Two Types of AGM batteries?

[Extemporaneous]

Below it from the Smart Gauge Owners Manual.
http://www.smartgauge.co.uk/pdfs/man...geman_r108.pdf
I guess what I'm most curious about, is the "additional chemicals" that they are talking about.
Dose anyone know what this chemical is?
Dose anyone have comments on the battery type settings or comments for AGM batteries mentioned below?

Thanks,
Extemp.

NOTE There are actually two very distinct types of AGM batteries with very different operational
characteristics. In one type the only real difference is that the electrolyte is held in a glass matt. This type
usually have charge voltages very similar to flooded wet cell batteries. The off load terminal voltages will
also be very similar to flooded wet cell batteries. If your AGM batteries are of this type then SmartGauge
should be set to battery type 1
The other type of AGM has additional chemicals in the battery (similar to gel cell batteries) and this type
usually require lower charge voltages and the off load

[GordMay]

Some common components of VRLA (AGM) Batteries include: Lead Oxide (Lead Sulphate, Lead Calcium Alloy), Tin, Arsenic, & Sulfuric Acid.

[Extemporaneous]

Gord, can you (or anyone else for that matter) shed some light on the "two distinct types" statement. I know that some differ, but is there a way to unequivocally know which type one is purchasing? Or is there disagreement with the statement?
Thanks,
Extemp.

Originally Posted by Extemporaneous

Below it from the Smart Gauge Owners Manual.
http://www.smartgauge.co.uk/pdfs/man...geman_r108.pdf
I guess what I'm most curious about, is the "additional chemicals" that they are talking about.
Dose anyone know what this chemical is?
Dose anyone have comments on the battery type settings or comments for AGM batteries mentioned below?

Thanks,
Extemp.

NOTE There are actually two very distinct types of AGM batteries with very different operational
characteristics. In one type the only real difference is that the electrolyte is held in a glass matt. This type
usually have charge voltages very similar to flooded wet cell batteries. The off load terminal voltages will
also be very similar to flooded wet cell batteries. If your AGM batteries are of this type then SmartGauge
should be set to battery type 1
The other type of AGM has additional chemicals in the battery (similar to gel cell batteries) and this type
usually require lower charge voltages and the off load

[GordMay]

There’s Flat Plate (rectangular) and Spiral Wound (Cylindrical) AGM geometries; but I don’t know that the chemistries are significantly* different.

* I’ve read that spiral wound construction allows for the lead alloy plates to be purer, as they no longer need to structurally support their own weight as in flat plate cells.

Smart Gauge offers some excellent tutorials; but I'm a little dissappointed that they don't explain their statement about additional chemicals resulting in lower charge voltages.

[Extemporaneous]

Originally Posted by GordMay

There’s Flat Plate (rectangular) and Spiral Wound (Cylindrical) AGM geometries; but I don’t know that the chemistries are significantly* different.

* I’ve read that spiral wound construction allows for the lead alloy plates to be purer, as they no longer need to structurally support their own weight as in flat plate cells.

Smart Gauge offers some excellent tutorials; but I'm a little dissappointed that they don't explain their statement about additional chemicals resulting in lower charge voltages.

Thanks Gord,
I was wondering if I missed something in my reading (never mind I've probably missed lots).
Regardless, I'll send an email to Smart Gauge and post their reply.

As far as their battery monitoring approach, do you understand it and in any of your conversational travels, have you heard how well it works?

Extemp.

[Extemporaneous]

See below, dialog with Smart Gauge.
You may have to read it form the bottom up. (me black him blue)
If there is such a chemical, I can certainly see why it would be added. Also I'm a little surprised at his battery choice (cheap flooded), but there is a logic there and I suppose it depends what your looking for/your boating habits. I don't think it would be a cruisers attitude but it may be others approach.
Any comments?

Hi again

My own personal preference is as follows (and I'll try to explain why):-

I use cheapo open cell wet cells on my own boats and have done for many years now. The type that are usually branded with something like "Leisure" stamped on the side. The reason being that given the same treatment there is no doubt whatsoever that proper deep cycle wet cells will outlast these cheapo ones by at least 5 times. They cost about 2 to 3 times as much and therefore it makes economic sense to use the more expensive ones. However, I have better things to do with my life than maintain and look after batteries. If I abuse these batteries then it will wreck the expensive ones just as easily as it will wreck the cheap ones. I therefore opt for the cheap ones.

