Do AGM's charge quicker?

Thanks Mex (I think). So I am doomed to my fate. I have to follow the rules or pay the price. It least I know what the rules are, from being on this forum. :) As long as it is not too impossible, I will follow the rules.

Take a gander at the group 31 charging specs of a FLOODED group 31 Rolls battery

http://www.rollsbattery.com/battery/31-m-130/

It isn't go/no-go situation. Your 16.7% will work fine but take the battery to 90 percent state of charge most of the time. And to 100% at least every 10-14 days.

You do not want sulfation meaning occlusion of the plates to harden -- it's similar to what happens to flooded batteries. I threw a freakin' fit at Optima in 2005 over this. I also pleaded with Concorde. They soon saw the light. And publications changed. They damned well knew who I was -- the tame tiger who eats the guy with the whip.

Below 15% of amp hour total is no-no. But 15% to 20% can be made up with fuller recharging above 85% - 90% and like with anything chemical TIME enters the picture in all facets of chemical reactions. Cheat one thing a bit and it has to be made up by percentages and time on the other factors.

Chemistry is cruel. It doesn't care if I agree with it or not. Knowing more throws more loops of slavery and dire knowledge of consequences around me. Don't cheat on these values is my recommendations BFL13. The charge percentage and recovery minimums are at the bitter minimum of acceptable limits.

Let those who ***** and moan about having to LEARN (adjacent to kiddieporn in their mind for utter repulsiveness). I do not have the money to be be dismissive about ignorance or learning. You wish to learn BFL and I am happy to share.

I would like to know something useful from the published specs, such as for my two 100AH AGMs , spec max amps about 27a each, where I now use my 55 amper on both (going over by 1a). What would happen if I used my 75 amper instead? 75/200 = 37.5%

It would be convenient if could use the 75 amper (in turn) on both the 250AH battery ( spec max 100a) and for the two 100s. Instead, I have to deploy the 55 and the 75. But you say, just use the 55 for both where 55/250 = 22%.

But then off- grid for a 50-80, I would not have the 75, just the 55, so that would take more gen time.

It would also be convenient if I could use the 75 amper without having to split the bank. 75/450 is 16.7%. The battery specs are silent on minimum charging rate. Mex is the one that says do 20% regardless of the published specs. Darn Mex anyway!

And I can't do 20% of 450AH ( 90 amps) with anything because I can't run my trusty 100 amper with my little 2200w gen or at home on shore power or it will pop the breaker. (My previous Honda 3000 did that 100 amper) This is entirely Mex's fault!

I originally thought I was home free as long as I kept the charger voltage at 14.4 until amps got down to 0.5 per 100AH. Easy peasy. Then this 20% came along and screwed it all up, so I have to split the bank and use different chargers. Drat!

Reality exists despite the best of guesswork. I have never torn down a dead AGM and found plates thicker than around .045". Plates do shed over time.

Do lithium batteries automatically come with cell to cell management systems? And user interfaces that allow real time monitoring?

And it is quite important to understand that charging to 95% SOC rapidly is much better than to go to 100% over several days time.

A 40 amp Megawatt adjusted to 14.4 volts can take over when a perverter cannot reach and maintain 14.4 volts at home. Plug in at night and set the alarm for the next day.

I've come to the opinion that battery manufacurer recommendations as to voltage and charge rates are generalities mostly designed to bolster the bottom line of those companies by minimizing potential warranty returns.

This of course is largely a guess as to how the battery is going to be used and recharged by the end user, and if they think 16.2v EQ is going to reduce returns by 0.03% over 15.5v, then 16.2v it is.

Personal Experience with My TPPL Northstar AGM says feed the SOB with high amperage regularly, and do not go too many deep cycles with low and slow solar as the only recharging source. If the voltage when cranking my engine is lower than desired, or overnight voltage is less than expected, then it is time to depleted it to 50% or Lower and stuff its 90Ah capacity with no less than 40 amps.

I would never recommend an AGM for those only capable of low and slow solar only recharges, or those who think their 2/12 amp garage charge is 'just fine' after they drain it dead as a doornail.

I've some experience with New AGM batteries, but only when they were new, A Crown31 that had NO CCA figure, whose voltage under light loads was unimpressive, and a new Lifeline GPL-31XT whose voltage retention under discharge and charge acceptance rate, and full charge resting voltage were Very impressive.

I cannot speak to each and every other AGM battery, I think anybody who does is to be ignored. I have figured out what my battrey needs to perform well, and it is now over 5 years old, over 1000 deep cycles, and if it failed tomorrow I would Buy another Northstar AGM, as I love that my alternator can feed it when it is well depleted safely, 106 amps, and it has delivered ,ore KWH per $ than any other battery I have ever used, ut I can also rechrge it battery than any other battery I have cycled to death

Can another group 27 other than Lifeline or Odyssey( who makes no 27) accept 106 amps? Perhaps, but for how long before max voltage is reached and amps taper?
NOrthstar and Odyssey AGM have less resistance by ~25% for the same size battery as Lifeline and ridiculously high CCA and PCA figures, at least when new.

