Air pumps for better battery charging

2

Comments

  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    Re: Air pumps for better battery charging

    Niel by looking at what is happening inside the battery I think the flow I have would be considered good.. Meaning the bubbles are not small and barely moving the acid nor is the flowing of the bubbles so violent as to look like the plates are "over washed"
    The opinion I have from an electrical engineer and another tech that knows more about batteries than me, both believe if this test is going to prove something then they think it looks "about right"..

    Sorry but I cant do this test endlessy using every possible combination possible.. As this test im doing comes under "possibly useful experiment" and was given 35 hrs total time to do it.. By 35 hrs I dont mean the test has to be concluded in 35 hrs but it means I can only spend 35 hrs of me settimg up ,the test equipment setting up the test items time attending to actual measuring and collecting results.
    Unfortunately I do have to do other work they consider more important if I want to get paid each week.:roll:
    It is also more expensive than you think to use the xray machine and its operator for nearly 3 hrs , and another expense using the ultrasound and having the approved opperator watch me use it..

    Believe it or not doing this set of tests and the costs of batteries and air pumps will be in excess of $10,000. im not kidding 10,000 $aus same as 10,000 $us
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Air pumps for better battery charging

    i know it's not cheap and isn't your money. i was only saying it could get more encompassing by a different rate of air flow. i agree that it should not be volcanic, but if your test comes out well for the medium air flow rate then it is possible too that a smaller air flow rate would've sufficed. i know you can't do that for all possibilities. heck if the air is heated it is liable to have an effect on the slower air flow rate of making it more vigorous because of the nature of hot air rising too. the reverse of this might be a failure to be effective when the air is very cold even with the medium flow rate.
    what we are going to get answered by your experiment if there is some validity to the method and if any decrease in capacity occurs due to sulfation.
  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    Re: Air pumps for better battery charging

    Some more anecdotal evidence for the improved charging efficiency using air pumps. The first is from: http://www.zvei.org/fachverbaende/batterien/publikationen/?no_cache=1&tx_ZVEIpubFachverbaende_pi1%5Bdownload%5D=269&type=98

    Which recommends charging regimes for traction batteries. And the second from a battery charger manual:
    http://www.maurelma.ch/Produkte/Ladegeraete/Fronius/Anleitung_Selectiva_plus.pdf
  • nigtomdaw
    nigtomdaw Solar Expert Posts: 705 ✭✭
    Re: Air pumps for better battery charging

    Stephen my batteries are Varta 2 volt tall slim FLA Traction batteries virtually identical to the ones you informed me you were thinking about getting recently, mine were 7 yrs old when I got them now 12 yrs old still all OK.

    When I got them they were all fitted with this air pump system well at least the batteries were. No sign of the pump when I got them . It consisted of a very narrow stiff tube about 2mm thick that was inserted through the top of the battery in one corner and went to almost the bottom of the battery internally. The top fitted with a O ring seal and a T piece connector to rout the air to and from other batteries.

    As some of the units were damaged I removed them and sealed the hole with blanking plugs from Varta. They informed me they were to assist in charging and were a optional extra and it was OK to remove them .

    The ideal that it improves charging efficiency is interesting. If memory is working OK I got the impression from Varta that it allowed for higher charge rates quicker charge times without damage rather than efficiency. I can see it would help mixing of the electrolyte. Ive added a little diagramm I did in publisher of the relevant way the air tube was situated hope it helps, Im not very good at drawing stuff.

    Anyway it appears to have been around for a while and if its still available today then I guess its passed the "Could Damage Battery Stage" 12 yrs seems to be good enough to pass "the test of time"examination;)

    Nigel
  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    Re: Air pumps for better battery charging

    THE FINAL PART 4

    The air into battery testing is now over .Unfortunately I cant give you printouts

    of all the data as to get permission to do that would take months.As all testing

    results are not allowed to be made public. Its hard to explain ,But will present

    here most of the useful information that I have obtained from the test.

