Evercool VV with USB charger/pass-through

[the.vapyre]

I keep hitting dead-ends trying to find proper components to build a variable-voltage mod using the evercool regulator with a built-in USB charger/passthrough. You can't charge 2 li-ion batteries in series so with one cell, you have to use a boost/buck Power Cell - LiPo Charger/Booster - SparkFun Electronics but those don't put out enough wattage.

A 7.4v battery pack Lithium Li-Ion 18650 7.4V 2200mAh Battery Pack L18650-2200-2 with a protection pcb takes too much to charge with the USB chargers http://www.sparkfun.com/products/10401 I have found.

Does anyone have any ideas?

 

[VpnDrgn]

Battery Junction has a universal charger for those battery packs.
Just scroll to the bottom of the page you linked for the batts.

I don't know about using as a PT though.

 

[Java_Az]

It can be done but the USB part is going to be a tough one. To charge two li ions in series or a pack you going to need at least 8.7 volts for most charging chips. So a USB thats 5 volts is not going to cut it. Running a boost regulator for just the battery charging chip is excessive. As far as i know i have not seen any boost charger chips in my travels. Your also not going to find these small li ion chargers pre made ( like the one you posted ) that will do series charging. So your going to have to design the charging circuit from scratch. Pretty much going to have to learn how to etch your Own PCB and learn the CAD software for that.

I am almost done with my MOD that uses the evercool chip and with have onboard charging. Had a bunch of stuff come up and haven't been able to work on it in almost 2 months now. Going to release it open source so anyone can make it. Might be a few weeks but hopefully it will be done soon.

 

[VpnDrgn]

Like Java says, it can be done but it is pretty hard core.

I talked to the guys at Battery Junction and they explained that the batt packs have the
appropriate pcb for multi cells and a poly switch for extra protection. The univ charger at the
bottom of the link for the batts is made for charging 1 to 4 cell packs at various different
voltages. Unless you are dead set on having the actual charging circuitry built into the mod
you can adapt my idea for charging without having to take out batts.
The following drawing is for a mod I plan to build after I figure how to make the enclosure
that I want to use. View attachment VV BOX MOD V2.pdf
Of course, you would sub your evercool circuit for the pre-fab board I noted.

 

[CraigHB]

To do it with USB, you'd have to come up with a circuit that breaks the batts out and then connects each one to a separate charger module. Perfectly do-able with the right mechanical switch. In charge mode, the switch connects each battery to a separate charger. In run mode, it connects the batts as required to power the atomizer. You'd need a double throw switch with three poles I think. Something like that, you'd have to draw it out. I know double throw slide switches with 4 poles are available so it shouldn't be a problem finding the right switch. Hopefully, one with a high enough current rating won't be too large.

It would be possible to do it automatically with a set of power FETs by slaving battery configuration to the trigger, but I believe that would be beyond the scope of what you're looking to do. You'd need to do some intricate PCB work for that.

You can use one connector with both charger modules. Just unsolder the receptable on one of the boards and wire it up to the other board. There is a 500mA current limit on older USB 2.0 connectors and ports. USB 3.0 is higher, 900mA. Powering both modules off one port should be fine, just make sure you are using USB 3.0 cables and ports. You can also use a USB charging port (usually a wall wart) which should have 1500mA capacity per the USB 3.0 specification.

Otherwise, to come up with a VV mod that has built-in charging, the easiest thing to do would be to use a single battery with the PTN04050C boost module. In that case, you could probably just tack on the USB charging module.

 

[bstedh]

I drew up something similar using two small charge circuits. This could be modified to use a STDP momentary so the charge circuit is disabled when vaping.

This would need to be refined some more but gives a good idea of where to start.

 

[the.vapyre]

Your last idea sounds easiest but does that booster put out enough current? What about using a dual-coil cartomizer? I don't mind using one battery though.

To do it with USB, you'd have to come up with a circuit that breaks the batts out and then connects each one to a separate charger module. Perfectly do-able with the right mechanical switch. In charge mode, the switch connects each battery to a separate charger. In run mode, it connects the batts as required to power the atomizer. You'd need a double throw switch with three poles I think. Something like that, you'd have to draw it out. I know double throw slide switches with 4 poles are available so it shouldn't be a problem finding the right switch. Hopefully, one with a high enough current rating won't be too large.

It would be possible to do it automatically with a set of power FETs by slaving battery configuration to the trigger, but I believe that would be beyond the scope of what you're looking to do. You'd need to do some intricate PCB work for that.

You can use one connector with both charger modules. Just unsolder the receptable on one of the boards and wire it up to the other board. There is a 500mA current limit on older USB 2.0 connectors and ports. USB 3.0 is higher, 900mA. Powering both modules off one port should be fine, just make sure you are using USB 3.0 cables and ports. You can also use a USB charging port (usually a wall wart) which should have 1500mA capacity per the USB 3.0 specification.

Otherwise, to come up with a VV mod that has built-in charging, the easiest thing to do would be to use a single battery with the PTN04050C boost module. In that case, you could probably just tack on the USB charging module.

 

[the.vapyre]

Also, with this booster, would I still be able to use the evercool?

To do it with USB, you'd have to come up with a circuit that breaks the batts out and then connects each one to a separate charger module. Perfectly do-able with the right mechanical switch. In charge mode, the switch connects each battery to a separate charger. In run mode, it connects the batts as required to power the atomizer. You'd need a double throw switch with three poles I think. Something like that, you'd have to draw it out. I know double throw slide switches with 4 poles are available so it shouldn't be a problem finding the right switch. Hopefully, one with a high enough current rating won't be too large.

It would be possible to do it automatically with a set of power FETs by slaving battery configuration to the trigger, but I believe that would be beyond the scope of what you're looking to do. You'd need to do some intricate PCB work for that.

You can use one connector with both charger modules. Just unsolder the receptable on one of the boards and wire it up to the other board. There is a 500mA current limit on older USB 2.0 connectors and ports. USB 3.0 is higher, 900mA. Powering both modules off one port should be fine, just make sure you are using USB 3.0 cables and ports. You can also use a USB charging port (usually a wall wart) which should have 1500mA capacity per the USB 3.0 specification.

Otherwise, to come up with a VV mod that has built-in charging, the easiest thing to do would be to use a single battery with the PTN04050C boost module. In that case, you could probably just tack on the USB charging module.

 

[Java_Az]

The PTN04050c has a max rating of 12 watts. So a dual coil thats 1.6 ohms total resistance @ 5 volts will consume 15.65watts. So you would be pushing it past it's rated maximum. The PTN04050c has a minimum voltage output of 5 volts. Although there are a few tricks to get the circuit to go lower they are not very efficient.

This is just my opinion but USB in any form is completely underrated for vaping. It might be ok for charging smaller batteries but not for a True passthrew mode. The evercool chip is a bad ... regulator. I would think twice about trading it off for USB.

 

[the.vapyre]

Nice idea and drawing! This must be how the Tekkeon works. Would switching between charge and vape be manual or would there be a way for it to be automatic or is that what this already does?

I drew up something similar using two small charge circuits. This could be modified to use a STDP momentary so the charge circuit is disabled when vaping.

This would need to be refined some more but gives a good idea of where to start.

 

[the.vapyre]

You are right. I don't want to trade it off. I am just brainstorming.

The PTN04050c has a max rating of 12 watts. So a dual coil thats 1.6 ohms total resistance @ 5 volts will consume 15.65watts. So you would be pushing it past it's rated maximum. The PTN04050c has a minimum voltage output of 5 volts. Although there are a few tricks to get the circuit to go lower they are not very efficient.

This is just my opinion but USB in any form is completely underrated for vaping. It might be ok for charging smaller batteries but not for a True passthrew mode. The evercool chip is a bad ... regulator. I would think twice about trading it off for USB.

 

[CraigHB]

bstedh got you started in the right direction by posting that schematic. You could slave the whole thing to a momentary switch if you can find one with the right throw and enough poles and high enough current rating, might be difficult to find one though. That' where you would have to use power FETs, so you could use a low current switch to do the whole task.

Boost regulators can never go much below battery voltage. The less efficient ones that use a diode rectifier can go about a 1/3 of a volt below battery voltage. So even if the PTN04050C can be run below 5V, you still have that lower limitation. The buck regulator is always going to give you the most power output (because you're reducing, not increasing voltage) and the widest voltage range. The booster I use in my single batt mod doesn't go below 4.1V when the battery is at 100% charge.

 

[bstedh]

Nice idea and drawing! This must be how the Tekkeon works. Would switching between charge and vape be manual or would there be a way for it to be automatic or is that what this already does?

This was just a concept drawing to figure out how the connections would be made. You can use the same idea however where the charge circuit is active when off and then deactivated when you push the button to vape. You can achieve this with multiple different layouts and switch/fet configurations but a STDP momentary would work for switching the battery + connection between charge and vape. You could even find a logic circuit that would do all the switching for you.

And like CraigHB stated your switch will determine how you lay out the circuit. I would start with finding a switch and working backwards from there. I saw a rocker switch that was DTDP that was momentary in one direction and toggle in the other that would be perfect but for the life of me I can't remember where I saw it.

 

[the.vapyre]

I like the idea of it switching automatically. I want it to work like the Ego passthrough. What specifically do I need to look for? I am totally new to this. I found this http://www.powerdirect.com.tw/DS/4098f.pdf

This was just a concept drawing to figure out how the connections would be made. You can use the same idea however where the charge circuit is active when off and then deactivated when you push the button to vape. You can achieve this with multiple different layouts and switch/fet configurations but a STDP momentary would work for switching the battery + connection between charge and vape. You could even find a logic circuit that would do all the switching for you.

And like CraigHB stated your switch will determine how you lay out the circuit. I would start with finding a switch and working backwards from there. I saw a rocker switch that was DTDP that was momentary in one direction and toggle in the other that would be perfect but for the life of me I can't remember where I saw it.

 

[Java_Az]

The Ego passthrough Is not really a True passthrough. The USB just charges the Battery. So there is no automatic switching when you plug it in. The chip you posted from linear is a QFN 3mm x 4mm The solder pads are on the bottom of the chip. they are not the easiest to work with. To give you an idea of how small they are i will post a picture of a board i made myself with a QFN chip thats 4mm x 4mm next to a dime. just letting you know how much fun these types of chips are to work with

 

[the.vapyre]

Wow! I don't think I am there yet but impressive. That would be OK to just charge the 2 batteries in parallel with one usb port. It doesn't have to be a true passthrough. What would I need to use them while they are charging?

The Ego passthrough Is not really a True passthrough. The USB just charges the Battery. So there is no automatic switching when you plug it in. The chip you posted from linear is a QFN 3mm x 4mm The solder pads are on the bottom of the chip. they are not the easiest to work with. To give you an idea of how small they are i will post a picture of a board i made myself with a QFN chip thats 4mm x 4mm next to a dime. just letting you know how much fun these types of chips are to work with

 

[Java_Az]

Thanks too bad thats a scraped design. Heat issues with the charging chip so i had to rework it really sucked cause the other side of the board i really liked alot. New design still has the eagle but just not as nice as this one

The evercool chip needs the batteries to be in series to work. Switching them to parallel to charge would work. I thought about that for my design but scraped the idea. You might want to wait and see my MOD when I get it done. It solves the problems but it is going to be advanced as far as Mod Skills goes. It wont have a QFN chip since I scarped it. The chip i moved to has pins so it is easier to work with. trust me if there was a easy way to add on board charging to the evercool it would have been done by now. Anyways back to work for me.

 

[CraigHB]

Yea, those QFN chips are a ....., but they are do-able with some good magnification. The charging circuit in my latest mod uses a 3x3 and 3x4. One nice thing about them, you can use vias to connect the large bottom contact to the ground plane. Get some good heatsink action that way. For example, the charger controller I tried in one of my first mods was in an MSOP package. It couldn't charge at a very high rate before going into thermal limiting. As soon as I changed it out with the same chip in a QFN package and a couple ground plane vias, I could run it full tilt all the way. I was hoping it would work out that way and it did so I was pretty pleased about that.

I've been using the QFN/DFN packages more and more lately as some chips are no longer available with external pins. Though, I don't know what I'm going to do when they start making them smaller than that. Might have to find a new passtime.

There is some risk involved in charging batts in parallel. What can happen is unbounded current flow if there is much of a discrepancy in voltage when the batteries are initially connected. I just read of an RC guy that vented a LiPo batt hard when connecting it in parallel with other batts for charging. They need to be the same within a couple tenths of a volt and that often does not happen when discharging them in series.

 

[the.vapyre]

THAT IS SO FREAKING COOL! THAT IS A WORK OF ART! HOW DID YOU DO THAT! And how could you solder such tiny connections! I could understand if it were a robot doing it but did you connect that little tiny chip by hand?

Thanks too bad thats a scraped design. Heat issues with the charging chip so i had to rework it really sucked cause the other side of the board i really liked alot. New design still has the eagle but just not as nice as this one

The evercool chip needs the batteries to be in series to work. Switching them to parallel to charge would work. I thought about that for my design but scraped the idea. You might want to wait and see my MOD when I get it done. It solves the problems but it is going to be advanced as far as Mod Skills goes. It wont have a QFN chip since I scarped it. The chip i moved to has pins so it is easier to work with. trust me if there was a easy way to add on board charging to the evercool it would have been done by now. Anyways back to work for me.

 

[the.vapyre]

YOU GUYS ARE TRUE GENIUSES AND I AM HONORED TO BE ABLE TO INTERFACE WITH YOU! PEOPLE LIKE YOU ARE WHAT DRIVES TECHNOLOGY FORWARD. THANK YOU FOR WORKING WITH ME! There is so much that I don't yet know and understand but I have become obsessed about it.

Yea, those QFN chips are a ....., but they are do-able with some good magnification. The charging circuit in my latest mod uses a 3x3 and 3x4. One nice thing about them, you can use vias to connect the large bottom contact to the ground plane. Get some good heatsink action that way. For example, the charger controller I tried in one of my first mods was in an MSOP package. It couldn't charge at a very high rate before going into thermal limiting. As soon as I changed it out with the same chip in a QFN package and a couple ground plane vias, I could run it full tilt all the way. I was hoping it would work out that way and it did so I was pretty pleased about that.

I've been using the QFN/DFN packages more and more lately as some chips are no longer available with external pins. Though, I don't know what I'm going to do when they start making them smaller than that. Might have to find a new passtime.

There is some risk involved in charging batts in parallel. What can happen is unbounded current flow if there is much of a discrepancy in voltage when the batteries are initially connected. I just read of an RC guy that vented a LiPo batt hard when connecting it in parallel with other batts for charging. They need to be the same within a couple tenths of a volt and that often does not happen when discharging them in series.