Where is the cheapest place to buy lithium batteries right now?

Discussion in 'OnBoard Electronics & Controls' started by DennisRB, Nov 1, 2014.

  1. Brian@BNE
    Joined: Jan 2010
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    Location: Brisbane, Australia

    Brian@BNE Senior Member

    Dennis:
    I'm a bit intrigued by some of this. Are your numbers from actual nights at anchor or calculated?

    I have 1820 W of solar and a 1284 Ah (12v) AGM house bank. At present I don't bother with any kind of power management: I'm running 2 fridges and an icemaker, and I leave the KVH M5 sat dish tracking all night and there are other incidental loads such as laptop. Overnight I typically use 400Ah. And my solar cant replace that in a day here in Brisbane given the usage from stuff above and other daytime power use. Any kind of shading, from antennas (or rigging on a sailboat) has a huge impact. I think your planned house bank capacity is way too small if you want to run an electric oven and a dive compressor.

    For an oven, why not get a fancy gas BBQ that can be used as an oven when required?

    For your dive compressor, if you have a large enough bank then supplementing charging with a Honda eu2000 would probably work. Depending on the compressor, the Honda can run it directly anyway. The eu is quieter than a petrol driven compressor, even if it is a Honda. I have both.

    I have a power boat, and 200A alternators on both engines. If I want to juice up the house bank then a short run somewhere does the trick. Even at 1000rpm I can get 300A from the engines, add the solar and recovery from the night's deficit isn't too hard to overcome. Now, I might soon get around to sorting out where all the Ah go overnight. Or maybe not.
     
  2. groper
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    groper Senior Member

    Well that sounds realistic... Having gas cooktop makes a big difference, I figured you would have electric cooktop aswell with the oven...

    Now what about a water maker? These suck a heap of energy unless you have one of the super expensive units which use energy recovery devices... 240v electric motor versions will also pull large start currents, 12vdc models cost a bomb...

    What about hot water, what are your plans for this?

    My plans go something like this, we have 1050w of solar at the moment, but no rig yet so I don't know how much the shading will effect things exactly yet.
    Gas cooktop, electric microwave, no oven.
    Excess solar goes to via a relay controlled dump load which is a 12v hot water heating element. A 240v element is also in there for shore power or via the inverter.
    Water maker is to be run from the Diesel engine via an electromagnetic clutch to the high pressure pump. So if we need to run an engine to charge batteries, we can also make water at the same time.
    If I had a dive compressor, which I would also like, I'd probably look at a petrol powered model as I doubt my 2kw inverter would be able to deliver the start current to start a typical electric compressor. What size inverter do you have? You should check whether it can deliver the inrush current required to start it... I'm not sure what's available in very small compressors these days? My 2kw inverter trips out trying the start a 2000w vacuum cleaner, and my 1kva genny won't even start my 300w household fridge...

    I hate noise too... But filling a tank only takes a few minutes... Charging your house bank takes hours... So too does making water...

    Gonzo, this notion that a sophisticated management system is required for lithium banks is one of the most repeated yet misinformed pronouncements I've seen on the net. It was fear mongering started by those with a vested interest in selling management systems. Nothing wrong with a management system, it's just not that sophisticated... All that's required is that the voltage is kept above a safe level, and below a safe level, and the voltages of all cells are balanced. This can be done without a management system by simply regulating the charge voltages to a lower than typical voltage used for lead acid, and using a low voltage cutoff. Intrinsic top end balancing occurs when the battery system is wired correctly with good low resistance connections via the charge regulation voltage alone. It has been proven by many, that house bank sized batteries are difficult to pull out of balance due to the relatively low C charge and discharge rates of these large capacity batteries. It is a different scenario for the electric propulsion systems which have relatively much higher charge and discharge rates compared to the battery capacity.
     
  3. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Hi Gonzo, although I agree that some form of knowledge is required to charge a power-pack consisting of many batteries parallel and in serial. Mine is now working for 4 years and I guarantee you, no explosions or fire. But when you make a power-pack from 40 or 60 single units, one has to make sure that all of them are charged, before paralleling them.
    4 years ago I was equal as worried as you sounds now, but Jeremy informed me, just place those damn things parallel and I did so. What a pleasure.
    The battery packs I proposed can be placed all in parallel, as each pack has the possibility to balance all 40 or 60 packs at the same time when paralleled.
    Gonzo, how do you think a 700 Ah LiP04 battery bank is actual constructed? One massive Lithium jar? Bert
     
  4. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    I work at one the Johnson Controls Litihium Ion battery research labs and actually make batteries by hand to test materials and methods of construction. To make a battery have a long life and an effective charge, the management control is critical. The basic building block of the batteries is called a "jelly roll". They are stacked layers, which is similar to other types. However, depending on the chemistry and physical construction of the cells, there is a maximum size. The name "lithium ion" is commonly used to describe a process that can use a very large number of configurations. Each is targeted for a specific use. For example, coin cells have a big surface to volume ratio so overheating is not a problem. The same material may melt if used to build a 300 AH battery. Many battery packs include a safety to prevent them from overcharging or charging too fast, but it is not a really efficient system compared to a true management control.
     
