Building a REAL charger

[puff-puff-pass]

OK...been a modder and tinker type person for several years. From reading alot of post here, it seems that a consistent, reliable charger is hard to get. Add to that, having multiple batts will mean needing multiple chargers. I find this to be uncalled-for. So i will make my own, and if all goes well, will make some for the public as well.

What I need from this community is information. LOTS AND LOTS of information. If you can fill in these blanks for me, it will help to speed along development. Please include e-cig model type so I can account for the variations in batts vs. models.

BATTERY CHARGING INFO
1) Max. Charge Voltage?
2) Charge Rate (in mA)?

BATTERY SPECS
1) Inside Diameter (thread to thread)?
2) Outside Diameter?
3) Collar depth? (distance from start of threads to terminal post)

Once I have a comprehensive list of specs, I can plan what parts I need and continue designing.

I hope to have a working model within a few weeks, then I will be looking for suggestions as to what people want to see included in the design as well as looking to have some sample batteries to test with. If you have any "half-cooked" batts that you no longer use, please send them my way for testing.

Cheers,
PPP

 

[Jaco]

Ok, I cannot post URLs yet... so do a google search for "bill bowden 2 cell lithium ion charger" (compuserve user) that has a schematic for a 2 cell lithium ion charger - the schematic on circuitdb is exactly the same as the one on his site.

Helps a lot

 

[Fox3]

Just a couple thoughts here.

First off, these are li-ion (IIRC) and they have strange charging characteristics according to someone I know who built on (didn't blow any up, but he is an EE) and I do remember him saying it was more involved that one might think.

You might want to consider looking at battery management microcontrollers and perhaps there are just battery management chips that do the job. Been meaning to disassemble my charger to see, but the smarts might well be in the battery pack itself (makes more sense).

Do be careful with exotic chemistry batteries!!!

The battery mount is just a screw thread, perhaps standard and probably metric. Thread gauge might give you that much.

Just my $0.02 . HTH.

 

[puff-puff-pass]

Just a couple thoughts here.

First off, these are li-ion (IIRC) and they have strange charging characteristics according to someone I know who built on (didn't blow any up, but he is an EE) and I do remember him saying it was more involved that one might think.

You might want to consider looking at battery management microcontrollers and perhaps there are just battery management chips that do the job. Been meaning to disassemble my charger to see, but the smarts might well be in the battery pack itself (makes more sense).

Do be careful with exotic chemistry batteries!!!

The battery mount is just a screw thread, perhaps standard and probably metric. Thread gauge might give you that much.

Just my $0.02 . HTH.

I have been reading alot about the microcontrollers lately. There are numerous IC chips out there that are "full bundle" chargeing controllers...with built in safety monitoring. The technology for smart charging has grown in leaps and bounds over the last 2 years.

 

[Jaaxx]

Here's my million bucks.

You need to design a charger with a clamping mechanism that does not rely on threads. Just a center electrode and an outer with some way to hold the battery in place. A "universal" charger for all battery types.

 

[Fox3]

I have been reading alot about the microcontrollers lately. There are numerous IC chips out there that are "full bundle" chargeing controllers...with built in safety monitoring. The technology for smart charging has grown in leaps and bounds over the last 2 years.

Quite true. Check out ATMELs line of AVR battery management micros. Quite impressive and I am real sure those are not the only ones now . I just happen to like AVRs and have all the tools.

Had to come back to this once I got to 15 posts , Check out the battery management sections at:

Atmel Products - Devices

 

[RjG]

All that's in my m401 charger is an LM393, and a couple transistors. One comparator switches 4.18v, (and the other side turns the LED from red to green when current stops flowing, most likely) . There's not much else in there on the secondary side of the circuit. It's capable of pushing 100mA

I'm curious, what makes you think the battery doesn't already have a battery management I.C in it?

These e-cig batteries have cutoff circuits already, I just assumed the charge controller is in that circuit too. Some batteries even blink when they are done.

My m401 pilot batteries are opposite, they blink when they start to charge and give no indication when they're done, lol. Either way, it appears to indicate some charging intelligence built in... I'm just guessing, I have no desire to rip one of my batteries apart yet to look, lol ;-)

 

[DaveyRoots]

Here's my million bucks.

You need to design a charger with a clamping mechanism that does not rely on threads. Just a center electrode and an outer with some way to hold the battery in place. A "universal" charger for all battery types.

awesome idea. you should run with this idea!

