Aquion Batteries?

ayurtdweller
ayurtdweller Registered Users Posts: 26 ✭✭
http://www.aquionenergy.com/energy-storage-battery


Is this for real? 3000 cycles?
I don't know whether to get on the bandwagon or not. What do Y'all think about it?
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Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Aquion Batteries?

    It's been around a long time.
    Notice how many people aren't using it? Not very practical for most people.
    3,000 cycles is not that great an achievement.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Aquion Batteries?

    42 AH per stack is also on the small size for an off grid home... I assume they have some system where you can parallel 10-20 stacks into a reasonable size battery bank.

    The other thing seemed to be a bit of an issue--They fuse the battery at something around 15 to 20 amps--You would have to watch your surge currents to you don't pop the string fuse. Don't "over size" the AC inverter/DC surge loads on this bank.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • PNjunction
    PNjunction Solar Expert Posts: 762 ✭✭✭
    Re: Aquion Batteries?

    I'm not sure there is a bandwagon unless you are a commercial customer that can accommodate the large size. It is NOT a lithium-based battery.

    Note that this is the work of Prof. Jay Whitacre, one of the same main driving forces behind lifepo4. It is funded by former Microsoft and Sun computer venture capitalists, among others.

    It is not very energy-dense, thus the cells are very large compared to capacity, and that is probably why you'll never see one in your car. :)

    So far, the only average guys able to get their hands on some had to agree to NDA's. Thing is, this is not a battery for an average-guy application usually. It was introduced AFTER lifepo4 got into consumer hands just a few years ago.

    You might think of it as an alternative to LiFePo4, but you must deal with it's lower energy density. However, other operating characteristics may make it a good fit for a commercial customer. One issue is that there is no competition. Unlike Lifepo4, which some of the major competitors are GBS, CALB, and Winston.

    Compared to a lead-acid bank, 3000 cycles is actually pretty good, but that is not it's only attribute. In any case, does the battery fit your application? Probably not unless you are commercial or have very special needs. Their charts actually show up to 5000 cycles up to 100% DOD, between C/4 to C/20 rates. Don't do this to your lead-acid battery or you'll immediately void your warantee. :)

    As a side note, don't confuse Aquion with Axion. Different batteries.
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: Aquion Batteries?

    Why would this be a good fit for commercial use. Like what?
    gww
  • PNjunction
    PNjunction Solar Expert Posts: 762 ✭✭✭
    Re: Aquion Batteries?

    The first thought is for applications like grid-stabilization, or anywhere you have a cyclic or PSOC need.

    The bigger issue is that it appears that only commercial entities can get hold of them, their pricing, and additional technical info beyond the teasers at the site. They may also have the gusto to deal with what appears to be for now a single-vendor.

    While I'd like to see more of this kind of information, a quick glance at the specs shows that they *seem* to react similarly to lifepo4, but have about twice the rated cycle life. That is, lifepo4 is rated at about 2000 cycles down to 80%, whereas these go 5000 to 100%. The drawback is that they are not tiny, so you better have space to put them in.

    Coming from Prof Jay Whitacre, this makes sense. And for purchasing departments that fear lithium batteries because they just don't know any different between the various chemistries, if they want that kind of performance without lithium involved at all, it may make sense.

    So, like all batteries, there are tradeoffs in everything. Evaluate those tradeoffs to make sure the battery and it's performance match the needs of your application.

    I guess some commercial guys have more answers. For now, I'm happy with batteries that I can actually get a hold of, and have competition amongst each other to match.
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: Aquion Batteries?

    PNj
    Thanks for the responce.
    gww
  • ayurtdweller
    ayurtdweller Registered Users Posts: 26 ✭✭
    Re: Aquion Batteries?

    So I have been in contact with them. Well actually they are sold through reps at Real Goods.
    Here is some of my emal conversation.....first there reply to my question of whether they sell batteries for small scale solar-

    Dear ayurtdweller,

    Your existing battery is 225 amp hours @ 24 volts nominal = 5400 watt hours

    Each S10 stack stores 1.9 kWh at 48 volts nominal. You can disassemble three 48 volt stacks and reconfigure for six parallel 24 volt nominal stacks, resulting in a battery with 5.7 kWh at 24 volts

    Each S10 stack costs $1,125 + $90 shipping to most US locations

    Cheers,

    XXXXXXXX



    and then I reply with this email......

