Recent content by 67carguy

BobBob said: Interesting. I'm ashamed that I did not think about running slower gate drive. 1uS is considered crazy slow in the world of switching power supplies, but I guess it insures that as the FET's start conducting, and the first few FETs start to conduct, they should operate as...

Ridethelightning: I saw they are still selling the massive FET switch. I can't quite read the part number on the FETs, do you know what FETs they're using? I'm so tempted to just order one, but they're using TO220 FETs, and I couldn't find any with really high peak current rating. It depends...

Tommy L: Well that's encouraging! Only 60 joules... I'm hoping I can keep the peak current around the same and just extend the time a bit to be able to weld a .15mm copper/.15mm nickel. just curious: Why so thick on the nickel? Was it simply availability or did you need to go that thick...

BobBob: I hadn't thought about a pneumatic Z axis but that would be a great way to get a controlled force. I was thinking of a spring-loaded head and a stepper type actuator. Fuyu Motion seems to have some nice stuff. All aluminum, seems well made. I just sent them an email. They even sell...

As BobBob states: Yes, I couldn't agree more. 112 x 40 = 4480 cells. probably north of 50,000 welds before it's done. So my thought process on that goes something like this: kWeld for all cell welding. Possible modified kWeld to do copper-copper end "plate" welds with tungsten electrodes...

yes, sorry if this is temporarily hijacking the thread. BobBob: Very interesting idea with machine screws in the middle of the plates. Took me a while to figure out why the screws don't short out the cells! You would want to use an INSULATED allen wrench of course.... I played around with...

So I've spent a week looking at this from many different angles. The spice model of the plate got me thinking. Then I estimated the cost of the plates, and their weight. All of a sudden my beautiful symmetrical single cell (40P) system doesn't look so great. The cost of the copper plates...

Update: I did a somewhat crude model in LTSpice of my 38P (now 40P for a square array) cell block with a 1200A load. I used measured resistance of nickel foil strips (using 4W milliohmeter) and then scaled and factored it up to 1.5mm copper plate (.060") I used a square array of 26650 cells 4...

[img][img] Wow.... at lot of great discussion. I too would like to express my thanks to the group for all the very constructive and thought-provoking inputs. As far as my own selfish interests: I'm building a car, I have to figure out how to package 112S x 38P = 4256 cells in the car...

I saw that thread, and it was very interesting. I have a few concerns though. I have not tried it yet, I'll need my kWelder to come in first. But from what I understand, the nickel melts right through the copper to form a weld with the cell. I don't know if anyone has done any detailed...

Hmmm... I was afraid it might be tough. I'm wondering if maybe I need a completely different setup to laminate the .15mm nickel to the 2mm copper. Actually, I've been so focused on the cell welding I'm forgetting this step does not involve the cells. Maybe I use more standard spot welding...

That's exactly my thought: There are people who have managed to weld THIN copper to a battery cell BUT: my fear is whether I can do tens of thousands of welds without burning through a cell bottom. Or after 4 hours of continuous welding I get delirious and don't notice I'm running a bit hot...

I'm on Long Island (NY) and we have a lot of local shops that would do this sort of work. With 224 plates I'm hoping for a quantity discount! It'll be a while before I have a final design that I can have quoted but I'll post them when I do. I ordered my kWelder tonight, and some nickel sheets...

Interesting, I didn’t realize they made a “manual” square punch. My assumption is that since I need 112x2=224 plates it will make sense to go out to a local shop and have them made to order on a punch press or a laser cutter. Of course I may go into shock when I see the price....

Disclaimer: Not sure what connectors they use, and not sure of your definition of weatherproof, but.... I have successfully used Silicone grease in connectors "under the hood" in an engine compartment. You can use regular grease, but it has a tendency to dry out and get thick and hard over...