Charging Question

[u_couple]

Hey guys, does anyone know if it would be possible to charge 2 x 14500 batteries using the ego switch & electronics, I have a box that I was gonna mod, taking a 14500, I now see that I could probably get 2 in there, and wire them in parallel for longer run times.

I`d like to screw the box closed, and don`t really have the space to install a charging circuit (if I used 2 x batteries) so thought of the ego switch, which has a charging circuit built in.

 

[Rocketman]

If you start with two brand new, equal capacity and charge, 14500 cells, wired them in parallel the ego charger will handle it. I use a 420ma eGo charger to charge single 18650, dual 18650 and 26650 mods. The eGo electronics is used for eGo type e-cigs up to 1300 mah so it should handle the charging current.
Keeping users hands off the batteries when putting them in the charger or taking them out sometimes damages the plastic wrapper (potential short later). Just make sure they are charged to the same voltage before connecting them.

Vent the box a little if it is plastic. A lot if it's metal.

 

[Debbie Lee]

Help please I need help with my two new trex batteries I just got them yesterday from Liberty Flights. One wasn't working at all and now the other one is not working but it was last night. How do you charge them how long etc.... I don't want to send them both back they are 1100mah

 

[u_couple]

If you start with two brand new, equal capacity and charge, 14500 cells, wired them in parallel the ego charger will handle it. I use a 420ma eGo charger to charge single 18650, dual 18650 and 26650 mods. The eGo electronics is used for eGo type e-cigs up to 1300 mah so it should handle the charging current.
Keeping users hands off the batteries when putting them in the charger or taking them out sometimes damages the plastic wrapper (potential short later). Just make sure they are charged to the same voltage before connecting them.

Vent the box a little if it is plastic. A lot if it's metal.

Thanks for the info buddy, happy bunny now !

 

[CowboyGoggles]

I hate to .......ize the thread but I'm new and don't have full priviledges yet.

if i'm out of line please let me know.

I am building a mod that i would like to charge off a 5v usb source.
I understand that to charge a battery you need to provide a slight overvoltage (within tolerances)parallel to the battery and the charging time should be proportional to the amperage needed to fully restore the battery.
I'm sure there is more to it when it comes to lithium-based cells but i have only ever built charging circuits for SLA batteries in my tinkering up until now.
so :

1: what batteries, if any, can be charged by a direct parallel to the usb output?
2: Will this require a regulator?
3: have any of you seen a schematic for this already.

once again sorry to hijack.
but my searches have not been fruitful

 

[WillyB]

I really have no idea what you are talking about.

But there is lotsa info on charging Li-Ions.

Start here.

Charging Lithium-Ion Batteries

 

[Rocketman]

Cowboy,

Please read up on charging Li-ion cells. Totally different animal than SLA cells.
Charging circuits that would run from 5 volt USB sources are cheap, small and easy to incorporate into a mod.

But don't try it until you understand the unique charging requirements of Li-ion. Have Fun

 

[CraigHB]

That sounded like the profile for a NiMH cell. The charging profiles between a Li-Ion and a NiMH cell could not be any more different. NiMH cells are charged with brute force, Li-Ion cells are charged with precision and delicacy.

Li-Ions require a very precise and unforgiving charging profile. If you are not an EE, the only option for a DIY Li-Ion charger is to use one of several USB modules available or use one of a myriad of charger controller chips which make it simple to build one yourself. It's certainly possible to build a safe Li-Ion charger with the most basic components, but I am an EE and I would never do it.

One note on parallel removable cells; Be careful to make sure they are both equally charged when you first insert them. You get high equalization currents if the state of charge differs by much at all. Also be careful not to accidently insert one backwards, pretty obvious what happens there. The protected cells will keep anything nasty from happening whatever the case, but you really don't want to rely on a cell's protection circuitry if you dont' have to. If using uprotected cells (like IMRs), you're taking a risk. Personally, any time I've used the approach of "I'll just be careful" gets me eventually when I am just not careful. My advice for running parallel cells is to go non-removable by incorporating a USB charging module into your mod.

 

[CowboyGoggles]

Thanx Craig that was the plan.

I pulled a sexy little LiPo cell out of a BLU pack PCC this week, and found that the tiny IC and board hiding under some glue on the contact end is an over/under voltage regulator(had to have google translate the data sheet). this is a protected battery!

So, the BLU is not a total waste of money. The cell is 3.7v(4.2v at full charge) @ 900mAh.
The output from my(now unused) BLU usb battery charger is 4.2v @ 240mA. it was designed to charge the L88b batteries.

The board from the charger and the LiPo cell together are about the size of a book of matches!
If i can charge this battery with this charger, and swap the usb connector on the board for a mini female connector, then i can build both into the smallest 3.7v mod i have ever seen.

Not only would it be stealthy(I work in a hospital), but it would be VERY cool.

