PINNED - Lithium battery conversion/info

[Scooterman]

The crimped bit of the crimp is the teeny weedy square impression indicated by the arrow. IMHO a pretty shoddy job done by Sunrise. You'd think they'd use one of the Hex type crimping tools.

[Burgerman]

I am always amazed at how people think all kinds of crimps are acceptable. I have seen so many failed ones in the olde custom car/drag race days, and while an aprentice on trucks in the mid 70s, that I hate the damned things. Unless a production line, and carefully controlled, and using the RIGHT crimps and crimpers with perfect controlled technique they are invariably all useless. They are an endless source of work for auto electricians. Solder them, and no matter how green, and manky they get over the years, they still work as good as day 1. Non of that shaking the wiring loom or banging things to make the lights come back on.

All these people that claim they "weld" the wires together, etc are all talking bollox. They look that way. Till the work a bit loose, and get a bit of water in there... Then the thigs start to corrode and go all green and nasty. Or get pulled out by some mechanic leaning on the wrong bits... Rubbish. Unless done much better than we can at home. Solder them.

[Burgerman]

These soft thin, nasty bits of copper tube can NEVER be crimped securely. They simply dont have enough strength.

These types are fine IF soldered.

[shirley_hkg]

Remember to acquire extra pins for various cable sizes next time.
Expendable @1.2p , itsn't it ?

[shirley_hkg]

File the blackened barrel's edge away , and solder. Will be good enough.

[shirley_hkg]

Remember to acquire extra pins for various cable sizes next time.
Expendable @12p , itsn't it ?

[Burgerman]

I buy andersons in packs of 25. I always get the 10 swg sized ones. Its easy to drill them for bigger wires. I periodically but the other 2 sizes as well. In packs of 10. So have options!

But the only ones I feel safe with crimp alone are the smallest 10swg ones, for 12, 10 SWG, and same ones drilled for 6mm2 cable.

For 10mm2 cable I always crimp, then solder.

[Scooterman]

These don’t look too bad BM. I might pop down there on my scooter if it stays dry.

https://www.screwfix.com/p/6mm-copper-t ... f-10/57550

I will take a length of 10 AWG silicon hopefully it might fit in what do you think? Next size up is 10 mm lugs but they will be far too big

[Scooterman]

Remember to acquire extra pins for various cable sizes next time.
Expendable @12p , itsn't it ?

They are cheap shirley, an excellent price, too far to go on my mob scooter though.

[Scooterman]

These don’t look too bad BM. I might pop down there on my scooter if it stays dry.

https://www.screwfix.com/p/6mm-copper-t ... f-10/57550

I will take a length of 10 AWG silicon hopefully it might fit in what do you think? Next size up is 10 mm lugs but they will be far too big

Screwfix ones were crap. These were cheaper and better quality. Photos lie!!!

https://www.toolstation.com/copper-tube ... ugs/p50266

[terry2]

Is there anything I can put in between the lug and the cells terminal?
So it will take up any area the lug is not touching?

[Scooterman]

Is there anything I can put in between the lug and the cells terminal?
So it will take up any area the lug is not touching?

Not quite sure what you mean Terry? How about a penny washer?

[terry2]

Is there anything I can put in between the lug and the cells terminal?
So it will take up any area the lug is not touching?

Not quite sure what you mean Terry? How about a penny washer?

I was looking at thin washers.

Some kind of paste that will take up the space(if any) the lug is not touching.
There is most likely nothing. But I thought I would ask.

A friend made his own lugs out of copper piping.

[Scooterman]

You could cut some shims out of an aluminium coke can or similar.

[terry2]

You could cut some shims out of an aluminium coke can or similar.

I have just seen a funny way of wiring these up.

A guy across the street who has solar panels.
He bought 4 200 AH\Amp cells like ours for the solar energy.

He used a copper plated washer the exact size of the terminal part, so it's a perfect fit.
He had some thick plated wire and soldered that straight on to the washer

The wire was spread about a 3rd of the washer. Never seen that before, so don't know what to make of it.

[Burgerman]

Trust me. Anything that uses bare copper will be crap. ESP on lithium with alloy terminals as that joint makes a 0.5V battery as soon as a little humidity gets into it from the air. It is 95% humidity today... All the graphs on the PL8 and that careful balancing will be out of wack.

Use nickel or tin plated copper. Not bare oxydised stuff. And if you clean it, it is already oxydised by the time it gets fitted. If it is clean it will react where the 2 metals are in contact and oxydise and etch the surfaces. Non of that is good. We are trying to balance to plus/minus 2mV while a 500mV potential exists between the two, which are great at reacting together where they touch.

https://www.finishing.com/78/97.shtml another discussion...

