Author Topic: Does anyone have experience with Chinese Lithium Iron Phosphate batteries?  (Read 486 times)

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Offline petect

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Hi  all
Does anyone have experience buying Lithium Iron Phosphate batteries from China? I’m planning on putting up a small semi-standalone  pv array. When $$ allows I would like to add some storage to  get me through the night. I’ll go to the grid for extended periods when the pv isn’t adequate.
 I’ve seen American made bats that seem to be high quality, with pretty high prices. I’ve also seen Chinese bats on aliexpress with prices that are easier to swallow. The Chinese bats have great specs  and certifications, but?????
Any experience with the sellers and the batteries would be greatly appreciated.  Also, do they play nice with your charge controller? What model controller are you charging them with?
Thanks in advance.
Pete in Ct

Offline lighthunter

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Re: Does anyone have experience with Chinese LiPO batteries?
« Reply #1 on: November 12, 2017, 01:43:36 pm »
Are you sure you didnt intend to say Lithium Iron phosphate chinese batteries (LiFePO4)?
Lipo generally refers to lithium-cobalt or some variant that yields about 4 volts per cell when full and down to 3.6 volts per cell. translated to a 12 or 24v system 3-series thats 12v-10.8v or 24v-21.6v

 By comparison LiFe VPC ranges from 3.6v-3.2v equating to 4 cells in series 14.4v-full -12.8v empty or 28.8v-25.6 (24v configuration).

Most inverters are designed for lead acid chemistry so the LiFe becomes the closer voltage match not to mention the discharge curve of LiFe is very stable without much sag under heavy load.

But then maybe I'm biased since ive used and like LiFe performance. As another current thread seems to point out, anything can be done with enough money ;)

I know nothing about cost/quality of lipo chinese other than many come from there so they have experience. LiFe GBS brand cells are good but probably not the best or cheapest.

Many on here will contend that dollar per watt some form of lead acid is the winner and I cant argue the point especially if you get a deal on some. The performance of LiFe is amazing but its expensive they do last longer to help offset cost but may still be pricier than lead acid. Lead acid is much more forgiving with mistakes, overcharge/overdischarge. Lipo would be one of the least forgiving outside of normal voltage could result in fire which necessitates a location or enclosure that can contain it.

Have fun with it whatever you decide :) hopefully others will contribute as I have not used Lipo for that application, works great for RC planes and boost starters though.

LH

Offline petect

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Re: Does anyone have experience with Chinese LiPO batteries?
« Reply #2 on: November 12, 2017, 04:09:19 pm »
Lighthunter   Yes I did mean to say Lithium Iron phosphate batteries. I didn't even know that there is a lithium-cobalt battery  :-\ Thanks for your comments despite my error.
Pete

Offline lighthunter

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Re: Does anyone have experience with Chinese Lithium Iron Phosphate batteries?
« Reply #3 on: November 12, 2017, 04:54:01 pm »
Your welcome :) in that case Ross probably knows the most about LFP.
LH

Offline rossw

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Re: Does anyone have experience with Chinese Lithium Iron Phosphate batteries?
« Reply #4 on: November 13, 2017, 03:15:12 am »
I bought 16 x 300AH/3.2V LiFePO4 cells and took delivery in April 2014.
Being Chinese, and being unfamiliar to me, I only got a 300AH/48V "nominal" bank to test the water with.
If I'd known then what I know now, I'd have just got 600AH worth from the start.

When I went back to get more, the company was uncontactable. Not sure if they went bust, got bought out and shut up, bought out and tied up to supply to one company only, or what.

My next batch, almost a year ago, was also LiFePO4, and made as 16 series packs, each pack being 3 parallel 200AH cells. So 16S3P, for a second "600AH/48V bank".

I very rarely see them drop below 53.0 volts, even after running the house and everything all night.
Under charge and "floating", they sit at 55.5V
So they are very "stiff".
I'm discharging them typically down to about 75%-80% overnight.