With regard to AGM and gel cell batteries I have a bit of a problem. They are, again, more expensive that cheapo wet cells but in my experience, given the same treatment, they don't actually last that much longer. A little bit perhaps, but not enough to justify the extra expense in my mind. But of course it's a personal choice.

Type 3 AGMs (and all gels) still suffer from sulfation (but not as much), and once it's happened there is nothing that can be done about it. With wet cells they can be equalised (which removes much of the sulfation). This, of course, uses water, but this can be replaced in open cells. It can't with AGMs or gel cells which is why they can't be equalised.

Type 1 AGMs are slightly different in that they can tolerate a higher charge voltage (for equalisation) without losing electrolyte. My own favourite for this type of AGM is the Optima yellow top spirals.

The only advantage in using normal AGM or gel cells is where they are going in an installation where heel angle (or even complete inversion) is an issue becasue they can't spill electrolyte.

As to the extra chemicals introduced. It is another acid that is inert as far as charge/discharge reactions are concerned. It doesn't get involved in the chemical reactions. These chemicals are a highly guarded secret by the manufacturers. Their purpose as as follows: When a battery is discharged the internal resistance rises as the SG of the electrolyte falls. If it falls as low as 1.0 then the internal resistance becomes almost infinite. The battery will then never, ever, charge. Even if it never gets this low, the internal resistance becomes quite high, so when charging commences, the battery draws very little current. The new added chemical maintains a certain minimum internal resistance so that even when the battery is deeply discharged it maintains a relatively low internal resistance so when charging commences the battery draws a much higher current. It also means the battery can produce a higher current when deeply discharged simpyl because the internal resistance is lower.

This chemical is also responsible for the higher terminal voltage for type 3 AGMs and gel cells.

It is, of course, entirely your own choice but of the many people I have contact with who have tried AGMs very few return to them and the usually end up back on wet cells. The only people I know who still use AGMs are the ambulance fleets and the MOD whose main reason using for them is that the slightly longer life given the same treatment suits them. They don't really care about the "3 times the price" only giving them an extra 50% of life. The RNLI who have to have batteries that can be inverted without spillage and light aircraft for the same reason.

Regards
technical@smartgauge.co.uk

SmartGauge Electronics
Brewery Offices
Burtonwood House
Bold Lane
Burtonwood
Warrington
Cheshire
WA5 4TH

Tel +44 (0)7950 359721
www.smartgauge.co.uk
www.masterplex.co.uk


----- Original Message -----
From:Extemp
To: technical@smartgauge.co.uk
Sent: Sunday, March 08, 2009 7:51 PM
Subject: Re: Smart Gauge Question

It does explain well enough that I will be able to identify batteries in my possession. Can you tell me more about the "additional chemicals" that your manual mentions?
Also, sense I am just about to purchase a new AGM house battery bank and don't have them yet:
1.Which do you feel (generally) is a better battery of the two AGM types you mention below?
2.Is there an AGM brand that you would recommend?
Right now I'm thinking of going with Trojan's.

Best regards,
Extemp.

technical@smartgauge.co.uk wrote:
Hi there
The problem stems from the fact that the people who sell the batteries are not the ones who make them. Consequenctly they don't know much about them.
There are two ways to identify the type of battery. Incidentally this problem is becoming more and more common, if you look at many modern chargers they have settings for 2 different types of AGMs and their customers are also having trouble identifying the correct type because the battery dealers are clueless about what they are selling.
Anyway, I digress. To identify the type of battery:-
Charge the battery at 14.2 volts for 24 hours. Then discharge for TEN MINUTES using a load of roughly 1/10th the capacity of the battery (so a 10 amp load for a 100Ahr battery). Then leave the battery to stand with no load and no charge for 48 hours. Then measure the terminal voltage. If it is above 12.8 volts it is a type 3. If it is below 12.7 volts it is a type 1. If it is inbetween these two then you need to wait another 24 hours to make sure it drops below 12.7 volts.
The other way is to look at the recommended charge voltage. If it is above 14.4 volts then it is a type 1. If it is below 14.4 volts then it is a type 3.
Does that explain it well enough?


On Sun 8/03/09 4:40 AM , extemp@canada.ca sent:

Please see below.

Below are some questions, below that in blue is from the Smart Gauge Owners Manual.

