charging new lifepo4

[theskip1]

I'm soldering them which isn't ideal because of heat. I'm using a heavy duty 100watt iron to make the solder process as quick as possible, the heat is only applied momentarily, I also use a large heat sink to track heat away where possible.
The cells I'm using were tabbed but the spot welds were so poor I pulled most of the tabs off with my fingers. I'm not a fan of pin point spot welds and believe soldering gives a much better joint.

yes i also believe soldering is best, but i found that even a 140watt iron was not fast enough so i use a large 1"x 2" copper iron that i heat with a blowtorch. this retains a large amount of heat that can be "discharged" into the joint very quickly and so stops the work from " cooking "

 

[theskip1]

I thouhg about trying one of these in my RC days.
Force 4 Cold Soldering Iron - Only £14.95 - Force 4 Chandlery
Not sure how good the joints would be.

no where near hot enough i fear

 

[theskip1]

have now tested the input and output of the bms as follows:-
battery fully charged:- input 40.5v output 38v
at point when it cuts out:- input 36v output 32v
does anyone know if these figuers sound right ?
tony

 

[onmebike]

have now tested the input and output of the bms as follows:-
battery fully charged:- input 40.5v output 38v
at point when it cuts out:- input 36v output 32v
does anyone know if these figuers sound right ?
tony

40.5v, 3.37v per cell when charged sounds about right.
36v, 3v per cell at cutoff seems a tad higher than needed for lifpo4's but better that than too low.
The bms will cut off if any one of the 12 parallel banks of cells drops to the cutoff point, check the individual banks.

 

[theskip1]

40.5v, 3.37v per cell when charged sounds about right.
36v, 3v per cell at cutoff seems a tad higher than needed for lifpo4's but better that than too low.
The bms will cut off if any one of the 12 parallel banks of cells drops to the cutoff point, check the individual banks.

by individual banks i presume you mean each bank of 18 cells ? in which case i have already done so, see pic page 3,