You can put the lugs back on the EVE batteries - CAREFULLY.

[K-fab]

Where the lugs on the EVE batteries are welded to the electrode is really tender. I've read a couple of other threads stating they've had issues with them coming off when tightening the bolts. - it's not just me being stupid.

disclaimer - I've been using tools for the last 53 years, my mom gave me a took kit when I was 7 and I've been messing things up since. I have a very good feel for "tight" and such. I'm also a machinist/fabricator so I can claim that I know what I'm doing, for the most part - including screw ups... (I like to call them teaching moments)

I had to disconnect the + lead of my 16S battery bank the other day. Reached up with the 10mm wrench (battery bank is over head), gave the 6mm bolt a turn and pop, the whole lug came off.
WTF?
THIS IS NOT GOOD!!!

Got on YouTube so I could get my certified battery repairman status and came across a couple of videos of people drilling and tapping the lug's base and reattaching it.

Easy enough. Well... kinda.

I screwed up (my typical action for a first try on darned near anything). Instead of using a drill press to control the drill depth as the bit broke through, dumbass me just grabbed a hand held drill and started in - carefully, but manually. Not smart.

The lugs are aluminum that appears to be cast over the copper electrode. The aluminum is nice and soft (easy to drill) and then it gets into the copper, which is much harder - well, springy. It doesn't flake out of the bit like aluminum, it strings instead and grabs the bit. I was waiting for the drill to break through and had plans of just being careful when I got there (can usually feel it as it breaks through) but was definitely surprised when it grabbed and plunged (and I know better...)

SPARK, SMOKE, SHIT!

Turns out that I shorted something out internally with the drill bit. Crap. I fixed the terminal and threw the battery back in the bank hoping it was going to play nicely with it's 15 friends but alas, no. I'd killed it. Time to order a new battery and do a bit of swearing.

Battery arrives yesterday. YAY. I pulled the disabled cell out of my bank and put the new one in place. As I'm tightening down the bus bar between the new battery and it's friend, pop, off comes the lug. SERIOUSLY??? More swearing. I'm absolutely blown away that it's popped the lug off at the weld. I did NOT ham fist the thing - I know better and have a good feel for this sort of stuff. The weld that holds the lug to the electrode is FREAKING TENDER!!!

Okay, time to fix this one - but I'm filled with more knowledge, i.e. DO NOT DO THIS BY HAND.

As I unscrewed the bus bar from the battery next to it, guess what - POP, off comes it's lug.

LOTS MORE SWEARING. May have even been one of those pissed off "stomp dances" that accompanied the swearing.

From my first mistake/repair attempt I've been able to discern that the lugs are not that thick and there's some sort of rubber mat underneath the lug, separating what ever's under it from the lug. (watched as many videos on the batteries as I could find trying to see if I could see any manufacturing videos - found a couple and yeah there's a protecting layer of rubbery something under the lugs - verified what came out on the drill bit - a thick gooey stuff).

I took very careful measurements from the top of the lug to the bottom of the hole I'd drilled and threaded in the dead battery. It's 5mm. The zip tie that I was using for depth measurement (because plastic won't conduct) actually went close to 20mm into the battery before hitting what ever it is under the gooey matting so I knew I had a little wiggle room.

I put the new battery in my mill and started taking itty bitty bites into the broken tab's lug. Right at 5mm it breaks through and touches that gooey mat.
Find the proper drill bit for a 6mm tap: M6 x 1 uses a #8 drill which is .199"/5.05mm in diam.

I was able to program my mill to do a 5mm deep, 5mm diameter hole in the lug. The end mill breaks through right at 5mm and no smoke or sparks accompany the break through this time (yay). The gooey mat also held the chips in place instead of letting them drop deeper into the battery. A small pair of tweezers was used to remove any spare pieces of metal left by the end mill. - and I'd coated the end mill in a thick grease to help capture as much of the stuff I was drilling out instead of letting it fall into the battery. (old trick, works well).

