Use insulated tools, double heat shrink works wonders for spanner’s etc. When not wrenching on the battery pack, cover the top with a sheet of hard plastic or thin hardboard or other insulating materials.
Nothing less expensive than that.
Groetnis
Yes. But I was more thinking about if you do this twice, and end up with different drops. A single one might not make that much difference.
It feels like this would contribute badly to “internal resistance” inside the battery, but I’m not basing if off of anything concrete.
I don’t have a feel either. But I suppose if a 2p MCB like in my pic is used there is access to the midpoint, so the volt drop can be shared between cell 8 and 9.
Yeah, this is probably the correct answer. Using fuses and MCBs inside-inside the battery feels like using technology to solve a social problem 
It is unconventional, I grant you that. However, I do disagree that technology should not be used to attempt to make things foolproof. ( Bloody foolproof is harder).
Reverse polarity protection for example? Who does everything right always?
Duct tape if you cheapskate like me, also works if you dont have the correct heatshrink or electrical insulation tape 
Groetnis
People kept asking me why those expensive BYD packs, this is why:
They are fully enclosed
The output terminals are fully enclosed even when not connected
They have internal contactors that disconnect the DC side and isolate them completely
They are modular and foolproof to assemble as there is only one way to go together.
Groetnis
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I taped up my torque wrench, but in order to make it still adjustable I still had to expose metal.
But, you can buy the 1000V fully insulated version for the cheap price of:
I think they are just isolated from the outside world.
If there was an internal short between cell 6 and cell 12 there would be sparks and no protection to clear the fault.
As long as the socket itself on the outside is insulated and the extension, if used, plus the handle tube of the normal torque wrench, it should be fine. The click head can be exposed, as it’s a single contact point. Normally if the wrench falls down, the socket has to get off the nut/bolt and if the outside is insulated, you should be ok.
Groetnis
The cells inside the module box is normally inaccessible, so that failure mode would be very unlikely. For me, should such occur, empty the CO2 after hitting the disconnects if I am around, then close the door and monitor or phone the fire brigade and the insurer…
Groetnis
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To a large extent, each one of us has to go through all the potential failure modes, decide on their probabilities and protect, prevent or eliminate them if possible.
Groetnis
I haven’t got it to hand at the moment, but I distinctly recall there was exposed metal in two places a distance apart, in order for it to remain fully functional. ( After taping).
Granted, I didn’t consider this when I made the purchase and there are probably other types that you will get away with.
Now, who among us would stop the job and go and buy another torque wrench?
Yes, there are things you can do, shorter busbars etc, and yet this fault happens with some regularity.
I am not suggesting you retrofit a commercial offering. I wouldn’t.
I do agree that likelihood versus potential damage translates into what we are prepared to invest in protection.
On the DIY side of the fence, this may present an improvement to the commercial offering.
But, I’ll ponder some more.
I have heard it said, ( I haven’t tested it), that the casing of these blue DIY Lithium cells is/may be connected to a battery terminal?
Is there any truth in this?
The concern seems to be that it may only be the thin blue plastic skin over the battery that is preventing an inter-cell short in the DIY builds.
Now I don’t know if that’s true or not, perhaps someone can confirm or deny it?
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So something else that has decided to give me grief is my octo Gx. It doesn’t want to connect to the WiFi anymore, tried multiple things but no go. So in the end put a WiFi extender router and cabled to the Gx and all good again. One day when I’m bored will pull in a dedicated cable.
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Are you using the antenna with the Octo?
As far as I know you can replace the antenna with another / stronger antenna if needed, so you might even try using the extender’s antenna if it’s removable and compatible. I’m still part of the dedicated cable is best club though.
Yeah it’s got the small antenna and it’s been working like that for quite a while now but suddenly just stopped working and doesn’t want to stay connected. I also think cable is best.
I do have a bunch of small external GSM antennas (around 900 / 1800MHz) with around 2 or 3 meters cable attached, if you would like to give that a try. No charge, but just pick up from me.
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Thanks that’s very kind of you, I have come right with the WiFi repeater router so for now it’s working. When I put up the next bunch of panels I will do the network cable at the same time while I’m in the roof then it will be permanently fixed