    The air pumps used were 12v DC with outputs of 1.1 cft per minute and a pressure of

    2.6 psi and consume 18 watts.
    These were the 3rd lot of pumps bought as the first ones bought could not give

    adequate bubbles evenly around all the plates. they only consumed 8 watts. The next

    ones bought were just to power hungry consuming over 25w. Anyone want 15 fish tank

    pumps?? just joke as all will be destroyed as they have been used in acid.

    Now a summary of the tests

    When under charge the acid temp of the non airpumped batteries avearaged 35 deg c.

    water loss 3 oz per day. Air pumped 29deg c water loss 2oz per day. these are per

    cell.

    Air pumped batteries on average took 25 to 30 minutes less to reach full charge.
    And held the charge for about the same amount of time longer during discharge.

    When examined with Xray machine the air pumped batteries almost no sulphation build

    up compared the non air pumped ones .

    What does all this prove??

    It does show that pumping air through lead acid batteries does shorten the time of

    recharging .Lengthens the discharge time.
    It would appear that air pumped batteries would certainly last longer than non air

    pumped ones..By observing the amount of sulphation on the non air pumped one to the

    almost no sulpation of the air pumped ones (the test has been going non stop since

    last november) about 3 months. My guess would be you would get about an extra 6

    months out of them if an average normal age was 4 years
    The reduction in water use would be an advantage to some users as less routine maintainance required.

    Is it worth doing ??
    In my opinion NO.
    Reasons.
    If the air pumps were running off the vehicles alternator then yes it would be BUT for us the airpump is going to be run off the solar panel charged battery/ies'
    They draw 18w x 24 = 432 whr.So it would take a 120w panel 4 hrs to make up that.
    OK there you have it . mabe some of you will do the maths and find it be worthwile for you..

    Sorry could not test every type of lead acid battery available, Baut it seems there are not many differences between types when doing this test.
    I cant do more longterm testing of those batteries now as the drilled one have now been removed by hazardous material contractors.. (they have holes in them and considered hazardous, as if knocked over acid woul spill)The authorities here dont consider plugging the holes as workplace safe.

    Costs
    10 batteries $2500
    15 air pumps $ 425
    Xray costs 36of them $ 180
    plastic tuning, connectors$ 60
    Battery removal $ 850
    10 x50 a shunts $ 160
    10 x 12v chargers $ 550
    Total $4725

    Total actual houurs spent by myself and 3 other technicians 36 at a work cost of about $1620
    As you can see just doing simple test on batteries costs money.

    If any one has a specific question not answered here and I have it Just ask and you will receive
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Air pumps for better battery charging

    This is golden!

    Thanks John for doing something the rest of us could only dream of. Your testing is valuable not just for what it showed about the air pump question, but also for the complexity and expense involved in conducting the experiment. We get a lot of people who think they're going to ask one simple question and suddenly have an epiphany that leads to the solution to all mankind's energy woes. This exercise shows just how difficult it is to even test a change and get verifiable results.

    Now how do we give this man a gold star? :D
  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    Re: Air pumps for better battery charging

    Thanks Cariboocoot.. its true to do even simple comparison test like that accurately requires more equipment and "throw away" items then most people would realize.
    I hope it helps some to decide if its a viable option for them.

    Im just in a workplace that has virtually every test piece of equipment that can be obtained to use.

    If any one else has a test they want to see done that involves some part of solar power I will always give it some thinking to see if it can be done..
    Believe it or not its not the cost of the items to be tested that is the deciding factor.

    Example we have tested nearly every charge controller available to destruction.
    And the results are PWM types are far more robust than MPPT ones.

    Sorry in advance cant tell much about grid tie inverters as they wont buy me any more. they bought one I destroyed it in one hour. but that not the main reason they wont buy any.:grr
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Air pumps for better battery charging

    Thank you Very Much for your efforts and posting results. Well, it's one less thing to worry about !