With regard to the portion in your manual about Type 3 AGM batteries, the manual talks about "genuine AGM batteries" and "additional chemicals" in order to setup the smart gauge properly. I have talked to battery manufacturers and others trying to establish what the 2 different types of AGM batteries you are referring to.
I have had NO luck.
What is this additional chemical that you are referring to?
Can you give me examples from different manufactures with reference to the actual model numbers for each of the two different types of AGM batteries to which your manual refers.
This would very much help me select new batteries which I need to purchase.

Thank-You in advance,
Extemp..

http://www.smartgauge.co.uk/pdfs/man...geman_r108.pdf

Setup mode – Battery type

On entering the setup menu the first item to be set is the battery type, shown as “bt x” where “bt” signifies
battery type and “x” shows the current selected type.
The battery types are numbered 1 to 7 and are as follows:-
Note that this is not intended as a full description of battery types. Merely sufficient information to enable
you to select the correct battery type for your batteries. If you are unable to identify the battery type from
the manual supplied with the batteries the following options will usually yield good results.
A. Telephone the supplier and ask them which of the following groups the batteries best fit into.
B. Ask the manufacturer the same question.
C. Visit the battery manufacturer’s website where they usually have full technical details of all
battery types (except one very large battery manufacturer whose “technical specifications” page
simply shows the battery dimensions and weight!).

Type 3 AGM - Absorbed Glass Matt (another type of VRLA)
Use only for genuine AGM batteries. These batteries behave in a completely different way to the
other battery types and SmartGauge will not operate correctly with any other setting.
NOTE There are actually two very distinct types of AGM batteries with very different operational
characteristics. In one type the only real difference is that the electrolyte is held in a glass matt.
This type usually have charge voltages very similar to flooded wet cell batteries. The off load
terminal voltages will also be very similar to flooded wet cell batteries. If your AGM batteries are
of this type then SmartGauge should be set to battery type 1
The other type of AGM has additional chemicals in the battery (similar to gel cell batteries) and
this type usually require lower charge voltages and the off load terminal voltages will be similar to
gel cells. This type require SmartGauge to be set to battery type 3

[camaraderie]

Wow...I would immediately disregard anything this guy tells you and listen to someone else. SOO much wrong in that post.
Get your Trojan AGMS or Lifelines and set it for Type 1 and forget the rest. Just make sure you give them a 100% charge at least every couple of weeks to keep sulfation at bay and then when you DO need to EQ..follow the mfr. recommendations carefully. MANY AGM's Can be EQ'd but they should only need it when you begin to see a loss of capacity.

Trojan AGM's are spec'd as high as 14.7Volts so 14.4-14.5 is probably a very good range. Max amps on bulk should be 20% of rated amp hours (which I think is overly conservative but is the spec they give) and finishing amps are 1/200 of rated ah's...so .5 for a 100ah battery. Trojan AGM's are NOT EQ'able like the lifelines. Hope this is helpful.

[Extemporaneous]

Originally Posted by camaraderie

Wow...I would immediately disregard anything this guy tells you and listen to someone else. SOO much wrong in that post.
Get your Trojan AGMS or Lifelines and set it for Type 1 and forget the rest. Just make sure you give them a 100% charge at least every couple of weeks to keep sulfation at bay and then when you DO need to EQ..follow the mfr. recommendations carefully. MANY AGM's Can be EQ'd but they should only need it when you begin to see a loss of capacity.

Camaraderie,
Attached is from Magnum Energy's ME-RC Manual.
They also seam to think there is a difference in AGM types, or at least the Lifelines. Perhaps there are more brands but their list only includes main stream brands.
Perhaps there is something to this?
Also, could you point out more specifically the points that are soo wrong. It would help me learn more quickly.

Thanks,
Extemp.

[Rick]

Having spent 30 years working with batteries, designing charging systems and battery monitors AND referring to electrochemistry textbooks and technical papers regarding lead-acid batteries (yes, AGM's of all types and gel-cell are still lead-acid) it is evident that there is NO set battery charged voltage that is "correct" with the exception of float voltage (specified at a specific temperature).

Having first-hand experience working with Xantrex, Heart Interface, Trace Engineering and Cruising Equipment I can tell you that NONE of the "charts" recommending charge voltages came from anyone other than marketing personell, NOT from electrochemists who design batteries. The marketing people are forced to attempt to give uninformed users some relevant form of recommendations in order to sell their products.

