6s1p Pack for VTOL drone using Molicel INR-21700-42A cells

[Kęstutis]

Hello, I'm building a fixed wing VTOL bellysitter.
It's going to have 2 6s1p battery packs one in each wing. I'll be using INR-21700-42A. The thing is I may be drawing 30-40 amps from each pack during the take-off and landings.

According to the ampacity of battery strips sheet by Matador I need a 4 to 5 mm^2 of copper or 16 mm^2 or nickel strips. Please correct me if I'm wrong on this.

My Chinese welder is good up to 0.15 mm strips max.
How should I make it work?
Stacking crazy amount (7 to 10) of strips on top of each other sounds bad. Getting a better welder?

I'm really tempted to grab a 120W soldering iron...

Appreciate your help.

 

[scianiac]

"Copper/nickel sandwich" buses for series connections is what you are looking for, possibly with slotted or parallel strips to further improve the max welding capacity of your welder.

 

[Kęstutis]

"Copper/nickel sandwich" buses for series connections is what you are looking for, possibly with slotted or parallel strips to further improve the max welding capacity of your welder.

Thanks! I've read this thread. Seems like I have to get a Kweld after all.

 

[beemac]

Hello, I'm building a fixed wing VTOL bellysitter.
It's going to have 2 6s1p battery packs one in each wing. I'll be using INR-21700-42A. The thing is I may be drawing 30-40 amps from each pack during the take-off and landings.

According to the ampacity of battery strips sheet by Matador I need a 4 to 5 mm^2 of copper or 16 mm^2 or nickel strips. Please correct me if I'm wrong on this.

My Chinese welder is good up to 0.15 mm strips max.
How should I make it work?
Stacking crazy amount (7 to 10) of strips on top of each other sounds bad. Getting a better welder?

I'm really tempted to grab a 120W soldering iron...

Appreciate your help.

Solder some 4-6mm2 wire to the strips before you weld them?

 

[Kęstutis]

Solder some 4-6mm2 wire to the strips before you weld them?

Awesome ! Soldered top half of the strips to the wire. Will form the wire that the copper is touching the battery contacts. Do you think this will do?

 

[beemac]

Awesome ! Soldered top half of the strips to the wire. Will form the wire that the copper is touching the battery contacts. Do you think this will do?

Looks good, only testing will tell. You could put strips under the wire too if your welder can cope with the sandwich. I'd pictured a wider nickel strip between the cells as usual with wire pre-soldered down the centre lengthways. Like you'd do on the first/last parallel group of a larger battery to attach the +/- wires. But I can't say which method is better or worse...