    Now I need ideas about a battery filler, that doesn't take time to pour water twice (from 2.5 gallon jug to gatorade bottle - then to battery cells) and costs less than a $2000 auto waterer. I've found that with the classic battery water jug, with the water mizer caps, the extra hight of the cap, will over fill the battery nearly to the top of the split ring, and then I can only get 2 cells, before the jug is empty, and have to refill it.....
    Took 3 gallons, last time, but that was a 3 month run in winter, plates in all cells were still covered, but I didn't want to water them on a rainy day/cloudy week, because that leaves the batteries discharged (less dilute acid) and I wanted a couple sunny days to give them a good absorb / EQ cycle. And in absorb, the temps rose about 20 degrees F, from 39F to 59F, in only about 3 hours. They cooled right down afterwards. Temp probe is the standard ring terminal on the battery post (Morningstar) and I wonder how much heat the copper cables conduct away from the posts.
    I wonder if I should move to a middle post, that the jumper is heated from both ends?
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    Re: Air pumps for better battery charging

    Thanks John, a great bit of testing!

    The consumption of the pumps is higher than I thought it would be, but I guess it could be shortened. E.g. only pump during bulk stage, or only pump when the generator is the charging source - reducing gen runtime by 30 minutes would be an immediate saving for me.

    My forklift bats are 70cm tall, so even without the advantages of the shortened charge time, the mixing up of the electrolyte with each charge should cause more even plate wearing and longer life.

    The bat manufacturer wants about 200 Euros for their air lift kit for 24 cells, so will definitely consider it once the PV is installed.... priorities, priorities.
  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    Re: Air pumps for better battery charging

    STEPHENDV you will only get the full benefits if the air pumps continuously. I did try one other battery with only running the pump during charging but the improvement was very small over not doing it at all,
    You cant use a lower power pump or it just wont have enough power to make the bubles spread evenly over all the plates.. And that would create a whole set of problems.("sulphation" on part of the plates that would then create areas above the "sulphation" that would the sulphate., The bubbles have to go smoothly up the full length of the plates.. its harder to achieve than it seems.., If your battery/ies have clear cases it wont be a problem but if the cases are not clear you just cant see the problem. That is why I checked by both XRay and an industrial ultrasound. items you may not have at home.
  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    Re: Air pumps for better battery charging

    Mmm, that is strange, because the forklift bats that come with air pump systems are just used during charging and not during discharge and they still claim a 15% improvement in efficiency.
  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    Re: Air pumps for better battery charging

    All I can say is thats the measured results I got,
    I dont know how they get 15% just doing it during charge as I only got that at best for continuous running of the pumps and it dropped to about 7% if only done during charging..
    Anyway its up to you what you decide to do. Im not here to try to talk you into doing anything.. I only present the test results as I measured them im happy everything went well and I think the results are as accurate as its possible to get.
  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    Re: Air pumps for better battery charging

    Oh yeah, fully appreciate that - and what's more: you have no financial stake in the outcome of the testing ;)

    BTW, how tall were the cell you were using?
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Air pumps for better battery charging

    Has anyone besides me noticed that a day after you do a full 3 stage charge or a EQ that if you tap lightly on the case or shake a battery you can hear them release a large hydrogen bubble that is trapped between the plates ?? I call it burping for lack of a better term. Most of my battery's are in stationary mounts even though they are on boats and don't get shaken enough to release them on their own. Where I have consistently done it to them they seem to have a longer life.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Air pumps for better battery charging

    Different batteries = different results.

    Since the forklift batteries are designed to have this optional feature they may well benefit more from it than standard FLA's. Remember how they need more frequent equalization?

    And yes, sometimes gently rocking a battery after charging will dislodge trapped gas. This is particularly true of older batteries (plates well, warp, get sulphated - creates places to trap gas). There is also the risk that what gets dislodged may be a piece of plate which will then short a cell. Just a caution.