  5. groper
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    groper Senior Member

    The chemistry we are discussing here is lifepo4. The cells are available upto 1000ah per 3.2v prismatic cell .
     
  6. BertKu
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    BertKu Senior Member

    O.K. Fair enough, I must have lost the track of advancement. But it is nice to do tests in a laboratory, but I have my own hard facts, more than thousand charges and discharges , with 40 LiFo4 batteries, without noticeable problems. Maybe I will only be able to recharge it 1650 times instead of 1700, so what. In my opinion, if I do not overcharge and keep an eye on the Voltages, the batteries seem to be happy. What a laboratory cannot control is the ambient temperature environment, which, when very cold or very hot could affect the lifetime more than a simple management system. A management system cannot control the temperatures when a battery is heated up in bright sunlight or left outside in freezing cold conditions. But that is my opinion. Bert
     
  7. gonzo
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    gonzo Senior Member

    We test them from +80C to -25C.
     
  8. BertKu
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    BertKu Senior Member

    Don't tell me that the lifetime is the same at those temperatures than at constant 25 degrees Celsius ambient. I have proof, that the battery lifetime is badly affected by extreme temperatures. More than the way a battery is managed. Yes, you are in a lab testing them at those temperatures, but there is no proof that the battery lifetime is not changed. Maybe one day the lab will come up with a solution, but at present temperature variations are a concern. In the meantime until the lab has sorted this problem out, I just charge and discharge on a level, I know will not affect the battery too much. Yes, not the most expensive luxury management system, but it works. Bert
     
  9. DennisRB
    Joined: Sep 2004
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    DennisRB Senior Member

    Hi Gonzo. I am talking about lifepo4 as others have mentioned. This tech is non volatile and paralleling pairs is fine if they are balanced first. Once connected they will always be balanced if you used large enough links. AFAICT the probs occur when they are put in series as one might be charged higher or lower than the others which could lead to reduced life. This is why I would use a sophisticated BMS with individual cell (or parallel pair) monitoring with a cell balance function. The bank will have relays for high and low voltage cut off, plus individual cell voltage displays etc.

    I am not sure if I will go 4 x 1 700ah per cell. Or say 4 x 3 parallel 200A cells to make 600ah. I do not believe putting them in parallel is dangerous going by my research. I do think that it will have redundancy though. In the 4 x 3 cell setup I can loose anywhere between 1 and 4 cells and still have a 400ah bank. Obviously I would need to rewire the bank etc. This is less hassle than loosing one 700ah cell then having a useless bank in the middle of nowhere.

    For the ultimate in redundancy you could make one 200ah bank by putting 4 in series with its own bms. Then do this 3 times then put it in parallel for 600ah. That would get expensive and complicated though.
     
  10. DennisRB
    Joined: Sep 2004
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    DennisRB Senior Member

    My numbers on how much I used overnight and what I put in from 800w are based on actually living on the boat in the Brisbane river. You use something like 10 times the power I do at present, but only have a little more than double my solar, but I have room for as much solar as you have. My fridges are small. I have LEDs, I use laptops for watching movies etc. I don't leave nav equipment on.

    When I am out passage making the draws will be higher, but I wont be filling any dive bottles then either.

    It all comes down to what you want and need to have running most of the time. Clearly my usual draws are very small, so I can do the occasional large draw for dive tanks or an oven.

    The planed items like dive compressor and oven Ah are easily calculated, which I showed. Around 120Ah to fill 2 dive bottles. That's nothing compared to your daily needs

    http://www.michaelmcfadyenscuba.info/viewpage.php?page_id=16

    The thing is the system I plan has good advantages at any stage of implementation. Its not like I need to buy the whole lot at once then have it fail and it will all be a waste. Additional 200Ah cells can be added as can be a honda gen. I do hope that the use of fossil fuel power charging can be kept down so low that running an engine will be satisfactory.

    I have not even come remotely close to requiring any fossil fuel charging in 6 months since I installed my 800w system. I have power to burn, and the plan is to start slowly by adding power drawers. But the lithium batteries are a key component of this system due to Peukert's law. Also this is supposed to be a performance cruising sailing cat. For a lead bank to have the characteristics I need it would be much too heavy.
     
