Hi,
I also ordered 24
310Ah cells but on Alibaba - from Shenzhen Beiersite E-Business Limited in middle of March 21. Got cells delivered in Juni.
Cells were thoroughly packed in foamed boxes to 4 cells. On checking the cells I found one cell sitting at 2.99V, all other cells were on 3.29V. One cell was damaged on one corner as it was dropped.
I filed a dispute after trying to negotiate with the seller. He claimed that all cells were tested before shipping, so it muss happened during transport...
In the dispute the seller suggested that he will send new cells if I agree and close the dispute. I did and was looking forward to get new cells. Instead of shipping new cells the seller refunded those two cells straight away! I was not happy and tried to escalate this face solution of the seller to Alibaba in opening another dispute - but Alibaba didn't reply. My second dispute was not even filed! The seller replied that he had refunded the cells and he would have send new cells only if I had placed another order!
Meanwhile I assembled the battery - same as Peter 3P8S and it turned out, that the 2.99V cell is playing crazy within a cluster of 3 cells.
On charging this cluster reached OVD first and drops fast in voltage after a short time without any loads on the battery!
Prior, I had all cells assembled to a 24V system and charged with my victron MP 2 with SBMS0 as controller. Then I re-arranged cells in parallel and toped all up to 3.6V, left its for 24h in parallel and reconnected the cells in 3P8S configuration.
Observing the SOC/voltage of the battery/cells I'm pretty sure that this block will not deliver the performance intended/ordered/expected.
Finally, I ended up ordering additional 4 cells from the same seller to get same brand of cells to swap cells which are not performing.
I'm very unhappy with this deal - next time I will consider buying Winston cells instead of this Chinese crap.
I posted this story already on FB and was blamed for can going for the cheapest cells - it is well known that these cells are not A-Grad...offer was for A-Grade cells...
To justify my purchase, I was not going for the cheapest cells on Ali, but for the most comprehensive deal. No tax no duties would come on top, only shipping - that was my criteria.
What I have learned from this deal - next time - if ever! - I will order more cells than needed. An additional set of four cells should? be enough
to assemble the desired system. After completion of the project I will sell these surplus cells for a reduced rate - unveiling the background/history. So I could reduce my loss...
Peter - I attached some pictures of my battery box, made out of 24mm plywood. Compression is achieved/maintained with stainless steel threaded rod. With a router I cut a 9mm groove in the plywood and inserted a sheet of 9mm plywood where cells are resting on. The bottom set of rods is right underneath this floor inserted to carry the weight of the cells. To secure the box on the floor I screwed aluminium angle profil into the wooden floor in the distance of the box, inserted the box in between and drilled holes through the box walls. The floor where the cells rest on is prox. 50mm from the bottom. From the inside I put metal inserts in to be able to fasten the box to the angle profil...Cells I wrapped in insulation paper - Dupont Nomex paper, pricy, but I wanna to be safe...
Box is approx. 1400x265 footprint, hight is 360mm...calculate 50mm floor, floor, cell hight plus an additional 30 to 50mm for bars, cables and rods.
As it was mentioned earlier, delivered busbars are somehow useless. Holes only fit if one puts cell flat next to each other, won't fit if in series. I made busbars from copper flat material, 20x3mm equals 60mm2. I'm also not drawing more then 150A with my MP2 24/3000/70.
I'm not happy with the busbars as its are rigid allowing no length compensation on temperature differences.
With this amount of capacity - once updated with new cells! - I'm hoping to cycle the battery only within 30 to 80% max - though giving hopefully a long lifetime...
My application is also RV. A word to the fuse - I fitted a T-class fuse from Blue Systems, 400A. It'll safely disconnect the battery from the RV in worst case. AC I'll get from my victron MP2 and hopefully disconnects by order of SBMS0 and DC loads are cut off via a victron BP. Since I only run small appliances like LED light, Truma gas heater and fridge, a 65A BP will do the job.
A suggestion to make life with SBMS0 easier - I bought cat5 lead and cut off one plug, jammed the individual cables into the green connector and mounted a socket for RS45 behind the wall and connected the individual cables to inverter, shunt, DSSR20 and BP. With this setup I only need to unplug the cable from the socket! Easy...
Frank
I used EBC-A20 to top up cluster 7...