Of course, I should have realized this.
I’ve seen several large box style packs use the wide nickel for both series and parallel, such as in this recent build by Al:
Not trying to call out his work, just trying to understand what’s going on. I can see that it’s doubled up, but is the length of the strips what makes this work? Can you estimate the carrying capacity?
40V 25A AC -> DC should do it when doing high power charging though need to make sure all the connectors and wires can carry the current without roasting. Recently saw article about my old dorm for the year I went to purdue had a small dorm fire from an esk8. Pretty sure the whole place was cinder blocks and tile so pretty hard to burn down but apparently they roasted the room and bad news for esk8. Was 1am so guessing was charging, be careful if trying to “fast charge” things.
It’s because the current is flowing across the nickel, not along it. Those look like p42a 21700 cells, stacked 7 wide. That means that nickel strip is a little less than 147mm long, let’s say 135. 135mm x 0.2mm = 27mm2.
Remember my estimate of 10awg copper equivalent was 24mm2 of nickel.
Math is fun 
Indeed! Especially now that our elementary school math teacher’s worst nightmare has come true and we DO in fact always have a calculator in our pockets!
What’s the difference?
The nickel is longer in one direction than the other.
Compare the usual “wide nickel” series method to the “narrow nickel” series method. See how much more area there is?
Sure, you could use like 5 pieces in the second arrangement, but what’s the point? More work for an uglier result.
Ohhh okay I see. Thanks for the explanation!
is your trampa 8s?
Output Voltage: 0-37V
LiFe/Lilon/LiPo/LiHv (1-8S)
cause otherwise that thing doesn’t work for you.
Backlash looking good or? 
I’d go for a little less. That comes from gears in general, not gear drives specifically though.
I run two 6s 20 ah lipos in series. I currently use a 10a 6s charger w duel output but I think it only does 5a under duel load. If I drain the batteries completely it takes 4 2hr cycles to bring them back to full
right split charging. lipos. makes sense. pardon my myopic unsplit lion pack thinking. 
why multiple cycles? shouldn’t the charger finish the job in one cycle?
oh. my charger has a “safety timer” to avoid accidentally over charging. is that something you can set longer?
but either way sounds like 8 hours so… bleh.
if it was pulling off 5 amps I’d expect that to be closer to 6 hours. ( lame estimate 20ah/5 * 1.5 for tail end charge. ). hmm.
What charger do you have with a safety timer?
Does anyone know what happens here?
It sounds like a belt issue? Do you have video?
True, the only reason is that wide nickel is like an ali exclusive and sometimes people don’t wanna wait
