Battery sleds

[awsum140]

Love the "scientific" methodology we're applying here.  It does give "real world" results, though, which are more important to me than what a bunch of test gear might show.

[dwcraig1]

I  plan on  letting the battery just live in there, if the HD2 fares better it will just stay in there for a long while.
I'm not expecting to be noticing any difference but we'll see.

[awsum140]

I'm happy with the HDs even after trying an HE.  Yeah, lower mah rating but heavier CDR.  I have three I rotate through in my ERM/DNA75.  I'll have to make a decision, though, when I get my low tank, side by side, DNA75s built...HD or HE?

[scooby]

Still a bit to do to finish this off, but after a lot of thought I think this is a good if not perfect solution.

[awsum140]

That looks good, Scooby.  Where'd you get that tube or did you make it?

[scooby]

It's the Fat Daddy vapes one mentioned in post 18 earlier in this thread.

The solder ring is a bit flimsy for 14 gauge and the nut only clamps it to the nylon disc. I did away with it and soldered direct to the nut
then encapsulated it in Sugru.

There was no need to slice into the tube but I felt it would give my less than dexterous hands a bit more room to work.

[awsum140]

The red top insulator threw me.  I have some of those and will be using them in DNA75s I'm working on.  I was planning on drilling out the screw and soldering into that.

[scooby]

That's a good idea, could even swap it for a meatier screw.

[jurdanas]

My opinion:
Not a good idea, when the battery is working (hot) - is growing, not working (cold) - is declining. Appears spaces. You destroy battery.

[awsum140]

I've gotta ask, how much to you think the battery expands, in length, when it gets warm?

[VapingBad]

18650, which is what this thread is about, don't externally.

[awsum140]

Even if they do expand when hot, normal operating conditions shouldn't produce that much heat.  Expansion might be a few thousands of a mm until it's hot enough to "cook off", then all bets are off.

[BillW50]

I saw a video on youtube showing how much lipos expand and shrink through charging and discharging cycles. And it was surprising quite a lot. Either in that same video or another one explained why 18650s and other canned cylinder shaped batteries don't. The videos must have been over a month back, because I can't find them in my history.

[VapingBad]

18650 can expand in very extreme conditions as has been demonstrated with a couple of tube mech mods where the battery has swelled and sealed the tube at very high temps, but I don't believe it is an issue here.

[BillW50]

Yes of course. Although I was thinking of during normal operation. I believe one of the videos mentioned the reason why 18650s doesn't swell like lipos is because they are wrapped too tight to swell. And if it is physically impossible to swell during normal operation like 18650s, you give up additional capacity.

[VapingBad]

It just an appendix to my last comment Bill and not at your or any other post in particular.

[scooby]

I've read in 'Battery University' that cylindrical batteries don't expand.

The battery is quite a loose fit in the tube diameter wise, and any slight expansion in the length, if there were any, will result in a more secure connection and be taken up by the give in the pos terminal.

Don't forget that the brass tube will expand also.

I don't think battery expansion with this setup is a issue.