18650 battery holder for dna20 build

[Matthew Keller]

I am in the process of building a dna20 mod and working out some sizing. One route is 2 tenergy nano tech 1200mah 15c batteries in parallel. Or an 18650 set up. I've been looking around and most seem to be real crappy. If I'm not mistaken the dna20 specs call for 20g wire for the battery to board. If anyone could point me in the right direction that would be awesome! Thanks!

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[Matthew Keller]

This is one of the ones I was looking at but it doesn't say what gauge wire it comes with.

http://www.amazon.com/dp/B00CQKBQBE/ref=cm_sw_r_udp_awd_JmuIsb0BPKV9P

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[retird]

Pick your enclosure and just replace the wire with 20 guage if it's not already 20 guage....

Evolv recommends 20 guage and at a minimum of 22 guage.....

 

[Matthew Keller]

Thank you for the heads up! I will go that route! I am actually going to buy both battery set ups and test both to see which fits better.

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[Matthew Keller]

It's going to be tight either way. I'm just hoping the contacts are going to be conductive enough.

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[mikepetro]

I am in the process of building a dna20 mod and working out some sizing. One route is 2 tenergy nano tech 1200mah 15c batteries in parallel. Or an 18650 set up. I've been looking around and most seem to be real crappy. If I'm not mistaken the dna20 specs call for 20g wire for the battery to board. If anyone could point me in the right direction that would be awesome! Thanks!

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Take a look at these, they even include some protection, this is what I ordered. They havent come in yet so I cant speak to them yet, but I like the concept. Mine should be here tomorrow, I will stop back in and give my opinion of them.

https://www.fasttech.com/p/1164901

 

[mikepetro]

Well, I got the bat holder in and I like it. The contacts are a thick stiff wire soldered to a PCB. They seem stout enough but i have not run current through them yet. At first glance though I do like these, it just remains to be seen whether can supply DNA type currents without warping the contacts.

 

[bapgood]

Well, I got the bat holder in and I like it. The contacts are a thick stiff wire soldered to a PCB. They seem stout enough but i have not run current through them yet. At first glance though I do like these, it just remains to be seen whether can supply DNA type currents without warping the contacts.

Did you buy two? I should have bought two, and my order with this is on it is still at FT (packaging...woot...woot) waiting for the Kraken clones I ordered.

The reason I ask, is because it would be great to know if there is was any reverse polarity protection, for either one or both cell. I find it hard to believe someone would go through the trouble to put in protection and not take in account for the very probable situation of putting one or both batteries in wrong.

Edit - Never mind, the big warning label indicates other wise

 

[mikepetro]

Yeah, I bought two, and no I dont want to test their warning label.........

 

[ecat]

If the designers are on the ball you'll find the -ve case contact will be unable to touch the +ve end of an upside down battery. Looking at the image it is hard to determine if this is actually the case but it does look likely.

 

[mikepetro]

If the designers are on the ball you'll find the -ve case contact will be unable to touch the +ve end of an upside down battery. Looking at the image it is hard to determine if this is actually the case but it does look likely.

By JOVE! You hit the nail on the head!
Buy that man a beer!

The gap between the protruding nipples on the negative terminal of bat holder has a gap of 11.11mm. I measured 4 different brands of batteries and the width of the positive terminal ranged from 8mm to 9mm. Indeed, any of the bats I have would not make contact if inserted upside down.

 

[bapgood]

If the designers are on the ball you'll find the -ve case contact will be unable to touch the +ve end of an upside down battery. Looking at the image it is hard to determine if this is actually the case but it does look likely.

Yeah I did notice that, but then I wondered about flat top cells.

 

[mikepetro]

Mine are flat tops, the 8-9mm still holds true even with them.

 

[bapgood]

Mine are flat tops, the 8-9mm still holds true even with them.

Well hot damn.....they just might be perfect if the contacts and circuit aren't resistance hogs

 

[mikepetro]

I shall soon find out..........

 

[bapgood]

I shall soon find out..........

Well you should be able to pull 20 watts until the battery is below 4v with the 5a protection circuit. It will be right on the edge, but you should be able to do about 16.5 watts down to the voltage cutoff.

 

[mikepetro]

the specs are actually a little confusing on that.

Maximal continuous Charging current 5A
Maximal continuous Discharging current 5A
Over charge detection voltage 4.325±0.025V
Over discharge detection voltage 2.5±0.05V
Over current detection current 9.5±1A

I am wondering if it is just "rated" at 5a continuous, but it looks like the "cutoff" is actually "Over current detection current 9.5±1A". That cutoff "implies" that it doesnt actually clamp it at 5a.

Not extremely clear.........

At any rate, it is a good starter piece for my first Mod, something break my teeth in on. If I melt it down I will just chalk it up as a learning opportunity.

 

[Matthew Keller]

Crap totally lost track of this thread. Great info though! I'm currently building one prototype with an 18650, one with some turnigy nano tech rind cells.

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[Matthew Keller]

Also I'm deciding if I'm going to throw a pair of ptc 3a resettable fuses in parallel or run without. Even at .7ohms and 20 watts it's only doing 5.35 amps.

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[bapgood]

Also I'm deciding if I'm going to throw a pair of ptc 3a resettable fuses in parallel or run without. Even at .7ohms and 20 watts it's only doing 5.35 amps.

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That's not how you calc the amp draw from the battery. A full battery is 4.2v, voltage cutoff is 3.3v iirc, and let's use 20w.

20/4.2=4.76 amps
20/3.3=6.06 amps