What is the optimal SOC range for cycling lead acid batteries?

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Comments

  • Blackcherry04Blackcherry04 Posts: 2,490Solar Expert ✭✭✭
    Re: What is the optimal SOC range for cycling lead acid batteries?

    I thought my company was crazy to spend $10 million for 1/10 of 1% gain until i found out it would make $300 million in 20 years. Long term 1 % can be huge.
  • northernernortherner Posts: 492Solar Expert ✭✭✭✭✭✭
    Re: What is the optimal SOC range for cycling lead acid batteries?
    ChrisOlson wrote: »
    My goal is to make off-grid living more affordable by making the right decisions on when to run generators, and reducing the costs of the consumable items like batteries. Without the data to see if what you're doing is working, all you got is the proverbial WAG.
    --
    Chris

    If you are willing to be a little patient, a new battery will be available soon, one that should have a very long cycle life and no issues with DOD. This has the potential to bring down the cost for off grid storage immensely.

    http://www.aquionenergy.com/energy-storage-technology

    This battery has been proven, and everything that the company says about this storage approach, sounds very promising! It is safe, reliable and affordable. Of course time will tell. Manufacturing is about to begin in the last quarter of 2013.
  • CariboocootCariboocoot Posts: 17,615Banned ✭✭
    Re: What is the optimal SOC range for cycling lead acid batteries?

    How can they say it's "affordable" if they are not yet being manufactured and sold? :confused:

    For the same reason I'll hold off on agreeing with "safe" and "reliable"; they said exactly this about Lithium batteries and that promise hasn't materialized.
  • VicVic Posts: 2,923Solar Expert ✭✭✭✭
    Re: What is the optimal SOC range for cycling lead acid batteries?

    There will always be something NEW on the horizon, or just beyond to wait for. If needs batteries for a system, buy what has been proven, else one may spend one's WHOLE LIFE a waitin', IMHO. 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.
  • ChrisOlsonChrisOlson Posts: 1,807Banned ✭✭
    Re: What is the optimal SOC range for cycling lead acid batteries?
    Some people will spend far too much time/effort/money getting a system that runs an average 58% efficient to run at 59% efficient. As an engineer of my acquaintance was fond of saying "talk to me about 10% or don't talk to me". :D

    I don't agree with that assessment.

    We decided 3 1/2 years ago that we're not going to live in a dark cave here, and we're not going to schedule every load because we got the power to run it when the sun is shining or the wind is blowing. We wanted the convenience and comfort that anybody that lives on utility power has. So I set out to make it affordable so our off-grid electricity doesn't cost us 75 cents/kWh. I got over 7 years of hand-logged data to go by, and now I got a much better fully automatic and more detailed logging system.

    If I would've gone by what everybody says is the "only way to do it", instead of gathering proof over the years that judicious and informed use of standby or prime generator power is much more economical and practical over the long term than batteries, we'd still be living in a dark cave and scheduling every load. And today we do it on less fuel in the generators than the average large off-grid system does using the "traditional way" and still scheduling every load and watching every watt.

    That's way bigger than 10%. But even if it was 1% the absolute joy of not having to majorly adjust your lifestyle just because you live off-grid is worth every bit of that 1% - especially to my wife.
    --
    Chris
  • CariboocootCariboocoot Posts: 17,615Banned ✭✭
    Re: What is the optimal SOC range for cycling lead acid batteries?
    ChrisOlson wrote: »
    I don't agree with that assessment.

    We decided 3 1/2 years ago that we're not going to live in a dark cave here, and we're not going to schedule every load because we got the power to run it when the sun is shining or the wind is blowing. We wanted the convenience and comfort that anybody that lives on utility power has. So I set out to make it affordable so our off-grid electricity doesn't cost us 75 cents/kWh. I got over 7 years of hand-logged data to go by, and now I got a much better fully automatic and more detailed logging system.

    If I would've gone by what everybody says is the "only way to do it", instead of gathering proof over the years that judicious and informed use of standby or prime generator power is much more economical and practical over the long term than batteries, we'd still be living in a dark cave and scheduling every load. And today we do it on less fuel in the generators than the average large off-grid system does using the "traditional way" and still scheduling every load and watching every watt.

    That's way bigger than 10%. But even if it was 1% the absolute joy of not having to majorly adjust your lifestyle just because you live off-grid is worth every bit of that 1% - especially to my wife.
    --
    Chris

    I never said you'd have to live in a dark cave to do it.
    Merely pointing out that a lot of people chase after tiny percentages and tenths of Volts when in reality the day-to-day demands on a system do not make such small details worthwhile.

    People are always trying to minimize systems: getting "precise" Watt hour number, "exact" battery bank capacity, and "perfect" array size. They end up with a system running on the edge which sooner or later doesn't run at all.

    And then I have another headache to deal with. :p
  • northernernortherner Posts: 492Solar Expert ✭✭✭✭✭✭
    Re: What is the optimal SOC range for cycling lead acid batteries?
    Vic wrote: »
    There will always be something NEW on the horizon, or just beyond to wait for. If needs batteries for a system, buy what has been proven, else one may spend one's WHOLE LIFE a waitin', IMHO. Vic

    It could turn out that way. But then again it could also turn out to be the choice for storage.
    How can they say it's "affordable" if they are not yet being manufactured and sold?

    Very, very long cycle life = affordable. :D
    For the same reason I'll hold off on agreeing with "safe" and "reliable"; they said exactly this about Lithium batteries and that promise hasn't materialized.

