Charging Li batteries out of charger?

[scalewiz]

I like the design of ThePuck which is one of the more common box mods. I always build my box mods with a charging port built in, which does a wonderful job of charging my NiMh batteries.

My question is, when building a box mod using only one Li battery, is it necessary to physically remove the battery and place it in the charger, or since the protection/charging circuits are built into the devices, can I run wires from the charger to a plug and plug it in to charge my single Li battery? This would be so much easier and cleaner to recharge. Of course, this would only work with a single battery as Li batteries cannot be charged in series.

 

[Stitches]

First, you need to be sure which type of battery you have. You say they are Li and I would assume you mean lithium. Generally, standard lithium batteries aren't rechargeable. Lithium Ion (Li-Ion) batteries are. If you are sure your batteries are rechargeable, then there is a circuit you could build to charge them. You need to be sure that you are delivering the correct amount of volts and amps to the batteries while charging so you don't damage them.

You say that you have made recharging circuits on all your other NiMh powered mods, what's different here? Maybe I'm missing a key ingredient to how this is much different from what you've done in the past other than circuitry.

I'd like to put down more, but without being sure of what you have I don't want to say something that you might try that could get you hurt or damage your property.

 

[VpnDrgn]

My first mod had a charging port. Here is my schematic. View attachment 3.7V BOX.pdf

Instead of trying to cram the charging circuit into the box,
I just added a female dc jack.




For the charger I just swapped out the batt connector on an Ego usb
charger for a male dc jack.


Now all I have to do is plug in my box mod
to charge instead of taking it apart to get the battery out.

Hope this helps.

edit - this was done with a protected lith-ion battery and an Ego usb charger

 

[scalewiz]

Yeah, I meant Li-ion. I was just wondering if the battery physically needed to be in the charger, such as if the charger would monitor the temperature of the battery as it was charging. I have seen such devices in battery chargers before, and of course this would require that the battery be in contact with the temperature sensor. If not, then there is no reason that the li-ion charger could not be in a separate box, and simply plug into the mod with a coaxial power connection.

The only other problem I see is overcharging. I really like to simply plug the box in as I retire for the night, and then unplug and use it when morning comes. Li-ion batteries seem to have a reputation to be extremely sensitive to external influences, possibly making them dangerous. I don't want to plug it in and then find my room on fire in the early morning hours!

Do most chargers/battery protection circuits prevent this in case they are left on charge for longer than needed?

 

[Stitches]

VpnDrgn has the idea. Great job by the way. We have the same 'helping hand' soldering setup. The one with the two alligator clips and magnifying glass? I like it.

If you have protected Li-Ion batteries, they have a temp vent that will vent the batteries to keep them from building up pressure and exploding in the event that they get too hot. If the vent blows, the batteries are toast but you're house most likely won't be. Now that circumstance comes about because of a battery failure and isn't something that should happen if everything is operating normally. You can see from VpnDrgn's diagram the basic idea I was describing and was hesitant to describe in more detail.

The idea here is that you are using the guts of a charger (the charging circuit I mentioned you could build) and plugged the battery into the charger using wiring. You can see that his DC jack jumps across the atomizer so there is no need to have the momentary switched pressed for the charger to charge the battery and means that the LED and atomizer that would be connected are also kept in an open circuit while the battery charger is plugged in. Now, if you press that button while the charger is plugged in, you have a problem. That could be a good reason you'd want to remove the battery from the device for charging.

"Do most chargers/battery protection circuits prevent this in case they are left on charge for longer than needed?"
Yes and no. Expensive chargers certainly can meter your batteries and know when they are charged. Even more expensive chargers (intelligent chargers) can be programed how to charge your batteries using anything from time to voltage readings from the batteries or just about anything you want. As your charger gets cheaper, understand that it will have less and less of these features. Very simple chargers simply supply current to the battery and have an LED that comes on when the batteries come somewhere withing the peak voltage output they are rated for, but still don't stop supplying current. This is why they say to take your batteries off the charger when the light comes on and not to leave them on there. Simply put, if you leave batteries on a charger too long and your charger keeps pumping current in them they are damage and their life is shortened.

Sorry if this made your idea complicated. Keep in mind that you're a modder! Grab your wallet and soldering gun, gird your loins, and keep your mods in your garage when they're charging so if they explode you don't loose your house! Good luck and I'll watch this thread if you have more questions. I'll do my best to answer them.

 

[VWFringe]

i think there's increased risk of shorts if using the atty connector, tho USB chargers usually only put out 250 mAh (take 8+ hours for 18650) but i think you can use a dummy cell in the charger with wires going to the charging connector

i think they're usually inserted into a flashlight with the wires going to a battery pack, but it seems to make sense that it would work IF you don't put it in backwards (some cheaper chargers handle polarity protection tho)

or so i'm tole - noob here