I have a complete knowledge and understanding of the difference between connecting battery cells in parallel, series or a combination of series parallel. And just so you know, I have spot welded many 18650 cells together successfully with nickle strips. I was not asking how to configure a battery, I was asking what was the best way to configure the cells into the cell holder that I had, didn't anyone see the picture I posted with my request for help, that is what I was talking about. Many thanks to those who posted helpful, courteous replies.
Thank you for your reply, I have about six months experience spot welding cells together , which probably isn't very long in the scheme of things, but I am confident enough to 'go there'. I understand that there may be serious implications if 18650 lithium ion cell battery packs are not assembled or treated with care. And I acknowledge your concern when it comes to welding equipment, I have to admit that I did build my spot welder myself but it has worked flawlessly since I adjusted the duty cycle timing.
Hi, Thanks for your reply. I fully understand the relationship between cells in series and cells in parallel, or a combination of the two. My cell holder is of an irregular shape and I just need to know the best way to create a 13s 7p battery pack with the cell holder I had. (see picture). I was ok with the first few cell groups but things became more awkward towards completing the pack.
It wouldn't surprise me if some people considered me a novice, as I've only been building batteries for about 6 months now. The spot welder I used was one I built myself out of microwave oven parts and a few additional components from amazon and ebay.
Thank you so very much for what appears to be the solution to my problem. This is exactly what I've been looking for. I have tried so many different cell combinations myself without being totally satisfied with the layout.My that does look complicated. I don't know whether this large image is in any way helpful.
Thank you for the prompt reply. I found the information you supplied very useful.
Hi, I put together these drawings on my computer to illustrate how I plan to spot weld the cell groups together based on the photo John Jones posted recently on this forum. I would be grateful for your comments. Hopefully I haven't made any mistakes. Any improvements or corrections to my battery pack would be welcome. If all is well then I will put together a graphic for the BMS wiring as well.
I am aware that there are a lot of fake, sub-standard batteries out there, it is a minefield. I will be checking the cell capacities over the next couple of days.
Your advice is greatly appreciated. The batteries I have were all bought from the same supplier at the same time from Ebay. I cannot guarantee the batteries came from the same factory but they all look identical. The battery packs had good reviews. And the voltages of the cells are within .01v and .02v of a volt of one another. 94 of the 100 cells are exactly the same voltage to two decimal places, I only need 91 for my 13s 7p battery pack. I will be doing a capacity check on twenty of the cells at random with my Imax B6's, one is genuine, the other is a clone. I also will be checking with a ZB2L3 module as well. I have fifteen of those.
I saw that you have now coloured both positive and negative ends of the cells and added the welding strips, it's very clear that you take great care. Congrats.
Thank you, I know that 18650's can be extremely volatile if not treated correctly.