    Because lead acid batteries only get only about 1/2 of the usable amp hours, is it possible to use an aquion bank with a lower ah rating? Is this even a product offered for sale?

    And what type of solar charge controller is needed for these batteries? And what charging rate? C10?

    Thanks


    and another response....

    Yes, you can design with lower amp hour rating for Aquion Na+ batteries compared with lead acid. Yes, they are available for sale, and have been since Dec 2013.
    Charge controllers manufactured by MidNite Solar and Morningstar can be custom programmed to work with Aquion batteries. Charge rate can be c/10 or higher, max charge rate is c/4. Same for discharge rates; c/10 will yield more watt hours of usable storage than c/4 discharge rate

    Does this answer your question?

    Thanks,


    With 3000+ cycles of 100%, it seems that these might be a great deal, but I am not sure that I want to be a guinea pig. My next email is to find out warranty information.
  • PNjunction
    PNjunction Solar Expert Posts: 762 ✭✭✭
    Re: Aquion Batteries?

    Wow! We're finally getting somewhere.

    It appears that each "stack" consists of 7 cells. Unless I did my math wrong, the nominal cell voltage is something like 0.57v each?

    When charging via solar, do you disable temperature-compensation, or do you follow the same temp-comp guidelines as Pb?

    Can you successfully charge them with a CC/CV algo, ie setting an upper "absorb" voltage setpoint, and allowing for absorb, if any? If so, what are the "end amps" - something like C/20?

    How much slop can you have with a balance difference between each cell? Is there some sort of master "bms" that one has to use, or can you use your own componentry for that?

    I'd love to know what the settings of the Midnite Solar and Morningstar are. Are these batteries finicky to charge, or can a CC/CV suffice?

    Very interesting. Too bad we can't get this kind of info on the site at this time - unless I'm just missing it.
  • qaggaz
    qaggaz Registered Users Posts: 2
    Re: Aquion Batteries?

    I see that the M-series batteries (which consists of 12 of these stacks) includes on-board temperature sensors. Can these be directly integrated with a charge controller? Also, as has been noted, there appears to be a hard limit on output current that may offset the usefulness of being able to use up to 100% DoD.
  • PNjunction
    PNjunction Solar Expert Posts: 762 ✭✭✭
    Re: Aquion Batteries?

    Are you talking about the C/4 max charge/discharge rate?

    My only guess is that this limitation is not due to internal resistance or Peukert, but merely how fast the materials can intercalate. Ie, in a lifepo4 battery, there are two main types - low/medium rate and high rate. The high-rate small cylindricals have a finer "grain" or "nano" particle composition, allowing for faster intercalation. The kinds that we use - like GBS, CALB, Winston, etc are low/medium rate types that don't have the nano structure.

    I'd be interested in seeing if intercalation in the Aquion battery is the limiting factor here. I'd also like to see more specs on any sort of "voltage sag" under a C/4 rate if there is any of consequence.

    Either way, I'll let somebody else get some, and make their findings. Sure you may be able to charge it up with a high-end controller, but what exactly are ALL of the paramaters so one can make a wise choice to make sure it fits their application?
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Aquion Batteries?
    PNjunction wrote: »
    Are you talking about the C/4 max charge/discharge rate?

    My only guess is that this limitation is not due to internal resistance or Peukert, but merely how fast the materials can intercalate. Ie, in a lifepo4 battery, there are two main types - low/medium rate and high rate. The high-rate small cylindricals have a finer "grain" or "nano" particle composition, allowing for faster intercalation. The kinds that we use - like GBS, CALB, Winston, etc are low/medium rate types that don't have the nano structure.
    But the limitation from intercalation will look a lot like an increased internal resistance in terms of its visible effect from the outside of the battery. It is just an internal resistance that will vary with the discharge history and the current being drawn.
    SMA SB 3000, old BP panels.
  • zoneblue
    zoneblue Solar Expert Posts: 1,220 ✭✭✭✭
    Re: Aquion Batteries?

    So they are for sale, really? The price isnt eye watering, and size/density isnt really that big an issue per se for off grid, but my first reaction was its size will make freight costs kill this thing. But they appear to have dealt with that in mainland US anyway.

