I'll discuss it a bit here first.
Are you using a protected battery in the device you wish to usb recharge ?
USB charger built in for nicostick
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I'll discuss it a bit here first.
Are you using a protected battery in the device you wish to usb recharge ?
Well, according to this page: Protection circuit Module (PCB) for 3.6V(3.7V) Li-ion (18650/18500) cell Battery
"3.6V Li-Ion Batery pack is overcharge
3.6V Li-Ion Battery pack is overdischarge
3.6V Li-Ion Battery pack 's discharging current is more than 2A."
The inbuilt protection circuit inside protected batteries not only protects against over discharge and overload current ('short'), but also over charge
Now, we know that a USB supply provides a stable and known voltage (5v), not much above what we need. The absolute maximum voltage that ww can give a lithium is 4.2 so the difference is 0.8v, a drop that could be achieved with perhaps 2 carefully chosen power diodes (with a forward voltage drop of 0.4-0.5). A 1n4001 type diode's voltage drop depends on manufacturer, so care is needed (could be anywhere from 0.2 to 0.8v). Then we need to limit the current; and to be very safe, 100mA. When the battery is at max allowed discharge this is about 2.5v left. So 4.2-2.5=1.7v. So the resistor we need would be 1.7/0.1=17 ohms; let's be safe again and round it up to 22 ohms (a standard resistor value). With a protected battery, this should work and be safe; but be somewhat slow. The charge current will tail off as the battery is charged.
By way of balance, a very cautious approach is discussed here: http://dev.emcelettronica.com/howto-use-usb-to-recharge-lithium-battery-li-ion
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It will be slower than the 100mA charger because there is no contsant current charging phase; but this uses only components with 2 legs
And we will be recharging long before the maximum discharge state is reached, where special soft recharging is best used; actually this circuit would be quite soft anyway.
If find an LED that has a 0.8v drop it could be used in series with a 22 ohm resistor; and that's all; as the battery charges the LED dims.
This is just theoretical of course and not recommended.
But if one did do this, the first step is to make sure there is no more than 4.2v after the diode(s), then add the 22 ohm resistor between diode(s) and battery.
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I'm watching this thread with great interest, as this will probably be my next mod (although with an M401 connector). The biggest reason I love this site is the passion people have for improving the technology. Stevo_tdo, you're a great example, and an inspiration for all the modders (and would-be modders) here, and kudos to you, kinabaloo, for your support in Stevo's efforts.
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My $.02: Since it seems fairly certain that the USB charger will charge the 14500, would it make sense to simply build a charging adapter for the NicoStick that has a battery connector on one end to connect to the USB charger and connect the other end through a standard power connector on the battery box? Perhaps I'm oversimplifying the issue, but it seems to me that this would be easier than trying to engineer a change to the charging board or designing new USB charging circuitry.
Alternatively, would it be difficult to build a desktop charging station (USB or AC-powered) with the necessary electronics inside, so you could simply "dock" the NicoStick in the same fashion as an iPhone?
I've considered an adapter made from wooden dowels (the same size as batteries) containing contacts at the end, that would just drop into the battery charger and plug in to the NicoStick, but your solution is much more elegant.
I'm still a newbie at this, so I'm probably just spouting in the dark, but I look forward to how this develops. Stevo_tdo, have you received your batteries yet?
Q4mK
- - - - - - - My $.02: Since it seems fairly certain that the USB charger will charge the 14500, would it make sense to simply build a charging adapter for the NicoStick that has a battery connector on one end to connect to the USB charger and connect the other end through a standard power connector on the battery box? Perhaps I'm oversimplifying the issue, but it seems to me that this would be easier than trying to engineer a change to the charging board or designing new USB charging circuitry.
Alternatively, would it be difficult to build a desktop charging station (USB or AC-powered) with the necessary electronics inside, so you could simply "dock" the NicoStick in the same fashion as an iPhone?
I've considered an adapter made from wooden dowels (the same size as batteries) containing contacts at the end, that would just drop into the battery charger and plug in to the NicoStick, but your solution is much more elegant.
I'm still a newbie at this, so I'm probably just spouting in the dark, but I look forward to how this develops. Stevo_tdo, have you received your batteries yet?
Q4mK
Heck no, I'm cheep. Ordered 2 14500's and a charger from focalprice.com and opted for free shipping. 7-14 business days delivery. Going to visit the wifes family this weekend though and will scrounge for some batteries there.
