USB mini ports for charging

[LukeTheDuke]

hey all sweet and simple,

can anyone point me in the RIGHT direction?

on my next mod build id like to incorporate an MINI usb port to the mod, as so i can use any mini usb plug to charge up the batteries, anywhere and on the go...

any help or input, DO'es and DONT's is mucho appreciated... thank you all for your time

ill be using 2 protected 14500 batteries

id use and have used the search input here, but i never get anywhere with it really, a bunch of not on topic posts and threads... but no worries thats why iam asking...

is this even possible? charge my batts without a charger and only a usb plugger? theres more to it than that right? a coupla resistors right?

 

[mikael b]

Hi i just spent 3 full days searching for the same thing...
Hope that someone can help...

 

[devast]

This or if you want it cheaper with some diy: this and you add mini usb connector to your mod.

 

[mikael b]

This or if you want it cheaper with some diy: this and you add mini usb connector to your mod.

Will work with 2 protected 14500 batteries ?
On the page it says thea they designed to charge single-cell batteries..

 

[jimbalny]

This one here looks very good AND has pass through power:
USB LiIon/LiPoly charger [v1.2] ID: 259 - $12.50 : Adafruit Industries, Unique & fun DIY electronics and kits

I believe a single-cell charger will work with 2 14500's as long as they're connected in parallel (3.7v) as opposed to series (7.4v). So as long as you're not going to use a 5v or step-down regulator for VV I think you're good.

 

[mikael b]

Thanks a lot.

 

[mv2envy]

Will work with 2 protected 14500 batteries ?
On the page it says thea they designed to charge single-cell batteries..

Depends. If your batteries are connected in series, then no. If they are connected in parallel then yes.

 

[CraigHB]

This one here looks very good AND has pass through power:
USB LiIon/LiPoly charger [v1.2] ID: 259 - $12.50 : Adafruit Industries, Unique & fun DIY electronics and kits

Nice part, first one I've seen that uses the MCP73833. The SparkFun board and the ones you see on eBay use the MCP73831 which is the most basic charger controller. Though I just noticed SparkFun offers a high speed charger with an MCP73843, but it uses a barrel connector instead of USB. Barrel connectors have much higher current limits than USB connectors.

I use the MCP73833 chip myself, though I use the higher output DFN chip package for a 1000mA charging rate with a 5V barrel connector. It's for a big batt mod with a max 5A charging rate. The one linked to in the previous post is set to 500mA which is the maximum for the MSOP chip package. The DFN package has much better heat sinking, but you have to set up the PCB for it. I've tried the MSOP package and it hits thermal limiting once you go over 500mA. Upon closer inspection, it looks like that part also uses the DFN chip so you could probably mod it to increase the charging rate. Just change out the 2k resistor with a 1k resistor where it says "prog".

One other comment about that part, you can see just by looking at the circuit traces on the board it's only providing an additional connector parallel to the battery connector for the load. It's not offering any kind of "passthru" circuitry other than that. On my own mods, the MCU sends a disable signal to the controller when the atomizer is energized. The charger controller will probably work fine without any kind of disable or bypass, but I do that just to be sure the chip does not get confused by the sudden change in load. The MCP73833 has several safety features that are not present on the more basic chips.

I hope the OP understands you can only use these parts on a single Li-Ion cell or multiple cells in parallel.

 

[LukeTheDuke]

so its a no go on mutli cells then....

.... what if you had your batteries in series AND parallel? at the same time some how... say a jumper wire for only the charger, and so on...

i know this is a llllooonnnggg long shot, but my mind wanders many differant places

 

[LukeTheDuke]

thank you all for the advice and input too!

keep it coming if youse like

 

[mv2envy]

In series, this simple mini usb charger will not work no matter how you wire it. In parallel it will work just fine, slow to charge, but it will still work.

In series, the only thing that you can do for in box charging is use one of these chargers Compact Battery Balance Charger for 7.4V- 11.1V Li-Ion pack

You will also need this plug Compact Battery Balance Charger for 7.4V- 11.1V Li-Ion pack

and this one Connector/Adaptor: Convert from 3 Pin Male JST connector to 3 Pin Female JST (XH) connector

What you want to do is take the male end of the 2nd plug, cut it off and custom fit it to your mod. the other 2 female ends of the JST plug you will solder together to make a jumper to plug from your mod to the charger. Thats it. Its not a usb charger, but it will balance charge your batteries without the need to remove them from your case.

 

[QBass]

I don't know exactly what this would require, but it seems you could have it set up to switch from series to parallel when the usb socket is plugged in (or receiving power). Wouldn't it even be possible to have it switch regulator circuits based on the status of this switch? It seems you could then even have a 5 or 6v regulated device using a booster circuit while plugged in and parallel then switch to a more efficient PWM circuit while cordless and in series. VV should even be possible along these same lines. I know this probably wouldn't fit in an eGo sized unit.

Just thinking out loud in a silent way with an uneducated mind.

 

[CraigHB]

There's seems to be some debate on balancing versus "pack" charging for a two cell series pack. Ideally, a three wire balancing charger will give you the best cell longevity and run time, but someone said there really isn't a whole lot of disparity in terminal cell voltage when charging them with a two wire pack charger. The RC guys always use a balancing charger, but they typically run packs with more than two cells in series which makes balancing more critical.

I haven't tried charging series packs myself so I don't know, but it would be interesting to see some data on it. In other words, how much difference is there really in terminal voltage between each cell when charging a dual cell pack with a two wire charger versus charging the pack with a three wire balancing charger. Would like to see the data over a number of cycles to see how wear affects the results.

