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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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26th May 2021, 10:19 am | #21 |
Octode
Join Date: Oct 2011
Location: Wrexham, North Wales, UK.
Posts: 1,457
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Re: Attaching to 18650 Li-ions
These batteries can withstand heat for a while but there is a limit as to how long the heat can be there for before a thermal runaway condition occurs.
I use these batteries everyday and use them hard, they do get hot but not dangerously hot, it's called vaping.
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Rick, the annoying object roaming the forum. |
28th May 2021, 6:31 am | #22 | |
Dekatron
Join Date: Jul 2009
Location: Sleaford, Lincs. UK.
Posts: 7,636
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Re: Attaching to 18650 Li-ions
Quote:
Andy.
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28th May 2021, 6:46 am | #23 |
Octode
Join Date: Oct 2011
Location: Wrexham, North Wales, UK.
Posts: 1,457
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Re: Attaching to 18650 Li-ions
A bucket of water won't stop lithium from burning, it has a violent reaction to water, similar to sodium.
Been there, done that, the underwater flames look quite pretty!
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Rick, the annoying object roaming the forum. |
28th May 2021, 7:00 am | #24 |
Octode
Join Date: Oct 2011
Location: Wrexham, North Wales, UK.
Posts: 1,457
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Re: Attaching to 18650 Li-ions
Another thing I forgot to mention was that the batteries should be in a flat state before applying any heat to them, they do self charge up to a point when heated, doing this to a charged battery runs the risk of thermal runaway, the upper limit for charging is 110%, most chargers stop above 90% to factor in self charging.
The above is from my own observation, other chemistries do not exhibit this strange behaviour and are considered safer.
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28th May 2021, 9:04 am | #25 |
Heptode
Join Date: May 2009
Location: Birmingham, West Midlands, UK.
Posts: 708
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Re: Attaching to 18650 Li-ions
If you find soldering the tags fiddly and irritating you can bridge the gap with a bit of copper out of some discarded mains 2.5mm T&E cable.
Clamp the copper onto the tag with a small mole grip (this will act as a heat disperser) solder, then ditto the other tag. |
28th May 2021, 10:19 am | #26 |
Pentode
Join Date: Nov 2015
Location: Oxfordshire, UK.
Posts: 171
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Re: Attaching to 18650 Li-ions
Hi
I have often repaired Camera/drill packs that use these cells and have very little space for interconnecting wires. I have found that solder wick with short pieces of heatshrink over them makes a good substitute for the metal strips welded to the original cells. I always treat these with respect and apply lots of heat for a very brief time. best done out doors or by an open door/window Kind regards RT |
28th May 2021, 4:47 pm | #27 |
Octode
Join Date: Jun 2006
Location: St Osyth, Nr Clacton, Essex, UK.
Posts: 1,482
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Re: Attaching to 18650 Li-ions
OP here and thanks for all the hints and tips.
I bought 4 cells and a charger (before asking advice...) and charged them up before trying to attach connections. I didn't know tagged versions are available. Anyway, not knowing whether the device's charger circuit was even functional, I thought charging the cells up before starting the assembly would give me the best chance for the inbuilt circuitry to work. And if it doesn't, I could make an assembly that just has the 3 cells and I'd have to charge them up externally. It was certainly great advice to use flux after sanding the cell surface. Normal multicore solder's flux just wasn't enough. I'm well on the way to completing the 3-cell assembly prior to attaching to the device's charger circuit, and no mis-haps so far. Thanks again and I'll update this thread when there's more news. Graham
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31st May 2021, 6:35 pm | #28 |
Octode
Join Date: Jun 2006
Location: St Osyth, Nr Clacton, Essex, UK.
Posts: 1,482
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Re: Attaching to 18650 Li-ions
Having scribbled connection details onto the original cells as I disassembled the battery pack it was fairly straightforward to reconnect and re-assemble the pack. Into the multitool it went and sadly the symptoms were just the same as they were when I suspected the original battery pack. (A burst of activity and then nothing).
So I'm now left suspecting the speed-control circuitry in the tool and it may turn out that I could replace the original cells. But for now, the title of this thread has been done, I think. Lots of useful gen revealed, thanks. Graham
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Half my stuff is junk - trouble is, I don't know which half! |
31st May 2021, 7:29 pm | #29 |
Octode
Join Date: Jun 2006
Location: St Osyth, Nr Clacton, Essex, UK.
Posts: 1,482
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Re: Attaching to 18650 Li-ions
Fixed - the Aldi Multitool that is. Nothing so complicated as the control electronics. The connections to the motor have rubber sleeves over them. Inside one rubber sleeve the conductor was severed so was only being held slightly in place by the rubber sleeve. As soon as the motor started to turn, the connection was broken. Oddly, the tap it, shake it test didn't throw anything up.
As a happy llama I'll cease spitting for a while. Graham
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Half my stuff is junk - trouble is, I don't know which half! |
31st May 2021, 7:33 pm | #30 |
Moderator
Join Date: Dec 2010
Location: Exeter, Devon and Poole, Dorset UK.
Posts: 6,823
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Re: Attaching to 18650 Li-ions
As Grahams problem is now resolved time famish this one off
Cheers Mike T
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Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk |