preferred method for stacking batteries end to end

Batteries, Chargers, and Battery Management Systems.
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parajared   10 kW

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preferred method for stacking batteries end to end

Post by parajared » Sep 19 2019 1:35pm

I think I want to build a 2170 pack except stacked end to end like in a flashlight. What is the current best way to build packs like this?

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BionicBlitz   1 W

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Re: preferred method for stacking batteries end to end

Post by BionicBlitz » Sep 20 2019 11:24pm

i dont think there is one.. best i could think of would be lay two down parallel touching, spotweld/solder a strip connecting them, then fold it over
qs205 5t, 28s li-ion 36Ah, 120a esc, homemade frame.

AngryBob   1 kW

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Re: preferred method for stacking batteries end to end

Post by AngryBob » Sep 21 2019 11:35am

It's been done, and apparently you can just nose-to-tail just like in a flashlight, with a copper contact with a small bulge in between, or nuts, and then some method to prevent compression pressure from flattening out the contact, or make the contact solid. Copper is fairly soft.

The tricky part is to maintain enough compression, poron foam seems to be the favorite choice, with the real key being to separate the compression from the electrical contact. Copper contact held in place by poron, for instance. You also need to restrain the cells from side to side movement.

Long-term usage results for such constructions are fairly sparse, and there do not seem to be many experienced users utilizing such a method. I am guessing there are good reasons for this.
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fechter   100 GW

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Re: preferred method for stacking batteries end to end

Post by fechter » Sep 21 2019 11:45am

I spot welded a strip across two cells then folded it. This works ok but the strip sticks out to one side a little.
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999zip999   100 GW

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Re: preferred method for stacking batteries end to end

Post by 999zip999 » Sep 21 2019 2:01pm

How big is the pack ? That's sounds good for a flashlight. Like 3s for 12v . Not a bouncing ebike.

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BionicBlitz   1 W

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Re: preferred method for stacking batteries end to end

Post by BionicBlitz » Sep 23 2019 2:50pm

i suppose you could get a perfect size tube so they cant move side to side like at allll (maybe use paper or something to shim them) then if theyre flat tops make a little copper ring so terminals get a soild contact and have some spring of somesort to compress them together.... welding would probably work better though
qs205 5t, 28s li-ion 36Ah, 120a esc, homemade frame.

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Toorbough ULL-Zeveigh   100 MW

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Re: preferred method for stacking batteries end to end

Post by Toorbough ULL-Zeveigh » Sep 23 2019 3:58pm

:arrow: honda preferred
Image

:arrow: diy preferred
viewtopic.php?f=6&t=4160


Image
Image

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parajared   10 kW

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Re: preferred method for stacking batteries end to end

Post by parajared » Sep 24 2019 9:45am

How big is the pack ? That's sounds good for a flashlight. Like 3s for 12v . Not a bouncing ebike.
Sorry I was thinking 3s 10ah. I'm into both electric bicycles and model airplanes. It would be for a long-skinny fuselage.

For model airplane weight reduction reasons I probably won't be doing a full-length PVC sleeve but I like the idea. The lightest option seems like the solder tab (with protrusion) idea.

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BionicBlitz   1 W

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Re: preferred method for stacking batteries end to end

Post by BionicBlitz » Sep 24 2019 8:29pm

18650 cells dont put out much current nd are fairly heavy.... so dont expect too much performance from them
qs205 5t, 28s li-ion 36Ah, 120a esc, homemade frame.

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flippy   1 MW

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Re: preferred method for stacking batteries end to end

Post by flippy » Sep 25 2019 1:02am

for RC use you are basically limited to pouches, using cans is not effective considering the added weight. you can add a lot more capacity just by using pouches for the same weight limit.
Lithium beats liquid dinosaurs.

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parajared   10 kW

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Re: preferred method for stacking batteries end to end

Post by parajared » Sep 25 2019 9:22am

BionicBlitz wrote:
Sep 24 2019 8:29pm
18650 cells dont put out much current nd are fairly heavy.... so dont expect too much performance from them
Right. For typical 5 minute "sporty" flights I like a good 30-40c, for 30 minute flights I want about 10c and for 1+ hours flights I only need 5c. For my intended use 3c is plenty fine. It will be 10 amps maximum draw and about 2 to 3 amps cruise on a 10ah battery. That would be 0.3c draw correct?
for RC use you are basically limited to pouches, using cans is not effective considering the added weight. you can add a lot more capacity just by using pouches for the same weight limit.
18650s are lighter than Hobbyking batteries despite the cans. Pouches sure sounds nice. I will have to look into that.

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flippy   1 MW

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Re: preferred method for stacking batteries end to end

Post by flippy » Sep 25 2019 9:42am

Probably not if you factor in power delivery.

What kind of amps/volts does the RC consumes on peak and for how long does it need to fly and what is the actual weight limit?
Lithium beats liquid dinosaurs.

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