Chargin eGoXL on Pila IBC

[Whistle_Pig]

I have 2 eGo fast chargers, one of which has already gone south, and I'm slightly uncertain about the other. I really don't trust $8 chargers anyway. Yeah, I'm supplying them with plenty of juice on the input side -- I wired a USB port directly to the 600W power supply in my computer.

I thought I saw something on the forums about doing this, but can't find it again. It'd be trivial to put a couple contacts on a tube, wired to an atty connector, and use a cradle charger for my eGo batts (900mah). The Pila charges at 600mA, so I think that's below 1C for the eGo. Can't think of any reason why this would be a bad idea.

If there's a reason why I shouldn't do this, please let me know. The Pila charger is already an almost planned purchase anyway, since I'm thinking of getting something like a Mako Midi.

 

[mdocod]

I don't see anything wrong with rigging up an IBC to any li-ion cell with a true capacity of ~600mAH or better. The problem is going to be whether or not the charge controls are inside the eGo battery "tube" unit, or outside. If there are separate charge controls inside, and the input voltage to the eGo is 5V from the normal charger, then the IBC won't charge it correctly.

Does the eGo tube come apart in some way such that you could remove the cell inside and charge it directly? That would be the ideal way to deal with this.

Have you thought about just picking up a BB and some 14500s, or a BB w/14670 tube and some 14670s? That would let you use your IBC and you could either use IMR14500s or protected 14670s and get great performance either way.

Eric

 

[Whistle_Pig]

Well, I don't know what's in the eGo circuitry, other than a PWM regulator, a MOSFET switch (I think it's a MOSFET), a protection circuit (I'm guessing), and whatever makes the LED light up and go blinky. I could dig through ScottBee's "Surprise" thread and see if there's a full accounting in there someplace.

The eGo isn't built such that the batt can be dropped in/out regularly. I think it's soldered -- have to see if there's a pic around of that.

I haven't measured the voltage supplied by the eGo charger, but I doubt it's 5V. Certainly, there's plenty of components on the board inside.

I was thinking about a BB for a while, but with the Mako, you can switch tubes and use bigger/smaller batteries, and that's attractive, if I decide I want more mAH.

 

[Whistle_Pig]

eGo guts.

In that neighborhood, various comments about the electronics inside it.

 

[Whistle_Pig]

Here it is folks -- my Pila IBCT eGo charging mod.

What you'll need:

• 5/8 wooden dowel
• 2) 1/2 copper end caps
• a dead eGo Fast USB charger
• Minor bits and pieces of electrical stuff
• Some tools

After cutting the wires from the PC board in a dead charger, I found I didn't have enough wire to just solder them back together, so I had to add in a bit. I soldered everything except final connection to the copper end caps, and didn't worry about insulation inside the charger casing, since I glued everything down before closing it up. I think the pictures pretty well show what to do.

As soon as I screwed the eGo onto it, the eGo LED flashed just like usual, and the charging LED came on on the Pila. It's been on there for about 45 minutes, and feels only slightly warm. And, as I type this, it's gone to full charge. Well, I didn't know whether that batt was fully charged, since last I charged it was on a defected eGo charger. Once I vape it, I'll come back and post how many hours it lasted, then lather, rinse, repeat.

Hmm, interesting. It's now cycling between GREEN ON and RED ON, and as it does this, the voltage changes between 4V and 4.2V respectively. I think this is the maintenance mode, but don't see anything on that in the unfortunately brief Pila manual.

 

[mdocod]

Hypothesis:

When the Pila IBC terminates the charge, the eGo goes back into the normal "mode" of bucking the output voltage to ~3.2V, which could theoretically show up as anything from 3.2-4.1V depending on the way it is measured. The pila IBC will not normally initiate a charge on a cell unless the voltage presented is less than ~4.05V. When the charge stops and the eGo goes back into it's normal output mode, the apparent voltage (that the IBC sees) drops below the threshold that will trigger the charge to start up again.

The constant attempt to initiate the charge again is going to be worse for the cell over the long haul. Most cheap li-ion cell chargers I have tested are flawed in that they do not properly terminate the charge. the IBC is one of the few chargers that does properly terminate. Well.... until now You have found a way to trick the IBC into not properly terminating.

Eric

 

[Whistle_Pig]

Well, that's an interesting thought. I do take it off right away -- since it takes only 2 hours to charge, it's easy for me to do that. But yeah, the circuitry of the eGo could well be causing an oscillation. Whether that actually gets to the cell itself, I don't know. The LED doesn't blink when this is occurring, so I wonder if the overcharge protection is kicking in before any charging current can be applied to the cell.

You gonna make it to http://www.e-cigarette-forum.com/fo...55015-colorado-vaping-meet-feb-19-2011-a.html ?

 

[Whistle_Pig]

Not completely mysterious is the futher observation that the Pila doesn't charge them to the same level as the eGo charger.

I had thought, today, that my batt went dead a little too quickly. So I charged it on the Pila, then put it on the eGo charger. The LED flashed, and the charger is indicating that it's charging. It'll be interesting to see how long it takes to reach "full".

ETA: I wasn't paying close attention, but call it about an hour to reach "full" on the eGo USB charger, after coming off the Pila.

 

[mdocod]

There are 2 possibilities:

1. The eGo electronics naturally buck the voltage in reverse as well, requiring a higher charging voltage than other direct drive devices. This is common with protected LiCo chemistry 3.0V cells that are actually 3.7V cells behind the regulator. In the case of those types of cells, it is not uncommon for the chargers to run ~4.4V to get the cell up to ~4.2V correctly. There was another thread here recently about using a 510 charger on an 808 cell. If this condition is true, then the 510 charger could severely damage and over-charge other ecig batteries.

2. The eGo electronics are not bucking the charging voltage, but the charger is for whatever reason charging the cell a little higher than the IBC would normally go. In my experience, IBCs are fairly consistent with a pretty tight tolerance at ~4.18-4.22V per cell as reported by most users (very few users report ranges outside of this). Many other cradle chargers I have tested (which may share their lousy charge methods with ecig chargers) don't throw a green light until ~4.23V or higher, and often will continue to trickle and float the cell up to ~4.27V if the cell remains on the charger even after the light turns green. The high resistance of the output circuit on most of these "floater" type chargers can lead to a very slow final top up, which may explain the long charge period to get the final top up there.

If you could slip a DMM into the circuit with the eGo charger and observe the charging voltage through the charge that would really reveal a lot about what is going on here.

Eric