery charger set to flooded battery mode. I use an
Ample Power Energy Monitor/Controller. The solar is set to cut off at
13.5 volts. Normally the batteries simply live on the solar and every
once in a while when the voltage gets low (3-5 days typically in port
or daily on passage) I charge them up until their acceptance rate is
~1 amp when using the charger and ~13 amps when using the
alternators. They also get charged when we motor for an extended
period. That's it.


I'm not seeing anything out of the ordinary. Do notice that may not be
cycling your batteries very heavily. Also, your energy budget seems
quite low! How do you live aboard? Washer? Microwave? TV? Computer(s),
refrigerator/freezer?

...

I have a 24v setup and when I listened around and did the math two years
ago, I settled for Hawker full traction at half the price mentioned in the
Victron article. My second choice would have been semi traction based on
price and power. ...


Cool. How's it been working for you? What's your set-up and what
kind of service have you put them to?

--Tom.

I have 12x2v Hawker perfectplus traction batteries with one 100A bulk
charger, a 35A 3stage Victron 1500w inverter/charger and a Victron
Multiplus 24/3000w/70 4-stage charger and inverter. The batteries are in
a big zinc-lined steel battery case in the engine room with vent to the
outside. Additionally I have 6 semi-traction bats of 230Ah with their
own two chargers, I can switch from the tractions to this bank if
necessary but normally I use them just for lights and for the diesel
central heating (pump, burner) in winter (really :-) and yes I live
aboard) I charge them using a generator or shore current, rarely with
two 100A alternators (one per bank) on the main engine (with 3-stage
chargers),I really have to be moving a lot for that. About 60%/35%/5%.
As for the semi-tractions (which were more heavily used before I got the
traction batteries), they have performed well so far but at their age
(5yrs now) there's nothing special about it yet. Very little maintenance
actually, although I do check them. And with 2yrs on them I guess I
can't say a thing about the traction batteries yet except that they are
doing their job. Definitely more water use than the semis, but distilled
water is cheap and it takes about 5 minutes to check and add some once
per two-three weeks. Equalize them at 32 volt about once a month.

On Jun 17, 3:07*pm, Salomon Fringe wrote:
...
I'm not seeing anything out of the ordinary. Do notice that may not be
cycling your batteries very heavily. Also, your energy budget seems
quite low! How do you live aboard? Washer? Microwave? TV? Computer(s),
refrigerator/freezer?

I wish I could answer the cycling question better. My tactic is to get
a charger of some sort on the batteries when the voltage starts
dropping below ~11.9v when hit with a load. That load is typically ~8
amps when the fridge and freezer compressors pop on. I'm not sure how
much DOD that represents. At sea with the autopilot, lights,
computer, SSB, etc and the solar panels usually shaded, they do get a
deeply cycled for sure.

As for loads, well, I think my boat is pretty systems heavy but we
stop short of the washer/dryer and microwave. We do have two
computers a 12v refrigerator and a 12v freezer each w/their own
compressor, an electric auto-pilot, SSB, VHF, RADAR, GPSs, 1500 watt
inverter, instruments, a diesel heater (seldom used), an electric
windlass and lights (and probably some other stuff I'm forgetting).
We live on board full time and cruise extensively. Our boat is a 42'
catamaran.

Your set-up is in a whole other league, though. I'm kind of in awe.
I can see with a bank that size that cost must be a much more serious
factor. How do you like 24 volts?

-- Tom.

On Wednesday 18 June 2008 02:25, wrote:

On Jun 17, 3:07*pm, Salomon Fringe wrote:
I wish I could answer the cycling question better.

Yes I wish there were battery monitors that would integrate the number of
kWh taken from the battery over its lifespan, and do something smart with
every low and high % charge so people could finally really check and
compare performance.

My tactic is to get
a charger of some sort on the batteries when the voltage starts
dropping below ~11.9v when hit with a load. That load is typically ~8
amps when the fridge and freezer compressors pop on.
....

Does your battery monitor show % discharge of your bank? If so that might be
better than relying on voltage that changes depending on load.

As for loads, well, I think my boat is pretty systems heavy but we
stop short of the washer/dryer and microwave. We do have two
computers a 12v refrigerator and a 12v freezer each w/their own
compressor, an electric auto-pilot, SSB, VHF, RADAR, GPSs, 1500 watt
inverter, instruments, a diesel heater (seldom used), an electric
windlass and lights (and probably some other stuff I'm forgetting).
....
What does your1500w inverter power? I suppose the inverter will be the
heaviest load at possibly 120A @12v.

Your set-up is in a whole other league, though. I'm kind of in awe.
I can see with a bank that size that cost must be a much more serious
factor. How do you like 24 volts?

-- Tom.

Cost is always a factor, but as I said, I have never met anybody that had
his AGM (or gel) batteries outlive even their semi-traction batteries and I
didn't feel brave enough to try to be the first to prove it with my new
main bank...
WRT 24v - I have never used 12v so I can't compare. I can see things getting
cheaper and easier to install when halving all currents. Especially when
you have some distance to go.
Apart from all navigation equipment and some pumps everything here is just
running at 230v through the inverters. So outside the wheelhouse and the
engine room I actually don't see much 24v.

On Jun 18, 3:11*am, Salomon Fringe wrote:
... Does your battery monitor show % discharge of your bank? If so that might be
better than relying on voltage that changes depending on load.

It does, but it's funky. I've fiddled with the Peukert a fair bit
(now trying 1.150) and with the charge efficiency % (97). Still, it
always tells me the batteries are worn down long before the voltage is
weak and then it shows them fully charged while they're still
accepting current. And it periodically has a two's complement / over-
run thing that sends it off into huge negative numbers sounds the
alarms and requires a re-set... It is a nice volt/amp meter, it does
a good job of controlling the alternators and it does an adequate job
of controlling the solar, but it's not all that useful as a battery
gauge.

...
What does your1500w inverter power? I suppose the inverter will be the
heaviest load at possibly 120A @12v.

The computers mostly. I also have some battery powered tools that I
recharge with it and a dremel tool that I run off of it and when we've
got cell phones we charge them, too. Typically it is off.

We're basically a 12v DC boat. Sounds like you're on the other side
of the coin being mostly 230 AC (50 cycle, I presume). In theory,
your way should save a lot on wire and transmission losses.

Anyway, I'm very happy with my AGMs and I'm glad to hear that you're
happy with your tractor batteries. I think we'll all be happier yet
when nickel, lithium or maybe even fuel cells are affordable.

-- Tom.