Malectrics power supply, Graphene or Ultracapacitor

[stompie79]

Hi All,

Noob getting into battery building. I got me the Malectrics spot welder for Christmas and I'm looking for thoughts on powering it. I'm leaning towards an ultra capacitor so wanted to put it out there and get some recommendations or thoughts on what I'm forgetting about.

The two options I am comparing are a parallel pair of Turnigy Graphene 3S batteries or a packaged ultracapacitor. Both options cost about the same at approx CAD$200.
https://hobbyking.com/en_us/turnigy-graphene-6000mah-3s-75c-lipo-pack-w-xt90.html?wrh_pdp=3
https://www.maxwell.com/images/documents/datasheet_16v_small_cell_module.pdf

I'm leaning towards the Maxwell ultracap as it
- should have a much longer life span then the battery, I won't be spot welding regularly and wouldn't want to pull the kit out and find the batteries output had significantly decreased (aging) or died completely.
- at Maximum Malectrics voltage it's closing in on the max Malectrics amps, 14V/0.0022Ohm (ultracap ESR) = 630A if I'm doing that correctly. I understand the malectrics max amps to be to be about 800A max

I did look at the kWeld kCap as another option for a similar price. Although the ESR is much lower and allows more amps, if I'm understanding it correctly, I'm thinking that I'll only be able to take so much of that (800A max) and the lower voltage will give me less opportunity to tweak the voltage. Am I missing something?

I'm planning to ideally start with 0.2mm nickel strips and then I'm interested in trying some of the copper & nickel "sandwiches" I've seen talked about here.

Thoughts, comments and ideas welcome.

 

[flippy]

the malectrics welder will not survive supercaps. do not do this.

go to your local car parts store and buy the cheapest 40Ah battery and use that. and get something to charge the battery if you dont have a power supply that can put out 14V.

the capacitor unit from kweld is matched to the kweld wich is designed to handle 2000A so its really not in the same ballpark as the malectrics. the kweld is more "industrial strength" versus the "consumer grade" malectrics.
not dissing the malectrics btw, i still have 2 in my workbench somewere as backup.

 

[spinningmagnets]

The Malectrics welder has proven itself to be adequate for welding the common 0.15mm/0.20mm thick nickel ribbon, which is adequate for cells that put out 10A peak, such as the popular MJ1, GA, 35E...

I'd recommend using the exact battery that has proven itself for the type of job you plan on performing. It is a precision timer, but it will only pass the dead-short amps that the battery is providing.

As stated above, the kWeld can use a higher amp-burst than the Malectrics with no damage. It is also more sophisticated, by its ability to adjust the timing on the fly, to insure all welds will recieve the same amount of total energy.

Of course, if the battery you use on the Malectrics does not drop in voltage or amperage during the welding process (let's say roughly 70 cells for 14S/5P, four pulses per cell, 280 weld-pulses) then the Malectrics should provide near identical welds for every cell.

I'm not saying the graphene pack wont work, I'm just saying I have done a lot of experiments that ended up being expensive. Now, I usually just copy what works.