How long my AGM takes when depleted to reach absorption voltge at 40 or 65 amps is a ruler as to its health. and this high amp recharge until amps taper to 0.5% seems like a restorative charge.

Voltage retention under load, is a ruler
How long it takes amps to taper to 0.5% of capacity regardless of initial amperage or state of charge, is a ruler, but apples to apples is preferred.

Without actually having another battery to compare these expected times/numbers too, I can;t say whether the Lifeline is better, or the Full river is just as good, or the Asian UPGs can easily accept just as high amperage safely. Experiment, measure their temperature, but blindly adhering to a max recommended charge rate, Never! not for me anyway.

Without data, its all just an opinion, and some data points I see written on forums, I just do not trust, and can't, unless I collect/witness it myself, as the human ego will dictate what the fingers type, and that could easily defy physics.

(I apologize for the two overt clippings below out of your comments above.)

MEXICOWANDERER wrote:
Something tells me my 31's will be alive and well at age twenty, if they are taken care of.

Well, now that's where the real rubber meets the road isn't it? For us types who have plenty of other things in life to take up our waning time and energy ... "how do we get 20 years out of stuff that we don't have to take care of"? Truly mess-around-free is the name of the/my K.I.S.S. game.

MEXICOWANDERER wrote:
I simply do not have money to waste. Period. I paid six dollars for a three-step manual knife sharpener that in a nutshell is a terrible sharpener. Fifteen minutes sharpening a knife yields a semi-sharp edge. No way around it I wasted six dollars.

Yup ... I hear ya. A few years ago I spent ~$70 for a manual knife sharpener actually Made in Japan. It really does the job day after day without complaining or requiring any taking care of. It does all of our knives whether they be Japan edge geometry (20 degrees?) or rest-of-world edge geometry by eventually forcing 20 degrees(?) on the edges. As would be expected though, I really had to try hard on figuring out how to pay for it.

Phil has suggested that maybe all AGMs can be hit with really high charging rates despite having max amps in their specs. ISTR Mex has hinted that.

Meanwhile, some AGMs do have minimum charging rates in their specs- same 20% mentioned for several. But some like my two different brands of AGM have no mention of a minimum charging rate, but they do have max rates specified.

Mex says to ignore that and treat them as though they do have a 20% minimum.

I find that 20% business to be a huge PITA, but I don't dare ignore Mex if I want to keep my AGMs healthy. I don't need to try a higher charging rate than specified, so that is no problem.

What is the truth then? Are all these deep cycle AGMs about the same, despite their different charging specifications, or not?

The big rave these days is lithium (and Bugatti charons, 1945 Chateau Lafitte Rothschild, pink flawless diamonds, white truffles, estate grown Darjeeling teas, etc)

But for ordinary folks the question seems to be: Yes or no, are the Lifeline batteries worth the extra cost?

In a nutshell, if a person is willing to take the extra time to observe the 20% MINIMUM STARTING OUT AMPERAGE rule in recharging, willing to not have the batteries sit for weeks and weeks partially charged, and every 6 months to a year discharge a floated battery then apply >20% charge rate then yes, the Lifeline is worth it. The reason is plate thickness.

Do Deka and Trojan manufacture their own AGM batteries in plant? This would mean East Penn manufacturing in Pennsylvania and Trojan in their two US plants...? I do not know. Do any of you know? For sure?

My own Lifelines are definitely not cycled daily or even weekly so they are not a valid reference.

But when open forums on sailboat cruisers who go years circumnavigating (off grid) and true off-grid homesteaders select Lifeline as being overwhelming # 1, the act is not lost on me.

Like my favorite example: My stupidity in trying to save money by buying DOUGLAS TIRES at Wal-Mart. Sometimes savings are a ripoff. The Michelins have outlasted three sets of DOUGLAS and still have >50% tread life remaining.

I would love to find -As good as Lifeline but at half the price- AGM batteries. Good luck. Something tells me my 31's will be alive and well at age twenty, if they are taken care of. Again they are mostly standby these days.

I just sprang for more costly 4.0 diopter reading glasses on eBay. They cost 4x the price of the cheapies. Are they worth it? The lenses are distortion free and I can now wear reading glasses for longer than 3 hours without getting a headache. You tell me if the twelve dollars readers are "worth it"?

Or if the Gates fan belt is worth double that of Continental or Dayco fan belts.

I simply do not have money to waste. Period. I paid six dollars for a three-step manual knife sharpener that in a nutshell is a terrible sharpener. Fifteen minutes sharpening a knife yields a semi-sharp edge. No way around it I wasted six dollars.

It would be nice to have an "average" income 800% greater than what it is. And a giant recycle bin out at the curb. Such is life.

Adios :)