Rocketman

Evaluation of 32650 (32700) Li-ion Protected cells
for a Boost/Regulated 4.0 volt single cell e-cig ‘Mod’

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Rocketman

This project started with 3 new 32650, 5500mah protected Li-ion cells purchased from Novae Products in June of 2012. The cells had no manufacturer identification or lot number. One of the cells had no output upon receipt and was returned to supplier. The remaining cells were charged and tested in the e-cig mod without the boost circuit using a 1.5 ohm cartomizer. On the 2nd charge cycle, cell #2 quit, no output. Opening the protective wrapper showed the cell to be charged to 4.11 volts and an unknown liquid/gel was found in the positive terminal cavity. It is believed that this is cell ‘electrolyte’ and contacted the protection board and shut it down. The board was removed from the cell and cleaned in 91% IPA, dried and now functions normally. The cell was set in a safe location over night and the electrolyte seemed to dry up. The top of the cell was cleaned and the positive terminal was found to have been etched by the electrolyte, possibly as a result of absorbing water vapor from the air. This cell was run through a 3rd charge/discharge cycle (1 amp charge, 2 amp discharge) and no further leakage was noticed.

It is not possible to examine the positive end without cutting off the protective wrapper so it is unknown if the leaking electrolyte was a ‘rare event’. The leaky cell obviously would not be considered reliable, but I have no evidence that these would be more prone to failure than any other type/brand.

The wrapper was removed from the third cell, and two replacement cells from the vendor and examined for any electrolyte leakage. Then run though 3 charge/discharge cycles and examined again. No leakage was found.

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Rocketman

Voltage drop @ 2 amps across dual Mosfets (#4825P, 9A/30V) = 70 millivolts (35 milliohms).
This is less than 20 milliohms across each Mosfet and is within specification.
Voltage drop @ 2 amps across Polyfuse (#260F, 2.6 amps continuous, 5 amp max) = 80 millivolts (40 milliohms). This is at the high end of specification (19 to 47 milliohms).
The board drops over 200 millivolts total at 3 amps. This voltage drop is noticeable when using Low Resistance e-cig Cartomizers (1.5 ohms).
The new protection board does eliminate the positive sense strip you find running down the side of other protected cells but the control chip in the new board does not seem to have over current protection thus the need for a 2.6/5.0 Polyswitch. While this is a safe approach to take, the voltage loss is noticeable in an unregulated e-cig. Cells with the control board on the negative end normally have over current protection incorporated in the control chip by monitoring voltage drop across the back to back Mosfets.

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Rocketman

Performance of the Protected Vs. Unprotected 32650 cells @ 2 amps. Graphs scaled to 100% of as-tested mah.
Approximately 5500 mah for the bare cell into a 2 amp continuous load and 5100mah with the protection board.

While the bare cell may be safely capable of more current drain, the configuration of the protection board limits this cell to continuous currents of about 2.5 amps (flashlight applications) or short current bursts up to 3 amps (e-cig applications). Cell output at a current higher than 3 amps will suffer from increased loses in the protection board Mosfets and Polyswitch. The primary benefit of this protected 32650 over smaller cells is the larger mah capacity not current capability.

In order to utilize the large mah capacity of these cells in an e-cig application I decided to utilize a 15 watt (5 volt/3 amp) boost regualtor. The regulator I used has a fixed voltage divider (47Kohms/18Kohms) to provide 5 volts output. The 47Kohm resistor was jumpered with 120Kohm, 1/8 watt resistor to provide a fixed 4.0 volts output. Four volts is close to the output for a ‘Big Battery E-Cig Mod’ for the first few ‘hits’. A net capacity of about 4500 mah is expected with the cell protection board and the Boost Regulator.

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Rocketman

The following photos show a few details of the ‘Mod’ construction.

Now to continue with the 'Vape Testing Mode"

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Meat Circus

Damn, dude. That thing is solid monster huge.

Rocketman

Not really that big when you are used to 26650 mods
Seems to float around 3.97 to 3.98 volts into any cartos I have tried.
This is an EMDCC, 1.5 ohm DCC for about 10.5 watts.

Here's the jumper location for the board I used (thanks JJ for the ebay tip)
Putting a resistor across the existing 47K gives these outputs:
150K=4.14 v
120K=3.99v
100K=3.85v

here's the jumper points:

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JohnnyJames

So that's this?

http://www.ebay.com/sch/?_nkw=DC%20t...d=363141270396

I'd be interested to know how close it gets to the claimed 3A out. A solid 2.8A amps would be all good, paired with a 26650 and a simple switch for 4.2 and 4.5V.

