Agm life expectancy?

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Comments

  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    Re: Agm life expectancy?

    backroad,
    you probably would spend too much in fuel if you go for 100% soc. the generator would only need be on to bring the batteries about to the 80-85% soc point and from there solar does far better.

    icarus,
    the 5-13% is for standard lead acid batteries. agms can easily take 20-25% (maybe more) and my sunxtender can go 100%.

    quabillion,
    just as i suspected the float setting is high. try about 13.4v. this could've slowly caused outgassing (i hope not). myself and crewzer saw between 12.8v and 13v depending on how long afterwards we were looking, but never should its at rest v be over 13v. my float setting is even lower at 13.2v for my sunxtender.
    i do question a bulk voltage setting as bulk is wide open and will switch to absorb at 14.2v so i'd place the absorb to 14.2v and float to 13.4v.
    as far as eqing goes i don't need to with 1 battery and i think rearanging the batteries may suffice better than an eq charge for you. this would mean a dmm to accurately determine the at rest battery voltages when disconnected from the interconnecting wires. these differences will be small as you may see a battery with 12.75v and another at 12.83v for example. after switching high/low battery positions and several cycles of charge/discharge still show the batteries haven't changed then and only then would i consider an eq charge so document everything you do so you know where you stand.
    i personnaly dislike the idea of eq charging an agm battery bank as they are voltage sensitive. i believe concorde changed up on me and is allowing up to 14.6v for eqing from the previous 14.4v max (not considering battery temp variations). there is no rule that you have to go straight to the max eq voltage they say as it could be a bit lower. most will eq for a couple of hours and standard batteries are often eqed again if it doesn't equalize on the 1st round. concorde speced an 8hr max on eqing and you shouldn't need anywhere near that much time as i had said.
  • lamplightlamplight Posts: 368Solar Expert ✭✭✭✭✭✭
    Re: Agm life expectancy?
    icarus wrote: »
    So if you have been off grid since '03,, are you still on the original batteries? If so,, with the usage pattern you describe I think you are doing pretty well. That is something like 2500 cycles to 65% soc. Not too bad. The concorde site suggests that at 40% dod, one should expect ~1500 cycles. (20% dod should yield upwards of 3000 cycles,,, 5000 at 10%).

    Tony

    that isnt bad at all. this is the spec on a MK battery that i was just browsing (looks like concorde are much much better)

    8a8d_cycling_capacity.gif
  • backroadbackroad Posts: 185Solar Expert ✭✭
    Re: Agm life expectancy?

    This is all being a great help to steer my mind in the right direction, if that's at all possible.:p

    The more that I think about the AGM's and figuring cost and AH capacity, I'm starting to lean another direction. I think that what I'm about to venture into is a fairly decent size of solar system, but a 48v bank really adds a bunch of money in batteries to get the same kind of AH output that my old 24 volt system did. Crown has an Idustrial Battery that has an 1090AH rating in 12 volts. 2 of these would be a little over $6,000. They carry a 10 year guarantee and are rated for a service life of over 20 years when treated properly. I'd only need 4 cables to wire them in. 2 between the two battery packs and two to tie them to the inverter.

    I know that I have to check water levels and that's really tough, but....There is one downside that I've found to a 24v system. To use a 3600 watt array, I'd need to use two of the MPPT Charge Controllers, but that's really not bad compared to the extra cost of batteries.

    Did I mention that the Crown Industrial batteries are actually very lite? Only 850lbs ea.
    Did someone say hernia?

    This will probably stir up the Hornet's nest....
  • mikeomikeo Posts: 386Solar Expert ✭✭✭
    Re: Agm life expectancy?

    I'm not quite sure what you are saying, if you double the voltage with the same amp hour battery capacity your have doubled the watts (power) stored as well as the money spent. I just acquired a set of refurbished DECA 6-D100-13 940 amp hour batteries (20 hour rate) for $1200 that test 100% capacity. They weigh almost 700 lbs each. I use these with an 1800 watt array which generates around 50 amps on a good day in Arkansas which is just barely a 5% charge rate. If I could afford to expand, I certainly would change out my 24 volt inverters for 48 volts that could still be controlled with a single MX60 or FM80 charge controller. This would match your double size array and be more efficient with smaller wire gauges.
  • crewzercrewzer Posts: 1,832Registered Users, Solar Expert ✭✭✭✭
    Re: Agm life expectancy?

    I have four size 4D AGM batteries wired for 24 V x 400 Ah, or ~10 kWh. After ~3-1/2 years I remain quite happy with 'em. They are cycled almost every day, and they seem to be holding up quite well. I really like the "no maintenance" feature".

    However, as noted, there batteries must be properly charged via a temperature-compensated charge controller. To me, that means no overcharging, and, almost as importantly, no undercharging ("deficit recharging").

