WARNING! The following article is from a tinkerer who can't do anything the easy way. The information provided is based on many assumptions and should not be followed too closely without your own research and testing. DO YOUR RESEARCH, TAKE PLENTY OF PRECAUTIONS , HAVE A PLAN, ALWAYS ERR ON THE SIDE OF SAFETY. Any injury, critical malfunctions, explosions and death due to following elements of details or procedure contained in these articles are at the risk of anyone reading these article and attempting to follow this information without a reasonable amount of knowledge in constructing Lithium Ion batteries and a strong knowledge of electricity is doing so at your own risk! Constructing large Lithium packs require an understanding and respecting of the dangers as well taking plenty amounts of precautions in constructing even a small pack. Do not attempt constructing any type of battery packs without proper prior instruction or training and again, having basic electrical knowledge, properly layout the pack plans are important. This is a project that I am researching and the total amount of equipment I own would make this worth trying. The actual expense if one were to start from scratch would out strip the amount in savings that is listed in my blogs. The information within these blogs are starting points for what is required to construct a battery pack and does not have all the answers, such as, technical details of voltage drop issues, internal resistance considerations, charging methods or structural techniques and so on. Those details depend on the application of the battery pack and exceed the scope of these articles.
XT60 plug... that took some practice to get a real good solder going, I had to use over 475 degrees Fahrenheit / 246 Celsius and 60/40 solder as the lead free stuff didn't take at all. The 12 gauge wire was tricky to squeeze into the lug end to solder. When I finished, I had a neat looking wire and it failed while testing it for routing and position. The pack to BMS requires a 90 degree bend and the distance was less than 50mm from pack to socket, but now, the total run of wire from the source contact to plug for the positive increases from about 55mm to 130mm, and the negative goes from a long 205mm to about 140mm. Does is matter will be the question later during the load test.
Seems the lug was not adhering to the solder at all and chances it needed a good cleaning... acetone to something...I do know the flux works good. The third try was a quick strip of the silicone sheath and a twist of the strands and then stuff into the lug with no buttering of either. The 500 degree solder was on top the wire strand bundles and lug at one corner and I kept on feeding the solder into the whole thing until I could see it leak out the edges. The third plug was complete and the test seems to show it will not separate as the second one did or not so quickly.
The high power output wires takes a paths up the side of cell 15 or 1 depending on how I should count. Along the side of the cell, but running along the bottom of the module is the positive wire and the negative towards the lid side of the module. Either way I should start and end the cell taps for the both wire in the optimal direction to reduce strain.
I designed a fitted fish paper protector for the high power wires and it will be the base for the separator for the upper and lower group. At 285mm by 21mm for the main section and maybe an extra layer in the middle at 150mm by 21mm.
Nearing the final plans, the included BMS taps are located and worth noting that the tap should lean towards the negative end of the cell in case of trauma to the outer cover, the direction of the cells are noted and follow the pinout chart from "The Board Garage" and the indication of all the connector strips are marked. Should the next thing to plan is build some jigs?
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