They appear to be a little hot, you might be able to reduce the pulse time a little bit (note that the lower the voltage of the welder the longer you need the pulse if you’re using a battery operated setup). But as long as they pass the pull test they are okay, if you want to have slightly better robustness try to stagger the welds because the positive electrode is weaker
Zach, great pearls of wisdom here. I was using a 12V 640CCA battery, so higher voltage than many of the spot welding setups that are used. Alternating electrode placement for welds is a great suggestion I had not thought of. I was changing electrode placement from left to right hands, but purely to keep the wear on the welding tips somewhat consistent. I did not alternate them every weld which I will do in the future.
XT90s loop keys are both the most reliable and cheapest way to safely disconnect a battery, realistically you do not need a fuse
+1 on the loopkey. They’re cheap, reliable amd easy to make. I put mine in the circuit where your 150 amp fuse currently is.
Thank you Zach and Common, I think this is the route I am going to go, remove the fuse and replace with an XT90 loop key. It will accomplish my battery isolation goal while it is unattended and remove the failure point during use.
Molicel’s stated life of ~500 cycles is given at 4.2A charging current per cell, and the data sheet also allows for up to 8.4A. So while 4A could be perfectly fine for speed and probably slightly better for cell life I’d personally go a bit higher to get as much range as possible in an hour or two of charging
Mr. Shiteside, This is something I am considering as well as I have not yet ordered my charger. The longer charge times do not bother me much as I typically only charge once a day when I get home, so I have a solid 6 hours before bed where it can be charged while watched. The utility of a faster charger is certainly there, just not sure if I really need it, and if I can get a little bit better pack life, then all the better.
This is not really correct. Mooch has performed testing on these cells and rated them at more like 25 - 30A continuous for best performance. You can read more about the nuances of p42a here → Molicel P42A cell discussion
Hi Glyphiks, This is great info, thanks. I am not really that much of a speed demon on boards, my main goal for this board is to be able to go up a 20% incline at 20mph and have a long range which I think is doable far under 90A of draw. I can go up the same inclines at 13mph with 950W of hub motor power, so even 40A total draw is double that. I will definitely be keeping an eye on voltage sag to determine if I should decrease the current draw.