    Lithium is inherently unstable as an element. Carbon, manganese dioxide, cotton and salt water are not inherently unstable, and are environmentally safe.
  • ChrisOlsonChrisOlson Posts: 1,807Banned ✭✭
    Re: What is the optimal SOC range for cycling lead acid batteries?
    People are always trying to minimize systems: getting "precise" Watt hour number, "exact" battery bank capacity, and "perfect" array size. They end up with a system running on the edge which sooner or later doesn't run at all.

    Oh, I've seen that happen. We got off-grid neighbors that got systems put in by "professional" installers that don't work all that well. They got cheap Trojan L-16's that have gone "flat" in 2 years and only got 75% of their capacity left (if that), they won't run their generator unless hell is freezing over because it's 8-10 kW on a little Outback 3524 and drinks fuel with a big sucking sound, and basically can't even turn on the TV unless they check first to see if their half-dead batteries are above 24 volts. They drool every time they come to our place and go, "how can you even do that????" Well, it's like our water heating system - lots of experience, lots of gathering data over time to figure out how to make it work, and trying many different things to see how it works.

    Microscopic data analysis is useful to fine tune something. Big Picture data analysis is useful to design something.

    If you start worrying about absorbing your batteries for precisely 3 hours every day, worry that if you don't absorb them precisely based on the sun rising and setting that they're going to stratify, and worry because your daily energy consumption is 8.22 kWh/day instead of your target 8.0 kWh/day, then you're using micro-management techniques instead of looking at the big picture. So while you're worrying about 1/10th of a volt to see if you can turn on the TV, in the big picture you already ruined your batteries because you bought too big of a generator and refuse to run it unless Life As You Know Is About To End if you don't.
    --
    Chris
  • VicVic Posts: 2,923Solar Expert ✭✭✭✭
    Re: What is the optimal SOC range for cycling lead acid batteries?

    northerner,

    Was not trying to be argumentative, There have been numerous similar posts here over some number of years. And, some of these emerging "technologies" may eventually yield a fairly large improvement.

    But, first there needs to be some early adopters to help the manufacturers work out the bugs. Then, often, there are those applications that can REALLY benefit from the nature of this new-ish battery. These folks pay a stiff premium (usually) to get, what is for them, a large benefit.

    Sometimes, for the new approach that really delivers some benefit, the person needing a cost-effective solution needs to wait a long, long time.

    That is all. There is a lot of demand for high-capacity, long life, and often light-weight energy storage. But, to me, the age-old FLA batteries, dating back to the 1850s do an amazingly good job for stationary cyclic uses, such as off-grid solar-charged systems.

    Opinions are mine, not to argue too much. 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.
  • arbyarby Posts: 101Solar Expert ✭✭
    Re: What is the optimal SOC range for cycling lead acid batteries?
    ChrisOlson wrote: »

    As voltage approaches absorb the controllers bring AC SSR's online that turn on AC power from the inverter to the water heaters.


    Chris

    Is there a "how to" of this process on the forum?

    Thanks in advance
    3310 watts panels, Classic 200 controller, 8 Surette S530's, Xantrex 5548 inverter, Honda EX5500 backup Genny.
  • VicVic Posts: 2,923Solar Expert ✭✭✭✭
    Re: What is the optimal SOC range for cycling lead acid batteries?

    Hi arby,

    I am not Chris, but in the interim, you can poke around on the MidNite Forum. Use the search term "waste not"

    Here is on such thread, there are quite a few:
    http://midniteforum.com/index.php?action=search2

    More later. 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.
  • northernernortherner Posts: 492Solar Expert ✭✭✭✭✭✭
    Re: What is the optimal SOC range for cycling lead acid batteries?
    Vic wrote: »
    northerner,

    Was not trying to be argumentative, There have been numerous similar posts here over some number of years. And, some of these emerging "technologies" may eventually yield a fairly large improvement.

    But, first there needs to be some early adopters to help the manufacturers work out the bugs. Then, often, there are those applications that can REALLY benefit from the nature of this new-ish battery. These folks pay a stiff premium (usually) to get, what is for them, a large benefit.

    Sometimes, for the new approach that really delivers some benefit, the person needing a cost-effective solution needs to wait a long, long time.

    That is all. There is a lot of demand for high-capacity, long life, and often light-weight energy storage. But, to me, the age-old FLA batteries, dating back to the 1850s do an amazingly good job for stationary cyclic uses, such as off-grid solar-charged systems.

    Opinions are mine, not to argue too much. Vic

    No problem debating the issue Vic. I realize that there may be a bit of a wait for some of these emerging technologies and some are not willing to wait. But it may be here sooner rather than later as well. Manufacturing from Aquion is scheduled to begin before the end of this year. Field testing of the batteries is currently being done, and continuing on an on going basis. According to the company, results look good.

    I'm not a big fan of FLA batteries, even though they're the most economical choice for storage at the moment. The biggest issue for me is their limited life span, and issues with state of charge and depth of discharge, etc... They are also not very environmentally friendly, their contents are potentially hazardous, and they gas out hydrogen and acid mist. I'm thinking I made a mistake in buying smaller L16 batteries, as they won't likely have a very long life. I just added another bank of (4) L16's, so that may prolong their life some what.
  • ChrisOlsonChrisOlson Posts: 1,807Banned ✭✭
    Re: What is the optimal SOC range for cycling lead acid batteries?
    arby wrote: »
    Is there a "how to" of this process on the forum?

    arby,

    As Vic noted, it is best to go to the MidNite Solar forum and study that one. This function is unique to the MidNite Classic MPPT charge controller. And it is not something that is easily explained in this thread.
    --
    Chris
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