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Topic # 148594 24-Jun-2014 12:28
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Only buy if you know what LiFePO4 is.  Pick-up only from East Auckland, because it is too hard to ship lithium batteries (unless you arrange where I can drop it off).

Our supplier sent us the batteries out of spec., so we have qty 77 that they are offering to staff at a discounted price of $12 each.  It is supposed to be minimum 9.5Ah, but came out as nominally 9Ah.  If there is enough interest then I can get them for you, but if not enough interest then they have to be shipped back to China.  Dimensions are 64mmx133mmx16mm with a 120mm wire out of one corner.  No protection circuit included, who needs it for safe LiFePO4 anyway?  Wires are spec'ed for 5A rating, but the battery can do about 45A if you use appropriate termination.

I have used a few for a while, 8 in series for my 24V EnviroMower and 4 in series for my 12V electric gate.  Mower was a mains charger, gate has a solar charger.  I've got plans to make a 12V DC UPS since my server PC, router, modem, etc. all runs off 12V so I don't see the need for wasting conversion power in a 240V mains UPS.  Balancing is very easy, connect an LED across each cell and then charge to 3.5V per cell (so a 12V pack is charged with a standard 13.8V-14V charger!).

Send me a PM ASAP if interested, I have to know within 1-2 days or it will be too late.  There must be enough interest before I can get them.  Note this is only for home projects, don't want to see these on TradeMe etc.




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  Reply # 1073353 24-Jun-2014 12:28
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Hey, have you listed a price, location and how much shipping would be to other parts of New Zealand? Also if you are asking for a PM make sure your Privacy settings allow your account to receive PM otherwise people can't contact you. Also note if you are selling something we ask you to offer to other members first. Links to private sales (including Trade Me posts) aren't accepted anymore and will be removed.




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  Reply # 1073548 24-Jun-2014 16:33
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Can I please have battery dimensions and and picture if possible?




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  Reply # 1073571 24-Jun-2014 16:54
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Little overkill for a gate opener aren't they ?  They're more suitable for high discharge systems .. unless you have you gate opening at Mach-1 ? :-)



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  Reply # 1073752 24-Jun-2014 22:00
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Dynamic: Can I please have battery dimensions and and picture if possible?

Dimensions are in the first post.  Will see if I can get a photo up, but it is a soft pouch with 2 layers of strong plastic shrink wrap (same as used for RC model battery packs).




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  Reply # 1073753 24-Jun-2014 22:05
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Mark: Little overkill for a gate opener aren't they ?  They're more suitable for high discharge systems .. unless you have you gate opening at Mach-1 ? :-)

No.  Ideal for solar because lead-acid needs to be kept fully charged but these don't care.  Also flat discharge curve so gate only slows down when battery is almost fully discharged.  Much higher cycle count.  Almost 100% efficiency (compared to about 65% for lead-acid).  Lead-acid is limited to 1C discharge rate, these are 5C (high energy version, not 25C high power version).  The list goes on.

Also ideal for replacing electric scooter batteries which will give you a much longer run time for the same capacity (due to the 1C vs. 5C discharge rate spec).

I've been working (designing products) with LiFePO4 for about 5 years now, yet to find a flaw (as long as you stay above -5 degC).




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  Reply # 1074057 25-Jun-2014 11:23
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