Well as far as the progression of the charger i've made some progress. Of course I won't say if it all works until I can test it for a little while after my batteries arrive. If i new how to draw a schematic (might have to learn today) I would run it by kinabaloo. Would allow incorporation of a m401 charger board or similar size one and allow charging or usb passthrough via a 3 position switch. On the same note, I can fit this all in the standard aa box. Just wish there was a 4aa box that was long or an aa box that was about 5mm wider and longer.
Of course what I would love to find is an enclosed double c box. That would be orgasmic. I know i could use a c battery flashlight but its much easier with a box with a removable side.
Of course what I would love to find is an enclosed double c box. That would be orgasmic. I know i could use a c battery flashlight but its much easier with a box with a removable side.
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Two options, one with a two-way switch (like the master on/off slider or a toggle, so long as its a SPDT type (a DPDT would work too)).
The above configurations are only required for getting the full (or nearly full) power of the USB in passthrough mode. Otherwise just draw from the battery while charging.
In all cases, the box labelled Atomizer has the push button for activating the heater coil.
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Does this make any sense.
Nearly. You don't need the 'one way' bit or two negative/ground lines to the atty.
Otherwise, it's ok.
However, if you wire the 2 way switch as i did in my second diagram, the battery remains on charge while using as a passthrough; perhaps not important.
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Better?
Yeah, if it will function as a passthrough while on charge that's a plus. Would like to flip switch to left = passthrough, switch to right = charge, switch neutral = battery power. Not have to stop charging to use passthrough but if battery is already fully charged, bypass battery for true passthrough
Yeah, if it will function as a passthrough while on charge that's a plus. Would like to flip switch to left = passthrough, switch to right = charge, switch neutral = battery power. Not have to stop charging to use passthrough but if battery is already fully charged, bypass battery for true passthrough
Better?
Yeah, if it will function as a passthrough while on charge that's a plus. Would like to flip switch to left = passthrough, switch to right = charge, switch neutral = battery power. Not have to stop charging to use passthrough but if battery is already fully charged, bypass battery for true passthrough
That will work
A three position switch:
* straight passthru
* vape from battery
* charge (if usb connected) & vape from battery
However, the middle position of the switch is not really needed; just unplug the usb cable (charging will only continue as necessary anyway). So a 2-way switch would be sufficient (same circuit).
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Two options, one with a two-way switch (like the master on/off slider or a toggle, so long as its a SPDT type (a DPDT would work too)).
The above configurations are only required for getting the full (or nearly full) power of the USB in passthrough mode. Otherwise just draw from the battery while charging.
In all cases, the box labelled Atomizer has the push button for activating the heater coil.
Kina - wouldn't you need some more components to bias the diodes in the diagram above? If I'm remembering correctly, there's nothing to prevent a 'double feed' to the atomizer in the config shown.
If I'm wrong, can you clue me in? Pardon my rustiness, but Electronic Principles class was a long, LONG time ago...
True; but no problem. The current will be almost entirely from the line at the higher voltage; or from both if they are about the same (say, 0.5v of each other, depnding on the diode's forward drop).
*digging WAAAAY back into memory* If I'm understanding you, whichever line is carrying more voltage, the backfeed into the other line will reverse bias that diode and block that feed, correct?
Here's a link to something i'm going to try also.
SparkFun Electronics - LiPoly Charger - Single Cell 3.7-7V Input
For single cell lithium ion or poly. No need to remove battery just plug in usb or dc
And from the way it sounds you could vape while charging
Thinking about pairing it with this
http://www.sparkfun.com/commerce/product_info.php?products_id=339
And put it in this ,= obviously after a slight date with my dremel
http://www.pololu.com/catalog/product/1152/specs
And hook it to the atty with this
http://www.sparkfun.com/commerce/product_info.php?products_id=8670
I figure if i'm going to tear apart a 12+ dollar charger I can buy one with usb already on
Just a simpler way of doing what i set out to do. Anyone could buy this and do it then
SparkFun Electronics - LiPoly Charger - Single Cell 3.7-7V Input
For single cell lithium ion or poly. No need to remove battery just plug in usb or dc
And from the way it sounds you could vape while charging
Thinking about pairing it with this
http://www.sparkfun.com/commerce/product_info.php?products_id=339
And put it in this ,= obviously after a slight date with my dremel
http://www.pololu.com/catalog/product/1152/specs
And hook it to the atty with this
http://www.sparkfun.com/commerce/product_info.php?products_id=8670
I figure if i'm going to tear apart a 12+ dollar charger I can buy one with usb already on
Just a simpler way of doing what i set out to do. Anyone could buy this and do it then
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