    ("Magic eye" batteries actually tell you to rock them after charging so the built-in hydrometer can get an 'accurate' reading.)
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Air pumps for better battery charging
    Has anyone besides me noticed that a day after you do a full 3 stage charge or a EQ that if you tap lightly on the case or shake a battery you can hear them release a large hydrogen bubble that is trapped between the plates ?? I call it burping for lack of a better term. Most of my battery's are in stationary mounts even though they are on boats and don't get shaken enough to release them on their own. Where I have consistently done it to them they seem to have a longer life.

    I find that happening when I fill the batteries, about 1/2 way 30% of the cells, I get a large burp of bubbles. 8 L16's bolted together, don't rock much.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Air pumps for better battery charging
    mike90045 wrote: »
    I find that happening when I fill the batteries, about 1/2 way 30% of the cells, I get a large burp of bubbles. 8 L16's bolted together, don't rock much.
    I usually make a grid of 2x2's and leave a space between the batteries. I hardly ever use buss bars, they look neat, but I have had them break the terminals off as the batteries age and the cases warp and expand. My experience is with banks of 6 V ( 8-10 )golf type get heavy charge and discharge cycles and are considered expendable after 4-5 years.

    I never considered the amount of money that some people have in a bank of batteries, until I started coming here. $ 8,000 would give me a heart attack.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Air pumps for better battery charging

    very interesting results john and has burst my way of thinking about it. apparently the air has been mixing the electrolyte and breaking up sulfation before it became too hard and explains the better results in running the pumps 24/7 rather than charging only. as you stated it is not very power effective being it draws power 24/7 and as such may not be worth the slightly extended lifespan. it does prove some effort to mix the electrolyte is very worthwhile in doing if it does not cost too much power. could it be hitting small potholes and ripples in the road have been extending car battery lives?:confused:
  • Peter_V
    Peter_V Solar Expert Posts: 226 ✭✭✭
    Re: Air pumps for better battery charging
    john p wrote: »
    STEPHENDV you will only get the full benefits if the air pumps continuously. I did try one other battery with only running the pump during charging but the improvement was very small over not doing it at all,
    You cant use a lower power pump or it just wont have enough power to make the bubles spread evenly over all the plates.. And that would create a whole set of problems.("sulphation" on part of the plates that would then create areas above the "sulphation" that would the sulphate., The bubbles have to go smoothly up the full length of the plates.. its harder to achieve than it seems.., If your battery/ies have clear cases it wont be a problem but if the cases are not clear you just cant see the problem. That is why I checked by both XRay and an industrial ultrasound. items you may not have at home.

    I have an EV that uses GC batteries. Would I need to run the pumps 24/7 or do you think I'd see an improvement if I just run them during charge AND discharge?

    If I could get 10-15% more range it would be worth the little extra power to run the pumps. The truck draws about 12-15kw when driving at 50-55 mph.

    Getting better charge efficiency would also save me money on electricity since I'll typically have to charge at night which means I have to pay taxes, etc. on the power even if I'm using power I earlier pushed to the grid.
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Air pumps for better battery charging

    I'll bet the EV gets enough sloshing around of the batteries, you wont see the air pump do much while driving.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • Peter_V
    Peter_V Solar Expert Posts: 226 ✭✭✭
    Re: Air pumps for better battery charging
    mike90045 wrote: »
    I'll bet the EV gets enough sloshing around of the batteries, you wont see the air pump do much while driving.

    Yeah, but the roads are pretty smooth here and my commute is almost a straight shot.

    However, I was thinking that the road vibration might be enough to cover the agitation on discharge, but I didn't figure he modeled that. ;)

    If John ran a test with the pumps running only during charge and discharge, that would come pretty close to me running them on charge and then manually (road vibrating them on discharge.

    If I have to run the pumps 24/7 then it's not worth the energy, running the pumps for 8-9 hours while I'm at work would more than cancel out the extra range.
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Air pumps for better battery charging

    While the batteries are idle/static, I can't see them needing any agitation.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    Re: Air pumps for better battery charging

    Mike I thought that also that it only be necessary to do it while charging but as I said in a previous post you simply dont get anywhere near as good a result as if its done 24/7.
    when but would they not be in a charge or discharge state ?as most solar batteries would be recharged daytime(obviously) and then discharged that night.
    But battteries even if doing "nothing" which is never really true as all batteries self discharge and that gives them the opportunity to sulphate the plates.
    The above makes for an interesting thought .. would batteries last a lot longer if they were air pumped when kept in storage??
    And thats the problem if you using solar panels to charge the batteries the power it uses for the pump is just too high. on a forklift or similar you have the mains charging the batteries each day so the tinyamount of extra power needed for the pumps isnt important. the extra battery life is.