The basic electrochemistry for ALL lead-acid batteries is essentially the same as far as users are concerned. To be sure there are different chemicals used in the plate "pastes" as well as the plate lead make-up. The formula describing the reversability of sulpheric acid, lead sulphate and lead oxide is the same for all as far as energy transfer (charge and discharge) is concerned. The fact that what is called half-cell equations differ slightly is of no concern as far as how one might charge the battery (at least for the batteries applicability to deep-discharge and high rates of current charge/discharge is concerned for cruising).

MY past posts describe just how fast one can charge a battery and there are various discussions regarding the so-called "Amp-hour law" taken from electochemistry texts. The three-step charging algorithm is a first appoximation to the Amp-hour charging method and CAN be exceeded.

There are VRLA (valve-regulated lead-acid) batteries used for things light emegency lighting that are not designed with sufficiently large plate interconnects to be used for high rates of charge/discharge and are, therefore, limited to charge rates...not applicable to us here where we use batteries designed with large plate interconnects.

None of the charger or inverter/charger marketing information (that I have read) properly describes just what constitutes a valid equalization cycle. Equilization is done with a constant-current source that terminates with time qualified by observation of the temperature, cell voltage and charge acceptance. NO manufacturers of chargers have that capability built in and, therefore the marketing people must compromise with a half-baked method which has no where near the efficacy of the proper method. Again, any time that you read what is an "equalization voltage" there is no such thing in the rigorous sense of equalization.

Here is a short description of charging: Float voltage is determined by the designed acid concentration and temperature period. There is a simple formula describing the at-rest cell voltage as a function of the specific gravity of the electrolyte. ALL AGM batteries follow this as well. With ANY lead-acid battery of any type use for deep-discharge high current applications You can safely charge the battery without excessive temperature rise or gassing by applying a charge current equal to (or slightly greater than..following my experience) the value of Amp-hours "missing" from the battery. This concept cuts through all of the crap regarding charge voltage because the voltage is always different as the battery comes up to full.

Now when the three-step method was first promulgated by Ample Power and then by Cruising Equipment and then implemented by Heart Interface (with their inverter/chargers) it was with the realization that simple voltage regulation in steps could approximate the Amp-hour law. We all wished early on that it was affordable to create a charger to exactly follow the Amp-hour law yet knew that a battery monitor would have to be married both to the battery as well as the charger to do that.

Further research in the lab and in the field revealed that ALL of the battery types would respond remarkably well using a true Amp-hour law charging regimen (I did this for years) and that many of the AGM batteries rejected by many users could be brought back from the dead by using a true equalization method. One REMARKABLE result of doing this is that if subsequent charge/discharge cycles were done using Amp-hour law charging they never needed equalization again as long as they were not left to long in a state of discharge before charging.

One observation that I have made is that the beginning charge voltage of the Amp-hour law charger would always be higher than 14.4V and usually below 15Volts. Does that give anyone a clue? It makes no difference weather one is using an AGM with a specific gravity requiring a float voltage of 13.2 Volts or one requiring a float voltgage of 13.9 or 14.0 Volts. Gel-cell batteries love this as well and tended to "look" more like the bettery quality AGM's like Fullriver today. Again, do not confuse float voltage with upper limit acceptance voltages that would keep charge current within the limit of the number of amp-hours missing from the battery as stated.

Hope that this helps cut through the crap regarding all the different acceptance or equalization misinformation out there.
Rick

[Therapy]

Rick,

I thank you for that.

I wish I understood all of it though.

That way I might understand if a Freedom 15 would do a "worry free" job of charging a pair of Lifeline 6V 300ah in series with a link 1000 in the mix.

[camaraderie]

Extemp...I had a nice big post prepared in answer to your questions but Rick beat me to it and did a much better job of it!
I would just confirm what he said by sharing a couple of factual items which reinforce his points and again deny the existence of two TYPES of AGM batteries.
1. The company you quote with the picture chart has TOP of the line inverter chargers ME series...that have ONE setting for ALL AGM batteries.
2. So do Balmar and Xantrex....one setting for all AGM's.
3. The voltage settings specified in your chart are quite a bit different than Lifeline (the only member of "type I") specifies on its own website.
4. Ditto the Type II settings for all others...East Penns don't agree.

So...as Rick says... Its' all somewhat BS and ANY AGM can be treated the same as any other AGM in the charging cycle...though EQ may be entirely different from brand to brand...and mostly unnecessary unless you've already tried to kill them through improper care.


BTW...My comments on so much wrong with his opinions refer to his opinions on costs and benefits and economics of different types of batteries which clearly reflect those of a part time boater who does not rely on his batteries for daily deep cycle and charging on the hook. For someone who plugs in at the dock and makes use of his batteries on weekends...fine. For cruising the equations are far different and his choice of el cheapo wet cells is the most expensive he could make as well as being a PITA to maintain.

