Anyone here making their own battery packs? Low cost battery spot welders?

[RIP]

My son has got into drones. I've taken a quick look, and making battery packs from 18350 cells is about half the price of a LiPo, gives more capacity, and can use automotive EV grade cells rather than kinder surprise Chinesium batteries.

What do you think ? Worth it? How much would I need to spend on a spot welder?

 

[m_c]

How much heavier are 18350 cells compared with similar capacity LiPos?

 

[RIP]

How much heavier are 18350 cells compared with similar capacity LiPos?

I need to keep the battery around 100g to keep the drone in the toy category (otherwise it cant be flown near people). This can be achieved with an 850mah LiPo or four 18350 cells which give 1100mah at lower cost.

 

[mr haynes]

i've replaced a few batteries and this one, so far, seems to have worked ok for me

https://www.amazon.co.uk/gp/product/B0CB63J4WY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

 

[ukracer]

My son has got into drones. I've taken a quick look, and making battery packs from 18350 cells is about half the price of a LiPo, gives more capacity, and can use automotive EV grade cells rather than kinder surprise Chinesium batteries.

What do you think ? Worth it? How much would I need to spend on a spot welder?

Where do you get EV grade cells from?

 

[Memmeddu]

Building your own battery packs would be a game in airsoft too...
Let's say a 7,4V battery made out of two 18350 cell will easily fit into AR pattern rifles buffer tube no problems.
And at least the double of the Ah capacity.
And surely the small electric motor would have all the amps it would ever need at disposal

 

[RIP]

Where do you get EV grade cells from?

Oh I wouldn't take that too literally, I'm old, and I more recently read that EV cell procurement has changed. But what you can do is look up high end cells used by OEMs like Bosch (Panasonic, Samsung etc) and Google a supplier like NU Batteries. Also worth calling the supplier and asking if they've verified the cells as genuine.

 

[Ian X]

I'll watch this with interest. Anyway, back to the spot welder, I see loads on Ali, probably all copies of each other. I want to know if they work. I have 6 batteries for a Hilti TE5A 24v drill and 8 have been recelled by a bloke in Belgium a few years ago with Ni-Cad so they are all slowly dying now. I would like to replace them with 18650 cells and a BMS. I guess I need 36 or 48 cells but no way will I solder them, tried that with Ni-Cad and have better things to do.
So which down and dirty spot welder that is not too redneck?

 

[Seadog]

 

[RIP]

Hey. I saw that. It's seems a bit too crude, it's relying on the car battery rating (internal resistance) to control the power of the spot weld.

 

[Seadog]

You can use a small bank of electrolytic capacitors charged from the battery, which will limit the amount of power delivered.

 

[RIP]

i've replaced a few batteries and this one, so far, seems to have worked ok for me

https://www.amazon.co.uk/gp/product/B0CB63J4WY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

View attachment 483022

This one has come up on Reddit and e bike sites, might be the one to go for. I wonder what cells it has inside.

 

[RIP]

You can use a small bank of electrolytic capacitors charged from the battery, which will limit the amount of power delivered.

How does that work? The capacitors discharge and do the spot weld? That sounds like it would be more consistent.

 

[Seadog]

Yes, the capacitors charge the same every time, and deliver a consistent current each time.

The energy in, Coulombs (Q), is easily calculated.

Q=CV
Where Q is the energy
C is the capacitance (Farads)
V is the voltage (Volts)

 

[mr haynes]

This one has come up on Reddit and e bike sites, might be the one to go for. I wonder what cells it has inside.

No idea on what's inside, got about 6mth ago and been fine so far.
Very simple to use, as long as you're an octopus
Seriously though, dead simple if you have summit to hold the batteries

 

[Turbo]

https://www.aliexpress.com/item/1005007125104503.html

I use this type of one to rebuild drill batteries with 18650 cells.

Provided you make the commonly known upgrades and use a decent car battery it is reliable and works.

You are limited on the thickness of nickel strip it will weld though. I use pure nickel stuff and I think it is 0.12mm.

What I really like is that you can attach a foot pedal as a switch. Otherwise it does the weld automatically as soon as you touch the probes. If you don't have the strip in the right place or you are not pressing hard enough its tough luck.

 

[Turbo]

Upgrade mods here.

https://endless-sphere.com/sphere/threads/want-a-battery-spot-welder-that-works-for-20.120951/

 

[Ross365]

It is possible to solder on to 18650's, using ordinary solder together with some flux. I've not done many, but I've had no problems. There are You tube vids offering advice; Ideally, it needs to be done with a hot iron and get in and out quick.

 

[ukracer]

It is possible to solder on to 18650's, using ordinary solder together with some flux. I've not done many, but I've had no problems. There are You tube vids offering advice; Ideally, it needs to be done with a hot iron and get in and out quick.

We used to use a 12 volt spec iron for the RC racing cells.

 

[Turbo]

It is possible to solder on to 18650's, using ordinary solder together with some flux. I've not done many, but I've had no problems. There are You tube vids offering advice; Ideally, it needs to be done with a hot iron and get in and out quick.

Wouldn't recommend any soldering on a 18650 or any lipo cell. Not good for the cell and the danger risk is high.
I soldered the first 18650 pack I built and it failed very shortly afterward due to bad cells, probably heat damaged from soldering.