PINNED - Lithium battery conversion/info

[Burgerman]

They are standard common M6 threads. Theres no olde imperialist threads in the world used anywhere in the world other than the USA today. And metric fine is not a commonly used size either. And not used on soft materials like alloys of aluminium anyway so you are safe!

[expresso]

so the yes 1mm pitch is what is needed - fine or standard ?

Not using the locktite - wouldnt that or can those grub screws come loose over time ? yes it is expensive - you only use a drop - but i end up with too much on mines many times - which is what i want to avoid - reason i am not using it either this time - going with lockwasher instead just to see how it works out


i guess you can check them after the summer and report back if any got loose - but i do like that idea with these kind of Cells -

[Burgerman]

Lock washers are a bad idea. Use flatwashers. Use stainless steel. No loctite is OK. If tight. And forget about pitch. M6 is all you need search for.

[expresso]

Lock washers are a bad idea. Use flatwashers. Use stainless steel. No loctite is OK. If tight. And forget about pitch. M6 is all you need search for.

i have the flat and lock washers for my current pack - with 10mm M6 headway type screws - you think not using locktite and no lockwasher will be fine ? whats so bad about lockwashers if they tighten down - they are just as flat as the flat washer - isnt that the purpose to keep from getting loose screws down the line ?

i can try it that way also - i just like to do it once and not have touch it during the summer at least - but i can try it and see - if the graphs start showing up bad or run into the same issue i just ran into it - which does seem like a connection issue - since each Cell checked out at 3.3V one at a time with no connections

[expresso]

i am not doing those scrub screws and nylon nuts on this pack - i want to just finish it up with the headway type screws i have already -

i want to get those scrub screws for my next pack .

[Scooterman]

my old PSU went up in smoke

This was a secondhand 24v 47A psu I bought along with a used pl8.

I stripped the thing apart, horrible crappy thing it is

The output terminals were loose and terribly corroded, and I think I detected signs of arcing. So I cleaned everything up and screwed everything down tightly, including the hexagonal terminal pillars which screw/bolt onto the pcb.

I'm hoping it'll now be okay? Before it used to start smoking when the charge amps hit the mid-teens. When I next charge the lithium I'll use this psu at 25A CC and see if it handles it? If it does I use it as a back up psu and going away psu.







Finished

[ex-Gooserider]

Like inch threads, there are at least two or three different pitch standards for metric threads, if you do the online search drill, you can find umpteen charts with specs on them.... However as BM said, MOST metric stuff is using the 'metric-coarse' standard... By usual convention, if specifying a metric size, specifying the pitch is optional IF using metric coarse pitch - thus M6 = M6-1.... IF using any of the other pitch standards then you are supposed to specify...

Note also that inch thread pitches define how many times you would need to turn a bolt to move the head one inch... Metric thread pitches define how far the bolt head moves in one TURN.... (which is why inch size pitches will always be bigger numbers than metric)

Nylock type nuts do not need to be used with lock washers or loctite if they are properly secured - the normal design requirement is to have at least one full turn of full diameter thread (not including any tapered starting threads) sticking past the top of the nylon insert.... In some 'mission critical' applications nylock nuts are considered 'single use' items, to be discarded if removed. My feeling is that none of our uses are that fussy, but you should keep in mind that they DO wear out, and discard any nylocks that don't show good locking action...

Split lock washers are good for use on mechanical connections, but are not ideal for electrical connections, especially lower torque ones - despite appearances they don't completely flatten out, so leave gaps between the parts. If a lock washer is desired, 'star' types are better as they have lots of little teeth that dig into the parts so that you get gas-tight connections between them...

The easiest way to determine minimum bolt (or stud) length is experimental - get a bolt and stack all the hardware you are planning to use on it, in between two nuts... Torque to expected value, and measure thickness of the stack with your caliper. Add the height of the nut, and if doing studs as Scooterman did, the length of stud needed in the hole... If in between sizes, go to the longer one....

ex-Gooserider

[shirley_hkg]

My mega G24 pack delivered 234Ah only.

Connections are temporary and need further attention, especially at the 2 ends.

[Scooterman]

It's quite pretty though.

We could print and frame some of these graphs and flog 'em (sell them) as abstract art.

[shirley_hkg]

We could print and frame some of these graphs and flog 'em (sell them) as abstract art.

Ummm …
typical arts & crafts by the handicapped .

[expresso]

@Gooseman - thanks for that detail explanation - the split lockwasher are what i have - the same ones that come with the headway cells - actually they are the ones that came with them - i saved all those in case - i think i may just try the scrub screws and nylon nuts -

since i would goin to use a 10mm screw - i should try a 10mm scrub screw as good starting point - not in a rush - i made all my wire connections and i think i just order some scrub and nylon nuts - and see how those work out - i like the idea better -

thanks

[Burgerman]

Nylock nuts will unscrew the studs...

Use stainless cap screws and flat washers!