[terry2]

Trust me. Anything that uses bare copper will be crap. ESP on lithium with alloy terminals as that joint makes a 0.5V battery as soon as a little humidity gets into it from the air. It is 95% humidity today... All the graphs on the PL8 and that careful balancing will be out of wack.

Use nickel or tin plated copper. Not bare oxydised stuff. And if you clean it, it is already oxydised by the time it gets fitted. If it is clean it will react where the 2 metals are in contact and oxydise and etch the surfaces. Non of that is good. We are trying to balance to plus/minus 2mV while a 500mV potential exists between the two, which are great at reacting together where they touch.

https://www.finishing.com/78/97.shtml another discussion...

Yes It was some nickel plated washers he got from a hobby show.

The wire he had was that flexible stuff(forgot the name) the wire was very fine and loads of strands.

Think I will try what he did when I take my cells out for a year.

[Scooterman]

If you want a simple solution and the wire isn't too thick you could just do this.

But I think soldered lugs is better.

Strip the insulation, form a clockwise shepherds crook, solder.

Then large washer, lock washer, nyloc.

[shirley_hkg]

Is there anything I can put in between the lug and the cells terminal?
So it will take up any area the lug is not touching?

What's the point of gaining surface contact with anything other than the terminal / lug itself.

More parts in the path , means more resistance.

The two faces in contact are not perfectly flat , so need a bit of deformation to get good contact. Thus , hard materials tend to get poor contact.

Learnt it the hard way.

[Burgerman]

This isnt difficult.

Dont use anything solid between two terminals because it cannot contact both correctly as they will never be at the same angles exactly. So solid metal bus bars = no.
Dont use bare copper, esp on alloy terminals = no.
Dont assemble untill you degrease and clean with steel wool, or green scotchbright cloth thoroughly = yes.
Do use plated terminal materials, like tin or nickel only = yes.
Dont crimp alone as it is not adequate, so solder! = yes
Use stainless steel bolts/and nyloc nuts and no spring washers = yes.
Use loctite on studs = yes.

Anything else may end up with problems.

[Scooterman]

and no spring washers

Why no spring washers?

[Burgerman]

Because they dont clamp evenly, and they dont achieve anything useful, They reduce pressure area, and if using nyloc nuts they are not needed. And the more contact surfaces there is the greater the resistance. Worse, they grab the ring terminal, so pulling the wire, to the right undoes the nut... You WANT it to slide. And the nut stay still. So nyloc.

[Scooterman]

Browsing hex key studs on eBay. As well as stainless for a few pennies more there are high tensile.

Wood hi tensile be a better choice? I’m thinking of the future if a pack needs to be disassembled for some reason I thought the HT threads might be less prone to strip?

But stainless would look prettier as it shiny like the aluminium

[Burgerman]

No.

[Scooterman]

[Burgerman]

Does aluminum react with steel?

It is unusual to see galvanic corrosion on aluminum in contact with stainless steel (passive).
In contrast, contact between copper, bronze, brass and different kinds of steel alloys (passive and active) and aluminum can cause severe corrosion. So it is advisable to provide insulation between the two metals.

From the metalurgy forum in te electroplating website I use.
This is also why copper bus bars are a bad idea... Unless plated in tin or nickel.

[Scooterman]

Ah! I assume stainless is passive with other metals such as copper and brass as well?

i shall remember that

[Burgerman]

Yes probably because of its nickel and chromium content.

Stainless steel is a metal alloy, made up of steel mixed with elements such as chromium, nickel, molybdenum, silicon, aluminum, and carbon. Iron mixed with carbon to produce steel is the main component of stainless steel. Chromium is added to make it resistant to rust.

It doesent seem to react with anything much. Not in any serious way. Thats why it doesent corrode or rust easily.

Theres always SOME reaction anytime different metals are in contact though. The amount usually depends on the natural voltage difference. So copper and aluminium is a really bad one, at around half a volt. You could make a good battery with those.

[Irving]

But because of its nickel & chromium content its relatively poor conductor of both electricity (50x worse) and heat (25x worse) than copper, so stainless steel in an electrical install is a bad idea as it wastes energy through high resistance AND gets much hotter because it can't transfer that heat away.

[Burgerman]

It doesent have to. The eletcricity goes from the top of the battery terminal, to the bottom of the ring terminal. The stainless bolt simply clamps it. Its job isnt to conduct. Similar to the ones on your car battery clamp.

In any case, I have a stainless bolt here and its resistance over 80mm (x m6) isnt measurable, just reads zero on my fluke and than has a special LOW scale for reading motor impedances etc. So while it may be true that its got higher resistance than copper, its still super low in this application and its a very short path too, and the power shouldnt be going that way anyway.

I might add that the aluminium terminals are also half as conductive as copper. That dosent matter either since they are large cross section. It also seems fine on the national grid too. Even stretching across the country. They just use a larger x section. Although I admit you wouldnt want stainless cables!