I received my 16x3.2v Lifepo4 310ah cells from Varicore.

[JoeyCharismatic]

I received my 16x3.2v Lifepo4 310ah cells from Varicore. Looked clean, similar voltages, charged up and now in top balance phase. Will capacity test, but all indications are this is a great product, and satisfied with the experience.

 

[time2roll]

No bulging? No dents? No scrapes? No bad terminals? All arrived at similar voltage?

Did you negotiate matching cells or is this a click and buy? How long did the shipping take?

Thanks for the encouragement

 

[JoeyCharismatic]

All arrived similar voltages, no bulging dents or scrapes. One spot of peeling of the blue wrapping on 2 cells, very minor. Click and buy. About 60 days shipping, I'd have to calculate, but I ordered 05/01/21.

 

[JoeyCharismatic]

Top balance at 3.6v. Held for 24 hours with no deviation.

 

[JoeyCharismatic]

Built 48v battery with Daly Smart BMS, Victron Snartshunt and Multiplus II 3000 48v/120v.

 

[JoeyCharismatic]

Performed first capacity test in a really clunky way, because I had no consistent load available. From 3.5v to 2.5v I netted 287ah on a 310ah nameplate - but there are some things to note.

1) One cell tripped the bms 2.5v shutoff when the others were still at 2.9v. While this is a balance issue most likely, I don't plan on using it outside the 2.9v-3.4v range, so I'm not concerned. I expected a 10% loss, and got better that. 287/310=23ah loss, or 7.4% less than nameplate.

2) The discharge test was performed between 30-60amps, which is higher than normal capacity tests because I didn't have the right equipment for a more precise measurement, though my hoover and no-name portable AC unit did the trick.

3) My Smart shunt is reflecting a higher voltage than my battery actually has, which is bizarre. Still researching the cause, but I performed the test anyway.

Now to figure out what to do with my battery...

 

[Jim1033]

Thanks for the update. I have the same Varicore 310 AH cells about the same time frame and ended up with about 287 AH as well. My BMS said still have 7.5 percent capacity which would have been 304 AH. I also started about 3.5v each. I can not complain. I do have a few cells that seem to charge quicker so getting a good top balance was a pain. I also had a couple that took forever to get to voltage. The resistance seemed fairly similar. So it must have been they had more capacity.?. The Daly smart BMS seemed to bring them down together but going up did not seem to do as good. I hope that does not mess me up keeping them balanced. Looking at a separate active balancer. Just think. Somewhere between 13kw and 15kw 16s. Just need about 3-4 more banks of that. ?? may take a while$$$

 

[JoeyCharismatic]

Thanks for the update. I have the same Varicore 310 AH cells about the same time frame and ended up with about 287 AH as well. My BMS said still have 7.5 percent capacity which would have been 304 AH. I also started about 3.5v each. I can not complain. I do have a few cells that seem to charge quicker so getting a good top balance was a pain. I also had a couple that took forever to get to voltage. The resistance seemed fairly similar. So it must have been they had more capacity.?. The Daly smart BMS seemed to bring them down together but going up did not seem to do as good. I hope that does not mess me up keeping them balanced. Looking at a separate active balancer. Just think. Somewhere between 13kw and 15kw 16s. Just need about 3-4 more banks of that. ?? may take a while$$$

Hey Jim! Sounds like you got decent value. I had similar struggles initially with balancing, but I think it was my own learning curve.

I found a few things were helpful:
1) Make sure that you have solid connections with busbars/higher gauge wire when balancing.
2) Bring the entire pack up to 3.6v in parallel and hold it there until the current is at a trickle, then let it rest overnight.
3) The voltage will drop (to as low as 3.4 volts), then recharge it back up to 3.6v.
4) Let it sit for 12 hours more, then disconnect the paralleled cells and measure each voltage. They should be identical to the hundredths, and at least 3.4v each, any less and the balance is unreliable.
5) Connect in series and set the charge parameter to ABSORPTION: 54.4v. It is far more important that the cells are balanced at 3.4v than at 3.65v, as there are some cells which will spike at the extremes.

Hope this was constructive, best of luck with your set up.

Care to share your inverter info and application, etc?

 

[Jim1033]

https://diysolarforum.com/threads/it-ain’t-pretty-but….23833/

This should show my thread it ain’t pretty. You are right about what you said. I balanced it for a day or so at low voltage but did not have a way to top balance at 3.65 volts. I am about to pull it all apart clean buss bars, put my new wires 2awg, mount bms safely, etc. I have learned a lot in a short time and realize how little I know. My big one is can or should I put a separate active balancer in the mix. Especially if my smart bms does some balancing. The hybrid inverter is a AliExpress 5500 I have to say so far it is ok. I do not like some of the parameters. The low voltage cut off high is pretty low for Lifepo4 (42-48v). I would rather it go to 52or 53 v. I have pretty low loads so far. Would like to be able to put 3 fridges on it in an emergency. Should be about 1 k max. Also like to get 8 310 solar panels. I have 4. We’ll actually 10 k on the roof grid tie but 8 emergency ones… lol. I love the forum. Thanks for the tips.

 

[JoeyCharismatic]

The journey is the destination, right? Have fun, and keep the community apprised of your progress. I'm new here too, and I was experimenting with a lifepo4 battery all on my own before I discovered this place. I have the Victron multiplus II 48v/3000w. Pretty customizable, but still not intuitive at times. I still need to do a full capacity test, and it will be easier once I have my EV back in town, because it's a high power load than can soak up a good amount of kWh. Ill let you know how it goes!