Greased up a 6 x 1.0 tap and started the threads into the hole - got about two turns worth of thread into the lug but was worried about the distance the snout of the end mill was penetrating into the battery. I needed to start the threads but didn't plan on using it to do the full threading cut. Didn't want to let the smoke out of this one so I switched to a 6 x 1.0 bottoming tap (once again, covered in thick grease to catch the chips) and very carefully tapped the hole through to 5mm deep.

To get as much clamping and surface area I machined a thick brass washer that fit in the lug's base. I placed the lug back on it's home (almost a snap fit), then the washer and then a 6 x 1.0 x 8mm bolt was used to hold everything together.

I repeated this on the other broken lug and now have two working batteries with bolt on lugs. I put them back into the rack and then VERY CAREFULLY tightened the bus bars and the battery's positive lead back in place. I used a wrench to hold the bus bar and lug while tightening the bolts.

So if you break a lug off of your battery it's not a total loss. Very carefully drill and tap and stick it back on.

btw, pic #3 is of my first attempt at repair (bad battery now) the corrosion is a result of spilling some of the liquid in the battery out - was unaware that they had it in them until I laid it on it's side. I was VERY careful not to touch/breath the stuff, as I don't know what it is and don't really want to find out if it has any side effects.

 

[42OhmsPA]

Excellent writeup.

 

[MrSparkle]

I come to think of a "trick" that I learned from a car mechanic regarding tightening/untightening wheel bolts. Same thing here.

If you hold the tool outwards from the center, then it is maximum torque on the center. If instead holding tool over the center, then the torque is less, because distance center to screw/bolt cancels it self out.

It makes huge difference on car wheels. Here the ratio is smaller, so I bet that effect is much smaller too. But still, this way one could lessen the risk of torque apart the assembly like this?

 

[Quattrohead]

Excellent write up and yes I have done the "fucking hell" dance many times

 

[AntronX]

The cell is now contaminated with aluminum shavings and moisture and will fail. The liquid is a blend of ethylene carbonate, dimethyl carbonate, vinylene carbonate and LiPF6 salt.

 

[Bop]

Didn't know about this, was looking at Eve's for a friend down south, but that is a definite turnoff...

Much prefer the 'holes' that just take a bolt as done with my Winstons- hell you can pick the cells up with those....


On my 400Ah ones, thats a M10 bolt!!! (if you manage to break one of THOSE off- your first name is Clark, and you wear a red cape and a blue suit with a big S on the front!!!)

 

[K-fab]

I come to think of a "trick" that I learned from a car mechanic regarding tightening/untightening wheel bolts. Same thing here.

If you hold the tool outwards from the center, then it is maximum torque on the center. If instead holding tool over the center, then the torque is less, because distance center to screw/bolt cancels it self out.

It makes huge difference on car wheels. Here the ratio is smaller, so I bet that effect is much smaller too. But still, this way one could lessen the risk of torque apart the assembly like this?

Very valid point - am familiar with it too.

The cell is now contaminated with aluminum shavings and moisture and will fail. The liquid is a blend of ethylene carbonate, dimethyl carbonate, vinylene carbonate and LiPF6 salt.

Interesting info.

I was very wary of particle contamination last evening. I milled the hole out in 1mm deep steps to limit particles. It wasn't until the last 1mm that I broke through. I was able to pick all of the shavings out of the hole - they went no further than the gooey mat below the hole.

When I tapped it I filled the flutes in the tap with thick grease so it caught shavings (old machinist trick).

I wondered about contamination with the air, though. I'm hoping that our less than 10% humidity is on my side.

What would be the signs and how soon would they show up?

 

[Suijkerbuijk]

Whats is normal the bolt tork ?
About 25Nm ?
I use only my Pinky to set the bolt tight .