    I accidentially took >5 kWh out of my AGM's a couple of weeks ago, but all equipment and loads seemed to be working fine. It took two days to recharge 'em!

    Here are links to reports:

    http://www.outbackpower.com/forum/viewtopic.php?f=1&t=848
    http://www.outbackpower.com/forum/viewtopic.php?f=1&t=1750

    HTH,
    Jim / crewzer
  • backroadbackroad Posts: 185Solar Expert ✭✭
    Re: Agm life expectancy?

    HELP! Can someone please stop my head from go'n 'round in hot laps...

    Even if I were to go with a 48 volt system, using 3 strings of 8 305ah AGM Concordes, i'm still only coming up with a 915ah battery bank. It would take 4 strings to match the AH's that I had previously. 3 strings of 8 are about $8,000...

    Because of my having nothing solar to work with currently, I have a real fear of hurting new batteries. I am not going to have any panels in the system when It's first started. I am going to start with a 12-15KW diesel generator, complete battery bank, inverter and all the little incidentals. Panels and charge controllers will have to come in on the second wave. Am I possibly taking too much of a chance with the somewhat fragile AGM's?
  • mikeomikeo Posts: 386Solar Expert ✭✭✭
    Re: Agm life expectancy?
    "HELP! Can someone please stop my head from go'n 'round in hot laps...

    Even if I were to go with a 48 volt system, using 3 strings of 8 305ah AGM Concordes, i'm still only coming up with a 915ah battery bank. It would take 4 strings to match the AH's that I had previously. 3 strings of 8 are about $8,000."


    1220 amp hours at 24 volts = 29280 watts = 29.28 kw battery storage capacity

    610 amp hours at 48 volts = 29280 watts = 29.28 kw same as above

    So you could put in 610 amps hours of 48 volt batteries and power everything the same as on your previous 24 volt system, but somewhat more efficiently.
    Hope this helps.
  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    Re: Agm life expectancy?

    "HELP! Can someone please stop my head from go'n 'round in hot laps..."

    no, as we'll leave that up to the professionals as to why you are making your head hurt by waging a war on agm batteries. fragile they are not and if you prefer standard lead acid batteries, then by all means please be my guest and buy them as you are still staying off topic with your rant as it has nothing based in fact to do with agm life expectancy. you can't give much to this thread as you've never even had an agm to my knowledge. if you would like to rant about the pros/cons of any batteries there are plenty of threads out there to add your opinions to or even create your own thread.
  • hillbillyhillbilly Posts: 334Solar Expert ✭✭✭✭✭✭
    Easy Neil

    Easy does it, he is on topic here... he started this thread. I also personally find this to be a worthy thread, there have been some interesting posts from folks who DO have experience with AGM's, and some reasonable concerns from some who do not (myself included). Seems like maybe you've let this thread get under your skin a bit too much... it's all about learning for most of us here.

    Backroads, don't think that any of us can make the "big decision" any easier. Always stressful dropping a big chunk of money on something (particularly something of uncertain lifespan to us). Just to give your head something more to consider; don't know about those crowns, but I do know that some of the bigger "industrial" type batteries can be easily broken down to their individual cells then assembled piece by piece (Surrette's and Hup One's for example, probably others too).
    Good luck, and thanks for the interesting thread.
  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    Re: Agm life expectancy?

    backroads,
    if i'm coming off too harshly i am sorry, but maybe your intentions were never fair to the agm to begin with and maybe the thread should've been retitled 'why i hate agms' or maybe 'why you should hate agms' or worse. it sounds more of a smear campaign rather than an inquiry. one could argue standard lead acid batteries are also fragile because they won't handle as large of a current without possibly damaging the battery. both battery types are prone to sulphatiion damages if the electrolyte depletes far enough and rewatering a standard lead acid battery won't stop it once it is there as that involves other efforts to get rid of it with questionable results. do understand that an agm is not ruined if it vents, only if it vents too far just as a standard battery if it vents too much. one cannot put it back into an agm is true though. i again reiterate that i don't care of your battery preferences as i'm not telling you to buy agms, but your disinformation and unfair bias is intended to falsely sway others against that type of battery from how i'm seeing it. there are pros and cons to all batteries, but that's not what the title indicates you're looking for to get from this thread and it is my job to intervene or question when disinformation is presented as anyone here can do also.
    you and others can question my intent here and you are free to do so, but i am obligated to do the same of yours. maybe you should clarify what it is you are looking for or what your intent with this thread actually is just for me and all else to know? above all, do not hold an unqualified bias against something you know little about and have never possessed as you aren't being fair or open minded about the agms in spite of the titled inquiry. should you prefer standards then fine why the inquiry with predermined smear let alone insinuate that nobody should get them? if you want to smear the agm batteries then let's change the thread title to suite and you must bear any consequences for the content you present and are subject to rebutal and criticism for that stance by anyone here and by me too, but as a member and not as a moderator. as members, moderators can also give their 2 cents on something if they wish to and the faster things are clarified, i think the better things will be for us, don't you think?
    i did overlook that you created the thread in the beginning, but rather than hijacking a threaded inquiry you are deceiving by a predermined attack on the battery and is why i overlooked who created it as you are being somewhat contrary to the titled inquiry. if i'm wrong about something here or missunderstanding something then straighten me out only as 1 member to another. if you'd like to change the title, i will have to do that as a moderator though.
  • backroadbackroad Posts: 185Solar Expert ✭✭
    Re: Agm life expectancy?

