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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

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    • CommentAuthordickster
    • CommentTimeMar 24th 2015
     
    Blimey, got my new PC up and running and found my way back to the forum.

    Had the tree doctor in and reduced height of trees so am one step further forward towards goal of PV array and stonkin' battery storage using LiFeYPO4. Still struggling with all things Lithium, but have found a company called Balqon in the USA that sells Energy Storage Systems (battery banks) in a box with cell balancing and BMS spaghetti all pre attached. And the price for a 16kWh job, $8225.00 . Now divide by 3 multiply by 2 = £5483.33 + shipping + tax etc etc. Maybe £8K still waiting for email to confirm.

    This is what I've been looking for. A decent price for decent gear for someone with not enough knowledge to be wiring up cell balancing/management stuff.

    Mr Winston Chung (of Winston Thunder Sky etc) is involved in the company so they should know what they are talking about.

    A typical LiFePO4 12v 200A = 2.4kWh battery in a well known blue box bought in the UK costs £2K.

    A typical LiFePO4 yellow battery bank of 8 x 3v 1000A = 24kWh not in a box from mainland Europe costs around £6.4K with cell management and balancing as a DIY add on requirement + shipping.

    So just thought you might want to check Balqon out.
    • CommentAuthortorrent99
    • CommentTimeMar 24th 2015
     
    Not sure what/who "blue box" & "yellow" refer too, but if you haven't already you might want to contact Ping Battery (google them). I have no connection to them but they are reasonably well respected in the e-bike world and are known for doing custom jobs if you contact them.
    •  
      CommentAuthorSteamyTea
    • CommentTimeMar 24th 2015
     
    £500/kWh, not bad.
    What is the cycle life of these batteries?
    • CommentAuthorEd Davies
    • CommentTimeMar 24th 2015
     
    Blue box is probably the SMA thingy like this. Or the one Navitron is selling.
    Yellow batteries would be the Winston ones: e.g., http://www.ev-power.eu/Winston-40Ah-200Ah/ (My current provisional plan is 16 of the 260 Ah ones).

    Be very interested to see how Dickster gets on with these.
    • CommentAuthordickster
    • CommentTimeMar 25th 2015
     
    Blue box is Victron I believe.

    Had no answer as yet as to total cost or whether the batts are balanced etc before shipping. I suspect that taxes are pretty nasty ie vat and import duty = 30% plussage.

    Cycle life is allegedly 3000 to 7000 depending on how they are used, all very approximate and unknown in reality.

    I'll just have to wait and see.
    • CommentAuthorSteveZ
    • CommentTimeMar 26th 2015
     
    If you have enough space to install larger storage batteries, have you considered NiFe cells. Lower energy density and harder to get hold of, but much more temperature and charging/discharging condition tolerant than pretty well any other battery system. They seem to last a long time too!
    • CommentAuthorEd Davies
    • CommentTimeMar 26th 2015
     
    Aren't NiFe cells very inefficient, though? AIUI they charge at a significantly higher voltage than they discharge so, though you get most of the amp·hours back out, you only get a relatively small proportion of the joules. If the cost per kWh stored over the lifetime is sufficiently low then this might be acceptable but it needs to be taken into consideration for complications like inverter input voltage ranges. It'd be interesting to know if anybody is actually using these for off-grid domestic use.
  1.  
    If I had to go off grid then I'd certainly be tempted by NiFe more than any other technology - I'm sure I saw an advert for a new company manufacturing them in the US now in Home Power magazine, certainly where weight and space isn't an issue and long term durability is then they look good value in the long term. Safer bet in many ways than lithium options.
  2.  
    Yup, be interested to see how you get on with this one Dickster. Me, I'm a bit of a Luddite and stick with what I know for my 'off grid' properties. That will be the trusty old FLA, I've tried NiFe Willie and wasn't impressed, didn't seem to work very well the the inverter/chargers at the time and horribly inefficient. Having said that they seem to last forever and can take 'dogs abuse'.
    Having explored all options in our 'off grid' new build, that will be totally powered by wind,sun, and water I went for FLA, but having worked with huge banks (.8mgWh) of LiFePO4 this last 17 months on our hybrid ferry, I'm severely impressed.
    Sure, there have been a few issues with the BMS, and yes, it is horribly complex but they still remain a staggeringly impressive 98% efficient. These are not figures 'plucked out of a hat' but measured with proper calibrated instruments.
    I'm pretty chuffed with my 800ah FLA bank for £3k but I'd be seriously looking at lithium when they need replacing.