But really you need a small tork meter for it.

https://www.amazon.nl/Haskyy-Momentsleutel-motorfiets-draaimoment-ratelsleutel/dp/B0C7CFQ4RH/ref=mp_s_a_1_1?crid=G9T082PJ7ID2&dib=eyJ2IjoiMSJ9.cDbdZ78XnppjyxMfW7oe-UvPR61XdmdEUMvMbO3VBlnYpKZglU2nEOoz96V0dJKbG-Ulk3s-CraqJFwpWlS-TqfqYVyhTDUub6v3VCE7vfHX-nd-abHjMtBW-EY1LvKhykARSgV3Z1rE10vy8N6uLr7XES2erBamEiwmWvDbgRw9ABrOR6HOh121fGK7pqd2K_4daW0j0BhraHsEqBqgOt998ivd4ZmuG-0o9sA_Opdqa2k9I0oPt8LdikFdjKXBV5NlXL9O8IwM4hZWA2fywvn0O_d8EAZObZmc90S2JtE.IT0hDt4IPGFC4ijkuz3n10jgsLegqrPMuVZ5gYDm6PY&dib_tag=se&keywords=moment+sleutel+50nm&qid=1726093692&sprefix=moment+sleutel+50nm%2Caps%2C128&sr=8-1

1-10 nm

https://www.amazon.nl/Haskyy-Momentsleutel-industrie-draaimoment-ratelsleutel/dp/B0CB61BNDV/ref=mp_s_a_1_1?crid=3OYXPH22U9U9O&dib=eyJ2IjoiMSJ9.1hQoOg1D8bla6gt_JbT07iCmVoO9SjEHkp-iX-kXucjoN3pW75Xob82ea5G_Fnr7cd2MyVXyH64Jdccabify2sWTtARcpAaeYYQz98ocT-dcP-RDDzW1I95jB8hT94dmzYQnUBt1W96oVpO5d3Ww6wWZ1pbLm2s5RHGxdkwzGNQFV2BZnOiSYruKTgR9piSybL1zyOwUqv-bfG66Nis5OBtP4JGJ-auRugcF3-Z6Ohq52RsIPaKes1tRyLFZUNy8rwFT9BUILMEOdfriC7ar6_n0O_d8EAZObZmc90S2JtE.954GRMp4wKGQH5qbAMvlUHENSSEoLFdHTdHU6vMC5HY&dib_tag=se&keywords=moment+sleutel+10nm&qid=1726129995&sprefix=moment+sleutel+10nm%2Caps%2C156&sr=8-1

 

[sunshine_eggo]

Whats is normal the bolt tork ?
About 25Nm ?

6Nm

 

[Suijkerbuijk]

6Nm

Wow that is really low

 

[sunshine_eggo]

Wow that is really low

From the linked datasheet:



Not at all. 4-8Nm has been in the EVE datasheets for years and is about right for a 5-6mm thread. The terminals in question are 6mm threads.

The bigger issue is the internals. It's rarely about stripping the threads or breaking a stud, it's about the supporting structure inside the cell can't handle high torque. These things are rectangular mush boxes with paper thin Aluminum housings. You shouldn't twist the crap out of them.

Most terminal issues are caused by folks that don't use a torque wrench.

Given that these terminals can be tightened/loosened using a second wrench on the terminal block to prevent transfer of the torque to the terminal base, there's zero excuse for what has happened in this thread especially given the OP's claimed experience and expertise.

Lessons learned:

1. Human torque wrenches are not accurate. Use an actual torque wrench.
2. Counter the torque with a second wrench on the terminal block

 

[Bananaman321]

pissed off "stomp dances" that accompanied the swearing

Funny you mentioned this I can absolutely relate it is probably the only dance I know however it is a good way to shake off the stress of the moment I think cursing and stomping is healthy you should not let that bottle up inside just be aware that others around you may get the wrong idea there's a time and a place for everything.

The more of this kind of stuff that I see the more reassuring it makes me feel about going with the single stud style battery post as there was that deciding moment at a difference of $2 more, hearing about issues like this makes me glad I cheaped out.

You might do an resistance comparison from the base material with some of your other cell to cell connections to see if there's any higher resistance the repaired cell that's the only issue I could see.