    But wheres the data / curves / user reports / fanfare? Scratchs head...
    1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,
    http://zoneblue.org/cms/page.php?view=off-grid-solar


  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Aquion Batteries?

    i too showed a tad of interest in these batteries as the whole concept of them and their push to commercialize them is born here in pittsburgh. the one person i know of with these batteries is at midnite and there's an nda involved. they may be good batteries, but without full disclosures available then i view it as more of an experiment while drawing on more government $.
  • ChicamaLefts
    ChicamaLefts Registered Users Posts: 1
    Re: Aquion Batteries?

    Hello,
    I am new to the forum and wanted to update anyone who is interested in what I have been told by the Aquion Rep as to the M100 battery banks. I live on the east coast, however the rep seemed to be on the west coast which I found very strange.
    I inquired about their M100 and got a quote. The quote was right around $14,100 plus $925 or so to ship to a residential home. I was shocked at the price since they are claiming to be competitive if not below Lithium Ion batteries which is not the case. However, I did get clarification as to the cycle life and some nice attributes to these types of batteries.
    *You can add new batteries to old batteries unlike Lead Acid since they are self balancing and no need for a BMS system.
    *100% depth of discharge the batteries have at least 3000 complete cycles
    50% depth of discharge they have at least 6000 cycles
    25% depth of discharge they have at least 12,000 cycles

    So if this is all true, 6000 cycles at 50% discharge is nice but the price is still hard to swallow. However, to have an completely inert battery bank at your home with your young children is a nice plus. No maintenance, no off gassing, no risk of a BMS failure are all things I think of. Would love to get others thoughts.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Aquion Batteries?

    i don't think there's that much to say as i think nobody will disagree with you. that is very pricy, but not that many are probably being manufactured at this point making the expense of manufacture a bit high. one can go through many golf cart batteries long before reaching that price tag. in time it may pan out to be competitive should they prove themselves to us, the end users.
  • xsnrg
    xsnrg Registered Users Posts: 10
    Re: Aquion Batteries?

    I have seen a few pictures of some installed now, but have not heard much about their performance or if they are meeting expectations. They have a lot going for them, for sure, but as mentioned, entry cost is not one of them. Anyone have a stack to play with?
  • Phen
    Phen Registered Users Posts: 5
    Re: Aquion Batteries?

    I got a quote for the S20 for $1150 per stack, plus shipping ($300 for three stacks, to upstate NY). The M100 is 12 stacks bundled together. Each stack is nominally 48V and 51 Ah, so I'd say the pricing is roughly competitive with LiPo4 (with better cycle life than Lithium if their info is to be believed). The main reason I'm vacillating is that there is so little actual experience with them in off-grid residential applications (as far as I can see). Their marketing/informational materials are a little short on important details like the answers to questions about charging parameters asked previously.

    This article http://research.gigaom.com/2014/09/aquion-energy-moving-forward-with-battery-storage/ seems to have outdated pricing and product information, so i think i'm going to ignore the actual prices in it but the interesting thing is they are suggesting prices may fall significantly in the next year. Unfortunately I'm not in a position where I can wait... i have to get something very soon. I really really don't want to do lead again. :p I may be in the market for more later... they say you can add stacks later.

    If I decide to go ahead with it I'll try to remember to post here again!
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Aquion Batteries?

    You are not going to get more than half the amp hours out of the Aquion batteries, the lower half of the amps, is below the cutoff voltage of the inverter. (your mileage may vary)
    And they have high internal resistance.

    These 2 issues mean you may need 2x the Aquion battery, compared to Pb-H2So4.

    And why only a 2 year warranty for a space age 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 ,

  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Aquion Batteries?

    Cause they are still in beta (?)-new model test mode as Halfcrazy has said?
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    Re: Aquion Batteries?

    Hey Folks!

    Been a while since my last post. I got pulled back in while researching a project for a client who has his mind set on a set of Aquion batteries. He had originally wanted a new 24 volt set of (4) Rolls 6CS25P and a Magnum MS4024PAE inverter but during some logistical delays he found some info about these "new" batteries and has insisted on them. I'm in a bit of a spot because he already ordered them while I was still researching and now I need to figure out how to make them work for the system.

    I have changed the design to a 48 volt system and now plan to use a Magnum MS4448PAE. (Minimum adjustable LBCO 36v / 1 minute, 34v is immediate shut down)

    This should be an interesting case. 8)
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Aquion Batteries?

