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Originally Posted by EVmetro
I confess to having an unusual drive to seek out ultimate efficiency and perfection when I build an EV
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My compliments on your drive and determination to achieve the best results that you can.
I see that you avoid doing what the off-the-shelf dies do - crimping uniformly around the lug, with a hex or octagon shape. You best results are from leaving the lug round on the 'bottom side' and only crimping the 'top' .. right?
For those of us with cheap chinese crimpers .. where the dies are removable and would be quite easy to change out .. do you have a sketch or drawings of your 'best-so-far' profile that you are willing to share?
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Without the proper instrumentation, it is not possible to study and record the resistance of every single connection real time,and being able to do this has really taught me the difference between a nice connection and the best connection.
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I would argue that there are many things that are not noticed unless you have spent a lot of time and effort to measure them well. But you have to be willing to invest the time and $$$.
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There are efficiency gains to be had with ultimate connections, even if they are not much. The other thing that is important about the integrity of a connection is how well it holds up over time. I have noticed that if I monitor my highest resistance connection over time, the resistance of that connection begins to get even higher faster than the resistance of my other connections. The better the connection, the longer it will last.
In the case of connections in my latest build, My controller is in communication with my BMS via canbus, and is programmed to derate my throttle as needed to prevent any one battery from dropping below whatever minimum voltage I program in. If there is a connection that has more resistance, it is calculated as a voltage drop, and my BMS will identify a lower voltage on that one battery and cut back my throttle to protect the battery. The battery is fine, but the higher resistance will effect the voltage reading. What this means is that I get less voltage sag and delta, and more throttle if my connections are perfect.
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Have you posted details on this BMS yet? I think I've read through all of your posts and I don't remember ... or was this a custom job?