[expresso]

Nylock nuts will unscrew the studs...

Use stainless cap screws and flat washers!

Oh really - i wouldnt have though that - thanks - was just about to order then -

so then i have all i need to continue - i will use 10mm headway screws - and leave out the lockwasher ? i would think that would loosen ? i want to avoid the locktite this time - i felt it was in the way and may have caused an connection issue -

just flat washer - no locktite - no lock washer ? would be Ok ?

[Burgerman]

Thats what I do. But with a tiny dab of blue loctite. On threads only. But should be OK without if tight.

[expresso]

https://smile.amazon.com/Thread-Stainle ... way&sr=8-6

this could work if using grub screws i think - with no washers at all or with a flat washer ?


https://www.ebay.com/itm/M6-Stainless-S ... 0003!US!-1


do you think its good to get at least these lock washers now to finish it ? or just finish it with the headway screws flat washer only ?

i hope not to remove it again - want to make sure it wont loosen this time -

thanks

[expresso]

Thats what I do. But with a tiny dab of blue loctite. On threads only. But should be OK without if tight.

i see - i will see what i get there - i always end up with a bit too much locktite - i feel it makes it worse for some reason with this setup - with the headway Cells - i have no problems so far and i used locktite for sure - on all of them - going on 4 years no sign of anything loose etc, -

i want to avoid unscrewing and screwing too many times on these cells - easy to strip the trend if done wrong once -

[Scooterman]

Shirley gave me the DVM . It'll come in handy along with odometer and cell checker.

The piece of rubber is to prevent me dropping spanners or some other metallic object through seat post hole resulting in

On the subject of cell checkers, the one I've got gives false readings. I wonder if it's cos it's a lipo checker and doesn't say it's suitable for lifepo4. But I didn't think battery chemistry would matter as it's only checking voltage?

[terry2]

Shirley gave me the DVM .

Sorry to hear that. Is there a cure

[Scooterman]

Shirley gave me the DVM .

Sorry to hear that. Is there a cure

Ha Ha very good!

[shirley_hkg]

Made it a very good looking dashboard .

[Scooterman]

Made it a very good looking dashboard .

[steves1977uk]

Like this SM...



Steve

[Scooterman]

That looks like KIT?

I liked the car they had in dukes of hazard. I remember people used to fit the DoH air horns to their cars, so funny

[steves1977uk]

It's K.I.T.T. SM (Knight Industries Two Thousand)

I used to like Boss Hogg in DoH

Steve

[expresso]

i re done the wiring with cables instead of the copper buss bars - what i found was - 3 loose connections - they were a starting to be stripped so i used a longer screw on those 3 with a lockwasher to thicken it and it tighten down nice now - the rest i didnt use lock washers and shorter screws - all tight - its charging now - so far so good - as long as they stay this way -

also changed the fuse to 100A - this is the 80ah ADD ON for the bounder -

[terry2]

i re done the wiring with cables instead of the copper buss bars - what i found was - 3 loose connections - they were a starting to be stripped so i used a longer screw on those 3 with a lockwasher to thicken it and it tighten down nice now - the rest i didnt use lock washers and shorter screws - all tight - its charging now - so far so good - as long as they stay this way -

also changed the fuse to 100A - this is the 80ah ADD ON for the bounder -

Do you find it better to make long cables than short ones?
Is there any advantage?
Any better than buss bars?

Mine take the shortest route.

[Scooterman]

Nice on expresso, neat job.

You don't want short straight links Terry, they need to be loke expresso's . So if cells move slightly when hitting bump is doesn't loosen the or strain the terminal connections.

On vibrating machinery you never terminate with straight cable, you always put a helix in the cable.

[terry2]

Nice on expresso, neat job.

You don't want short straight links Terry, they need to be loke expresso's . So if cells move slightly when hitting bump is doesn't loosen the or strain the terminal connections.

On vibrating machinery you never terminate with straight cable, you always put a helix in the cable.

I have and been fine so far.

I do have 3 straps holding them together. And the height is a very tight fit.
It's a good job my battery bay has a plastic sheet at the top as standard

And I've just had a tracking number from the people who I got the cells from. Wonder what they have sent me?

[Scooterman]

My mega G24 pack delivered 234Ah only.

Connections are temporary and need further attention, especially at the 2 ends.

Is the discharge curve steeper than just lithium because it's a discharge curve for a combined lead & lithium pack?

[Scooterman]

Another long ride on scooter yesterday. Gonna do a few more miles, discharge to 3.0v with PL8 and note down dashboard voltmeter reading. So I will have an idea along with odometer when pack needs recharging.

One thing I've noticed BM, is that the scooter speeds up and becomes more responsive after a few miles and I wonder if the current flowing through the cells warms them up so they work more efficiently than when cold? It's not just placebo, because I've fitted an accurate speedo. It gains about 0.5mph top speed and pulls away from standstill quicker. It becomes more fun to ride after a few miles