This 
very Import to not see the magic smoke
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I had one minor mistaque. I was welding the p tabs and it judt poped off and landed on that and shorted it out. B4 i even had time to react it was vapourized. Everything still looks ok in that aera. I now vover the part of the battery that i have already welded with elextrical tape.
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Just a bit confused with what you said. Do i solder the balance leads first then the b- plug. Also what is a jst? And where would the charging fuse go? Sorry for asking so many questions.
You can solder the leads in whatever order (before or after the B- lead) you like as long as you have the BMS plug disconnected. However before plugging in the BMS (the white plug where all the leads go is a JST type plug) you have to connect the B- on the BMS to the battery.
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It is very easy to have an accident with all those exposed surfaces. This is why I cover everything with painterās tape except the area I am working on.
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I lernt that the hard way.
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Ok im gonna write it in steps
- Solder the b- from the battery to the bms
- Solder on the jst plugs( just to confirm. They are welded on the positive side twards the negatove)
- Solder on the p+ wire and a fuse inbetween the charging curcit and the p+
I would proceed like this:
- Solder the wires from the jst plug to the battery. (not plugged in !!!)
- Solder the b- to the battery and then the BMS
- Plug in the jst connector
- Solder the p- to the BMS and the charging portās -
- Solder a wire from the batteryās + to the charging portās +
For many of these steps order does not matter however 2 must always be done before 3.
The fuse can be inserted after the charging port either in the - or + pole. It does not matter.
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Ok i think i understand almost everything. I Just dont know where to put my jst wires on the battery.
Haha I use always such paint tape. It is so dangerous without
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Would this be the correct way to wire it?
i numberd off each wire on the pack
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This should be correct.
Awesome! Better hope this pack is always in balance because it would take the BMS a million years to balance a pack this big. 
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Would you be able to send me a picture of your bms connected. So i could see where the power wires go?
Sorry meant to respond earlier.
Think youāre on the right track.
This is the diagram i send to people whom ive built batteries:
To ensure you balance leads are correct, measure voltage:
See section
Method 1: Cell voltage relative to overall battery pack
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All the pictures I have from this battery are here:
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What protection do I need to use 18650 holders? Plan is 12s4p of 30Q using 12 holders drilled into the deck with tiny wood screws and connecting the tabs on the holders to each other with continuous pieces of 10awg. Covering with adhesive foam to protect from vibration/abrasion and the enclosure is galvanized sheet steel. What else do I do?
- wrap cells in more heat shrink
- add fish paper on the positive terminals
- douse the whole thing in type II silicone
- something else
These are the holders Iām using (not exact link but this has dimensions) https://www.amazon.com/Battery-Parallel-Batteries-Soldering-Ltvystore/dp/B07CWK81BJ/ref=pd_day0_hl_107_3/138-8184915-7614058?_encoding=UTF8&pd_rd_i=B07CWK81BJ&pd_rd_r=40aa7a46-62ce-11e9-8c99-472c1499fd9d&pd_rd_w=2R9mS&pd_rd_wg=hbfiM&pf_rd_p=ad07871c-e646-4161-82c7-5ed0d4c85b07&pf_rd_r=44VTMSEW7MPSK1SBA5C1&psc=1&refRID=44VTMSEW7MPSK1SBA5C1
This is the layout, its just enough to leave 0.5" on each side for bolt tabs
Could you elaborate that a bit more?
Usually this holder are rated to idk 0.5-2A or something. So you want to add 10awg to make them work for a higher current?
Cover it with polyimide tape because it comes off clean and doesnāt leave ANY residue
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See how the tabs that contact the battery are visible above the cell when itās inserted? I want to solder to that exposed area so the distance from the cell to the solder of the 10awg is only a few millimeters
Iām cutting the pins on the bottom off so it sits flat