I will be watching your thread in the future to see if you have any reoccurring problems I find this kind of stuff interesting as it is similar to the kind of predicaments I get myself into.

Good luck in your future repairs I look forward to reading more.

 

[crossy]

I've had to do something similar, but in my case it was 100Ah cells that came with stupid M4 drilled terminals which stripped at the slightest whim. OK, I may have been wearing my gorilla outfit at the time, but M4 really is silly small.

To replace those with M6.

• Measured the depth of the existing holes (7mm).
• Carefully drilled to that depth with a regular 5mm drill (definitely use a pillar drill and a depth-stop).
• Finished the hole with a 5mm flat-bottom drill (easy to make, look on YouTube). You need every thread you can get in there.
• Tap the hole finishing with a bottoming tap (or grind the end off a plug tap, use lots of water when grinding so you don't lose the temper).

I would absolutely avoid breaking through into the cell innards.

I actually ended up epoxying a stud into one of my first attempts, that connection doesn't seem to be any worse than the ones I managed to do properly. Obviously, don't get epoxy on the electrical mating surfaces (OK, clean it off well).

EDIT Just so we know

 

[K-fab]

Most terminal issues are caused by folks that don't use a torque wrench.

Given that these terminals can be tightened/loosened using a second wrench on the terminal block to prevent transfer of the torque to the terminal base, there's zero excuse for what has happened in this thread especially given the OP's claimed experience and expertise.

Lessons learned:

1. Human torque wrenches are not accurate. Use an actual torque wrench.
2. Counter the torque with a second wrench on the terminal block

I won't argue with this one bit.

---> I flat out screwed up. <---

I'll own my mistakes every time and share with others so they don't do the same thing. I will say that this is a new case/scenario/experience for me as I've never worked with these batteries before and it would appear that I found their limit pretty quickly. I'm now trained by the school of hard knocks.

They're like working on RC airplanes - delicate.

I was also very careful to use a second wrench on the lugs and/or the bus bar as support/counter the torque when I put it all back together.

Funny you mentioned this I can absolutely relate it is probably the only dance I know however it is a good way to shake off the stress of the moment I think cursing and stomping is healthy you should not let that bottle up inside just be aware that others around you may get the wrong idea there's a time and a place for everything.

I am generally very calm, cool and collected - you want me in emergency situations as I don't get all freaked out I just focus on the hand at task (have had some emergency training over the years). Been this way since I was a little kid.

That said, when I do decide to get unhinged (usually at something STUPID that I've done), I've always found it to be a great way to release the pent up energy. Yell a bit, stomp around, call myself an idiot, etc.. 5 seconds of and I'm off on my merry way, generally laughing at the situation afterwards.

Fortunately I've always worked alone (only child syndrome) so I don't make a scene with my co-workers.

@crossy - I have a full fabrication shop - probably have 6 or 7 sets of taps, metric and SAE both course and fine thread and all three selections of taper, plug and bottoming from 1.5mm (so tender!) on up. I used to own a CNC machine shop so tools and tooling are plentiful. I do appreciate the info though - may be helpful to someone.

Here's an example of some of the stuff I'm capable of making: Delicate kaleidoscopes - even the fasteners are my design.



To off road vehicles (ground up, full tube chassis) - The Mini-Raptor

 

[hardtop]

Didn't know about this, was looking at Eve's for a friend down south, but that is a definite turnoff...

Much prefer the 'holes' that just take a bolt as done with my Winstons- hell you can pick the cells up with those....

View attachment 243281
On my 400Ah ones, thats a M10 bolt!!! (if you manage to break one of THOSE off- your first name is Clark, and you wear a red cape and a blue suit with a big S on the front!!!)

Those are nice, but the Winstons weight a lot more.

 

[Andrewr05]

A lot of people don't know how much force is actually applied with as "little" as 6nm.

6nm when applied to an an everyday screw with all of its surface area is like fifty THOUSAND psi.

A screw is just a lever, with all that comes with the application of a larger force on one end and torque multiplication on the other "end".

 

[Bop]

Those are nice, but the Winstons weight a lot more.

Weight isn't that much of an issue for a 'house bank' (it is a factor in mobile applications like motorhomes, caravans and EVs obviously), and the heat toleration of LYP versus LFP makes it the far better choice for my local conditions (where summer temps can be weeks on end of 40-45C plus, and sometimes even much higher...) LFP really suffers under those conditions, with charge throttling required, and it shortening their service life (by a considerable margin...)

Last summer, a town (I used to work nearby) was at 52C for several days (thats 125.6F for the yanks)- and that was the air temp...
Add another 5-10C for charging temps to the mix, and thats well into the 'danger zone' for LFP...

 

[time2roll]

I would have recommended some conductive epoxy for that terminal.

 

[baipin]

Has anyone explored TIG welding, even tacking, broken terminals? Heat control could be a problem given this is a battery, and given that much aluminum would act as a heat sink... However, aluminum pop cans are around 40 thou to 20 thou thick - and those can be reliably TIG'ed without blowing through - I imagine it could be possible? I know it would be with microTIG, but, could a typical TIG setup be adapted?

Alternatively; friction stir welding? Would keep the heat nice and localized.

 

[RCinFLA]

Take torque stress off of post while tighten.

 

[Bananaman321]

Has anyone explored TIG welding, even tacking, broken terminals? Heat control could be a problem given this is a battery, and given that much aluminum would act as a heat sink... However, aluminum pop cans are around 40 thou to 20 thou thick - and those can be reliably TIG'ed without blowing through - I imagine it could be possible? I know it would be with microTIG, but, could a typical TIG setup be adapted?

Alternatively; friction stir welding? Would keep the heat nice and localized.

I think the problem with tig would be that it heats the base metal too much you need something faster so it can make the weld and cool as the aluminum quickly wicks away the heat into the battery.

 

[baipin]

I think the problem with tig would be that it heats the base metal too much you need something faster so it can make the weld and cool as the aluminum quickly wicks away the heat into the battery.

Right, and this is why microTIG machines exist, I suppose - they heat a nearly microscopic area - I guess the price you pay for seeing if extremely fine voltage/current control with a normal TIG machine could suffice, is a bit costly to your health and safety, though...

 

[Suijkerbuijk]

Right, and this is why microTIG machines exist, I suppose - they heat a nearly microscopic area - I guess the price you pay for seeing if extremely fine voltage/current control with a normal TIG machine could suffice, is a bit costly to your health and safety, though...

Living dangerous make life more exciting

 

[HughF]

Micro tig only works well on alloys that can be welded with DC.

I got so lucky with my eve and envision cells, did both types up with a cordless impact

 

[740GLE]

Where the lugs on the EVE batteries are welded to the electrode is really tender. I've read a couple of other threads stating they've had issues with them coming off when tightening the bolts. - it's not just me being stupid.

disclaimer - I've been using tools for the last 53 years, my mom gave me a took kit when I was 7 and I've been messing things up since. I have a very good feel for "tight" and such. I'm also a machinist/fabricator so I can claim that I know what I'm doing, for the most part - including screw ups... (I like to call them teaching moments)

I had to disconnect the + lead of my 16S battery bank the other day. Reached up with the 10mm wrench (battery bank is over head), gave the 6mm bolt a turn and pop, the whole lug came off.
WTF?
THIS IS NOT GOOD!!!

Got on YouTube so I could get my certified battery repairman status and came across a couple of videos of people drilling and tapping the lug's base and reattaching it.

Easy enough. Well... kinda.

I screwed up (my typical action for a first try on darned near anything). Instead of using a drill press to control the drill depth as the bit broke through, dumbass me just grabbed a hand held drill and started in - carefully, but manually. Not smart.

The lugs are aluminum that appears to be cast over the copper electrode. The aluminum is nice and soft (easy to drill) and then it gets into the copper, which is much harder - well, springy. It doesn't flake out of the bit like aluminum, it strings instead and grabs the bit. I was waiting for the drill to break through and had plans of just being careful when I got there (can usually feel it as it breaks through) but was definitely surprised when it grabbed and plunged (and I know better...)

SPARK, SMOKE, SHIT!

Turns out that I shorted something out internally with the drill bit. Crap. I fixed the terminal and threw the battery back in the bank hoping it was going to play nicely with it's 15 friends but alas, no. I'd killed it. Time to order a new battery and do a bit of swearing.

Battery arrives yesterday. YAY. I pulled the disabled cell out of my bank and put the new one in place. As I'm tightening down the bus bar between the new battery and it's friend, pop, off comes the lug. SERIOUSLY??? More swearing. I'm absolutely blown away that it's popped the lug off at the weld. I did NOT ham fist the thing - I know better and have a good feel for this sort of stuff. The weld that holds the lug to the electrode is FREAKING TENDER!!!

Okay, time to fix this one - but I'm filled with more knowledge, i.e. DO NOT DO THIS BY HAND.

As I unscrewed the bus bar from the battery next to it, guess what - POP, off comes it's lug.

LOTS MORE SWEARING. May have even been one of those pissed off "stomp dances" that accompanied the swearing.

From my first mistake/repair attempt I've been able to discern that the lugs are not that thick and there's some sort of rubber mat underneath the lug, separating what ever's under it from the lug. (watched as many videos on the batteries as I could find trying to see if I could see any manufacturing videos - found a couple and yeah there's a protecting layer of rubbery something under the lugs - verified what came out on the drill bit - a thick gooey stuff).

I took very careful measurements from the top of the lug to the bottom of the hole I'd drilled and threaded in the dead battery. It's 5mm. The zip tie that I was using for depth measurement (because plastic won't conduct) actually went close to 20mm into the battery before hitting what ever it is under the gooey matting so I knew I had a little wiggle room.

I put the new battery in my mill and started taking itty bitty bites into the broken tab's lug. Right at 5mm it breaks through and touches that gooey mat.
Find the proper drill bit for a 6mm tap: M6 x 1 uses a #8 drill which is .199"/5.05mm in diam.

I was able to program my mill to do a 5mm deep, 5mm diameter hole in the lug. The end mill breaks through right at 5mm and no smoke or sparks accompany the break through this time (yay). The gooey mat also held the chips in place instead of letting them drop deeper into the battery. A small pair of tweezers was used to remove any spare pieces of metal left by the end mill. - and I'd coated the end mill in a thick grease to help capture as much of the stuff I was drilling out instead of letting it fall into the battery. (old trick, works well).

Greased up a 6 x 1.0 tap and started the threads into the hole - got about two turns worth of thread into the lug but was worried about the distance the snout of the end mill was penetrating into the battery. I needed to start the threads but didn't plan on using it to do the full threading cut. Didn't want to let the smoke out of this one so I switched to a 6 x 1.0 bottoming tap (once again, covered in thick grease to catch the chips) and very carefully tapped the hole through to 5mm deep.

To get as much clamping and surface area I machined a thick brass washer that fit in the lug's base. I placed the lug back on it's home (almost a snap fit), then the washer and then a 6 x 1.0 x 8mm bolt was used to hold everything together.

I repeated this on the other broken lug and now have two working batteries with bolt on lugs. I put them back into the rack and then VERY CAREFULLY tightened the bus bars and the battery's positive lead back in place. I used a wrench to hold the bus bar and lug while tightening the bolts.

So if you break a lug off of your battery it's not a total loss. Very carefully drill and tap and stick it back on.

btw, pic #3 is of my first attempt at repair (bad battery now) the corrosion is a result of spilling some of the liquid in the battery out - was unaware that they had it in them until I laid it on it's side. I was VERY careful not to touch/breath the stuff, as I don't know what it is and don't really want to find out if it has any side effects.

Where did you order these cells from? These look like knock off eve dual threaded terminals.

Do you see threaded inserts in each of the terminals? Looking at the picture it sure looks like it’s non threaded insert, just bare threaded aluminum.