    Thanx Hillbilly.....

    Niel.....Can I buy you a couple of adult beverages....I have no intention of waging war on AGM's. In fact, I haven't ruled out anything at this point, whether it be AGM, Flooded, Industrial or 24 or 48 volt bank. I just happen to have the time currently, to consider this all very carefully. No money currently, means lots of time to think and maybe too much time...I haven't even ruled out staying with Outback products as I never really did have a problem with them, just very confusing for me. I've been trying to contact these manufacturers and talk with them directly. Tomorrow is my day to talk with Crown's industrial division.

    Thanxs all for your outstanding input and patience, even yours Niel :):):):roll:
  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    Re: Agm life expectancy?

    ok so this is you mostly thinking out loud then and deciding which to go with. as i said it really won't matter to me which you ultimately get. agms are not fragile because of the stringent voltage thing. if it outgases a little it will be ok, but you won't replace it as you know. outgas alot and you're sunk just as hitting the plates on a standard would cause troubles. i can feed 100a into my pvx 1040t which no standard battery will tolerate very well. that's an amp for every amphour. you would have electrolyte boiled out of a standard battery and you know agms are very efficient at charging up. in a nutshell what would you say you are having trouble with in deciding? maybe doing columns for each with pros and cons will help you.
    i certainly would not fault you for going with a standard just for the price, but none are cheap these days. would it be possible for you to just try a single agm in some capacity to compare? if done at the same time as the main bank it will give you a rough lifetime and performance comparison. got a pv, cc, and load to dedicate to something like this? if i were in your shoes i probably would go with the standards for the main bank as you are recouping a costly loss and maybe go with one dedicated agm now or later for trials. if after a while you find you like the agms and figured the price factor into it too then go with it at that time down the road when you need to replace your batteries. by then there will be more reports as to how long people are still using their agms.
    btw, there is another company that makes agms called c and d. it's been awhile since i went looking and i don't even know if they sell to guys like us or not, but maybe info is available from them. they do provide for cell towers i know that.
    again i'm sorry and peace if i missunderstood where you were coming from.:cool:
  • DapdanDapdan Posts: 313Solar Expert ✭✭✭✭✭✭
    Re: Agm life expectancy?

    Hey guys,

    I wish to add my 2c of limited knowledge. you can in fact rehydrate a vrla. I have been doing some research on some agms i got for free from a telecom company local. the brand is gnb. I actually have opened the vents and added a set amount of water to the cell and have observed an improvement in the rest voltage. i am not equiped to really confirm if this is an increase in capacity but i have some white papers from others that this has been done successfully at that. In some cases batteries with 5% capacity were recovered to 60+ capacity. I have only had them for about 2months and have been cycling them, and adding water to try and improve their voltage readings.

    I can confirm that they are able to be stored for a long time with very little discharge. the particular brand i have reports 1% discharge per month but test has show it to be highter. On one particular whited paper the writer refer to cells that were sitting for 2.5yrs and only discharge by 0.011v over that time from the condition that they were released from the factory. they further stated that at the rate of discharge it would take 4.5yr for the cells to totally discharge. I can atest to this because the cells i got were never used and infact were still on the original shipping crate. There was a packing slip that indicated that the cells were shipped in 98 and the manager who was incharge of the substation (also the guy that help me get them for free) only charged them up end of 08 otherwise they we sitting in a corridor doing nothing on their shipping crate with some original wrapping plastic still on them and loads of dust. I would estimate the environment was about 75F it was a/c for the telecom equip. I took home the batteries and fully charged them and got a rest voltage of 2.08-2.10v. cycled them a couple of time and still the same voltage. I then opened the valve and added water then cycled now the rest voltage is 2.10-2.12v. apparently a brand new cell should read 2.15-2.17v. I have let these cell run my entire house for 48hr straight -no prob. This my friends is an extreme example of how not to store cells (10yr discharging and probably half of those years fully discharged) and they are still performing. I suppose at there price appro $1000 per cell (mine is the absolyte IIP 100A-19 900ah) it should work like that.

