John in CR wrote:My question is why cut the factory tab connections at all? In the example above with VT cells you've taken 1p5s and cut the factory tabs and made 10 new solder connections to make them 5p1s, but for what purpose? 1s certainly isn't useful, except maybe as a battery for a LED light, so those 5p1s blocks need to be connected with others in series to be a useful pack. Breaking up a perfectly matched 5s pack seems like a waste to me, and it multiplies the amount of work by about 10X.
eg Lets say you have 10 of those 1p5s packs and want a 5p10s pack (37V6ah), then after just 5 simple tab on tab solder connections to connect pairs of packs in series, you're ready to attach your leads or bus bars to the five 1p10s strings. The other way will require 100 solder connections for the same 5p10s pack. Call me lazy but I'd much rather make 5 easy tab on tab solder joints than 100 solder joints, one at each end of each battery. Plus I see our biggest risk during DIY battery construction as being the heat risk of making solder connections to the batteries, and disturbing the time proven factory tab weld construction is asking for trouble in addition to creating lots of work.
John.. I know it might appear a strange decision, but let me explain:
The original nickel link are too wide compare to the diameter of the cell. and that will create a DANGEROUS short possibility to thecell next to it. in fact, the large nickel link will touch the green plastic shin of the next cell and fo rthe negative tab, there is no worrie, but fo rthe positive tab, WE MUST BE CAREFULL
Plus when you solder the nickel sheet link, it will melt the green plastic that is touching and will short to the negative shell of the cell that is VERY close to the positive tab!!
that'S why i preffer recommanding my method.
Byt, by usig my method oc cell assembly i never had any problem after 7000km if hard ebike ride and alot of vibration over 432 cells ASSEMBLED BY THIS WAY
yes... 432 cells so it's 861 connections....
These really thin nickel link are very SHARP and i found that on the positive tab, when you put many cell together i parallel , these sharp edges can puncture really easy the green skin of the cell next to it.
By doing the methode above, you also add a kind of soft interface from teh cell to teh bus bar and it help absorbing vibrations. The dual plied side of the nickel link act like a little spring.
I already had some issue reported by some Makita pack buyers that did not pay attention to that ( eventhoug i always ensure that people that buy teh cells will HAVE the skill and knowledge to assemble their pack) and they had some short at this exact place.
You MUSt pay attention to that ! when assembling your pack!!