Internal usb charging; best/safest method?

[Digital-Dragon]

So, I really want to be able to charge my 18650's inside a box mod, ideally by plugging in a mini or micro usb cord.

I have read that this is possible, though some suggest using a dc jack instead of usb, and some others suggest using a 510 or eGo/riva charger and taking the internal electronics out of an ego/riva batt and wiring in that, and then using only the aw imrs since they are unprotected like egos.

My main question about all this is about safety.
1) What is the easiest/safest way to internally charge a single 18650? (Either protected or aw, and I don't care about dual batt charging, at this point I just want to figure out how to charge a single batt safely. I'll tackle a tekkion style mod eventually.)

Some other questions;
2) I assume that simply screwing one of my 18650 single batt mods onto a ego/riva charger would work, but I have no idea how safe it would be, do you? And should I use protected or aw batts if I try that? (Which I won't unless I'm assured it is okay to do.)

3) What would I also need to do if I want to use the usb breakout board from madvapes or a similar one? I want it to stop charging and activate a green led when it is done charging. I have a few links saved that I got here on ecf, sorry I forgot who posted them originally.

LiPo Charger Basic - Mini-USB - SparkFun Electronics
or this?
http://www.adafruit.com/products/259

4) Should I use a fuse or some other type off protection, and what is the best method for installing them?

I don't expect total safety, but I want as much peace of mind from this as my tr-001 charger gives me. Also, I know the difference between a passthrough and internal charging, I don't need passthrough capability, but I would like to be able to use it while it is plugged in.

I'm sorry about all the questions, hope they are acceptable. I have been a lurker for so long... these questions got all bottled up inside me and it feels good to release them. Any other tips/info you have about internal charging is appreciated, and if you only want to answer one and not all of my questions thats fine. Thanks for your input in advance folks!

 

[Deadite]

In mine I'm just using a 18650 cell from a laptop connected to a protection circuit like this one.
Because of it's small size a used a mini USB connection and wired it to the out/charge terminals of the protection circuit as directed by it's data sheet. I use an lithium ion smart charger with a USB cable I adapted to the charger's connection.

I don't use a fuse or any other protection other than what is provided by the protection circuit.

Hope that gives you some help/direction.

 

[Java_Az]

#1 either of the chargers you posted will work to charge a 18650. But the max on those are 500mA which means for a 2800mah battery your looking at about 7 to 8 hours to fully charge. Also Question #3 LED should be built into the charger it self not something you want to add afterwards. The second link to a charger you posted looks like it has build in LED's one for charging and one for when it is done.

#2 no it wont work without the ego type circuit to let it charge without the switch pressed. Most mods use a direct switch , battery to switch other side of switch to the atomizer battery connector. A ego charger wont work on that type of mod unless the switch is pressed on .

#4 Using a protected battery is all you really need as far as protection. You can add a ptc fuse or poly switch but that's a bit of over kill for a single battery mod if you ask me. If it is going to be a sealed mod be sure to add vent holes

Edit: Looks like the first charger has a status LED from what it says on the page. so both have built in LED's

 

[Digital-Dragon]

Thanks Deadite, I like that link. But I don't want to have to use a special charging cable, I want to be able to use a regular mini/micro usb cable...

#1 either of the chargers you posted will work to charge a 18650. But the max on those are 500mA which means for a 2800mah battery your looking at about 7 to 8 hours to fully charge. Also Question #3 LED should be built into the charger it self not something you want to add afterwards. The second link to a charger you posted looks like it has build in LED's one for charging and one for when it is done.

#2 no it wont work without the ego type circuit to let it charge without the switch pressed. Most mods use a direct switch , battery to switch other side of switch to the atomizer battery connector. A ego charger wont work on that type of mod unless the switch is pressed on .

#4 Using a protected battery is all you really need as far as protection. You can add a ptc fuse or poly switch but that's a bit of over kill for a single battery mod if you ask me. If it is going to be a sealed mod be sure to add vent holes

Edit: Looks like the first charger has a status LED from what it says on the page. so both have built in LED's

Thank you Java! I had been wondering about charg time... I think less than 8 hours is okay with me, but if there is a quicker way to do it I'm all ears. I knew those usb boards had leds, I just was not sure if they are the best thing to use, but they seem good.