 

[puff-puff-pass]

Quite true. Check out ATMELs line of AVR battery management micros. Quite impressive and I am real sure those are not the only ones now . I just happen to like AVRs and have all the tools.

Had to come back to this once I got to 15 posts , Check out the battery management sections at:

Atmel Products - Devices

Will take a look.
Have been looking into the MAXIM and LINEAR battery mgmt ICs.

 

[puff-puff-pass]

All that's in my m401 charger is an LM393, and a couple transistors. One comparator switches 4.18v, (and the other side turns the LED from red to green when current stops flowing, most likely) . There's not much else in there on the secondary side of the circuit. It's capable of pushing 100mA

I'm curious, what makes you think the battery doesn't already have a battery management I.C in it?

These e-cig batteries have cutoff circuits already, I just assumed the charge controller is in that circuit too. Some batteries even blink when they are done.

My m401 pilot batteries are opposite, they blink when they start to charge and give no indication when they're done, lol. Either way, it appears to indicate some charging intelligence built in... I'm just guessing, I have no desire to rip one of my batteries apart yet to look, lol ;-)

This is the info I am trying to find out

If anyone has any input into this, please let me know.

 

[puff-puff-pass]

awesome idea. you should run with this idea!

I can't run....I been smoking analogs too long! *cough cough weez*

 

[puff-puff-pass]

Has anyone identified a manufacturer or model number on a battery?
Anyone at all?!

 

[ratfink]

This is the info I am trying to find out

If anyone has any input into this, please let me know.

The battery management circuit is on the battery itself, all you need to do to charge them is provide regulated 5V power.

If what nuck is saying is correct... The comparator checks for a voltage rise from the load as the battery circuit latches off the charge this is to check when to signal the done light.

 

[Fox3]

[ ... ]

I'm curious, what makes you think the battery doesn't already have a battery management I.C in it?

[ ... ];-)

I'm pretty sure they do. I keep trying to get around to digging around on the Motorola site and see if they have battery management uCs but with all going on I haven't gotten there yet.

I keep getting tempted to trash a battery for a USB passthrough but with my failure rate on the 801 atomizers I am afraid to do anything that will lower working resources until my 901 and 510 get here .

It is possible to do all that with discretes and if I can get a good look at the electronics inside the battery I might be able to tell. Then again maybe not with SMT parts often having special identifiers, especially if they are custom masked stuff.

I had *assumed* (heh) that one wanted to charge a separate battery other than the supplied ones. In which case a charge controller would be a wise idea .

The only thing I have seen so far was unidentifiable but certainly appeared to be an 8 pin SMT. I'm not familiar with battery management to know what might be available but I know it can be done with an ATMega8L and a handfull of discretes (no, I didn't do it, but I was fairly close to the one who did set one up to charge a cell phone battery).

PLEASE let my 901 and 510 arrive EARLY next week or at very least the spare atomizers .

 

[RjG]

Cool, I play with Atmel micros too, wicked little things I attempted to make a NiMh universal charger (x number of cells) before - but gave up on it because the resolution of the ADC made me have to manually switch the divider to pick a voltage range... what did your friend do for that? A schematic would be cool

 

[Vince1]

Check out- Charging lithium-ion batteries - It covers charging and other things to consider.

 

[RjG]

If you're wanting to build a charger for a "MOD" device, you can skip a bunch of steps and start off with batteries with a charge controller built in already. They're cheap,
example: DealExtreme: $4.75 TrustFire Protected 14500 3.7V 900mAh Lithium Batteries (2-Pack Blue)

Then you have the advantage of a low power cutoff built in as well.

 

[ratfink]

If you're wanting to build a charger for a "MOD" device, you can skip a bunch of steps and start off with batteries with a charge controller built in already. They're cheap,
example: DealExtreme: $4.75 TrustFire Protected 14500 3.7V 900mAh Lithium Batteries (2-Pack Blue)

Then you have the advantage of a low power cutoff built in as well.

Those don't have integrated charge circuits they just have short and overcharge detection that prevents the battery from venting flame.

 

[Halehouse]

With all the new powermat charging systems that have been showing up at CES this year. It would be nice to have a carrying case that you could screw the batteries into. That way when you get home you could just toss the case down on the charging mat and it would begin charging the batteries. This way you wouldn't have to pull the batteries out, screw them into the charger, then make sure not to forget them the next day when you leave the house. You would just grab your case and go.

 

[Duckies]

I would pay dearly for a battery charging station (line of charging "ports") where I could just line up the 901 batts and let them juice. I have seen a few in the modders section and think this is an awesome idea.