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19707 Posts in 1262 Topics by 5041 Members - Latest Member: jorand December 16, 2017, 04:22:59 AM
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Breaktru Forum  |  eCigarette Forum  |  Modding  |  Topic: LG 18650 D1
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Author Topic: LG 18650 D1  (Read 22184 times)

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Offline redwolfe

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Re: LG 18650 D1
« Reply #50 on: June 16, 2013, 08:53:16 AM »
Hey Craig,

I was reading about batteries last night on one of the flashlight forums and came across the LG D1 18650 charts. I noticed that these cells are not typically meant for high-drain applications. They seem to be rated for a 2c max discharge. Yet you seem to be having no problem using them. How is that?

I personally would feel more comfortable seeing those new orbtronic pd2900 mah cells in there. I have 2 of them and they have been working wonderfully for me.

Offline CraigHB

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Re: LG 18650 D1
« Reply #51 on: June 16, 2013, 05:44:12 PM »
I'm running two in parallel.  That gives me a max discharge of 12 Amps which is nominally 45 Watts.  Normally it's not advisable to use parallel cells because large equalization currents can occur, but the cells are non-removable and permanently wired which eliminates the issue.

Otherwise, the taller discharge curve really simplifies things in terms of design.  Mainly the fact they are fully discharged at 3.5V open circuit and they have low internal impedance for a round cell, about 60m Ohms.  They behave more like a LiPo cell when comparing discharge curves.

I've been using this mod I built with them for a few months now.  The run time seems to be holding up well so the cells seem to be fairly durable.  That's always the question that takes some time to answer.  Though, the LiPo cells definitely hold up better, but since the ICR cells have so much more run time and they don't need to be charged nearly as often, I still come out way ahead in terms of cell longevity.

Offline CraigHB

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Re: LG 18650 D1
« Reply #52 on: June 16, 2013, 06:12:49 PM »
Oh, I didn't comment on your second question.  The NCR18650PD would be a viable option, it's probably one of the best cells to use, but the one ding is it has a rather steep discharge curve.  To get the full run time out of it, I'd have to go with a 2.7V MCU supply which means a complete redesign of my circuit.  My design uses a 3V MCU supply since it was originally done for a LiPo cell.   They have the tallest discharge curve of any Li-Ion.  The taller curve of the LG ICR cells allows me to use the same design.

The option was to use a cell with a taller discharge curve requiring only a change in the charger controller part number (which is trivial) or redesign the whole thing from the ground up.  I used a cell that works for my design rather than a rework of my design for a particular cell.

Another advantage of the LG cell is higher Watt-hours.  Since the curve is taller with the LG cells, I get more run time since it's directly proportional to a battery's Watt-hour rating.  That's in part a function of cell voltage.  Higher cell voltage means more Watt-hours which is where the rubber hits the road in terms of run time.

Offline GreenAir

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Re: LG 18650 D1
« Reply #53 on: July 11, 2013, 09:05:20 PM »
Hi guys

first i need to explain how and why i landed here:
i was checking http://lygte-info.dk/ for some specs for sanyo/panasonic discharge curves and somehow the best one was always the LG D1
LG D1? what the.... LG makes bats? Do they have have an own fab? from the data it sure looks like it!
ok, ask uncle G... tataa.. here i am! :-p

since i'm kind of drunk i couldn't compute what this forum is realy 'bout, but man that mod looks fine!
you're only talking about the cell and some screws, but what' s that board!?

i'm into modding flashlights, but as far as ecigs go i only do some caps cutting and rebuilding vivi heads.
i'll do some more reading tomorow, but it sure looks like there are some tech savvy people here!

 ;cheers; haha... even the smileys are raw here!  :rockin smiley:

Offline CraigHB

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Re: LG 18650 D1
« Reply #54 on: July 12, 2013, 04:02:46 AM »
Hi GreenAir, welcome :)

I think this is probably the best place to find e-cig modders building stuff from the ground up. 

Flashlights and e-cigs have a lot in common as far as power requirements.  Higher end flashlights typically use 10 to 20 Watts over a range of voltages above and below the voltage of a single Li-Ion cell.  So do e-cigs.

Yes, LG Chem makes Li-Ion cells.  They've been making Li-Ion cells just as long as companies like Panasonic and Samsung.  You don't see them much at the retail level, but the LG cells are used quite a bit in laptop computer packs. 

The LG ICR18650 D1 is a really amazing cell.  It has the lowest internal resistance of any ICR 18650, I've bench tested about 66 mOhms.  Other ICR 18650 cells are typically 80 to 100 mOhms.  That and the higher operating voltage means more power delivered to your appliance.

That higher operating voltage is both its advantage and its disadvantage.  The advantage is the cell has higher energy density.  In terms of energy, the ICR18650 D1 carries just about as much as a Panasonic NCR18650B even though the LG cell has 3000mAh compared to 3400mAh for the Panasonic cell.

The down side is you need a non-standard charger for the LG cell.  It uses a terminal charging voltage of 4.35V compared to 4.20V for a standard Li-Ion.  Removable round cell chargers like that are not available.  Though, you can find charger controllers with a 4.35V terminal charging voltage then make a USB charger adapter.  It's what I've done for the e-cig mod I use them in.  The LG cells perform impressively.

Oh, that board is of my own design.  It carries a 36 Watt booster, an MCU that controls everything including a display, and a USB charger.  I've been building e-cig mods for a few years now and that board has evolved over several iterations.  The one pictured is probably going to be my final design.  I don't think I can improve the function or reduce the size any more than I have.


« Last Edit: July 12, 2013, 04:50:34 AM by CraigHB »

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