That makes sense about the ego circuit, thanks for explaining how that works. I'll let that idea go I think.

So far I've built a puck, 2 single batt unregulated 18650 mods, and a vv with the kit from madvapes, all box mods in mint boxes. I really want to do this internal charging the right way, so I don't have to worry about it while I have it plugged in and charging.

Would it be okay to vape while its plugged in?
I feel like I almost have enough knowledge to make this happen, but any other suggestions about this are greatly appreciated!

 

[slimest]

I use this board: 2Pcs USB 5V Lithium Li-ion Battery 1 Cell Charger Board US3 | eBay
Here is my mod: http://www.e-cigarette-forum.com/fo...ck-boost-stick-based-happy-vaper-booster.html
The charger seems to work reliably. You can use your cigarette either as passthru or an autonomous system. Just works.

 

[Digital-Dragon]

I use this board: 2Pcs USB 5V Lithium Li-ion Battery 1 Cell Charger Board US3 | eBay
Here is my mod: http://www.e-cigarette-forum.com/fo...ck-boost-stick-based-happy-vaper-booster.html
The charger seems to work reliably. You can use your cigarette either as passthru or an autonomous system. Just works.

Thanks slimest, I like seeing how others are going about this.

Also, if any other of you folks reading this have made an internally charging mod, please show/tell about it here!

 

[Java_Az]

This charger is settable up to 1 amp with soldering a threw hole resistor to the board. https://www.adafruit.com/products/259 . would cut charging time down to around 4 hours or so.

 

[Digital-Dragon]

This charger is settable up to 1 amp with soldering a threw hole , resistor to the board. https://www.adafruit.com/products/259 . would cut charging time down to around 4 hours or so.

I read that, I've been doing a lot of reading, spec pages... One seemed to say it was less safe to charge at 1amp then half that?

 

[Java_Az]

I read that, I've been doing a lot of reading, spec pages... One seemed to say it was less safe to charge at 1amp then half that?

1 amp charge rate for a 18650 is no even close to unsafe, unless you using some knock off batteries. For example a Panasonic 18650 3100mah battery has a max charge rate of 3.1 amps. Although charging at 3.1 amps will effect the life of the battery it is still safe to go that high. For the longest life you want to cut that 3.1 in half so 1.55 amps would be well into the safe range and the battery will last a lot more cycles. For quality li ion batteries a good rule of thumb is to charge at Half of capacity so a 18650 2600mah battery would have a max charge rate of 2.6 amps and a ideal charge rate for longevity of 1.3 amps

 

[Digital-Dragon]

Thanks again, I'll totally kick it up to one amp when I use it.

 

[Digital-Dragon]

Also, can this LiPo Charger Basic - Mini-USB - SparkFun Electronics be used while charging? I assume so... I know the big one can because it has two jst connections, one for batt-in and one for batt-out.
The big one - https://www.adafruit.com/products/259 is too big for the box I have in mind, but it seems like a great mini usb charger, so maybe a bigger box is in order...
Can this https://www.adafruit.com/products/354 be used for our purposes? It's 2 cells each with a 2c rating, seems like ecf recommends 5?

And finally, come on folks, I know some more of you have built-in charger mods you wanna show off...!

 

[slimest]

The charger should work, why not.
About 2C or 5 C. It does not matter, how many C. You should concider your real maximal current. In e-cigs even if you use a step-up converter, real currents are no more than 4-5A (it's about 14-16 watts on the heater for 3.7V battery). This battery can be used even for bigger currents.
Actually no need to choose exactly this battery, you can use any cylinder accumulators with capacity 2.2A-h and more if you connect them in parallel forever. You will get needed capacity and appropriate loading ability.

 

[CraigHB]

#4 Using a protected battery is all you really need as far as protection. You can add a ptc fuse or poly switch but that's a bit of over kill for a single battery mod if you ask me.

In general, that's true, but I would add some notes.

You're pretty well covered with any protected cell, but there's nothing wrong with a backup. The protection circuits used on a cell are not 100% guaranteed reliable. Though, cells like the Panasonic NCR18650A have a built-in PTC in addition to the required protection PCB. Not all cells are guaranteed to have that, but it's becoming the standard for ICR cells.

When using a regulator to step-down voltage, you do have a backup in that the regulator will sense an over-current condition and limit input current. However, with an unregulated mod or boosted mod, you're fully reliant on the cells protection circuitry. In that case, a backup may be something to think about, especially of the cell does not have a built-in PTC.

Of course, when using an unprotected cell such as an IMR battery, my feeling is you absolutely must have some over-current protection even though the chemistry is "safer". IMR cells typically do not have built-in PTC devices. Again, for a regulator that steps down voltage, you have a some over-current protection. For an unregulated or boosted mod, you have no protection and I think adding it is a must when using an IMR cell or other uprotected cell with that particular configuration.

 

[Digital-Dragon]

Thank you CraigHB, this is the direction that I have been hoping the conversation would go. I have parts for vv that I'm about to build, but am still using unregulated mods atm. I have both trustfire protected 18650s and aw imrs (which I prefer of course, and what ecf recommends) so the part you said about imrs strikes a cord with me and is something I've been thinking about for a while. I'm going to incorporate multiple layers of protection into all future projects, just to be as safe as possible. Feel free to post links to those panasonics or other ircs... Or any other pertinent links... Thanks again.

 

[MadmanMacguyver]

I recommend a separate protection PCB in the mod so you have the option of using any batteries you choose in the mod safely...they sell chargers to go with the PCBs also...be sure to pick a PCB w a matching cutoff to the batteries you will be using...safer that way

 

[Digital-Dragon]

I recommend a separate protection PCB in the mod so you have the option of using any batteries you choose in the mod safely...they sell chargers to go with the PCBs also...be sure to pick a PCB w a matching cutoff to the batteries you will be using...safer that way

Thanks for the advice, this is more of the way I was hoping the conversation would go.

I feel like I'm totally competent with all this stuff as long as I have a definite plan of action, and I think I basically do at this point, but all the options in that link kinda overwhelm me... I'll spend some time studying it though.

Also, I should have just titled this thread "various ways to do usb charging as safely as possible." Because I really think on-board charging is the wave of the future for mods, and I'm totally interested in finding out the different ways to do it, and have it be as safe as my tr-001 charger.

 

[MadmanMacguyver]

lol...Actually I am prototyping several internal stacked batt mod designs one of which is smaller than a pack of cigs...

to give you an Idea of how careful I am being w regards to safety....I didn't switch to a Li-Ion chemistry from NiMH and NiZN for 6 Mo after I started vaping due to seeing a flashlight on my friends hip explode...(no injury except his pride)

eventually after I get everything in order the smaller unit's design will be posted in the modders forum...

anyway good luck w your modding....

 

[Digital-Dragon]

My first mod was also a ni-mh. It is basically a "puck mod" in a newman's box (of course.) I hadn't thought about adding usb charging to that, only my 18650 mods, but now you have got me thinking...

Edit: I'm now eagerly awaiting your design post.

 

[CraigHB]

The charging profile is totally different comparing NiMH to Li-Ion. NiMH charging is purely current driven so charging voltage needs to be considerably higher than nominal cell voltage, usually about 1.6V per cell plus overhead for the charger. With 4 cells in series, you need a 9V source ideally. USB is only 5V. Also, you need a NiMH charger and there are no USB modules available that I've seen. You'd have to build one yourself with a NiMH charger controller chip. You could use a boost regulator to bump the voltage high enough to charge a 4 cell NiMH pack. Though, it would be complicated compared to a USB Li-Ion charger.

Another issue is loading. With a Li-Ion charger, you can throw the intermittent load of an atomizer on it. It doesn't cause a problem for the charger. Since NiMH chargers typically monitor changes in current to detect when the charge cycle is complete, the cells have to be undisturbed and completely isolated until charging is finished. You wouldn't be able to charge and vape at the same time like you can with a Li-Ion powered mod.

 

[Digital-Dragon]

Thanks HB, I thought there would be some complications with that idea. No problem though, I like 18650's better anyway, and less complicated the better.