[Rick]

Yes, you should be able to set up the charge parameters for the Freedom via the Link1000. One thing to keep in mind that in addition to the "charged parameters", Puekert exponent, and battery type you can "lie" to the unit by entering in a low value for temperature which will raise the acceptance and float voltages as desired, but get used to doing this by doing it a few times.

Note also that with the Link1000 if you enter the equalization mode and then immediately enter it again the Freedom charger should always go to float if your shore power gets interrupted and you don't want to keep going back through the acceptancy cycle. Only an obscure part of the manual.

[Therapy]

Originally Posted by Rick

Yes, you should be able to set up the charge parameters for the Freedom via the Link1000. One thing to keep in mind that in addition to the "charged parameters", Puekert exponent, and battery type you can "lie" to the unit by entering in a low value for temperature which will raise the acceptance and float voltages as desired, but get used to doing this by doing it a few times.

Note also that with the Link1000 if you enter the equalization mode and then immediately enter it again the Freedom charger should always go to float if your shore power gets interrupted and you don't want to keep going back through the acceptancy cycle. Only an obscure part of the manual.

I read the manual a couple of times.
I have not learned it though.

Maybe when I have the stuff in my hands.

[Extemporaneous]

Originally Posted by camaraderie

Extemp...I had a nice big post prepared in answer to your questions but Rick beat me to it and did a much better job of it!
So...as Rick says... Its' all somewhat BS and ANY AGM can be treated the same as any other AGM in the charging cycle...though EQ may be entirely different from brand to brand...and mostly unnecessary unless you've already tried to kill them through improper care.

Ya, that's the problem with reading more than one thing.

Originally Posted by camaraderie

I would just confirm what he said by sharing a couple of factual items which reinforce his points and again deny the existence of two TYPES of AGM batteries.
1. The company you quote with the picture chart has TOP of the line inverter chargers ME series...that have ONE setting for ALL AGM batteries.
2. So do Balmar and Xantrex....one setting for all AGM's.
3. The voltage settings specified in your chart are quite a bit different than Lifeline (the only member of "type I") specifies on its own website.
4. Ditto the Type II settings for all others...East Penns don't agree

The info I got off Lifelines website is the same (exactly in the middle of what they range) as what I posted for bulk and acceptance and 0.1v different on the float. That's quite a bit different?
Regardless, Rick covered it.

Originally Posted by camaraderie

BTW...My comments on so much wrong with his opinions refer to his opinions on costs and benefits and economics of different types of batteries which clearly reflect those of a part time boater who does not rely on his batteries for daily deep cycle and charging on the hook. For someone who plugs in at the dock and makes use of his batteries on weekends...fine. For cruising the equations are far different and his choice of el cheapo wet cells is the most expensive he could make as well as being a PITA to maintain.

Perhaps you didn't read his email. That's okay, I'm certainly not defending him, but I was curious as to what was so wrong with it. You didn't like his approach I guess. It's not an approach I'd take either.

Now if I could just automate Amp-hour law charging .

Regards,
Extemp.

[hellosailor]

Never heard of "Type1" and "Type3" AGMs and that's after talking to makers and distributers as well as the usual swarm of web sites. That this fellow says life is too short to bother taking care of batteries--when AGMs with a proper charging system are essentially maintenance free--speaks loudly to me.

that he thinks Optima yellow tops take optimizing, when JCI (the maker) doesn't recommend optimizing at all AFAIK, speaks again. And the Yellow top is a "dual use" SLI/deep cycle hybrid, the "Blue top" is the marine deep cycle battery.

Spiral wound AGMs are exactly the same as flat plate AGMs, the only difference is that they are wound instead of stacked, which in theory makes them cheaper as well as more reliable. In practice--they're about 30-40% more expensive and they have about 10% less capacity than flat plate batteries, since they are sticking a "round peg" in the "square hole" of a battery profile.

Pass the salt, please. I'd need more than a grain to believe that guy.
There IS one different type of AGM on the market. That's an oddball which claims to provide better performance by using a gel electrolyte ABOVE the plates to provide more electrolyte. I haven't heard anyone besides their maker claiming that accomplishes anything though.

And of course, every battery maker tweaks their metal alloys a bit differently, which results in slightly different optimum charging profiles and voltages.