←back to thread

Glubux's Powerwall (2016)

(secondlifestorage.com)
388 points bentobean | 2 comments | | HN request time: 0.604s | source
Show context
ianferrel ◴[] No.43549073[source]

>the solution came with rearranging and adjusting the cells to ensure the packs worked more efficiently.

>Glubux even began disassembling entire laptop batteries, removing individual cells and organizing them into custom racks. This task, which likely required a great deal of manual labor and technical knowledge, was key to making the system work effectively and sustainably.

This kind of thing is cool as a passion project, but it really just highlights how efficient the modern supply chain is. If you have the skills of a professional electrician, you too can spend hundreds of hours building a home battery system you could just buy for $20k, but is less reliable.

replies(6): >>43549197 #>>43549208 #>>43550703 #>>43551134 #>>43551753 #>>43562271 #
supportengineer ◴[] No.43549197[source]

There HAS to be a way to automate this process and make it work at scale.

replies(11): >>43549383 #>>43549397 #>>43549447 #>>43549497 #>>43549521 #>>43549609 #>>43549625 #>>43549952 #>>43550129 #>>43550429 #>>43551649 #
joshvm ◴[] No.43549397[source]

You would be amazed how many battery packs are multiple 18650s in a trenchcoat. Even EV battery packs use them. Though it does raise the question - wouldn't an old EV battery be a better solution than stripping apart laptops?

replies(6): >>43549465 #>>43549535 #>>43549883 #>>43550510 #>>43550616 #>>43550707 #
0_____0 ◴[] No.43549883[source]

There's a lot that goes into manufacturing battery packs beyond the cells. How's your thermal path to ambient in your home wall battery? How is the inter-cell thermal isolation? Is there a path for gas discharge in the event of a cell failure? Is the pack appropriately fused at the cell or module level? When a cell fails, does it take the whole pack with it, catch someone's apartment building on fire and kill a family of 5, or merely become stinky with a hotspot visible on IR?

How good is your cell acceptance testing? Do you do X-ray inspection for defects, do ESR vs cycle and potentially destructive testing on a sample of each lot? When a module fails health checks in the field, will you know which customers to proactively contact, and which vendor to reassess?

Yeah lots of batteries are 18650/26650 in a trenchcoat. The trenchcoats run the gamut from "good, fine" to "you will die of smoke inhalation and have a closed casket" in quality and I think that bears mentioning.

replies(2): >>43550211 #>>43550821 #
ericd ◴[] No.43550821[source]

Where would you put this battery in that trenchcoat gamut? Inside a server rack, fwiw. https://signaturesolar.com/eg4-lifepower4-v2-lithium-battery...

Was definitely one of the harder parts of our solar install to get comfortable with.

replies(2): >>43551988 #>>43552493 #
1. Shog9 ◴[] No.43551988[source]

Bigger, fewer, more chill cells, fairly robust trenchcoat.

(IIRC, these packs are 16 100ah LiFePO4 cells in a steel case w/ built-in fuse, breaker, and BMS that monitors individual cell health and pack temperature, w/ automatic cut-off if any of that goes out of spec. The weakness is primarily the MOSFETs on the BMS potentially failing shorted. Fortunately, they've added some sort of additional fire suppression beyond just "steel case" in recent-ish versions of these packs)

replies(1): >>43553707 #
2. ericd ◴[] No.43553707[source]

Ah yeah, unfortunately I think we have the version before they added fire suppression, but at least it’s a more relaxed chemistry. Thanks for the analysis!