Just got delivery of my 280AH CATL batteries

fopoku2k2

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Aug 20, 2020
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My order of 16pcs of 3.2v 280AH CATL cells from alibaba just got delivered to me in West Africa - Ghana.
I decided to order from Shelly Fang (Shenzhen Jidian Technology Co., Ltd).
Took roughly 3 months. Packaging is very good. cells looks to be in very good condition.
I checked the individual voltages and apart from two of them that read 3.18v and 3.20v, the rest read 3.19v

My question is can I just assemble them with a BMS and start using the cells or i should connect them in parallel leave them to sit for a while to balance?
 

Groscout

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May 2, 2021
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My order of 16pcs of 3.2v 280AH CATL cells from alibaba just got delivered to me in West Africa - Ghana.
I decided to order from Shelly Fang (Shenzhen Jidian Technology Co., Ltd).
Took roughly 3 months. Packaging is very good. cells looks to be in very good condition.
I checked the individual voltages and apart from two of them that read 3.18v and 3.20v, the rest read 3.19v

My question is can I just assemble them with a BMS and start using the cells or i should connect them in parallel leave them to sit for a while to balance?

Good afternoon from Washington - U.S., Congratulations on the battery purchase! I would absolutely balance before use. Here's a good top balancing guide with information on how to quickly balance and place them to service.
 

upnorthandpersonal

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should connect them in parallel leave them to sit for a while to balance?

Just to repeat what's also in the guide: just setting them in parallel will not balance the cells. You need to put the cells in parallel and attach a power supply set to 3.6V (max 3.65V - set before connecting the supply). Also make sure there are proper leads (size wise, and ring terminals) on the supply. Whatever you do, do not change the voltage on the supply while connected to the cells. This deserves repeating a few times.
 

Bubba1

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Feb 6, 2021
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I connect in series with BMS and charge close to 3.65 then parallel to top Ballance. You can do it in a day or two compaired to a week. Monitor closely in case your BMS doesn't high voltage disconnect. Another word don't go to bed with the charger on until you know everything works.
 

fopoku2k2

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Aug 20, 2020
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Thanks for all your help. I managed to get a DC power supply today. rating is 30v, 10A. feels very light in weight. Thought these things were heavy. I hope it works . . . . :). Ok so my next questions are:
1.0 Do I really need to connect a BMS when charging each 4pair of cells?
2.0 If question 1 is YES, since I only have a bms for 16s, is there anyway to configure this to only work with 4 cells

Thanks for reading and all your swift responses
 

Bubba1

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I didn't use a BMS but I watched carefully and checked each cell to make sure none went over 3.65. Once they approach 3.45 the voltage goes up quick. Be careful how ever you do it.
 

fopoku2k2

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Aug 20, 2020
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I didn't use a BMS but I watched carefully and checked each cell to make sure none went over 3.65. Once they approach 3.45 the voltage goes up quick. Be careful how ever you do it.
from what my voltages are (3.19v), how long do you think it would take me to get to say 3.45v?
 

Walkdog

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Jul 18, 2020
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from what my voltages are (3.19v), how long do you think it would take me to get to say 3.45v?
My order of 16pcs of 3.2v 280AH CATL cells from alibaba just got delivered to me in West Africa - Ghana.
I decided to order from Shelly Fang (Shenzhen Jidian Technology Co., Ltd).
Took roughly 3 months. Packaging is very good. cells looks to be in very good condition.
I checked the individual voltages and apart from two of them that read 3.18v and 3.20v, the rest read 3.19v

My question is can I just assemble them with a BMS and start using the cells or i should connect them in parallel leave them to sit for a while to balance?
How are these working out for you? I have a 4pc ordered and am learning how to top balance them once they get here. I ordered through Docan Technology (Shenzhen) Co., Limited and dealt with Daisy. She was very helpful of course.


Where i ordered from, hope i did not go against website rules, if i did please moderator take it off. I'm very new and of course trying to make these batteries work is even more new to me
 

fopoku2k2

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How are these working out for you? I have a 4pc ordered and am learning how to top balance them once they get here. I ordered through Docan Technology (Shenzhen) Co., Limited and dealt with Daisy. She was very helpful of course.
I tried by best to balance them but because I had s relatively small power supply (30v, 5A) it was taking forever so I just charged individually to 3.27, contact in parallel add let sit for a few days. I assembled them three days ago and these are my findings:
1.0 initially there were huge differential voltage differences
2.0 these different vintages would shut down the BMS after a few hours
3.0 Daly BMS tries to balance but it still did shut down for a second time yesterday
3.0 it's been about 24hrs since the last shutdown. Been fully on the batteries since. I hope the BMS has finally managed to balance the cells quite a bit


Where i ordered from, hope i did not go against website rules, if i did please moderator take it off. I'm very new and of course trying to make these batteries work is even more new to me
I just heard about this supplier this week. I've currently requested for s quote. Hope to order from them. My last supplier has very bad customer service. Takes forever to reply my messages.
 

Short_Shot

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When you connected in parallel and let them sit, do you mean to let them sit on the power supply?

They will virtually never balance if left to do so passively.
 

fopoku2k2

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I actually arranged them in two sets of 8 cells and let them set on the power supply for a couple of days. this didn't seem to be working since I was not noticing a change in voltage and was not confident in the power supply that I got. So i removed them off the PS and let set by themselves for about a day or two.

I know what i did was not balancing. I plan on doing the following on my next batch
  1. get a bigger and better power supply next time. preferably something to handle 48v
  2. connect cells in series with BMS and use PS to charge up to 3.4
  3. disconnect BMS, arrange cells in parallel and use PS to charge up to 3.6
 

DJSmiley

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Aug 13, 2020
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Even with 5A you can do a topbalance. It only takes forever.

Assuming 50% SOC on arrival, means you have to charge 16x280x0.5 = 2240Ah.

With 5A that's 448 hours, or approx 19 days.

And yes, due to the flat curve of LFP, this will be barely noticable in voltage, just be patient.

Faster option might be charging them into 2 24V packs, with a BMS set to 3.65V HVD.
That will allow you to charge 8 cells to near fulll, requiring 140Ah at 24V. Thus with 5A charging it will take approx 28 hours, 56 hours for both packs.
Once that's done (single cell hitting HVD) reconnect in parallel and finish topbalance. That will probably take another 10-20 hours, depending on the difference between the cells. So in total 3 days or so.
But you do need to have a (8s) BMS with 3.65V disconnect which you can trust and does work as supposed!
 

fopoku2k2

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Even with 5A you can do a topbalance. It only takes forever.

Assuming 50% SOC on arrival, means you have to charge 16x280x0.5 = 2240Ah.

With 5A that's 448 hours, or approx 19 days.

And yes, due to the flat curve of LFP, this will be barely noticable in voltage, just be patient.

Faster option might be charging them into 2 24V packs, with a BMS set to 3.65V HVD.
That will allow you to charge 8 cells to near fulll, requiring 140Ah at 24V. Thus with 5A charging it will take approx 28 hours, 56 hours for both packs.
Once that's done (single cell hitting HVD) reconnect in parallel and finish topbalance. That will probably take another 10-20 hours, depending on the difference between the cells. So in total 3 days or so.
But you do need to have a (8s) BMS with 3.65V disconnect which you can trust and does work as supposed!
you are sooo right. sorry for my bad choice of words. it did actually work. I meant to say it was very slow.

I thought about the last option but unfortunately I do not have an 8S BMS and didnt want to wait for another 3 months for it to be delivered. would definitely be getting one with my next order
 

Scph9002

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1, Assemble the cells as 16s and just start charge them via bms untill bms shut down because of cell high voltage. I am assuming you already have solar panels and charge controller for 48v lifepo4? Use that to recharge.
2, paralell all 16 cells and top balance with your power supply to 3.65v. This should not take a long time and you are good to go.

You cant use daly bms to balance cells. Its balancer draws 35mA and is as far as i understand only designed to keep cells from voltage drifting over time due to differences between internal resistances between cells.
 

fopoku2k2

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1, Assemble the cells as 16s and just start charge them via bms untill bms shut down because of cell high voltage. I am assuming you already have solar panels and charge controller for 48v lifepo4? Use that to recharge.
2, paralell all 16 cells and top balance with your power supply to 3.65v. This should not take a long time and you are good to go.

You cant use daly bms to balance cells. Its balancer draws 35mA and is as far as i understand only designed to keep cells from voltage drifting over time due to differences between internal resistances between cells.

I guess that was what I should have done from the first day. So what you are saying is:
  1. set my hybrid inverter C.V voltage to 58.4v
  2. charge series connected sells with BMS till BMS stops charging
  3. remove BMS, arrange cells in parallel and use PS to charge to 3.65v, 3amps (since its not advanceable to set to the full current of the PS)
 

lexio

feel the balance 3.65
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yes that is the trick

after bms shut off

you can also parallel cells and charge first to 3.5v let the amps drop to 0.1 amp and then go to 3.61v and let the amps drop to 0.1
this is done so your cells wont be in the upper knee for a long time

always set your voltage on the bench-top and then connect them to your cells

assemble your pack
then drain your pack to 3.0v a cell (now your cells will be flat again )
now clamp our pack

recharge pack to 56v
if you have done it right
delta v shoot be less hen 0.07v

question:
1 what are the shipping and importing cost to Ghana
2 and pictures
 
Last edited:

fopoku2k2

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Aug 20, 2020
Messages
66
yes that is the trick

after bms shut off

you can also parallel cells and charge first to 3.5v let the amps drop to 0.1 amp and then go to 3.61v and let the amps drop to 0.1
this is done so your cells wont be in the upper knee for a long time

always set your voltage on the bench-top and then connect them to your cells

assemble your pack
then drain your pack to 3.0v a cell (now your cells will be flat again )
now clamp our pack

recharge pack to 56v
if you have done it right
delta v shoot be less hen 0.07v

question:
1 what are the shipping and importing cost to Ghana
2 and pictures
currently my shipper charges me $350.00/cbm. This rate includes shipping and all import duties.
 
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