  11. Brian@BNE
    Joined: Jan 2010
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    Brian@BNE Senior Member

    OK, if you have been a liveaboard for 6 months you will have good numbers. Your systems are clearly efficient. In a cat LiFePO4 is definitely the way to go so hope you can locate a supplier, as you set out to do in your first post. Are you anchored out or at a marina, but not plugged into the grid?

    I use my boat as a second home and have a lot of luxuries and systems, but also use LED's and turn off nav gear. At present my overnight Ah use does not limit me, but next year when I cruise up north I will anchor out a lot. I would like the flexibility of a few days in one spot with no need for genny etc. Knowing how to reduce my overnight Ah burn will help with that. I need to do two things: firstly improve my solar output. Although a bit over double your capacity I am not getting double the charging output. Secondly, the gap between our overnight Ah usage is so huge that there has to be some easy wins for me. I just need to find where they are - I don't think I have any short circuits anywhere, but its not far short of that it seems.
     
  12. DennisRB
    Joined: Sep 2004
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    DennisRB Senior Member

    Hey Groper.

    The boat came with a Spectra water maker. Its 12V and is very energy efficient. Even though it will use a fair few Ah, its not a daily draw. Sensible operation will have the water tank full when the sun is out. Clearly things like water generation, dive tank filling and oven use are not daily draws. They are used every now and then, which will not tax the system with sensible operation. As experienced cruisers we don't waste water.

    Now for hot water! The boat only came with a 240V 2000W heater plus engine cooling system heating. Changing to gas will only cost money. Turning on the existing elec costs nothing. Thanks Peukerts law I cant really even see how many Ah this would use unless I fit a smaller element. The 300Ah AGM bank is not adequate for running 200 Amps for any length of time. It does not take long before the battery voltage drops below the inverters low cut off point, and the efficiency is 50% of what it would be with a lithium bank.

    However this is also easily calculated.

    Usings 44C's data on water usage an this http://www.phpdoc.info/brew/boilcalc.html

    Thats only around 54ah @ 12V. Which seems doable, but note it wont cost anything to try. Since everything is already there, well besides the batteries. Which I would want anyway since the 300Ah ex telstra bank is only a stop gap measure. The HWS would be activated once the lithium bank is full like you suggest. I think this will do fine 95% of the time. If not I can start the engine. No huge loss.
     
  13. DennisRB
    Joined: Sep 2004
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    DennisRB Senior Member

    Your boat and luxuries must certainly be higher than mine with your draws! But we are a little more conservative. We are on pile moorings, with the panels always facing the sun with no shade. I absolutely know shade will reduce the output when cruising, which is why I am ready to add much more solar to compensate. There is no shore power. My fridge and freezer are small marine units. The freezer hardly even runs at all to stay at -10C
     
  14. DennisRB
    Joined: Sep 2004
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    Location: Brisbane

    DennisRB Senior Member

    Groper. I hear you in regards to the use of "sophisticated charge systems" and I agree 100%. However compared to the cost of a lithium bank setting up something like this costs nothing. Not sure where this lies on the scale of sophistication.

    http://minibms.mybigcommerce.com/products/HousePower-BMS.html

    Your plans for engine driven watermaker etc are sound. I already have the electric unit. You are correct that an electric dive compressor will tax the **** out of an inverter on start up. Its doubtful that my existing compressor will be able to start it. However a powerful inverter has many uses. The Bauer compressors have a 1.5kw motor for the 110V version and the 240V version has a 2.2kw motor. It would be good if they also had a 1.5kw 240V version. I could live with the taking a few minutes longer to fill. I understand getting this to work is not an easy task, but I am keen on doing all the research I can to see if its feasible. The electric compressor has many benefits to me. Less noise, it can be permanently mounted due to reduced cooling requirements and no exhaust fumes. Typically the petrol units need a storage place then need to be dragged up on deck each time.

    If I was engineering a system from the ground up a main engine driven dive compressor would probably be the best option.
     

  15. DennisRB
    Joined: Sep 2004
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    Location: Brisbane

    DennisRB Senior Member

    Here is a quote I got back from Alibaba

    Description Quantity/set Unit price /USD Total sum(USD)
    Lithium Ion Battery 12V600Ah(with BMS) 1 3,009 3,009
    Air Freight To Brisbane 851 851
    Total Price 3,860




    Description Quantity/set Unit price /USD Total sum(USD)
    Lithium Ion Battery 12V600Ah(with BMS) 1 3,009 3,009
    Ocean Freight To Brisbane 350 350
    Total Price 3,359
     
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