 

[mv2envy]

Well with protected cells you face the problem of one of the cells reaching 4.2V sooner than the other and the protection circuit kicking in and cutting the circuit to the other battery which hasnt reached full charge yet. This could shorten the life of the cell.

With unprotected cells, you risk overcharging one of the cells over 4.2V while the other one is below 4.2 tricking the charger into thinking the whole pack hasnt reached 8.4V yet.

The former (protected cells) poses no danger, just the risk of shorter battery life, while the latter poses a big danger in overcharging a cell and making it vent.

Balance charging is the safest way to go. Longer battery life is just a plus at this point IMHO.

Now I have tested cells out of my dual 18650 mod (in series) and they are pretty close to each other when they are drained, but not identical. Usually, one of the cells will die faster than the other and the protection circuit will kick in killing the circuit while the other battery has enough charge to be over the protection circuit default value. When I place both of the batteries on the charger to charge, i notice one battery finished charging sooner than the other by a couple of minutes.

 

[LukeTheDuke]

hmmm iam loving this conversation...
iam learning so much its great to have more research and opinions


lemme throw another wheel in this, as i know nothing about this also...


what about using those same lipo packs in the RC world... also MAIN concern would be can you find protected versions of say a 10V pack or 8.5 or even 7.5 VOLT PACK....

i DO know that those lipo packs can be VERY unstable and dangerous though... prolly a bad idea per say, but iam hoping juss MAYBE technolgy may be uptodate on lipo packs.. prolly wrong though,

id still like to use the batteries we use today, and have a built in charger...

 

[mv2envy]

Like I said, built in charger for a dual cell (series) PV is not so simple. Its very simple for a single cell or dual parallel cell setup, but not for a series setup.

 

[devast]

Nice part, first one I've seen that uses the MCP73833. The SparkFun board and the ones you see on eBay use the MCP73831 which is the most basic charger controller. Though I just noticed SparkFun offers a high speed charger with an MCP73843, but it uses a barrel connector instead of USB. Barrel connectors have much higher current limits than USB connectors.

If 500ma charging current is adequate for your application, i don't see any reason not to use these cheap charger controllers. Yes it's a very easy, basic implementation of cc/cv charging. It perfectly does the job it's supposed to: charge.

 

[CraigHB]

One thing about cell protection is that it's not something designed to be relied upon for charging termination. It's more of a last ditch effort to protect the battery from venting to due an over-voltage condition. A 3.7V Li-Ion charger is supposed to terminate charging at exactly 4.2V (plus or minus only a few hundredths of a volt), Anything much lower than 4.2V results in an incomplete charge. Anything much higher damages the cell. The protection has to engage somewhat higher than 4.2V in order to allow a charger to work nominally. Relying on a cell's built-in protection will result in some amount of damage to the cell which translates to reduced cell longevity.

What could potentially happen charging two protected cells in series with a two wire charger is that the protection on one cell may kick in at say 4.3V leaving the other cell at 4.1V. One cell endures some damage while the other is not compeletely charged. The condition would be progressive damaging one cell more and charging one cell less every charge cycle. I don't know if this would actually happen, but it's possible. Would need some real world data to say for sure.

 

[CraigHB]

If 500ma charging current is adequate for your application, i don't see any reason not to use these cheap charger controllers. Yes it's a very easy, basic implementation of cc/cv charging. It perfectly does the job it's supposed to: charge.

Other than the power source, there is little difference between a USB charger using the MCP73833 controller and more expensive cell chargers that plug into the wall. They all use similar controllers. The MCP73833 is a full featured controller with all the bells and whistles. It uses a 3 tiered charging profile. The only "better" charger is the Pila which uses a 4 tiered profile.

Most of the USB modules I've seen so far use the the MCP73832 or MCP73831. These are more basic controllers that use a 2 tier profile, are not high speed capable, and do not have additional safety features. Many of the "plug-in" chargers also use the most basic type of controller.

It's a matter of the controller not necessarily a matter of where the power comes from. Though one thing I can ding that USB module for is it does not appear to utilize the temperature monitoring the MCP73833 controller provides. That's one of the key safety features and it gives me a level of comfort knowing it's implemented properly in my mods.

 

[dreamerman]

Nice part, first one I've seen that uses the MCP73833. The SparkFun board and the ones you see on eBay use the MCP73831 which is the most basic charger controller. Though I just noticed SparkFun offers a high speed charger with an MCP73843, but it uses a barrel connector instead of USB. Barrel connectors have much higher current limits than USB connectors.

I use the MCP73833 chip myself, though I use the higher output DFN chip package for a 1000mA charging rate with a 5V barrel connector. It's for a big batt mod with a max 5A charging rate. The one linked to in the previous post is set to 500mA which is the maximum for the MSOP chip package. The DFN package has much better heat sinking, but you have to set up the PCB for it. I've tried the MSOP package and it hits thermal limiting once you go over 500mA. Upon closer inspection, it looks like that part also uses the DFN chip so you could probably mod it to increase the charging rate. Just change out the 2k resistor with a 1k resistor where it says "prog".

One other comment about that part, you can see just by looking at the circuit traces on the board it's only providing an additional connector parallel to the battery connector for the load. It's not offering any kind of "passthru" circuitry other than that. On my own mods, the MCU sends a disable signal to the controller when the atomizer is energized. The charger controller will probably work fine without any kind of disable or bypass, but I do that just to be sure the chip does not get confused by the sudden change in load. The MCP73833 has several safety features that are not present on the more basic chips.

I hope the OP understands you can only use these parts on a single Li-Ion cell or multiple cells in parallel.

Can you kindly share some schematic or tutorial on your mods using MCP73833 to charge and vape at the same time. thank you.