Cells from Battery EVO

[Shamoke]

I ordered this package from Battery EVO: https://batteryevo.com/battery-evo-12v-lithium-lifepo4-150ah-2-kwh-135a-bms-kit/
Received the battery cells yesterday and first thing I did was check the cell voltages. Three of the cells have hand written stickers stating the test voltage of the cell, I presume from the time of packaging because they match my readings.

Cell one: Meter 2.9 Tag: 2986
Cell two: Meter = 2.9 Tag:2988
Cell three: Meter 2.9 Tag:2986

All is good even if they in a low state of charge. They sent me a data sheet via email this AM after I asked. Their data sheet claims a discharge voltage of 2.5 v so these cells are ok.

Now for the fourth cell... This cell has no test sticker on it at all, I even checked in the box in case it fell off. So no idea if it was even checked before shipping. Cell four reads 2.2 volts and that seems like it may be damaged to me. I am afraid to put this pack together and try to charge it because of this bad cell and so far Battery EVO has only responded with the aforementioned data sheet.

So what is your experiance with Battery EVO and their cells and have you use any cells in this condition before and how are they performing now? Yes the listing states that these are reconditioned but I expect them to be matched.

 

[Shamoke]

 

[RCinFLA]

2.2v is okay. The primary reason for 2.5v min spec is for time margin. No real damage occurs until cell drops below 1.5v. At 2% capacity per month self discharge it will not take long for a 2.5v cell to drop below 1v.

I don't like that they are being sent out so low in voltage however. It gives me the feeling they have been sitting around for a long time.

 

[Shamoke]

Thank you for this info, it makes me feel a bit better about that cell and that it may be ok. I am with you on the low state of charge though, how ever as long as there is no long term damage to the cells capacity it should be ok to use in this pack I'm guessing.

 

[Shamoke]

An update on these cells. The low volt cell is bloated much more than the other cells so I compressed them into a pack. I charged the 2.2 volt bloated cell up to 2.8 volts, just 0.1 volts below the other cells and then installed the printed circuit buss bar board and have the pack on the charger. I'm concerned about that bloated cell causing issues but have hopes that it will "recover" well enough to be useful in the pack or that BatteryEVO will send a better cell. I love the idea/design of these diy packs they are selling but I wish that had done a better job in sending out matched cells. I understand that they are sold as "refurbished" cells and expect then to have some wear but they need to be matched and not bloated as bad as the one I received.

 

[Shamoke]

Another update:
I finally got around to putting these cells into a parallel pack and charged them at 3.64 volts until the amps dropped to zero. I then let the pack sit for 6 hours and took it apart. The good cells sat at 3.53 volts and the bloated one was 3.38. 30 minutes later I tested again and the three good cells still read 3.53 but the bad one was down to 3.11 volts.
The bloating is much less after they sat in the compress rig for the last two weeks while I was too busy to get back to them but the voltage difference and drop in that cell tells me that it cannot be used in a pack. So I have written to BatteryEVO to see what, if anything they will do to remedy this situation.

 

[Substrate]

The time needed for doing a "rested" voltage test is 12 hours.

Typically a fully charged cell will settle to approx 3.38v after 12 hours. If cells after 12 hours or even a few hours more are higher than 3.38v, then they are overcharged and should be discharged a little bit.

After the 12 hour test is done, and you have taken your reading, continue on resting for another 24 hours and measure again.

If the rested voltage has dropped more than 0.1v, that indicates that the cells are approximately beyond the normal 80% capacity limit when most are traded in or recycled, since they no longer fulfill the capacity for the application they were designed for.

In the meantime, with known mismatched cells, I'd be tempted to charge each one individually. Then assemble into your pack. Apply a discharge for awhile with your application, and then either top-balance the whole bank, or let the bms (if it has bleeder resistors or other balancing circuit) fine tune the balance with a few repetetive charge/discharge cycles. - doesn't have to be full discharges -

 

[Larry619]

Another update:
I finally got around to putting these cells into a parallel pack and charged them at 3.64 volts until the amps dropped to zero. I then let the pack sit for 6 hours and took it apart. The good cells sat at 3.53 volts and the bloated one was 3.38. 30 minutes later I tested again and the three good cells still read 3.53 but the bad one was down to 3.11 volts.
The bloating is much less after they sat in the compress rig for the last two weeks while I was too busy to get back to them but the voltage difference and drop in that cell tells me that it cannot be used in a pack. So I have written to BatteryEVO to see what, if anything they will do to remedy this situation.

Hello, any updates with your experience with BatteryEVO and the bad cell?

I’ve been thinking about buying from them.

 

[Shamoke]

Hello, any updates with your experience with BatteryEVO and the bad cell?

I’ve been thinking about buying from them.

Yes, I am sorry for not updating earlier. BatteryEVO e-mailed me a return label for FedEx so I packed the cell and sent it off. A week later I asked about the replacement and they said that they had not received the return yet. The next day they found the returned cell and would send out the replacement the next day. I got the new cell a few days later and it was closer to the cell voltage of the other three and held the top off charge like the other three.

I assembled the pack for a 12 volt battery and put it in a milk crate with the BMS box, a near perfect fit by the way, and put it into service in a backup system using an MPP Solar PIP – 1012LV-MS inverter/charger all in one. It has been working well so far and I do not expect any trouble out the system because it is not being worked much at all. I did test it by flipping the breaker off and running my security camera system, a computer, and three shop lights while I also used my vacuum sealer and an impulse sealer for about 2 and a half hours with no problem.

My takeaways from my experience with BatteryEVO:
Pros:
1. I like the design of the BMS box, cell connection PCB and cable connections.
2. The price is half the cost of a Battle born but has 50% more amp hours.
3. Initial shipping was quick and free.
4. Their web site is easy to navigate and order from. (Hint Hint Amy Zheng)

Cons:
1. They never should have sent out that bad cell, they claim all cells are tested before shipping but that one did not have any test sticker on it like the other three cells did showing it's voltage at testing. The cell was clearly bloated much more than was acceptable just by visual inspection, no excuse for that in my opinion.
2. They do not cross ship so any issues take much longer to fix than they should. It is true that I was too busy with work to test the cells and discover the problem but it still took nearly two weeks after they had been contacted.
3. I had to reroute the wiring inside the metal BMS box to make one of them long enough to reach it's battery lug, something that another $0.50 worth of wire would have prevented.
4. The BMS was taped to the inside of the metal box with double sided take and came loose in shipping and was rattling around inside, another issue I had to fix but the BMS suffered no apparent damage so I'm not too worried about it.

All in all I am not sorry that I bought this kit but I will probably stick to buying new cells and sourcing my own BMS and wiring ect. I will try to get a picture of the assembled pack in the near future.

 

[Shamoke]

BatteryEVO not our company products, so what do you mean "Hint Hint Amy Zheng", I think that is not me?

I was refering to their website and how easy it is to order direct from it. I was not trying to associate you with them.

 

[Shamoke]

Yes, as totally different company, but found same name so I think that is not me. Thank you

Again, I never said nor implied that it was you, I mearly trying to point out to you that their website is a lot easier to navigate and order from than your web site is. It was a "hint" to you that your website could stand some improvement. Nothing else was implied here.