PINNED - Lithium battery conversion/info

[Scooterman]

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

[Burgerman]

No you need a amall phone for calls. And a PC for computering.

[terry2]

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

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

[shirley_hkg]

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.

[snaker]

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?

[Burgerman]

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.

[Scooterman]

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...

[Burgerman]

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.

[Scooterman]

But nobody listens.

I do BM

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

[ex-Gooserider]

But nobody listens.

I do BM

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

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....

ex-Gooserider

[Burgerman]

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.

[terry2]

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

[Scooterman]

Hi all, sorry for the late reply. Cheapie generic superglue probably wasn't the best thread-locker to use . 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 access batteries nearly kills me


My image actually posted right way up for a change . I have to use post image as my mac takes an age to resize images when running OS X. Not enough RAM me thinks

[Burgerman]

Nothing wrong there.

[Scooterman]

Nothing wrong there.

[biscuit]

I'm struggling with my new 40Ah prismatic cells. Their terminals are M10 studs. I can't get it right with the wiring. I'm fine with the balance connectors, soldering the DB9 is no big problem it turns out, though no doubt attaching M10 ring terminals to 22ga balance wires will also be difficult. Can anyone tell me how to specify ring terminals correctly, so I can get ones that fit the studs and the wire?

I'm ok with being hit-and-miss with the lugs, but the cell connectors and output leads are also giving me some grief. I can't figure out what size to use - I've discarded the 6 gauge as it's too thick for me to work with, even for the cell connectors. The controller is a VSI, it draws 50A maximum. The Vienna chair has what looks like (errm - the insulation looks like) 12 gauge for the battery-controller wire. What wire gauge should I use on my pack?

I should ask in mm² because SI is much more versatile and sensible, but AWG is so much more visual! But I have a conversion table, so I'm ok with either.

Meanwhile, while I faff around with wiring, I also have cells that need to be looked after. Burgerman, can you make a suitable preset for me to slowly charge the cells individually and leave for some days while I fiddle around with wires some more?

[Burgerman]

yES, LATER. bUSY WITH CAR WAXING AT THE MO!

yOU NEED 6MM2 BATTERY CABLE. a 60a FUSE (MIDI) And my stupid keyboard is doing that thing again.

You need ring terminals with a 8mm hole. And 6mm2 cable entry.
And 8mm hole with whatever sqmm the balance wires are...

Why soldering difficult? Use a turbo torch lighter, some flux. And do not overheat it. Then it does itself!

[foghornleghorn]

I'm struggling with my new 40Ah prismatic cells. Their terminals are M10 studs.

You need ring terminals with a 8mm hole. And 6mm2 cable entry.
And 8mm hole with whatever sqmm the balance wires are...

M8 ring terminals are going to be a tight fit on M10 studs

[Burgerman]

M10? Really? Yes you might struggle a bit! Never saw any of those on lithium!

If so then obviously a 10mm hole.

[shirley_hkg]

OT8-10 for 8mm wire , I guess

[biscuit]

Yes I assumed M8 or M6 studs but when they arrived, it was M10

My hands are too shaky and weak for soldering, crimping, lining up cells for wrapping, using any small things... At least I will never have trouble with the terminals being too small, though.

Reminds me - Shirley posted a picture once, of a very nice connector, idk what it was called, but it looked good for using with poor dexterity. If you see this, Shirley, can you find it?

[biscuit]

Cool connector. What's it called ?

Shirley, that's your post, from a few months ago in this thread. Are you able to obtain these connectors? I can't use Andersons. These look good.

[shirley_hkg]

Dunno. But its huge! Unless thats a photo trick.

I don't know neither .

[Scooterman]

Was it a d-sub connector? I have one spare if you need one, I bought more than I needed off Shirley.

[biscuit]

No it was a bulky looking thing, Shirley posted a photo of it here in late April last year - but my link to his post was a failure. I'm using xt90's or may have to use xt60s with db90 for the balance wires, my hands can hold those plugs, but not comfortably. Thank you for the offer!

[biscuit]

No you need a amall phone for calls. And a PC for computering.

IMO you need a PC for wheelchair programming and battery charging, and if you enjoy being bossed around by a machine and learning how to do stuff you used to know how to do until the last version , then for that as well. And a phone for everything else. Btw Burgerman if you're using word for your text and your caps lock sticks, iirc you highlight the offending text and press shift+F3 to cycle through the cases.

[Burgerman]

Word? Not for typing on this forum. I use a web browser. The real answer is what I did yesterday. And banged it as hard as I could on the bench. It worked great. Caps lock still sticks. But now has several keys missing too! So its fixed. Because now I gota get another one!

I have a draw here full of miceless cords for the same reason. Because thats the bit that was left afterwards.

[shirley_hkg]

Was it a d-sub connector? I have one spare if you need one, I bought more than I needed off Shirley.

Page 116 of this thread !

[shirley_hkg]

Did a quick match of 16 cells to form my 2P8S @EVE-LF105 pack , and perform a 200Ah discharge.

Voltages of the 8 groups stayed closely packed , till the last Ah.

Will be a pretty balanced pack , down to 24V.

Chair's battery ran out of storage. PL8 switched to its internal discharge mode, AUTOMATICALLY.

[shirley_hkg]

Only 1 mV , while discharged to the last 0.1 . . . . amphere hour.