diy solar

diy solar

Short Circuited my 48V 120Ah Build (I'm fine)

Yep-- If the fuse isn't in the loop of the short it can't blow ---This thread has me thinking about Fussing both pole + and -
If you short across one cell you're SOL
 
His fuse is rated 2700A IR. It would have blown, all right (if completed short circuit had gone through it), but it might have blown up.
 
Is that because his short was outside of the battery?
Also, sould the fuse blow if terminals within the battery are shorted?
I shorted the busbar from one cell to another cell busbar and my fuse didn't blow. The fuse was on positive terminal of the cell next to the one I shorted.

The short in question was external to the pack, and thus would have blown the fuse. If you short the pack internally an external fuse won't be in the load path.

Fusing mid pack is sometimes done on larger packs, 48V would be low, but not unheard of for this practice. Generally speaking properly protecting the terminals is a better approach than adding fuses at random. Fusing won't protect against shorting both terminals of the same cell.

Using properly insulated tools is also important when working on a pack. Random fuses aren't a solution to that problem either.
 
The short in question was external to the pack, and thus would have blown the fuse. If you short the pack internally an external fuse won't be in the load path.

Fusing mid pack is sometimes done on larger packs, 48V would be low, but not unheard of for this practice. Generally speaking properly protecting the terminals is a better approach than adding fuses at random. Fusing won't protect against shorting both terminals of the same cell.

Using properly insulated tools is also important when working on a pack. Random fuses aren't a solution to that problem either.
Thanks for the reply. I assumed what you say is true but it is good to have verification.
I did insulate all tools I pass over the battery. Those are a small ratchet with 10mm socket, torque wrench and another wrench I use to hold the backside nuts on my fixture rods.
 
Argh - the saga continues - XUBA only have CATL 120Ah cells and not the Higee that I have and cannot provide a spec sheet for the CATL brand - they only provided the exterior dimensions which are within 1mm of my Higee cells. Will wait until the Higee cells are back in stock with them or try and find another seller with Higee cells.
 
Since you are going series only, you could use the CATL cells without much issue I think? Can them meet your current needs?

They couldn't provide a data/spec sheet for the CATL cells, so all I could go off was a google search of the CATL cells which appears to show the same specs - I mainly need the higher discharge rates and both were 240A continuous and 360A for 30s and the spec sheet via google showed that. Impedence for the Higee was <=0.3 while it was <=0.4 for the CATL which I assume would not make a difference.
 
Two quick points ..

  1. Careful about using gloves - if they're not designed for these situations (most aren't), you'll melt rubber/whatever right into your skin if something goes wrong
  2. One reason to fuse a pack in the middle is it breaks the pack in half such that the maximum potential is now half of what it used to be (further reducing risk in places the fuse can't protect)
 
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