SEQURE SQ-SW1 with supercapacitors instead of lipo

I’d like to use supercapacitors instead of lipo or lead acid batteries for safety reasons

Do you think i can power the SQ-SW1 with the following setup:

12v 30A DC power supply
3s2p. 2.7V 350F LOW ESR supercapacitors (soldered on a SMS and balancer)


1- Power Adapter Transformer AC 100V-240V To DC 12V 30A

2- 2.7V 2.85V 3V 50F 100F 220F 360F 400F 500F For Super Capacitor Farad Balance Protection Board Plate

3- Balance Board Equalization Circuit Lithium Titanate Battery/Super Farad Capacitor Protection Board

4- BCAP0325 P270 S17 Maxwell Technologies | Mouser

Thank you

1 Like

Why would you use supercapacitors? Aren’t they like super low capacity? Also looked at the specs, 270A? That’s super high, probably not what you would want with esk8


This is for a spot welder, not in the esk8 its self.

Since the caps are basically a short circuit, hooking them up to a power supply is going to trip the overload protection on the psu. You would need a constant current power supply. Most of the LED drivers will do that, or power supplies that people modify for charging would work. Meanwell HLG series for example.


The supercapacitors will be used for spot welding.
Check these



i think you are spending too much time working out if you can, and not enough time working out if you should. Ultimately it’s your board but the fact that the potential difference varies so much (and will initially fall crazy fast) means it’s probably not the best idea. You will probably have to put in some resistors to reduce the rate of discharge. However it will still be more expensive and worse than a battery imo. Also if they short circuit without going through the resistor, you are looking at a lot of damage.

TLDR: you can, but its a really bad idea

also yes the setup will probably be able to charge it, but make you will have to stop and charge quite often. have a look at the charge and disahcrge curves if you haven’t already. you can charge to 90% quite quickly, although the last 100% is going to be a pain

1 Like


isn’t it the role of the spot welder to manage the rate of discharge?
They’ll be continuously connected to a 12v 30a power supply.

a little bit more expensive, 20 or 30 euros.
why worse?

they’re going to be securely wired

1 Like

They shouldn’t short cuircit. I’m sure you know what you’re doing with wiring to ensure they don’t, but the spot welder will not manage the rate of discharge.

1 Like

Someone please correct me if I’m wrong but I don’t think you need to either balance or use charge protection on supercaps. it’s in the nature of capacitors to simply stop taking power when they are full.

I built a super cap spot welder once, I think the control circuitry was a kit and I probably charged it with a bench power supply. It didn’t work very well but it’s possible that the nickle strips I threw at it were too thick.

Yes, here it is…


You definitely need to balance series-connected caps and prevent overcharge! It’s in the nature of caps to pop if exposed to a voltage over their rating :slightly_smiling_face: An unbalanced string of caps will cause one or more to go to a higher voltage than the others.



The role of the spot welder is to manage the length of discharge.

The welder cannot manage the rate.


Ok. The SQ-SW1 input voltage is 8-14V, and the general welding current is controlled at about 1100A.
How many BCAP0325 P270 S17 should i connect
In parallel?


It’s not controlled.

It’s an effect of the resistance of your welding material, the thickness & length of your wires, and your power source.

The welder cannot and does not control the current or rate of weld. It only controls the length of time that the weld happens for. All those other things are effects of your power source, wire, electrodes, procedure, and nickel choices.


It probably has an overcurrent trip that shortens the pulse if it detects > 1100A. Still, not what you want.

There are some fancy welders for arc welding that will use high frequency DC-DC conversion through a transformer to precisely regulate the power.

The bigger problem with this idea is that supercaps hold very little energy. You might go 1000 ft before draining them.

Yes i think that’s what the vendor meant. He was probably saying don’t go over 1100A.

yes, but provided your charger stays at one voltage you should be fine. The nice thing about capacitors is that the rate of charge is an exponential decay, so increasing the current should be fine. As battery mooch said though, too high a volatge will definitely pop it.

By this do you mean few welds? Reading this i dont feel people understand he wants to use the capacitors as a power source for a spot welder to make a regular liion battery, unless the language used in intentionally confusing…


Just to come at this from another direction…the OP doesn’t want to power a board using these caps. He wants to power a spot-welder with them.



In that case, they are far too big and actually hold dangerous amounts of energy for the application.

11V is also quite high for a capacitive discharge spot welder.
The IR of lead acid batteries helps limit the current.

The supercaps have a much higher power density, which can make them more dangerous to handle.

Ok. So How do we calculate the energy release of a 4s2p power bank using these capacitors?
Is it a dangerous setup? Thank you