I haven't had any "superior" (allegedly) American cells to compare them to, however I know at LEAST one american seller sells the chinese cells as "american made", so don't let that fool you. I've heard good and bad stories about most cell technologies. My own experiences are that LiFePO4 is probably the best of the currently available technologies and I wouldn't hesitate for a moment going the same way again.

Offline petect

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Re: Does anyone have experience with Chinese Lithium Iron Phosphate batteries?
« Reply #5 on: November 13, 2017, 10:00:20 am »
rossw
Thanks for the information - very helpful.
It seems like your experience with buying Chinese has been good. Do you remember which company you bought your  second set from? Any issues dealing with the company, shipping, etc?
btw  where are you located. That might make a difference with shipping.
Thanks again
Pete

Offline rossw

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Re: Does anyone have experience with Chinese Lithium Iron Phosphate batteries?
« Reply #6 on: November 13, 2017, 03:35:34 pm »
Thanks for the information - very helpful.
It seems like your experience with buying Chinese has been good. Do you remember which company you bought your  second set from? Any issues dealing with the company, shipping, etc?
btw  where are you located. That might make a difference with shipping.

I'm in south-eastern Australia.
Shipping over a hundred 200AH cells (I got some for a mate also, and a few spares for me), cost the princely sum of $50 and took 3 weeks (yes, by sea). All the customs, clearances, duty, tax, port charges etc added a bit, but they still came in way below anything I could find locally.

The company I dealt with was fine, kept me updated with the order status. The factory even hand-picked the closest "matched cells" they had. (I'd told them I was making a battery at each of two different locations). No extra cost but it did add a week while they tested.

I can't recall the supplier offhand, I can go back through my records. Whoever you choose, just do your homework. Check you really ARE getting prismatic cells, not bunches of smaller round cells or foil packs stuck in outer boxes. Phone or at least email them. Ask specific technical questions and make sure you get the answers you expect.

Make or buy cell monitors and cell balancers. MONITOR your system. This is true of any battery you get, but especially so with lithium.

I am not a fan of all-in-one BMS with LVD/HVD/OCD. I have no DC loads. My inverter has LVD and HVD. My charge controllers will stop charging over a specified voltage. I have fuses in each bank. I see the normal BMS more as extra failure points than a safety device.

Offline lighthunter

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Re: Does anyone have experience with Chinese Lithium Iron Phosphate batteries?
« Reply #7 on: November 14, 2017, 06:40:33 pm »
Did you keep the second bank separate from the first or did you put em all together for 900AH bank? 

Im guessing it would require a lot more expense to keep separate and i would think it be no problem to connect together at the +-48 terminals once volts are matched.
LH

Offline petect

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Re: Does anyone have experience with Chinese Lithium Iron Phosphate batteries?
« Reply #8 on: November 14, 2017, 07:20:35 pm »
Hi Rossw
I was pretty much with you until I got to your last paragraph, then it seemed like you switched to another language - maybe you did  :-[.  It also dawned on me ( I think) that you were buying individual cells and assembling them into batteries.   So now I've gotta ask why? Better quality product? Less expensive? Is this something I should look into, or it this something best left to the pros?
Thanks
Pete

Offline rossw

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Re: Does anyone have experience with Chinese Lithium Iron Phosphate batteries?
« Reply #9 on: November 14, 2017, 07:21:59 pm »
I had originally considered selling the 300AH bank, but then decided I really liked the extra capacity in reserve :)

Each bank has its own cell-balancers.
Each bank has its own cell monitoring.
Each bank has its own fuse (for my convenience, at the centre-point of each string).
The banks are connected in parallel, but using 2 x 1M lengths of 35 sq mm cable as "balancing resistors".
They track remarkably well. I rarely see more than 120A of charging current, but it seems to very nicely balance itself, 2/3 to the 600AH pack 1/3 to the 300AH pack, on charge and discharge.