Recent content by GalFisk

Also, when you do have a regen brake, the numbers pan out differently. If it's set up correctly, it'll start regenerating before the mechanical brakes engage, so all the brake energy goes to regen when you brake gently, and the mechanical brakes only engage at all when you brake heavily.

That looks neat. .2mm is probably overkill though. I used .1mm on the cells and .15mm for interconnects. I only used .15mm where I could solder it, as it didn't weld well with my capacitor welder. With .1mm I had no worries about the energy deposited into the cell when welding. Edit: I also used...

Looking good. Maybe I'll try lanthanated W when my current stick runs out. Do you know why that one was recommended? Did you have any issues with using it? My only issue (after increasing the clamping force on the electrodes) is copper sometimes sticking to the probes and having to be ground...

I can happily report that my build (20s17p battery for a 3kW EU moped) is now complete, and that the common port BMS handles regen without any issue at all. The only annoying thing is that the event log of this smart BMS fills up with "charging" events for every time I brake. Edit: if you want...

I'm using 1.6mm diameter sticks, and I found that when I shortened the electrodes and increased the clamping force, I could go from a 41 ms to a 1.5ms welding pulse. Before, there were shims around the electrodes, and tightening the screws squeezed the shims more than the electrodes. Without the...

I've had quite good results now with the tungsten electrode+0.1mm copper foil, though it took some experimentation and tweaking. I'm using a pure tungsten TIG stick. Which is quite brittle, but can be cut and polished with a Dremel cutoff wheel without cracking. Here's the beginning of the...

It has a common port for power and charging, so it should be able to treat the regen voltage as a regular charging input, provided the regen current doesn't exceed the max charging current. That's my guess; I've not tested this myself yet. I'll try it in my next build.

The ?? wires are probably for an NTC thermistor or a high temp cutoff. If they're shorted, it's a cutoff.

Here are a couple of rows of test welds on some junk cells using 1.6mm pure tungsten TIG stick probes. The offset welds on the lower row are just an artefact of sloppy cutting of the test ribbons. The upper row of welds is on the positive pole. Edit: my inspiration for trying tungsten came from...

I used both at the same time; 0.13mm nickel-plated steel on top of 0.1mm copper to be precise. I tried infinite and non-infinite slots in only the copper, only the nickel, and both. I got good welds sometimes, but not consistently, on used cells with some nickel remnants. The best welds were...

I never could get the sandwich method working reliably with my capacitor-based spot welder and copper electrodes. I suspect that this welder is a bit anemic, because even at the highest pulse lengths and infinite slots in both the copper and the nickel-plated steel, the copper just didn't stick...

Conducting heat out safely is probably easier than getting air in safely. If you want a meaningful amount of air to enter through a filter, you need a pretty beefy fan. Think vacuum cleaner territory. And you still need to keep moisture from condensing inside. Oil immersion cooling would...

For SLA, you can do without a BMS, and connect the charger directly to the batteries. They're less explody and can handle overcharging. Those and up-front costs are pretty much the only advantages of SLA. Converting to Li-ion would give you more range AND less weight. I've done several...

Switching between packs is the easiest. Paralleling packs with the same voltage using diodes comes next. You can also diode parallel packs with different voltages, as long as you accept that one will drain before the other, each one has a low voltage cutoff, they're charged separately, the load...

They're tiny bimetal clickers (which should make them as mechanically distinct as microswitches or tactile pushbuttons) with a guaranteed max contact resistance after 10k clicks. I'll put all of them (NC contacts) in series and connect them to the on/off input of the BMS. If any thermostat trips...