My experience with VariCore 3.2V 280AH Lifepo4

[clyndes]

I ordered 8 of these on Feb 1st 2021 for $899.74 shipping included. I received them in Vermont USA on April 7th. I did run into the Chinese New Year holiday.

While I waited I made some cardboard prototypes of the cells and made my enclosures. I am using two Overkill Solar S4 120 Amp BMS.

After top balancing I did a capacity test and one battery of 4 cells gives me 270AH and the other gives me 277AH.

I do not know the manufacturer of these cells so I included a picture. Can anyone tell from the picture who made them? They have a barcode that says scratch, and there were small, hopefully cosmetic issues. The ad specified that they were new. I've gone through 2 full cycles and other than the less than advertised capacity they seem to be working fine.

I had originally thought I’d buy the SOK batteries but when they were out of stock decided to take the plunge and try making my own. These ended up costing about the same once all was said and done but have more AH and I understand them a lot better because of having to set them up. Hopefully I won’t regret going with VariCore.

I will post a follow up message with a description of my system and a few (quite a few) questions I have. I thought I would keep this short and to the point.

 

[Gazoo]

Most likely they are CATL's. I don't know if they are 271, 302, or 310ah CATL's. Could be 271's. Since you have the measurements you could search the forum to confirm since others have purchased CATL 302 and 310 cells. Or contact VariCore and ask them.

 

[RStone13]

FREE.

Range of application
Product name:	lithium iron phosphate cell
Shell Material:	Aluminum
Nominal capacity:	280Ah
Minimum capacity:	280Ah
Internal impedance:	0.1 ~ 0.3mΩ
Nominal voltage:	3.2V
Discharge end voltage:	2.5 v
Recommend constant current:	280a (1c)
Recommend constant current:	140a (0.5c)
Charging voltage:	3.65 v
Maximum continuous discharge current:	280a (1c)
Life cycle (80% dod):	4000 cycles
Charging temperature:	-5 60 60 ° c
Discharge temperature:	-30 60 60 ° c
Dimensions (l*w*h):	205*174*72mm
Applies to:	Engine start batteries, electric bicycles / motorcycles / scooters, golf carts / trolleys, power tools ... Solar and wind energy systems, motor homes, caravans ... Backup system and UPS.
Shipping list:	3.2V 280Ah Battery*4 Screw*8 Copper sheet*4

Brand Name: VariCore

Certification: CE

Origin: CN(Origin)

Weight: 5.25kg

Size: 174*72*205mm

 

[Northernchateau]

Not to jack your thread but I have a couple question/comments for forum users:
1. what is acceptable range of capacity on any battery ?
2. how accurrite is the voltage reading on the charger used to top balance each battery?
3. what range limits were used on the test?
4. how fast was the battery discharged?
If there is not some standards it will be hard for any of us to compare apples to apples.

 

[RStone13]

Not to jack your thread but I have a couple question/comments for forum users:
1. what is acceptable range of capacity on any battery ?
2. how accurrite is the voltage reading on the charger used to top balance each battery?
3. what range limits were used on the test?
4. how fast was the battery discharged?
If there is not some standards it will be hard for any of us to compare apples to apples.

This post should be in Beginners Corner

 

[Northernchateau]

This post should be in Beginners Corner

Are those questions answered someplace? Because in IMO if you are going to post result the test parameters need to be with the data.

 

[Gazoo]

Are those questions answered someplace? Because in IMO if you are going to post result the test parameters need to be with the data.

1. what is acceptable range of capacity on any battery ?

The acceptable range depends on one's expectations. If one buys a "commodity" 280ah cell and it delivers 270ah's, is that acceptable to you? It would be to me considering the price I paid for them vs buying new Grade A cells directly from the manufacturer or through a distributor selling new Grade A cells and the cost would be 2 to 3 times more.

2. how accurrite is the voltage reading on the charger used to top balance each battery?

The cheap power supplies I have seen people use on this forum are fairly accurate. It's always suggested to use a DMM to verify all voltages.

3. what range limits were used on the test?

Most people know in order to properly capacity test cells the range needs to be 3.65 volts down to 2.5 volts to get the total ah's of the cell. If testing the capacity of cells in series then the lowest capacity cell will determine the total ah's of the battery. Whenever cells are connected in series a BMS should be installed. I suggest fully charging and discharging the battery until the HVD and LVD of the BMS kicks in to make sure the BMS is working properly. This also gives one the opportunity to test the capacity of the battery.

4. how fast was the battery discharged?

Discharging at high C rates has little effect on the capacity of the cell vs low C rates. From what I have seen it amounts to a few ah's difference or less.

If there is not some standards it will be hard for any of us to compare apples to apples.

I have observed many posts of others capacity tests. A few have not completely charged and discharged the cells but have posted the voltages. Going by that and looking at the graphs one can get a good idea if the cell is a dud. Most of us are not using lab equipment however the cheap coulomb counters are fairly accurate. I use my BMS which has a built in coulomb counter.

I did not capacity test each of my cells. I tested the capacity of my battery. Had the capacity not been acceptable then I would have capacity tested all of the cells.

 

[Northernchateau]

The acceptable range depends on one's expectations. If one buys a "commodity" 280ah cell and it delivers 270ah's, is that acceptable to you? It would be to me considering the price I paid for them vs buying new Grade A cells directly from the manufacturer or through a distributor selling new Grade A cells and the cost would be 2 to 3 times more.


The cheap power supplies I have seen people use on this forum are fairly accurate. It's always suggested to use a DMM to verify all voltages.