    Attachment not found.take a look at the "energy curve". They assume your 48V inverter is going to function down to 40VDC before it disconnects. That's not likely, so a lot of power is going to stay in the "stacks" and never get used. So you will need a larger stack to get useable power.

    And the Voltage vs Energy indicates high internal resistance (Peukert loss), which is why you need to parallel many stacks , with only a 2 year warranty.

    You can't possibly exceed >3000 cycles in 2 years, only 700 cycles (in a reasonable household), so a disgustingly short warranty seems odd for a pricey new product.
    Magnum MS4448PAE. (Minimum adjustable LBCO 36v
    And what happens to the input amps, as the battery voltage drops:
    500W load @ 48V = 10A. 500w @36v = 14A
    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 ,

  • toothy
    toothy Registered Users Posts: 29 ✭✭✭
    Re: Aquion Batteries?

    Hello

    Let me begin by saying that my grasp of these issues is tenuous at best, but I’ll try to muddle through.

    A question, the graphs Mike has shown are for one stack, so wouldn’t most off grid users be OK with these things since their performance looks quite a bit better in the lower amperage range? If I want to weld I’ll turn on the rattle trap, I do that anyway.

    If I am getting this correct my 6-10 amp @48V average load would be spread over say 12 stacks? It would be nice to charge them quite a bit harder, but if they don’t ever need to get to float just add a bit of juice and wait for some sun.

    I agree with Mike, if they believe in them a better warranty would be nice. But if they really don’t perform as advertised a long warranty would only be useful as toilet paper anyway because they probably won’t be around in 2 years, not unheard of in the renewable industry.

    On the usable voltage range, my Outback VFX3648’s (42-68 VDC), would be happier with another module in each stack.

    On the price they sort of shot themselves in the foot saying how much they were going to come down in the future, but I wasn’t given my FLA’s and they piss me off! Having a battery with no maintenance, that you could treat like dirt and it would like, or at least tolerate it, sounds like nirvana to me.

    The lack of real world user reviews is a bit troubling but they are really new to the market.

    Your thoughts will be appreciated.

    Thanks Wade
  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    Re: Aquion Batteries?

    Thanks Mike,

    Any input is helpful. This is uncharted terretory for me.
    I was figuring to have the AGS settings around 40v and set the LVCO at 36v. It looks like 40v would be around 80% of the stored energy under fairly light loading. I am quite concerned about how much and how relatively quickly the voltage will lag with a c10 load. Other than a modern energystar fridge the loads are fairly light but still I wonder if the generator start/connect time will be fast enough for low voltage start triggers or if I will need to set the the AGS voltage higher. Or, will I need to use load start amp triggers and will that be fast enough at the lower SOC range? There will definately be some experimentation needed here.

    Also, how much will the voltage recover once a load is disconnected; what is appropriate for the reconnect voltage? (Magnums' LV reconnect is factory set in relation to the LVCO and presumably set with lead-acid in mind) One thing I will be adding to to the system is an iota type charger (one that will turn on regardless of the battery voltage) so I won't have to worry about "jump starting" a discharged battery if voltage is too low for the inverter/charger to turn on.

    Will the Magnum's fairly high surge capability help prevent the battery voltage from lagging from momentary loads surges (motor starts, etc...) as compared to an inverter with lower surge capacity such as an Outback FX?
    :confused:

    ...off to work.
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: Aquion Batteries?

    I just read a post on the otherpower forum.

    http://www.fieldlines.com/index.php/topic,148534.0.html

    The point of the referance to the post is the simular voltage width. Flux is like a hero on that site and he brings up one posible ideal.

    Maby some kind of buck/boost between the battery and inverter. Just something to think about.
    gww
  • toothy
    toothy Registered Users Posts: 29 ✭✭✭
    Re: Aquion Batteries?

    Hello SolaRev

    I'm pretty sure inverter surge capacity is what these batteries REALLY don't want.

    Wade
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Aquion Batteries?

    @ SolaRevolution
    Depending on how many parallel stacks there are, the surge loads may be OK. And then there is the re-charge issue, because the cells have high resistance, you can't recharge quickly, so the generator is going to handle the loads for a long slow recharge. Experience and data logging of the system will be your friend, to get the generator setpoints dialed in.
    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 ,

  • Deveak
    Deveak Solar Expert Posts: 38 ✭✭
    Re: Aquion Batteries?

