Purchased new batteries but no terminals/studs were installed

[VeganBiker]

So I purchased 64 new LF304 cells from Alibaba: https://evebatteryglobal.en.alibaba.com/product/62430842455-926611901/

However I somehow failed to notice/realize what Oliver Li Meant when they said it has M2 laser Positioning hole. I'm not trying to figure out how to actually hook these up.

My goal is to make 3 48v packs and 2 24v packs.

Having read other posts here I have seen people suggest tig welding the terminals on ones that broke off but I have not seen anything indicating anyone actually did this.

The other option I can think of is drilling 6mm into the top with a 5mm bit then tapping it with a M6 tap, I asked the seller about drilling into the top and this was their response:
We suggest using laser welding
It's risky.
if you do 6mm, it might will cause some bad thing.


I have mig and stick welding experience and am planning to get a tig welder anyway but I also have a drill press so I could drill the terminals.
Since the cells have the m2 laser hole I would not have to worry about centering the drill bit.

Do anyone have some advise/suggestions?

I still need to inspect the cells to see if they meet their specifications, I have only opened one box so far and all the cells were from February 2023 but different days and sequences. they don't have the grade B marking on the QR code but I need to peel off the top to see if they were given new QR codes.

I'm located in Central NY(Central NY state, not New York City) if anyone knows of places that might be able to help.

Thank you

 

[sunshine_eggo]

The terminals can't take much torque without damaging the connections inside the cell. IIRC, most are limited to no more than 8Nm of torque. If you can drill and tap without excessive torque, M6 internal threads with grub screws work well.

 

[VeganBiker]

My current plan is to drill and tap, I think the 8Nm is to prevent stripping of the existing threads which in this case I don't have a hole to thread.
I also attached images in case people were curious how they arrived, the pallets were wrapped in black plastic.

 

[Alkaline]

Man Eve makes good cells but clearly has no clue on selling them.

I would not drill tap find someone that can fiber laser weld them. I think they use a 2mm laser.

If you drill too deep you will go into the cell body, someone posted a picture of this a few years back, ruined the cell.

 

[VeganBiker]

Man Eve makes good cells but clearly has no clue on selling them.

I would not drill tap find someone that can fiber laser weld them. I think they use a 2mm laser.

If you drill too deep you will go into the cell body, someone posted a picture of this a few years back, ruined the cell.

You wouldn't happen to know the search terms to find this thread? I'd like to see what happened to the cell.

 

[VeganBiker]

I got a response from the seller saying it is OK to drill 6mm into the cell terminal.

I also finally got them all unboxed and visually inspected and found 2 with issues based on the inspection document.

I also attached the details of my 64 cells and the inspection document, I find it interesting that they were produced Feb 5th-12th with the majority made on the 12th.

I'll now proceed to drill one cell to see how it goes and report back, still waiting on my grub screws to arrive but I have some M6 bolts I can use with washers until they arrive for electrically testing the cell.

 

[Supervstech]

Do you have a drill press?
The hole needs to be perfectly aligned...
And the depth is critical. No way I would wanna do it.
Aluminum is difficult to drill into.
Need constant lubrication, and exact drill control.
Easy to size the bit, and snap it off, or damage the terminal...

 

[sunshine_eggo]

Man Eve makes good cells but clearly has no clue on selling them.

EVE knows their shit. We aren't the market.

EVE sells them to EV builders who always use integral welded bus bars and want flat faces.

 

[schmism]

My current plan is to drill and tap, I think the 8Nm is to prevent stripping of the existing threads which in this case I don't have a hole to thread.
I also attached images in case people were curious how they arrived, the pallets were wrapped in black plastic.

That is certainly the kind of crating I would hope for coming from china. I know a number of people on the forum got burnt by poor packaging on cells in the past.

Its unfortunate you failed to clairfy with the vendor the terminal type that would come on the battery. Some have reported drilling them, as others pointed out its a delicate process that if it goes wrong will destroy the cell. I don't know of anyone (who has posted) that has sourced laser welding terminals in the US.

 

[kromc5]

Will be interesting to see how the drilling goes the aluminum is crazy soft on these cells.

 

[VeganBiker]

That crating actually had 6 completely empty boxes and 2 with only 2 cells each and they were placed in the crate in a method that evened out the weight. only the top had empty boxes, the bottom was full.

I just finished drilling the positive terminal without issue. I had been wanting to get a drill press for a long time and this gave me a reason to finally get one, along with metric drill bits. I just realized my M6 tap does not start the threads quick enough so I need to get another tap.

I've never had any issues drilling aluminum before, its a fairly soft metal but can cause galling on the drill bit and that's when you get issues. I'll probably drill the other terminal then call it quits until I get a new tap.

I drilled with the 2.5mm bit then the 5mm bit. Easy peasy. But no way would I try doing this with a hand drill.

 

[Supervstech]

Ya need a “blind tap” to get the right thread pattern.

 

[42OhmsPA]

Aka a bottoming tap. It only has 1 - 1.5 threads that are tapered at the bottom.

 

[42OhmsPA]

Also, it would be a great idea to put a shaft collar on your bit to give you a positive stop once you hit your depth.

 

[VeganBiker]

Well one cell drilled, bottoming taps ordered, the drill press has a measurement on it, both holes were drilled the same but it seems i hit copper on the Negative terminal.

Ignore the scratches on the cell, I accidentally caused them when centering the drill bit. then checking to make sure both were drilled to the same depth after seeing the copper/copper looking color.

Cell is still reading 3.30v

When I get the grub screws I will be using a threadlocker on them as the primary contact area is the cell terminal not the screw and I don't want them to move.

 

[42OhmsPA]

You could throw together a simple jig and fix it to the drill press... slide the cells into it so they are automatically centered.
I did something similar when I was making my buss bars

 

[Supervstech]

Another issue is height of cell when in place to drill.
I would get a vice that holds securely the cell, and a strap that holds the cell down.
Most good drill presses have a positioning plate... maybe find a placement of the cell so rotation centers the terminals...

 

[Rocketman]

Instead of threadlocker - I used silver epoxy to lock my grub screws in.

My reasons were threadlocker doesn’t conduct any electricity - my grub screws and silver epoxy could conduct some… but the real reason is epoxy is much better “glue” than I figured threadlocker would be.

I was going to put up a picture- but all it shows is a dap of silver epoxy on the end of the grub screw

Good Luck

 

[VeganBiker]

Instead of threadlocker - I used silver epoxy to lock my grub screws in.

My reasons were threadlocker doesn’t conduct any electricity - my grub screws and silver epoxy could conduct some… but the real reason is epoxy is much better “glue” than I figured threadlocker would be.

I was going to put up a picture- but all it shows is a dap of silver epoxy on the end of the grub screw

Good Luck

I'm going to stick to threadlocker after looking up the cost of the silver epoxy, I don't think its worth it for my loads. I don't expect a single battery in either of my setups to even reach 100A, maybe 80A at most, on a peak load

 

[Rocketman]

the silver epoxy I used was about $20 from Atom Adhesives. Amazon now has a 2.5g from them for 13.99 now. Because so little was used - if I remember correctly I only used about 1/3 of the package for eight cells. The hard part will be the set time of the epoxy- getting it on the screws and then set to the proper depth x all your cells.

Well good luck whichever way you go!