Most people know in order to properly capacity test cells the range needs to be 3.65 volts down to 2.5 volts to get the total ah's of the cell. If testing the capacity of cells in series then the lowest capacity cell will determine the total ah's of the battery. Whenever cells are connected in series a BMS should be installed. I suggest fully charging and discharging the battery until the HVD and LVD of the BMS kicks in to make sure the BMS is working properly. This also gives one the opportunity to test the capacity of the battery.


Discharging at high C rates has little effect on the capacity of the cell vs low C rates. From what I have seen it amounts to a few ah's difference or less.



I have observed many posts of others capacity tests. A few have not completely charged and discharged the cells but have posted the voltages. Going by that and looking at the graphs one can get a good idea if the cell is a dud. Most of us are not using lab equipment however the cheap coulomb counters are fairly accurate. I use my BMS which has a built in coulomb counter.

I did not capacity test each of my cells. I tested the capacity of my battery. Had the capacity not been acceptable then I would have capacity tested all of the cells.

Thank you for your reply. I just think it is important to post your test parameters alone with your findings.
After looking at cells on Alibaba and Aliexpress I am guessing there is a lot of questionable quality out there.
I have been involved with solar for approx 7 years but everything I have done thus far is off grid and being I am in upstate NY it always has been SLA or AGM since it sees below freezing all winter long. (can't use a heating pad when you run low on power)
Lifepo4 is new to me and users seem pretty anal about top balancing and capacity so I am just trying to get on the same page when I test.

 

[RStone13]

This post should be in Beginners Corner

My apologies, I misunderstood your post.

 

[clyndes]

Not to jack your thread but I have a couple question/comments for forum users:
1. what is acceptable range of capacity on any battery ?
2. how accurrite is the voltage reading on the charger used to top balance each battery?
3. what range limits were used on the test?
4. how fast was the battery discharged?
If there is not some standards it will be hard for any of us to compare apples to apples.

Hi, original poster here. I'm also brand new to Lithium so I am probably not the best source. Always something to learn.

1. I decided to keep the batteries. Waiting months for another batch or paying 2 to 3 times more for US sourced guaranteed grade A isn't in my budget.

2. This test was done using a Renogy DCC50S DC to DC charger which was handling the LiFePO4 charging parameters, being powered from my lead acid bank being charged by my Progressive Dynamics PD9280V AC to DC charger / DC power supply. This was the second charge / discharge cycle after charging in series with the BMS, then reconfiguring in parallel and charging to 0 amps with a 10 amp DC charger, the one recommended by Will Prouse on his tools page. Confirmed cell voltage immediately with my DVM.

3. The actual voltage for over voltage and under voltage was being handled by the Overkill Solar 120A BMS at default settings. Overvoltage 3.65, Undervoltage 2.5, Package Overvoltage 14.6, Package Undervoltage 10.

4. I believe my charge / discharge rate to be somewhere in the vicinity of .1C. I have these 2 batteries hooked up in parallel. They are being charged by the DCC50S at a maximum of 50 amps or 25 amps each. For discharge I have a 1000 Watt Xantrex pure sine wave inverter powering my wife's hair dryer which on medium heat is drawing 50 to 55 amps, split between the 2 batteries.

See attached picture for my test setup, currently in the basement, waiting for it to stop snowing before being installed under the couch in the RV.

 

[Northernchateau]

Hi, original poster here. I'm also brand new to Lithium so I am probably not the best source. Always something to learn.

I am in the same boat as you. I started out with and will continue to run deep cycle 12v LA batteries in some applications and will use LifePO4 where I can. I have a funny feeling years down the road we will all be talking about some other new battery or storage technology.

 

[clyndes]

Thanks to Gazoo I think I have CATL batteries. Doing some research on line it seems they do not have 280AH batteries but do have 271AH and 310AH. This means I may have properly functioning, new, maybe even grade A 271AH cells.

The only issue is VariCore advertising them as 280AH which I can live with.

 

[RStone13]

Thanks to Gazoo I think I have CATL batteries. Doing some research on line it seems they do not have 280AH batteries but do have 271AH and 310AH. This means I may have properly functioning, new, maybe even grade A 271AH cells.

The only issue is VariCore advertising them as 280AH which I can live with.

Post #3 above is the spec page for your battery. I bought the same ones from the same company. Mine also tested about the same as you

 

[clyndes]

Most likely they are CATL's. I don't know if they are 271, 302, or 310ah CATL's. Could be 271's. Since you have the measurements you could search the forum to confirm since others have purchased CATL 302 and 310 cells. Or contact VariCore and ask them.

Gazoo,

Thanks for that picture. I agree they look like CATL's.

I requested a data sheet from VariCore and just received it. It was in Chinese and Google Translate says it identifies these cells as coming from Huizhou Yiwei Lithium Energy Co., Ltd. Some searching shows that this company is a subsidiary of EVE so VariCore is indirectly saying these are EVE cells.

At this point I'm not returning the cells so this isn't going to affect anything. I'm just posting this as further documentation of my experience doing business with VariCore.

 

[Gazoo]

Gazoo,

Thanks for that picture. I agree they look like CATL's.

I requested a data sheet from VariCore and just received it. It was in Chinese and Google Translate says it identifies these cells as coming from Huizhou Yiwei Lithium Energy Co., Ltd. Some searching shows that this company is a subsidiary of EVE so VariCore is indirectly saying these are EVE cells.

At this point I'm not returning the cells so this isn't going to affect anything. I'm just posting this as further documentation of my experience doing business with VariCore.

Maybe they sent you the wrong data sheet? I have never seen EVE cells with those types of terminals and vent caps. I know it's a hassle but I would question VariCore about the validity of the data sheet.

Returning them would be costly and I would keep them too. It's better to negotiate for a partial refund since the cells don't meet the advertised capacity and VariCore is advertising them as EVE cells.. Of course that's up to you.

Could you post a close up photo of the QR code? It might help to confirm they are CATL's.