PINNED - Lithium battery conversion/info

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Re: PINNED - Lithium battery conversion/info

Postby Scooterman » 16 May 2019, 18:21

How is your Lithium pack going Terry? Have you redone the dodgy thread with a helicoil? Sorry if you’ve already said, I’m on my phone and it’s a bit small for reading back through thread, need a bigger phone :cussing
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Re: PINNED - Lithium battery conversion/info

Postby Burgerman » 17 May 2019, 07:17

No you need a amall phone for calls. And a PC for computering.
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Re: PINNED - Lithium battery conversion/info

Postby terry2 » 18 May 2019, 09:32

Scooterman wrote:How is your Lithium pack going Terry? Have you redone the dodgy thread with a helicoil? Sorry if you’ve already said, I’m on my phone and it’s a bit small for reading back through thread, need a bigger phone :cussing


The pack going great.
I haven't replaced\fixed anything as it's still charging great.
I'm on my phone as my pc died..boooooo
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Re: PINNED - Lithium battery conversion/info

Postby shirley_hkg » 21 May 2019, 05:03

Burgerman wrote:I am using a bottle of 2700 and it replaced my 270... Not sure what the difference is.


One M4 stud got loosen under LOCTITE 243, and torn all thread . Have to swap to LOCTITE 2700. :cussing
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Re: PINNED - Lithium battery conversion/info

Postby snaker » 21 May 2019, 07:55

Can loctite reduce the contact surface (e.g by mistake or improper use)? Do you have any good video that instructs using loctite in a right way?
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Re: PINNED - Lithium battery conversion/info

Postby Burgerman » 21 May 2019, 19:32

Possibly. If you use too much. You should try to limit its use to the thread. You dont need much. That isnt designed as a contact surface.
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Re: PINNED - Lithium battery conversion/info

Postby Scooterman » 23 May 2019, 07:36

Shirley - Do the M4 threads feel a bit flimsy for size of cable/links you're using?

I wonder why Eve make large lifepo4 cells with M4 size threads? I guess they have their reasons...
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Re: PINNED - Lithium battery conversion/info

Postby Burgerman » 23 May 2019, 08:32

Because the depth for the thread is limited. You always want the thread depth to be at least 2x the diameter in soft metals. But you also must NOT overtighten anything in aluminium alloys. Its much weaker.

So screw in a stud, FULL DEPTH, with permanant loctite. It need not be tightened! The loctite fixes it solidly.
When your cell arrives. ONCE.

Then use a nyloc nut, and flat washer, and do not overtighten. The stripped threads will then never happen. But nobody listens.
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Re: PINNED - Lithium battery conversion/info

Postby Scooterman » 23 May 2019, 09:43

Burgerman wrote:But nobody listens.

I do BM :D

I was too cheap to buy locktite so used some superglue from Poundland :oops: . It's really good value, 3 bottles for a pound :dance
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Re: PINNED - Lithium battery conversion/info

Postby ex-Gooserider » 28 May 2019, 03:06

Scooterman wrote:
Burgerman wrote:But nobody listens.

I do BM :D

I was too cheap to buy locktite so used some superglue from Poundland :oops: . It's really good value, 3 bottles for a pound :dance


Cyano-acrilyc adhesives (aka 'Super-Glue') tend to be very good for tension strength (i.e. the commercial where the guy gets picked up by his hard hat...) but not as good in shear (hit the joint sideways w/ a hammer and the guy would have gone splat...) it is also not real good at resistance to environment - humidity will break it down in time....

The stuff in the discount 'Dollar Stores' also often will either be the cheapest grades (usually) and often past its 'sell by' date - it does have a shelf-life and while it will last past it if not opened I would be hesitant to trust it for any critical applications.... Basically it may work OK now, but I'd worry about how it will hold up long-term....

OTOH Locktite will last as long as the connection....

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Re: PINNED - Lithium battery conversion/info

Postby Burgerman » 28 May 2019, 12:00

Everything metal that I ever used superglue on corrodes like hell. All rusty and brown and never comes apart. So it may work better than intended.
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Re: PINNED - Lithium battery conversion/info

Postby terry2 » 28 May 2019, 21:16

Burgerman wrote:Everything metal that I ever used superglue on corrodes like hell. All rusty and brown and never comes apart. So it may work better than intended.



I have the loctite 2700 Green version if I ever needed it.

Oh. And my graphs are spot on now it's been used a bit :)
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Re: PINNED - Lithium battery conversion/info

Postby Scooterman » 29 May 2019, 14:42

Hi all, sorry for the late reply. Cheapie generic superglue probably wasn't the best thread-locker to use :oops: . It wasn't purely because I was too stingy to buy locktite, but at the time I didn't know which bottle colour/number to buy. And I had some superglue in the drawer and was eager beaver to start building my 2x12v packs after many months of head scratching and grey hairs for BM and Shirley.

But I didn't put the superglue on the thread as I thought it might act as an insulator, so just put a small bead on the end of each stud before screwing in.

Over the last couple of charges I did notice the IR of cell 1 creeping up (2.0 ohms, 2.8 ohms) but I think that was because the negative from the controller and charge lead was probably worked the connection loose when bouncing over ruts and pot holes on the road.

But I was pleased with the graph once I re-tightened connections and strapped down floppy +ve and -ve power leads. Fingers crossed it'll last cos lifting scooter seat off to