    If anyone wants to see the white papers i have collected on the cells and the different test carried out on them let me know i will post the links. In fact i have raise this already and post a thread about them already on this forum.


    http://forum.solar-electric.com/showthread.php?t=4624


    Cheers...
    Damani
  • backroadbackroad Posts: 185Solar Expert ✭✭
    Re: Agm life expectancy?

    Just for the record, I have used AGM batteries for over 15 years in my vehicles. I've done the worst thing to them that a battery can have done to it. I've discharged them down to zero by letting them just sit in vehicles that were not used regularly. It's hard to get them to come back up, but they always seem to do it. I really like the fact that I can use the AGM in my Willy's and not worry about battery acid problems in the chassis and battery compartment. This one vehicle in particular, I will run nothing but the Optima AGM, no matter what their life is, and I get a pretty consistant 3 years use out of.

    There is no need to retitle this thread that I've started. I've gained a bunch of information from it and that what I thought this was here for. I am done with this thread and will move on. Sorry to aggrevate anyone.
  • QuabillionQuabillion Posts: 22Registered Users
    Re: Agm life expectancy?

    But before we all leave, I just want to say, "AGM RULES!!! WWOOHHO :)
  • VicVic Posts: 2,906Solar Expert ✭✭✭✭
    Re: Agm life expectancy?

    Personally, I've found this thread interesting, and did not feel that anyone had anaxe to grind regarding AGMs.

    And Niel, you devote an extraordinary amount of time to this Forum lending valuable advice and guidance. Much of which is probably taken for granted my most of users like myself. Realize that this is a thread derailment, but anyway ...

    Thank You very much Niel for alll that you contribute to this great site. This is by far the most objective and helpful site that I've found for RE/Solar stuff.

    Thanks, too, to Northern Arizona Wind & Sun, a very top-notch supplier -- very honest, helpful, knowledgable and fair pricing too boot.

    Thanks, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    Re: Agm life expectancy?

    thank you, as i try, but i'm not infallible and i guess i still don't know what he's looking for in this thread.:confused: i did say sorry twice if i was misunderstanding and if he wants to sulk that's up to him.
  • backroadbackroad Posts: 185Solar Expert ✭✭
    Re: Agm life expectancy?

    Niel, that's about enough of the personal attacks. I am not and never been mad or have I ever had a vendettta about anything on this most helpful forum, and I WE keep this up, I just going to have to contact the moderator....:):):) Thanx again for all the help. And I mean this in all good ways. This group is and has always been fun for me and If I've come across negatively or "sulkingly", please forgive me. I apologize sincerely

    "I STILL WUV U"
  • lamplightlamplight Posts: 368Solar Expert ✭✭✭✭✭✭
    Re: Agm life expectancy?

    :grr :confused: ;)
  • backroadbackroad Posts: 185Solar Expert ✭✭
    Re: Agm life expectancy?

    VERY VERY FUNNY:cry::blush::D:p
  • lamplightlamplight Posts: 368Solar Expert ✭✭✭✭✭✭
    Re: Agm life expectancy?

    i think one of these posts said the efficiency was in the 97% range.. for you folks running them about 4+ yrs what does your battery meter report for efficiency after a few yrs in use?
  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    Re: Agm life expectancy?

    i don't use one even though i have a trimetric for there's too much guesswork in the meter to suit me so i don't use it in that capacity. i don't see a need at present to load test the battery which would put undo stress on it and lessen my cycle life without need to.
  • QuabillionQuabillion Posts: 22Registered Users
    Re: Agm life expectancy?

    My link10 claims a 98% charging efficiency as of today.
    I recall it being 99% a few years ago.
  • crewzercrewzer Posts: 1,832Registered Users, Solar Expert ✭✭✭✭
    Re: Agm life expectancy?

    Careful about "charging efficiency". There's overall efficiency (Wh out/Wh in), and there's Coulombic efficiency (Ah out/ Ah in). Coulombic efficiency of AGM batteries is typically in the ~98% range.

    HTH,
    Jim / crewzer
  • lamplightlamplight Posts: 368Solar Expert ✭✭✭✭✭✭
    Re: Agm life expectancy?

    hi Jim
    thanks for the clarification, i meant ye ole laymans terms ;) charging efficiency as in watts in / watts out. .
  • crewzercrewzer Posts: 1,832Registered Users, Solar Expert ✭✭✭✭
    Re: Agm life expectancy?

    In terms of Wh out / Wh in, or energy efficiency, AGM's are typically about 90% overall. Coulombic efficiency is quite good, but it still takes ~14.4 V during absorption stage to push the battery voltage back up to ~12.8 V full SOC. Efficiency at lower SOC's is better.

    HTH,
    Jim / crewzer
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