    But any agitation seems to help . I wrote this way back in post #3 ?I use "truck" type batteries for solar storage as deep cycle batteries are just not available where they are used,, What I do every few months is put them in the back of my truck take them for a ride over very rough dirt road (about 16 miles 20klm) then as soon as they home again they are recharged . and they seem to charge better,and hold the charge better..
    At least this has all got you now thinking of ways that you can best improve the life and shorten the charging times and increasing the discharge times.. be it by air pump ,vibration or combinations.

    If you are all wondering it makes only a tiny difference to the air pumping if the battery is short or tall.. if the supply of bubbles is good at the base and evenly distributed they follow the same way up the sides , distance makes almost no difference.. I f battery very tall say above 24" then a more powerful pump will give a slight improvement but at the expense of using more power for the pump.next size up used 24w
  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    Re: Air pumps for better battery charging

    If anyone is interested I sell nothing have no friends or relatives that sell or supply any items used for solar power.
    It makes not the slightest difference to me what you buy or use.
    Where I work sells nothing its only a test facility. for many different things,
    we do xray testing
    ultrasound testing
    pressure testing
    vacuum testing
    various electrical tests
    mechanical testing
    testing items for other uses outside the manufactured designed use
    testing electrical and mechanical engineers designs of "things" after they are built
    product testing for various government agencies before purchase orders are placed
    Our best toy is our capacitor bank mounted on a self propelled platform it has a charge capacity of 100,000 farads at 24v.. its destructive power is just the best fun you can have:cool:
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Air pumps for better battery charging

    john,
    would you be willing to test 2 identical batteries in an identical standard setup for loads and charge, but with one getting some vibrations?
  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    Re: Air pumps for better battery charging

    Niel cant do it right at the moment as we busy doing a big testing job(sorry cant tell you what it involves) but mabe can in about 2 weeks time as have still the undrilled batteries. Yes we have a vairable shaker machine it has a capacity of over 1,000kg (about 2000lb) .

    Will do 2 tests one shaking only while charging the other shaking 24/7 .
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Air pumps for better battery charging

    sounds good john. hey, don't forget the one that isn't shaking so we can compare to what most peoples' installs are like at their homes.;)
  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    Re: Air pumps for better battery charging

    of course will compare the non shaken with the shaken ones. I will just set the shaker to a very mild shake as if too violent it can cause internal battery damage..Ive seen that happen when a battery is mounted on the same platform as a diesel engine,
    ewes all gunna hav to wait for 2 weaks ta start then 1 munth afta that for result
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Air pumps for better battery charging

    I remember an old gag IC part data sheet, where vibe testing was done on an 8 cyl engine, with only 6 spark plugs. Much to harsh for a battery
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    Re: Air pumps for better battery charging

    I've asked the question about these systems to a tech support from another battery manufacturer (TAB) who's available on one of the Spanish RE forums. To summarise, his responses were that these systems are worth the trouble on tall celled batteries because:

    - You get homogenous density throughout the plate, no stratification
    - Less water consumption
    - less temperature increase
    - longer life because of lower temp and less stratification
    - Overral energy savings even factoring in the consumption of the pump.

    With some additional notes:
    - You still need to do EQ every month at least to prevent sulfation.
    - Pressure of air must not exceed 0.25-0.3 bars

    These systems used to be available for stationary bats as well as tractions, and they (TAB) are going to reintroduce them for their range of stationary batteries.

    Since they're not very expensive, I'm going to take the plunge and try one of these systems out, will post some pics here when it arrives.