I just wanted to get some feedback from an EE before I solder it all together because I know how volatile these cells are..

will the charger drain the battery if left connected to it while power is not supplied?
incorporate a switch to disconnect?
Is this even a safe charger for this battery?

 

[CraigHB]

Typically, chargers are designed not to draw any current when the battery is connected and the power source for the charger is not. I've checked the MCP73833 controller I use in my mods and it does not register any idle current draw on my meter which has 100nA resolution. However, I've read the eGo chargers do have an idle draw. Might be time to invest in a good DMM to be sure. Check the meter reviews at the EEVblog for the $50 and $100 product ranges.

You can also check the functionality of the charger with a DMM. Measure terminal voltage (when charging is complete, should be 4.2V plus or minus 20mV) and voltage differential when charging from a discharged state. For example, if the battery is at 3.7V, it shouldn't go over 3.75V when the charger is on, in other words, differential between battery voltage and charging voltage should never be more than 50mV. You can also directly measure current flow when the charger is running with the battery low and make sure it's under 1C or 900mA. If the charger passes those tests, it should be safe.

 

[CowboyGoggles]

Typically, chargers are designed not to draw any current when the battery is connected and the power source for the charger is not. I've checked the MCP73833 controller I use in my mods and it does not register any idle current draw on my meter which has 100nA resolution. However, I've read the eGo chargers do have an idle draw. Might be time to invest in a good DMM to be sure. Check the meter reviews at the EEVblog for the $50 and $100 product ranges.

We (Makers Local 256)have a Fluke fatboy at the shop. I'll get down there this weekend and test it.

Yes. EEVblog=WIN!

Thanx for your help!!

I'm waiting for the connectors to arrive, and I'll be posting pics and results next week.

Take Care!
CG

 

[CraigHB]

That was fast, should have added a reply. Check my edit, added another P on charger testing.

 

[CowboyGoggles]

just looked
That's VERY good to know!
I'm learning a lot from you. you are in all my posts.
It seems like there are only a few ppl here who really KNOW their electronics. maybe for these specific queries I should just message you directly?

That might help me... but then again having a thread allows the info exchanged to be shared with the community...
sorry, thinking and typing.

Well met, sir.

CG

 

[harmonic]

I'm waiting for the connectors to arrive, and I'll be posting pics and results next week.

i look forward to seeing this as i have a couple unused pcc i have thought about turning into mods. i had only thought of adding a connector and switch to the existing pcc box so it can also still be used to charge a stick batt and have storage but the guts could fit into something tiny like a keychain hummm

 

[CraigHB]

It seems like there are only a few ppl here who really KNOW their electronics. maybe for these specific queries I should just message you directly?

That might help me... but then again having a thread allows the info exchanged to be shared with the community...

You're right, best to discuss this stuff publicy, sort of defeats the purpose of a forum otherwise. Yea, there's a few of us electronics geeks on the forum here. I suppose the stuff seems like FM (freaking magic) to a lot of people, but I'll tell you, some times it seems like FM to me too. Somtimes I'll be working on a circuit and it will be like, "that shouldn't do that." or "how can that crappy design possibly work as well as it does."

 

[CowboyGoggles]

I'm also looking into using PSP batteries. I have several of the DX 3600mAh(so they say) PSP batteries and a housing from a psp slim I re-shelled a few years ago that i can whiddle down for a case. . they're: 3.7volts, protected, tiny, lightweight, modular. just waiting to get the 510 connectors and some more juice.

 

[DaveP]

I understand the quest for building your own. I was a field engineer in the electronics field for over three decades and was a Radio Shack experimenting freak. But, when it came to charging my ecig 14500 batts, I spent $15.95 on a Trustfire charger and saved the time for other pressing issues! When my batteries are ready, it turns green.

Maybe I'm missing something here. It must be the challenge,

 

[CowboyGoggles]

I love knowing how things work. and I love having 1-off stuff. I fix my own cars. build my own stereo equipment. make my own clothes do my own tattoos(with machines I built), I'm a true Do-It-Myself-er.

 

[CraigHB]

I understand the quest for building your own. I was a field engineer in the electronics field for over three decades and was a Radio Shack experimenting freak. But, when it came to charging my ecig 14500 batts, I spent $15.95 on a Trustfire charger and saved the time for other pressing issues! When my batteries are ready, it turns green.

Maybe I'm missing something here. It must be the challenge,

In most cases, you're right. You have to pick your battles with circuit design. However, sometimes there's just no way around desiging something from the ground up.

If you're building mods with built-in charging you can either use a ready made USB charging module or build one using a controller. It's actually pretty simple to do one yourself with a controller. They design the chips to be pretty easy to wire up and they do everything that needs to be done. Though one thing I wish they had that they don't is input over-voltage protection. Though, I doubt the round cell chargers have it either.

 

[CowboyGoggles]

FINISHED!
come and see!
http://www.e-cigarette-forum.com/forum/battery-mods/256390-mods-i-built-over-weekend-l-k.html#post4980791