    I considered it at one point when i read all those great marketing graphics and points...until i saw the price tag. 48 volts and like 50-80 AH or something like that for over 1000 bucks. I could have over 1000 AH of lead batteries for that and they do make long lasting lead, they are hard to track down but specialized battery manufacturers make them. Tubular cells with some sort of additive in it to prevent sulfation. I tracked one down in the midwest called SBS industries that had one over 2000 cycles and a 10 year warranty, the record was 23 years. This battery might have a future but i am not paying the early adopter fee. Yeah its 100% DOD but cost is cost. Also it limits our choices of inverters and 48 volts is moving into the shock hazard zone.
  • xsnrg
    xsnrg Registered Users Posts: 10
    Re: Aquion Batteries?

    Trojan T-125, granted not the cheapest lead battery to be found, but of good quality- at 6v batteries, you need 8 of them to get to 48v. If you are lucky, you can find the T105 for 160. Let's use 150 for easy math.

    150*8 = $1200 for 225 Ah of good lead battery, but you should only use the top 25% for best battery life, so you get to have 55Ah of usable space to play in with the lead battery and good life. You also have to worry about watering, SoC monitoring, generators, etc to make sure you stay above 75% SoC. The price seems to be about the same at this point. The Aquion claims to have longer life, but only time will tell. If it does, it gets a lot cheaper as soon as you replace the Trojans. The part where the price starts to be scary though is the amount of stacks you need to be able to handle surge current. From their own admission, they are quite soft, which likely means a higher internal resistance. This also means that charging the battery back up is also going to take more time. More stacks are needed in parallel then to handle more charge current, and more peak output. The stacks are comprised of individual cell elements though, so if you don't want 48v, break them in half for 2x24v. Supposedly they don't suffer the balancing issues of lead acid either.

    I am looking at every option I can find, Ultrabattery probably won't be available for wider distribution until at least Q3, but is certainly intriguing depending on the entry price. Aquion is available now (barely, high lead times I understand), but softer and expensive entry. AGM is, well, AGM, and has some merits and some shortcomings. I won't even go into gels. Flooded lead acid carries a lot of unused weight, making it appear cheaper than some others, but may not be by much. Edison Iron carries a huge entry fee, ongoing maintenance, and efficiency is lower than most. Various lithium type cells I need to learn more about, very compact and light, but special charging parameters-- very efficient and high energy density, but expensive. Forklift lead is perhaps the most economical if you know what you are doing and have the ability to maintain them well. The tubular cells I looked into recently as well. They are seemingly a type of forklift cell that uses cylindrical plates for more surface. I haven't gotten any pricing, and need to learn more about them too. I know there are some other companies that are coming out with cells that will be direct competition to Aquion as well, but not sure how soon. If Aquion drops their price quickly and ramps up production, they may have and hold the corner for a while... until China copies them for 1/3 the price... so much going on in the space right now, and I need new cells yesterday. Fun times.
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Aquion Batteries?
    PNjunction wrote: »
    Wow! We're finally getting somewhere.

    It appears that each "stack" consists of 7 cells. Unless I did my math wrong, the nominal cell voltage is something like 0.57v each?
    Either your math is wrong or the stack consists of 7 multicell batteries and not 7 cells, since a stack is 48V.
    SMA SB 3000, old BP panels.
  • northerner
    northerner Solar Expert Posts: 492 ✭✭✭✭✭✭
    Re: Aquion Batteries?

    It appears that one S20 stack now contains 8 battery modules. Battery voltage is rated 30 to 59 volts. But lets say about 40+ to 59 volts that are accessible by most inverters. That means that each module varies between 5+ to 7.37 volts.

    My question is the possibility of adding one more battery module to the stack to raise the bottom end voltage, and thus more usable energy for the inverter? The top end voltage may be too high for some inverters, but should work with an Outback model, and perhaps others? Also depends on how much higher the charging voltage is as well? I haven't seen any charging curves posted by the company yet.

    9 modules per stack would turn the 40+ to 59 volt range to 45 to 66.37 volts, thus more usable. The Outback FX 3648 is rated with an input voltage of 42-68 volts, so some leeway on the top end, but not much?