Acceptable Wiring

Looking to ensure I’m not making a mistake. Since I’m using the @Winfly design for my battery enclosure, I’ve got the tin copper braid for my main positive and negative leads from the battery pack which solder to XT90 male connectors.

On each female connector, I’ve soldered a 10AWG wire to one of the terminal posts. The two wires then combine on one XT90 female.

So I have one empty terminal post one the respective XT90 connectors from the braided wire - I’m showing a 22AWG cable from the empty negative post to the B- on my BMS and a 22AWG cable from the positive empty post to my charger port. I’m wondering if that’s OK - using the empty terminals on the XT90 connections in this way?

I made a somewhat crude 3D sketch in Fusion 360 attachedFinal Wiring Diagram v9.f3z (2.0 MB)

along with a screenshot.

Battery is a 12S4P Panasonic ncr18650bd. Got a 4 Amp charger using the DC 5.5 * 2.1 power connection with a 10 Amp automotive fuse between the C- on the BMS and the charging port. Got the loop key with the special XT90 connector. The rest is straightforward enough for me from all the other posts on the forum.


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Looks good to me, but then again, I’m no EE. We do have lots of them, though. As far as I know, it’s fine to use connectors like this. Did you already build or do you already have the battery pack? I’d suggest different cells if you have the option.

thanks. I do have the cells so I’m going to see how it works with them. The board is for my 14 yr old son so I don’t think he’ll push it too hard at first. But a nice use of these holders is it’s pretty easy to change out the batteries at a future time.

That’s a much more acceptable use case. Especially if you don’t live in the mountains. 3d printed holders that allow them to be slid out?

There are some threads on the @Winfly design for a battery holder. He has the files on Thingverse. So you can certainly 3D Print them. The detailed discussion is on another forum not very popular here :slight_smile:

Instead of 3D printing them, I milled them on my CNC out of Delrin and added a centered hole at the top for a set screw to ensure pressure on the braided wire above the terminals. I’m sure you can add this to the 3D printed model. I tightened the set screws too much early on and compressed the positive terminals on some of the batteries. Hopefully the set screws will remain in place under riding vibration. Haven’t tested that yet but they seem secure.

It’s bulkier than spot welded packs, but I haven’t needed a spot welder. And I’m using the compression to hold the BMS wires in place in lieu of soldering. So cut open the shrink wrap and remove the kapton tape and you can change out the batteries. At least that’s the concept. I’m not an EE but I’ve read the stranded wire can handle 40 - 70 Amps or continuous, so should be good for more robust builds… I won’t be pushing that.

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I’ve seen photos of these holders. They have a nice aesthetic. I’ve got a CNC router in a box that I’ve neglected to put together because I just can’t find the space. Even thought about mounting it on the ceiling, lol. I guess 3d printing gets me by until I can figure it out. I admire compression builds, they take some ingenuity to get right.

Just gonna bump this to see if there are any more comments before I start soldering :grinning_face_with_smiling_eyes: