Headway Battery rust

[BMI]

Olaf,
What puzzle me why they abondoned well profen threaded stud terminal design.
MC

Easy answer. It was quite often a case of customers overtightening cells and snapping off the terminals since they are hollow and soft (aluminium/copper).
The factory engineers decided it was a better cell design to use an internally threaded terminal rather than threaded studs. I agree also. It makes for a more compact cell.

View attachment 10Ah PSI style vs LiFeTech XPS cell size comparison.JPG

 

[frodus]

Frodus, everobody tech-oriented knows terminals are not for any load bearing .

All I was saying is, that is most likely the reason the epoxy cracked. You say its a problem with the cell, I say its a problem with the installation/user application..

 

[Jeremy Harris]

MC,

I have no problem with a bit of investigative probing to try and establish the truth. What I was reading in this thread was a pissing contest between a couple of vendors, both of whom were doing themselves no favours.

Jeremy

So if someone is telling what you know are to be complete lies do you believe it is best to keep quiet and say nothing or try and set the record straight?

How the heck do we separate truth from bullshit?

From my perspective, as a potential customer, the ONLY source of reliable data I'd trust would be that from respected users with no connection to a battery vendor. I certainly wouldn't trust the vendors on this thread, as things are so confused and muddied by all the claim and counterclaim bullshit that it's not at all clear if any of you are being wholly truthful.

Jeremy

PS: I am in the market for another battery pack at the moment, I want around 60V, 30Ah with a peak discharge rate of around 200A, continuous of maybe 80A, so the topic is generally of interest.

PPS: I also have 64 10Ah headways, some are slightly rusty after a couple of years use. They were good value though, with better performance than I expected for their low cost.

 

[AndyH]

Frodus, everobody tech-oriented knows terminals are not for any load bearing .

All I was saying is, that is most likely the reason the epoxy cracked. You say its a problem with the cell, I say its a problem with the installation/user application..

It could be operator error. It could also be a production problem. I've worked with composites in the past (homebuilt airplanes and commercial parts production) and know that epoxy won't bond to improperly prepared surfaces...

Andy

 

[miro13car]

frodus,
I also agree that he most likily overtightened terminal.
Look up above post.
"factory engineers decided..."
epoxy repair thread shows that screw terminal can be overtightened also.
factory engineers?
why Taiwan engineers came up with exactely design as Chinese Headway?
strange to me.
That's what bothers me.
were not those Headway engineers who designed screw terminal?
CHINESE SUPPOSE TO COPY FROM OTHERS.
so factory engineers decided on contract with Headway? You don't need engineer for this!
Headway
screw terminal showed up well before BMI/LifeBatt ended selling threaded stud terminal cell.
MC

 

[miro13car]

exactely Andy,
very good point.
Can you expect epoxy to bond to surface which has speckels even of rust?
certainly not
MC

 

[AndyH]

Olaf,
What puzzle me why they abondoned well profen threaded stud terminal design.
MC

Easy answer. It was quite often a case of customers overtightening cells and snapping off the terminals since they are hollow and soft (aluminium/copper).
The factory engineers decided it was a better cell design to use an internally threaded terminal rather than threaded studs. I agree also. It makes for a more compact cell.

View attachment 2

Rubbish. The studded cells continue to perform as designed and are still racking up miles in bikes, motorcycles, and plug-in hybrid packs.

I suspect the real reason for the change in the cell is likely that the desire for a larger profit margin. Hindsight suggests that the quality problems - even with a 'brain transfer' - might not have been worth the reduction in cost. Discrediting one's predecessor is seen by some as a good marketing decision...

Armin - nice picture. How much 'smaller' is your 40166 cell than a 40138 cell? :wink:

[edit]

PSI 40138 studded cell - 171.1mm overall length. Length doesn't 'grow' when adding terminals or fasteners.
LiFeTech X2E - 166mm overall length. Length grows with added terminals and fasteners.




[/edit]

 

[miro13car]

"factory engineers decided.."
decided to design or to contract Headwy?
tHE PROBLEM IS WHEN THEY "DECIDED" hEADWAY ALREADY HAD SCREW TERMINAL CELL.
pUZZLE AFTER PUZZLE.

MC

 

[frodus]

exactely Andy,
very good point.
Can you expect epoxy to bond to surface which has speckels even of rust?
certainly not
MC

If it was a production problem, then you'd see a lot more people with this problem, and I certainly have not seen or heard of any expoxy issues other than this isolated incident.

If its 1 out of 10's of thousands of cells that we know are probably out there, I don't think its a production issue.

 

[Ypedal]

re that epoxy issue, if you look at the picture, the cells are strung lenght wise cell to cell with a threaded stud going into both cells end to end.. likely some flex in the pack resulting in epoxy breakage. i don't see this as an engineering issue, but a usage problem.

 

[AndyH]

If it was a production problem, then you'd see a lot more people with this problem, and I certainly have not seen or heard of any expoxy issues other than this isolated incident.

If its 1 out of 10's of thousands of cells that we know are probably out there, I don't think its a production issue.

Give it time. :wink:

I'm not saying it's the sole answer, just a factor and/or possibility.

Maybe it's only one technician not working with clean acetone and not all of them. Not all the airplane parts I worked with were returned either - only the ones that failed during installation. :wink: The aerospace paper-trail allowed us to find the guy that wasn't sanding the part before adding surface filler...

Andy

 

[dragonfire]

this busbar seems to be the culprit, maybe helped by clorine chemicals ( washing owder, pool equipment, fertilizer...) around the storage area.


different types of metal have different values in matters lie magnetism and electrical leading ability, so 2 different types of metals tackled together will lead to rust.

this is why bolts at airplane aloy and copper rooftop platings are of th same material than the sheets, a citroen will rust like nothing and the classic landrovers allways had rust in after 3 aears at the interconnect of the aloy car body and steel chassis.

having actual voltage on these like on batteries will work as a catalyst for rust, same with chemicals and temperature conditions commonly found in a florida garage.

i wouldn´t blame the manufacturer for this allthrough details can still be improved- for example the white quasi-ceramic ring that protects the terminals can break on flex not uncommon in a array of srewed-together cells.

but, once th protective coating is removed i am positive also the BMI batrteries would rust in the same fashion so i don´t get why BMI is jumping in just to bash on a former business partner of them ?

 

[dragonfire]

on a unrelated side note, the headways 40152 with 12 ah as stated to be BMI exclusive are now tested by Goped/ Patmont motor werks and will by soon be available as upgrade for their electric scooter lineup.
PMW states they are made by Headway and the pictures show them in a nice and shiney headway -blue, so... i doubt PMW is part of this conspiracy or would order batteries for an american made product out of australia (china is allready a stretch, but PMW also offers american made LiPo cells, too).

 

[dragonfire]

If it was a production problem, then you'd see a lot more people with this problem, and I certainly have not seen or heard of any expoxy issues other than this isolated incident.

If its 1 out of 10's of thousands of cells that we know are probably out there, I don't think its a production issue.

Give it time. :wink:

I'm not saying it's the sole answer, just a factor and/or possibility.

Maybe it's only one technician not working with clean acetone and not all of them. Not all the airplane parts I worked with were returned either - only the ones that failed during installation. :wink: The aerospace paper-trail allowed us to find the guy that wasn't sanding the part before adding surface filler...

Andy

some grade of slight surface spot rust is acceptable.

Ford motors was using slightly rusty crossbars ( that enforce side inpact tabilty and are mounted in behind the dashboard), the part is visible if you have the glove compartment upopened and there was a flood of complaints according my car club magazine about that.

Ford said that the rust is only cosmetical, surface and will not increase to a noticeable level anyways as the metalurgy will keep the rust at the surface only.
So it´s not like a little spot of rust would allready render the part useless or necessarly lead to it rusting through within short time only.

 

[BMI]

Armin - nice picture. How much 'smaller' is your 40166 cell than a 40138 cell?

We don't make a 40166 size cell (cell size is always designated by body length only- as with PSI cells).
Our sizes are 38123, 40152 and coming soon 40176 (under test in Japan).
The above cell case/body sizes are manufactured using either "high power" or "high energy" LiFePO4 powder formulations (depending on the end use of the cell).

 

[BMI]

on a unrelated side note, the headways 40152 with 12 ah as stated to be BMI exclusive are now tested by Goped/ Patmont motor werks and will by soon be available as upgrade for their electric scooter lineup.
PMW states they are made by Headway and the pictures show them in a nice and shiney headway -blue, so... i doubt PMW is part of this conspiracy or would order batteries for an american made product out of australia (china is allready a stretch, but PMW also offers american made LiPo cells, too).

Any cell manufacturer can make any size cell. 40152 is just a size only. How well two cells of the same size will perform comes down to-
1) the "magic powder" used to manufacture the cell.
2) the quality control and manufacturers testing of the cell to ensure it is up to spec before releasing it to the market.

 

[scoot]

I have been avoiding this thread for some time now, until today someone raised it to my attention, and HOLY CRAP... what a storm

While i may regret this, I want to attempt adding some clarity to this epoxy thing. A couple of moths ago I assembled a pack with some standard production 38120S cells from EVC. I am a pretty strong fella (think Lennie from Of Mice and Men). During that assembly, I was screwing one cell into another (set screw in between) and applied force like nobody's business when i felt the epoxy joint break free. As I was twisting with my large hands like a drunken sailor, I was not the least bit surprised... at least I knew from that what the limitations were.

I set that cell aside and completed the pack with a spare I had. After reading the last several posts in this thread I decided to go get a better look at that cell. I pealed away the heat shrink and used one of my button head hex socket screws, and turned the terminal ever so slightly more to see where the separation occurred. Mind you that took quite a bit of force also. The outcome was that the epoxy plug had separated from the outer can.... not the terminal itself. Notice also there is no sign of crumbling epoxy or rust on this cell. All in all I am very impressed with how sturdy these puppies are.

Now as for the epoxy thing on the new 38140se cell I have, only time and close inspection will reveal any useful information... and when i am damn good and ready, I'll pull that pack apart and report back what I find. But for now, I going to proceed with my other tests. I think it is pointless very unfair to all of us to jump to any conclusions or speculate how or why that particular epoxy joint failure occurred on that pre-assembled pack. At least now i understand how simple of a repair it is likely to be... that was the whole point of me starting that thread. Here are some pics of the 38120S cell whose neck I broke :

 

[AndyH]

Armin - nice picture. How much 'smaller' is your 40166 cell than a 40138 cell?

We don't make a 40166 size cell (cell size is always designated by body length only- as with PSI cells).
Our sizes are 38123, 40152 ...

Fair enough. Let me restate the question. You said your cells were more compact than 40138 studded cells.

Since your cells is 166mm long overall without hardware, and since bolt heads for 6mm bolts are about 5mm each, that suggests to me that your cell has (to coin a phrase) a minimum operational length of 176mm overall, and that length will likely increase once lugs are installed.

The 40138 cells are a bit shorter overall and their length doesn't increase when adding lugs or hardware. At 171mm long overall, isn't the 40138 cell shorter in use?

How is the Headway-style cell more compact?

Wait. Duh. Sorry, man - I'm not thinking straight. It's more compact IN THE BOX! It's smaller when it's unpacked from the factory! Gotcha. Never mind.

 

[999zip999]

Hay Scoot thanks for exploring the limits of battery techology without these steps forward and these forum to give US the courage to cut the duct tape or pull the rubber feet off the charger and find the all the srcews to see the INSIDE. Limitations is the line we set ,to step OVER !

 

[AndyH]

While i may regret this, I want to attempt adding some clarity to this epoxy thing.

Brilliant, Scoot - thanks! Facts are much, much better than a bunch of people trying to guess what might have happened.

 

[scoot]

I appreciate your comments fellas.

I finally got around to pulling these pre-assembled 12 ah packs apart. At first glance it "appeared" that the negative lugs on the 12ah cells protruded out a little bit further than standard 10ah cells. But upon closer inspection, I found that to not be the case.

Notice the depth of the epoxy beds


View attachment IMG_1618.JPG

In case anyone was curious about the appearance under the epoxy:

 

[miro13car]

Rust shown is terrible.
Would sombody even think that spraying with conformal coating would stop metal can from rusting?
No kidding.
electrochemical cell we are here talikng about, rust is iron oxide, what about galvanic effect?
russt will grow , only give it a time.
MC

 

[frodus]

fine miro13car,

don't buy headway then, and stop bitching.

 

[scoot]

I just inspected the other 7 cells and there was not the tiniest evidence of rust.

Also, a contributing factor to the epoxy plug failure (besides the relative shallowness of the epoxy beds in this particular "test batch"), was that the OEM pack assembler failed to stabilize the cells at the mid point of the pack where the set screw are used to join them end to end. This allowed the cells pairs to flex outward away from the pack, and given the poor packing/shipping procedure used, I wouldn't doubt that is where/when the failure actually occurred. A simple winding of strapping tape in that area would be enough to adequately stabilize the cells. I can attest to this myself based on my experience thus far with my first 10ah packs. I will pass this cautionary note on to the OEM who so kindly provided me with the opportunity to try out these gem quality blue Sapphires.

These cells are too good for this country boy

 

[miro13car]

more bitching,
as for $18 cell it is not bad.
but give it a time, discharge it to say 60% DOD for 8 yers and we will see, eaten by rust?
MC