EVE battery terminal repair

davidnordstrom · Jun 5, 2024

Hi quys,
Just mounting the last screw on my batterypack. Notice that one of the terminals is coming loose in the welding. Any ideas on how to repair? Its an EVE 304Ah from 2023

hwy17 · Jun 5, 2024

Oh no. Unfortunately no there are not known good ways to do that.

Drilling and tapping to bolt it down would be the only possibility, but the terminals are very shallow.

davidnordstrom · Jun 5, 2024

hwy17 said:
Oh no. Unfortunately no there are not known good ways to do that.

Drilling and tapping to bolt it down would be the only possibility, but the terminals are very shallow.

Yes, if only it was known how deep and wide one could go!
Do you think welding could be an option? That assumes the current is thought to go through were it is currently welded, if you know what I mean? I'm guessing it is now required to hold any significant force downwards to create a connection there?

hwy17 · Jun 5, 2024

davidnordstrom said:
Do you think welding could be an option? That assumes the current is thought to go through were it is currently welded, if you know what I mean?

It has always been assumed that only a laser welder can do it fast enough to avoid heating the terminal too hot. Eve has a spec for how hot it can get.

hwy17 · Jun 5, 2024

The 304 spec sheet from EVE may also specify the depth of the terminal. I think the welded center you have still stuck on the terminal would help to add depth.

davidnordstrom · Jun 5, 2024

hwy17 said:
It has always been assumed that only a laser welder can do it fast enough to avoid heating the terminal too hot. Eve has a spec for how hot it can get.

OK, and you can't just do it in small steps and let it cool in between?

hwy17 · Jun 5, 2024

davidnordstrom said:
OK, and you can't just do it in small steps and let it cool in between?

Community has always thought no but if you have aluminum welding ability it would be cool to have someone try.

I don't know aluminum welding, maybe the terminal would have to get too hot to get any pool going at all, if that's how it works. Aluminum is an effective heat conductor so it's going to be sucking the heat out of the weld fast.

Partimewages · Jun 5, 2024

Find a local aluminum laser welding service. Just an idea

740GLE · Jun 5, 2024

You did that at 6nm? Or were you really hauling in it?

davidnordstrom · Jun 5, 2024

740GLE said:
You did that at 6nm? Or were you really hauling in it?

I noticed it was loose as I was tightening it. Didn't notice a crack or anyting... guessing it was defective from factory but I first noticed it now. Used a torgue set at 6nm, but I never got to the click before noticing.

740GLE · Jun 5, 2024

Where did you order the cells?

Can you take a detailed picture of a terminal without anything connected?

Curious if you have threaded inserts in those.

davidnordstrom · Jun 5, 2024

740GLE said:
Where did you order the cells?

Can you take a detailed picture of a terminal without anything connected?

Curious if you have threaded inserts in those.

I bought them from eelbattery.com. They were quick to respond before, but on this issue I have not yet recived a reply. Maybe it should be a warranty issue, what do you think?

S Davis · Jun 5, 2024

That looks like the terminal got pushed down, probably in shipping and wasn’t noticed.

740GLE · Jun 5, 2024

Those also don’t like like true Eve spec terminals with threaded inserts.

As for root cause I agree with Davis, weight on the terminal weakened it and you were the last straw.

I’d inspect the other cells for how flat those terminals are.

zgk51 · Jun 12, 2024

This is a worry.
I'm waiting delivery of some used cells myself where some might have this problem... I briefly considering tig welding them myself but the thing with aluminium welding is everything gets super hot because of it's high conductivity. Steel is possible to do a quick pulse and keep it localised but for aluminium this is not possible. So laser welding would be the only way.
You could drill and tap? Or perhaps drill a shallow hole and then use some sort of self-tapping tapered fastener similar to a wood screw. Perhaps a BRASS screw? (assuming brass had higher conductivity than steel.... I'd have to look that up) or an aluminium screw? if you could source or machine one.

Steve_S · Jun 12, 2024

Screw Hole Depth is 6mm to point.
You can drill it out with a 1/4" HSS bit with a depth stop so you don't go too far (you have a small grace with these terminals because they do not go into the physical cell). So do it slowly and cautiously as it is soft aluminum.
Use a M6 Helicoil Kit & Rethread with that & insert the helicoil and voila.
Example: https://www.amazon.ca/Helicoil-5546-6-Metric-Coarse-Thread/dp/B0002KKPXK

Remember, you don't need to over torque and strip the threads and BE CAREFUL not to Cross Thread !

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