    Good luck, Paul
    • CommentAuthorSteveZ
    • CommentTimeMar 27th 2015
     
    For what it's worth, I found the following article on an unfortunately named website, but the info seems to be kosher from a guy who has a NiFe system working. Some useful supplier data on there as well.

    http://www.survivalistboards.com/showthread.php?t=276932

    In summary, NiFe cells can be neglected, frozen, overcharged, fast-charged and can be deep discharged, and suffer no ill effects. You should get 20 years out of them quite easily. The charging requirements seem far more lax than those for Lithium or Lead Acid.

    I must remember that things which seem too good to be true, usually aren't :bigsmile:
    • CommentAuthorEd Davies
    • CommentTimeMar 27th 2015
     
    Thanks SteveZ - interesting thread. Bit distressed by the first post which seemed a bit confused on what a watt is (why do people find this so hard?) but the rest made more sense. Useful to see his confirmation of the problem of the discrepancy between the charge and discharge voltage.

    Seem to be roughly the same price as LiFeYPO₄ - around £0.40/Wh.
  3.  
    http://www.survivalistboards.com/showthread.php?t=276932

    One of my favourite forums :-) Seriously though, much as I admire his enthusiasm he's a little biased and fails to address their poor efficiency. I'm sure they are exactly what HE needs, but as most of the people on there seem to believe, nay aspire to 'TEOTWAWKI'. Sure, if you believe in 'Total Global Financial Meltdown' or the coming of the New World Order' where it's every man for himself and he who has the most assault rifles rules. Then I'm sure a battery that will see you to your grave is the right choice, for their aint gonna be any spare cheap FLA's available due to the 'Great Zombie Apocalypse' or whatever. However, I'd be more inclined to go for Lithium technologies for their far superior efficiency or FLA's for simplicity.

    As they say on 'Survivalists Boards', "just my 2 cents worth" :-)

    Cheers, Paul
    • CommentAuthorEd Davies
    • CommentTimeMar 28th 2015
     
    Sometimes people worry about the complexity of LiFe[Y]PO₄ cells. As far as I can see [¹] they're quite simple and not much different from lead acid:

    1) Don't over discharge them.
    2) Don't overcharge them.
    3) Once they're charged stop charging them.

    The difference is that for LiFePO₄ they really mean it. Lead acid will have its life shortened by overdischarge. LiFePO₄ will be destroyed. Lead acid cells will tolerate a bit of overcharge and, for wet (as opposed to gel, etc) will actually benefit from a bit of bubbling once in a while to keep the liquid stirred up. Lead acid can be left on trickle charge once they're full but LiFePO₄s hate it.

    On the other hand, lead acid cells need to be kept full and any time they spend standing less than fully charged reduces their life whereas LiFePO₄ can, and actually prefer, to be left somewhat discharged so long as they're not left so long that their (slow) self-discharge results in them over-discharging. In this respect LiFePO₄ are much more suited to off-grid use.

    The consequence is that you really need to monitor the voltage of each cell in a LiFePO₄ battery and stop discharging when the weakest one is getting low and stop charging when the strongest is full. To get the maximum capacity out of the battery you therefore want the cells to be reasonably well balanced. On the other hand, if the cells are a bit out of balance it's not a disaster - it just means the usable capacity of the battery is reduced a bit until they're brought back into balance.

    Many batteries made out of lots of small cells, as used in electric vehicles, have battery balancing built in. There's good experience, though, to indicate that batteries with small numbers of large cells in series don't really need this as they'll stay pretty much in balance for quite a lot of cycles if started off correctly. In fact, because the cells don't like to be trickle charged once full there's a positive advantage to not doing continuous balancing as this avoids the strongest cells being trickled while the weaker ones catch up.

    Apart from needing voltage monitoring on each cell I don't think there's much more to running a LiFePO₄ battery than a lead-acid one. The hassle is that most solar charge controllers and the like are set up for lead-acid and don't play well with LiFePO₄.

    [¹] That is, as far as I can see from copious reading of multiple sources and some playing with a few 20 Ah cells over a couple of years.
  4.  
    Yes, Ed, my initial experience with LiFePO4 and the 'complicated' BMS put me off them but after well over a year of 'trouble free motoring' with 216 modules I'm converted. There have been issues with the BMS but these have all turned out to be 'connection and vibration' related, none off which would be of concern in a static 'off grid' situation. The efficiency is truly staggering, the now defunct manufacturer claimed 98% but even after 17 months of daily discharge to 20% I would say it's more like 99%

    "There's good experience, though, to indicate that batteries with small numbers of large cells in series don't really need this as they'll stay pretty much in balance for quite a lot of cycles if started off correctly"

    Yup, I'd agree with that.

    Cheers, Paul
    • CommentAuthorEd Davies
    • CommentTimeApr 1st 2015
     
    Dickster, might be worth talking to these people: http://www.sustainables4u.co.uk/TESS.php

    They're mostly for on-grid storage (which I can't see the point of for an individual as the energy market is at the moment) but do mention off-grid.

    Don't know where you are but I think you're less likely to have import duty or support issues with a company in West Sussex than one in the US.
    • CommentAuthordickster
    • CommentTimeApr 2nd 2015
     
    All interesting stuff.

    here's a bit more detail on my investigation of Balqon.

    Take their 48v 27 kWh unit @ $12,565.00 . + shipping ($800.00 approx) = $13365.00

    Exchange rate $1.47 / £ = £9091.83

    + import tax (10%) = 10000.00 + VAT at 20% = £12,000.00. As near as dammit.

    Whilst the cost is a lot more than you might like, it's massively cheaper than any UK outfit (Thanks Ed, have investigated) and the good news is that the batteries are pre balanced and left charged at 50% for transit, so they really are plug and play (famous last words).

    So having perhaps solved the "where to get the batteries from" question I now move on to charge controllers, inverters etc.

    But when all that is done, the sad fact is that my "little bit of knowledge is a dangerous thing" grasp of all things electrical will pull me up short of actually doing the install myself and so will have to find a very competent someone willing to do the job for me. (along with 2 kWpk PV).

    Even if I could actually learn all that is needed to be learnt, it's too much of an investment for me to risk cocking it all up.
  5.  
    Hi Dickster,

    I would try and get a hold Peter Chow of 'Sustainables 4U' this is his forte and he does have a 'track record' with lithium. He quoted me for a 28kWh pack and charge control in 2012, it was in your 'ball park', in fact it was less, but that was three years ago using the now defunct Winston modules.

    Good luck, Paul
  6.  
    Sorry Ed, never read your link!!! but yes, definitely wiser dealing with Peter as he has done at least one major 'off grid' job. I was very tempted to use him but three years ago I just didn't have the confidence in lithium. Were I to do my 'off grid' setup again with the budget I have now then I'd definitely go that way.

    Cheers, Paul
    • CommentAuthordickster
    • CommentTimeApr 7th 2015
     
    I was in touch with Peter 18 months ago. Unfortunately, the 'Sustainables 4U' website doesn't suggest that too much is happening there at the moment and unfortunately this has instilled a lack of confidence in my wallet department (not necessarily justified). Geographically he is a bit too far away, meaning any problem solving might be logistically unviable.

    Not sure if Winston is actually defunct or not.
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