I put in a $2.60 bid on one w/free shipping.

BTW I bought a booster and a so called buck-booster off eBay,the kind complete with trimmers that were completely useless.

Rocketman

I don't know how close to the claimed 3 amps @ 5 volts, but at a reduced voltage of 4 volts it drops less than 0.02 volts from no load to 2.65 amps. I would think it would do 4.2 volts @ 2.8 amps, but be pushing it for 4.5 v @ 3 amps (1.5 ohm cartos). Maybe close.

Does an OK job to level out voltage from a discharging cell.

fsors

I like that voltage I normally hover around 4V myself
Very cool work RM! How big is the board?

Vapin Noob

Thats a rockin mod!

Heay, just noticed your meter. Same brand as mine, harber freight right? Though, I paid the 2$ extra for the backlight . When you got yourse did you have to clean leeds to get good readings? Its a great lil meter but I swear mine was assembled right next to where they do something with coaldust lol. Had to swabout leed holes three times to get black dusty gunk out and sand both ends of leads to get stable ohm readings. But all works fine now, but for 6 bucks having to clean and sand didn't seam like too much of a pain, and less of a head ache than returning a 6$ meter lol.

Rocketman

You would have to trim the corners for it to fit flat and crosswise in a 1.25 inch tube, it should fit long ways down in a .75 inch tube



Bet yours didn't come with the "Carto Meter" ports on the side

fsors

RM, so this circ, with the resistors, will buck as well as boost to maintain 4V?

Vapin Noob

Somthing tells me yours didn't either

JohnnyJames

Sounds good enough Mamu was pushing the DNA, hell that only does ~11W for a lot more money.

Will pair it up with the King Kong 4000mAh INR26650 I got. They also have a protected Li-Ion now but haven't seen the tests.


Well you know how the Chinese like to lie about mAh.



It's only a 1A test and they dragged it to 2.6V (Panasonic drags them down to 2.5V for their Li-Ion mAh), but still, nice.

Rocketman

If you can still find them the IMR 26650 kicks butt at 2 to 3 amps. You can tell from the discharge curve, 2 amps ain't nothin. The Hybrid 26650 does well also.

These 5500 mah cells do quite well at 2 to 3 amps without the protection board. It's the PolySwitch that chews up some of the voltage. But for an application with user replaceable cells, not having that positive sense strip has some safety value.


We'll have to wait and see how the bare cell does when I TWIST the neck off a sacrificial lamb when it comes in

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Shekinahsgroom

Is this the manufacturer of the King Kong cell JJ?

Rocketman

These seem to test out pretty well. Waiting on another run to be produced.
They are Li-ion, unprotected so some type of protection would have to be added.

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Rocketman

Sorry I missed your question.
You don't want to run this type of converter as a buck converter. The converter won't run. Current will pass thru the inductor and blocking diode and will be about .4 volts below cell voltage. The minimum output should be greater than loaded cell voltage. Most cells will drop to 4.0 v loaded with the first puff.

hagstrom

So you want the charge to last for a week Rocket ??? WOW

Hey 18mm wide fits a BuzzPro tube HUMMMMMM '

Rocketman

Naw, just all day. When I'm at home, no problem, but if I'm out and about I can go through a pair of 18650 cells a day.
Quick trip to dinner with the wife, eGo, river trip, 26650.

I thought the 32650 would be the ticket but the protection chews up voltage. Plenty of mah, but the volts are weak after 12 to 14 hours Mosfets and a Polyfuse.
I've got more efficient protection devices, but the drop-in long D cell sounded like a good idea.
I salvaged the idea with the booster. Better than 5000mah going into the booster. All day vape. Any day.

hagstrom

I get 12=16 hrs from a BP !! ya I know you do not like parallel cells ! ( buck reg. is much more efficient using a battery from all of my tests )

Anyhow I bought one ( ebay module ) to try just for fun .

Rocketman

I was considering replacing the Sckottky diode with a higher current one to gain a percent of two but so far it seems to be holding. I'm not pushing the board to max like some might. Since it's the only one I have at the moment I didn't want to test limits.

and I agree. Buck gains a couple percent. But I've got 5000mah to play with

I did consider making a stacked 32650 with an OK-R (I have the pipe)

berger

Holy moly!...how many ml do you use in a day?

fsors

RM, What would happen if you had the chip resisted to 4V and you put a fresh 4.2/4.1V battery in her?