How to solder/connect LiFePO4 batteries

[suprted1]

Hello folks,

I have a nice e-bike setup of 27S 12A and Lyen controller.

But I bought LiFe cells without tabs, a terrible mistake. Is there anyone that have suggestions how to connect them properly ?
I tried soldering with flux, drilling a small 2mm hole in the batteri and enter a screw in the hole, and solder on the screw.
But nothing makes a rock solid and steady connection.
Spot welding is considered, but I dont know where to find equipment like that. Tried to make a small setup with a car stereo condensator. But it didnt work out very well.

Spot welding near Bergen, Norway wanted
Or any other ideas how to make proper connections between the cells.

Cheers, Arnfinn

 

[dnmun]

some of the small battery shops who sell consumer batteries have small spot welders and you could ask them if they would spot weld it together for you.

i was able to talk one kid who worked there to spot weld a tab onto a cell for me once before his boss, the store owner told him not to since i did not buy the battery from them. but the one tab was all i needed since that was the aluminum side and i could solder the copper side.

there are people on the sphere who have built there own spot welders too who might help you.

i recently tried to repair a spot welder for wake at the ebikestore here and it blew up in spectacular fashion when i put it back together and wired in the transformer. big plasma.

 

[agniusm]

What are the bolts for on each terminal of the cell? I would think that you just need to make copper interteminals and bolt it all together. That looks like Liao cell to me.

 

[suprted1]

What are the bolts for on each terminal of the cell? I would think that you just need to make copper interteminals and bolt it all together. That looks like Liao cell to me.

Its the same as these : http://www.goldenmotor.com/batterypack.htm
Liao ??? unfamiliar name to me....
Yepp they look like the Liao chinese batteries.... Had to google that...

 

[_Chris_]

If there is a thread on the positive and negative terminals you could try putting them in copper crimp lugs. Usually you crimp them witha big crimper but they can also be soldered in using a blowtorch flame and some solder. tap yor holes with a plug tap to hold the lug in I would use 4mm square wire minimu and 6 is better for dc.


http://www.schnap.com.au/wiring-accessories/lugs/copper-crimp-lugs-4mm-and-stud-4-mm-pk-100.html

 

[suprted1]

If there is a thread on the positive and negative terminals you could try putting them in copper crimp lugs. Usually you crimp them witha big crimper but they can also be soldered in using a blowtorch flame and some solder. tap yor holes with a plug tap to hold the lug in I would use 4mm square wire minimu and 6 is better for dc.


http://www.schnap.com.au/wiring-accessories/lugs/copper-crimp-lugs-4mm-and-stud-4-mm-pk-100.html

A few rounds of M2/M2,5 threads, I dont think will last with any crimp lugs, but thanks.
And drilling into the battery I find creapy, because I dont know how deep I may go. Before anything bad happends.

I made a DIY spot welder yesterday with trafo from a old microwave oven, but I need a bigger trafo.
Measured it at 2,7 Volts without anything connected. And at 165Amps when connected.
But I need 4-500 of Amps.....