I’ve posted some photos on this thread a while back
Basically the plan is to draw up to a 100A
In theory the battery should be able to handle it.
I Don’t really understand how your answer Corelates to my question.
Lots of solder joints
And I’m a bit scared to test out the xt90 since I crammed 4 15avg cables in both sides so If there could be a fault it’s most likely there.
Again, I’m looking for methods to safely test
I understand the concept but how does that help me?
It doesn’t, but you gave us nothing to work with, write down everything you used to make the battery and take pictures of the configuration and all the connections
But no there isn’t a good way to test a pack to get a definitive answer, the best test would be hook it up to a load and monitor the voltage across the cells and pack as a function of ampacity, and watch the whole pack with an infrared camera. If the pack gets hot then you’re running it to hard
Instructions unclear, dick stuck in fan
Seriously though, bench testing isn’t done around here much for packs. Which is why so much effort goes into the prep work. That’s a llt smart bms? Did you get any of the thermal sensors into the pack? If you’re worried about it - monitoring it is the best way. Hit it with a multimeter and check all the voltages and make sure it’s all nominal then send it. Take a few short easy test runs and check on voltages and temp sensors them give it a look and see if you need another bit of fish paper or some silicone.
What are the specs? Couldn’t find them in the link but im kinda slow sometimes. Did you take any build pics? Unsolicited advice: write the specs on the battery and the cells you used and the date, you’ll thank yourself later if you need to track down that info and it also lets you look back and see how it performed - if capacity drops off harder than it should or something else happens you’ll have a reference for improvements.
Everyone on here is trying to help, and im no expert - I don’t see alot of engagement on the previous post you made either so I wanted to try and help you out. Communicating via text requires extra clarity and over explanation or it could send you in the wrong direction with bad advice. And show off your shit - 100a pack is cool a fuck - tell us how and why man throw me a bone 
btw I can’t quite see how you made your wiring harness, do you have a pic that shows how it’s all connected? What did you weld it with?
Less test, more prep and send it
Edit: was digging in you post history, is this the 4p 30q pack you were working on? Seems ok by spec and execution. Send it and keep a close eye on the bms
This is what I was looking for.
Thanks man!
I made some pics, I don’t want to photo dump here so I’ll upload it and link the thread.
Actually a 12s4p P42A pack
Unfortunately I haven’t really photographed the progress but all welds and solders are about the same consistency, same looks.
This is the thread containing all the pics i have
RIP serviceability 
It’s the tradeoff haha streets are really shitty and I use it every day to go to work, rather trade the serviceability against being sure nothing vibrates and rubs
New battery pack, not been charged. Has been on a loop key since assembly. I went to charge it last night for a maiden run today but the charger light didnt go red nor did the fan start up like it usually does. Charger still works and charges a different deck.
I thought id neglected to plug in the charge cable so i took it apart today to correct and found that it was connected > headed to the app and discovered this…
rip. two cells dying at once is pretty bad luck
Oooooffffffff
Seems highly unlikely to me that they are actually dead.
I’d be tipping there is something wrong with the balance wires.
There is always hope. 
Hey guys!
Could someone point me in the right direction? How do you calculate current density for the S connections? Maybe some working examples?
Its straight forward with this one:
each cable carries the current of two cells, all parts of the nickel only carry current from one cell.
Dont mess up the soldering and its perfect.
On the other hand:
This way, to my knowledge, you have to take into account that the current density is going to be higher so if the diameter of the solder cant support it, it might create hotspots.
How do you calculate the optimal current flow with a big sheet of nickel, how do you spread out the series connections?
I think this is not specific enough. Maybe I’m missing something, but there must be more
You are overthinking, and asking a bit too scientific questions that don’t need to be answered for if you are making a battery for yourself or someone else, if the goal of this post is to know how much nickel you need for a series connection you went too deep, on the other side if you’re really interested about where the current flows and how good luck finding your answer.
Anyways for a series connection 30mmx0.2nickel should be plenty because the current is only travelling about 1.5cm and on that short distance the ampacity of anything is quite large
U can calculate current density based on the amount of paths and resistance. 100 amps going thru two parallel paths is going to split evenly so be 50 each unless the resistance between the paths vary. With multiple paths if one has more resistance it will also heat up more increasing it’s resistance changing the ratio and reducing current through that path
Looks good. No notes.
There’s no way way to calculate the current density other than to divide the estimated current by the number of series connections and then decide if the current level per connection is too high or not. This assumes the resistance of the series connections (including the soldered joints) are about the same.
We have no data or guidance for making that decision though other than the gauge of the nickel and wire at those connection points.
But IMO, it’s mostly common sense. A wire that can easily support 50A probably won’t result in an excessive temperature rise (or power loss) in its series connection when 50A is flowing. This is due to the lack of heating of the joint by the wire and the ability of the wire to sink heat from the nickel if it’s sized properly.
So, optimal current flow? As low a current level per series connection as you’re willing to go based on your preferences/priorities for temperature rise and power losses. More series connections = lower power losses = more better. But more series connections = more work, higher cost, more weight = more bad.
Find the balance that works for you.
As for the physical location of each connection, spread them out fairly equally unless you have some sort of offset of the spot weld points. It’s not critical unless you have huge spikes of current that would result in high power losses without optimizing the placement.
