chasing microohms
Added 2025-06-12 01:16:23 +0000 UTCI awoke the log splitter switch from its slumber today to plan out its upgrades. I used this for the 100 car battery project, and although it had its quirks, it reliably switched the bank without adding much in the way of additional resistance. In fact, its resistance when firing was far less than 0.001 ohms!
The 400 car battery project is going to require much bigger switch contacts. For one, the higher currents will wear them down faster, but I also need to have more space to attach cables. Cable lengths will also be longer with this bank since it will be much bigger, so this means I need thicker cables or at least more cables in parallel to prevent adding much in the way of cable resistance. This all adds up to enormous switch contacts, maybe 50 pounds or more a piece!
The amount of copper needed for this project is incredible. The copper alone will cost more than nearly any other project I've made on my channel. It's quite heavy to move around too, but of course, it's nowhere near the 14 tons of batteries I'll be moving around. I'm in for a good workout!
Stay tuned!
Comments
the switch does melt! the first switch was not properly aligned and initially made contact along a line, and it surprisingly made little difference to circuit resistance. the only issue this causes is a slow turn on. the first contact points explode, but the spring mechanism forces the plates closer together and any unevenness just melts through. even though the main contact points are molten during firing, the log splitter mechanism had no issue ripping them back apart afterwards. of course i could run into issues with more current though. on a similar note, the copper "work" blocks were very tattered after doing so many runs, and anything i'd stick on there near the end would only make contact at a few small points. once again, those points would just vaporize, and the spring mechanism would push them closer allowing larger liquid contacts of very low resistance.
styropyro
2025-06-17 16:17:40 +0000 UTCI have no idea how you can switch such high current without the switch melting. You would need that the whole contact face closes simultaneously. If it is only a little off, the first spot of the contact closing will put all current through there for a millisecond before all the rest is contacting. Is that a problem or not?
Gunstick
2025-06-17 14:56:56 +0000 UTC4/0! there are bigger wire sizes but 4/0 seems to be the best price per ampacity, so i'll be running a bunch of 4/0 cables in parallel
styropyro
2025-06-14 17:03:36 +0000 UTCWhat awg are you using for the cables?
Dayton Casey
2025-06-12 09:44:01 +0000 UTCImagine the gains from moving them all
noinamg
2025-06-12 01:54:18 +0000 UTC
