Today I turned on my welder after repairing the broken trace and from my understanding one of the 2 diodes is dead, and my welder is constantly in state of “remove short”
Should I just replace the diode and it will work fine again?
This diode is the same as the littlefuse one right?
Mouser wants 20€ for shipping for a 4€ item so looking at ebay 
Thanks
That was to be expected, because the copper trace had a reason why it failed. This indicates that either the MOSFETs are shorted (unlikely) or one of the two TVS diodes at the right.
First remove it, and run through the calibration but without connecting the probes during SHORT, to see if the unit is good otherwise. You should manage to get to an error in the SHORT step, and please also write down all displayed data from both steps.
That’s not the correct one. Earlier models used a SMDJ28A at the upper right position, but I have changed this to all SLD8S28A. That is available from Digikey, but if you have trouble sourcing then also I or my US reseller Keith can supply you with spares, depending on where you live.
Thanks for helping me, should I remove both and do calibration or only the one that failed?
When doing the diode test,one works and one doesnt
Sadly Digikey doesn’t ship to me, and I need some electrodes anyways from you so if you could sell me 2 to replace that would be great!
Okay, just place an order but please make sure to send me an extra email so that I catch that. The TVS diodes will be for free.
Thanks a lot, I will place the order in a day or two and email you, definitely the best product and customer service from all the products I bought!
My 2x Turnigy Graphene 6AH are now only doing 1400amps on average and I’m useing 0.22mm nickle more and more at about 23J so time to upgrading to a 3rd.
I’m never going to get a 3rd AWG10 in the XT150 and there still getting pretty warm that I have to take a brake after every p group. so upgrading to AS250 that can take AWS6 so why not upgrade the supply cable as I’m at it as that also gets warm
AWG 6 silicon cable arrived to upgrade the supply cable. (It looks chunky wonder how big the connectors are going to be) AS250 at the post office still. Dig thro my boxes see if I have 16mm2 crimps with a small hole
Was looking at the 2S Hard Case Turnigy Graphene Batters that have a really good C (continues current compared) rating to other Turnigy Graphene
Turnigy Graphene Hard Case 90C Constant / ?? Burst
Turnigy Graphene Panther (Green) 75C Constant /150C Peak Discharge (3s)
Turnigy Graphene (Red) 15C Constant / 30C Burst
Thay only come as 2S and I haven’t yet been able to fined there internal resistance as well as been 35% cheeper
To see if thay might be useable in theory compared to 3S
KWeld Resitance 42mOhm or 0.0042ohm
To calculate the recommended minimum 800A weld current
0.0042ohm*800A=3.36V minimum KWeld Voltage
2S - minimum KWeld Voltage = Remaining Voltage
7.4V-3.36V=4.04V
4.04V/800A=0.00505=5.05Ohm internal Batter Resistance
To calculate the 1500A weld current
0.0042ohm*1500=6.3 minimum KWeld Voltage
2S is 7.4V-6.3V=1.1V
1.1V/1500A=0.00073Ohm=0.73mOhm
2S Battery Internal Resistance to weld at 800A 0.00505 (5.05Ohm)
2S Battery Internal Resistance to weld at 1500A 0.00073Ohm (0.73mOhm)
3S Battery Internal Resistance to weld at 800A 0.009675 (9.7mOhm)
3S Battery Internal Resistance to weld at 1500A 0.0032ohm (3.2mOhm)
It appears you will struggle to get the higher Amps but should be a very good cheap option if any one finds out the internal resistance would be good to see what Ah Hard Case Pack works best
Just use 2 of these in series 
I run my kweld on 4s aswell
In theory you better of in parallel as long as you have the 3.36V minimum to overcome the resistance of the KWeld and enough voltage to compensate for the battery resistance. The rest is just dissipated in heat with in the system.
Has anyone used the KCap with lipos?
What would you want to do that for, just curious?
Use weaker lipos or something?
Needs a 8.2v input max and will only output 1200A
If you have good lipos it probably do more amps
The KCap can output up to 2000A, my main concern is how to plug a Lipo to the KCap in order to avoid a suden in-rush of current aas the lipos do not have any adjustable limit of current.
Can I safely charge the kCap and the Lipo at the same voltage and connect the lipo to the input of the kCap?
I’d like to know what’s the correct procedure to connect a lipo to a kcap module, the manufacturer states you need a power supply of minimum 10A to recharge it between welds, but does not say anything about lipo procedures with kcap
kCap has an input and an output side. Input side is 70A max because of the MOSFET based disconnect switch, output side is direct connection to the ultracaps. Both sides represent dead shorts when the caps are discharged, hence you cannot directly connect a Lipo. Precharging the caps with e.g. a power resistor is okay, but connect the Lipo to the output side then. This is because there is no current limit when the caps are heavily discharged for whatever reason, and the Lipos will give everything they have to recover from that.
One kCap delivers 1100 to 1200A for welding, two in parallel deliver 1600A to 1700A. Initial calibration is a bit tricky, because that may hit the 2000A current limit. In this case, charging them to a bit lower voltage is necessary to go through that procedure. The simplest way of doing that is to disconnect the charger, and try calibrating until it passes.
The intended procedure to connect any power source to kCap, regardless of the type, is to use a charger. The kCap product page lists a few options, and kSupply is one of them.
Correct, after a year of using or so they dropped from 1700 to about 1450A welding current, 2 in parallel are enough to weld .3mm nickel, especially if its perforated, I’m welding perforated .3mm at 53J or so
We’re do you get that from?
