spinningmagnets said:
Current status is...trying to find the "swift code" so I can wire transfer money to Mahindra bank in Mumbai. I will encourage them to open an account in a US based bank to simplify wholesale business to dealers...
I'm very keen to know the price per cell the end user will have to pay .... I have been using the standard black holders which work out at 9c/cell but this is unacceptably high ... some big powewallers have spent many hundred $ s on these ... there's no need for any of this !!
My aim is to develop the ultimate system , no holders , no busbar , spot welded , it's a work in progress , it will be quiet similar to the way some build their bike batteries ....
I suspect the price of nishi's system will be over a dollar per cell ... ridiculously expensive an inappropriate for powerwallers , even for bikers these holders make the battery bulky and heaviercompared to what is now standard , a big consideration.
spinningmagnets said:
Current status is...trying to find the "swift code" so I can wire transfer money to Mahindra bank in Mumbai. I will encourage them to open an account in a US based bank to simplify wholesale business to dealers...
As to fusing. I realize this forum has evolved from "DIY powerwalls" into "Second life storage", which emphasizes its most often discussed subject of repurposing affordable used cells that still have quite a bit of life left in them. When it comes to used cells, I strongly agree that fuses are very important. I would like to repeat my research that indicates...soldering a thin wire from a fuse onto the positive end of an 18650 cell is the most appropriate style. between the two ends, the negative is clearly the most sensitive to heat-damage. In fact, soldering onto the negative end might be a contributing factor in cells going bad.
So...how to connect onto the negative end? Spot-welding clearly works, but it makes replacing a cell that has gone bad, into a somewhat annoying task. For a low-amp connection, I believe a pressure-contact is adequate and desirable. If one cell in a 20P group has "gone the way of the buffalo", then the remaining 19 cells will still do fine while providing 1/19th more amps each, compared to before. You notice the fuse is fried, and you replace the bad cell with a newer one. The negative is a pressure-contact, and the positive is a soldered fuse-wire.
I'm not saying that this is the best idea for me, or even a good idea for anyone. I'm just saying it might be worth experimenting with, yes? Plus...with all the smart builders here, why can't we design a pressure contact for the positive end that incorporates a replaceable fuse? How hard can that be?
Many illogical statements in that post ... you have assumed used cells are more dangerous and so should be fused . but a pack build with new cells , after hundreds of cycles is composed of used cells , does this represent a danger ....
The danger with these cells is when they are punctured or crushed , a fuse will not help this ... I believe tesla started all this nonsense because of the pressure they were under from lawsuits , in bad accidents crushed cells caught fire ...what could they do .... NOTHING ... but they had to APPEAR to do something .. they know the public understands fuses keeps things safe , so they spent 1c per cell putting in fuses and told the public problem solved ... 2 years latter nothing is solved , the fires still continue , in very rare severe crashes ...
You also assumed if a cell goes bad it will blow the fuse , it won't , just slow discharge all cells in parallel the fuse stays intact ....
Millions of bike users and others have been using unfused cells at very high drain rates for many years with no trouble and these batteries all contain "old and used "cells after 300 cycles.