quick 18650 charging question

[vshadowheart]

I was wondering if you could hook one of these

5V Mini USB 1A Lithium Battery 18650 Charging Board Charger Module LED TP4056 | eBay

up to a couple of 18650 batteries that were run in parallel inside your mod and charge two batteries with this one unit. I am thinking a DPDT switch, one side is using battery power to vape, the other switch is charging both 18650 batteries off of the USB port?

 

[xyle666]

should be able to will just take forever to charge em both

 

[vshadowheart]

thinking I could use the machine all day or two and then flip the switch over to charge, plug it in and let it charge all night long

 

[vshadowheart]

Does anyone well versed in 18650 batteries know if this will work like that. Could it charge two batteries that were hooked up in parrallel? I am thinking it might only half charge them then see them at a full charge when they are only at 4v total. I am also wondering if this would be safe to charge them with, could it work in a sealed (although vented) mod, or would it blow up on me?

 

[bapgood]

It will charge them fine in parallel.

Blowing up would likely be from the charger being faulty and over charging or a dead short pulling to much current from the battery to fast.

I can't speak to the quality of that charger but it should work fine. Charge time for two 2000mah 18650's should be in the 4 hour range.

 

[vshadowheart]

For some reason to me it seems like the circuit should read more than 4v as it is charging and cut them off?

 

[LucentShadow]

Two batteries of the same voltage connected in parallel will still have the same voltage applied to the rest of the circuit. It's when they are connected in series that the voltages would be added together.

You could not charge two batteries in series, but charging two batteries in parallel would work. Current flows at different levels between different potentials, so they will equalize as long as they are in good condition.

Charging two batteries in parallel is less safe than individually charging them. There are cell chargers out there that do that, though, but the safer ones monitor each battery independently. It's generally not a problem as long as the batteries remain pretty equal throughout their usage.

 

[vshadowheart]

does this look safe to you

 

[LucentShadow]

does this look safe to you

No, that looks like all 4 battery terminals are shorted to each other, to me. Even given that I'm not sure if any of those apparent connections are isolated in any way, that looks like it would cause a spectacular result to me.

Those batteries are in series. You can't try to charge them in parallel without breaking their series connection. I don't see how that could work with any realistic circuit design.

 

[vshadowheart]

what about if it was set up like this?

with one position connecting the positives in parallel for charging, and the other position being a master off switch, and the third connecting the positives in series for high voltage vaping?

 

[LucentShadow]

what about if it was set up like this?

with one position connecting the positives in parallel for charging, and the other position being a master off switch, and the third connecting the positives in series for high voltage vaping?

That hurts my head a bit, but I think that I get the idea...

First, let me make it clear that I don't think this is a good idea, but it seems to me that you will try it anyway, so:

That's closer, but still a problem. The series connection needs to be open before the + charge lines are closed, or you will have a problem. Looks like that switch setup would work for that. I don't like the possibility of the vape switch being activated in charge mode.

That's still leaving parallel paths from the charging side when in vape mode, though, which is really bad. I think that you'd have to open all four connections from the charger to the batteries individually for it to work.

If you haven't built the mod at all yet, I'd suggest getting a boost circuit instead, so that you can just run from 3.7v.

 

[LucentShadow]

double post....

 

[vshadowheart]

Firstly let me say thank you very very much for all the help.

Interestingly enough I intended to buy some boost circuits and hit the wrong link and ended up buying 10 step down circuits. When switched over to vape mode the parallel positive path would be broken, leaving only the series path going through the switch, and when in charging mode the batteries would only be connected to the charging board as a parallel connection.

 

[retird]

I agree with LS......if you haven't built it yet consider a boost circuit.....but if you still plan on using the LM2596 buck circuit I suggest your mod have removable batteries so you can remove them from the mods for charging....

EDIT: just read your last post...sounds like you are h..l bent on making your mod as you say you want to, I will only say you are asking for trouble....hope your injuries are not too severe....wish ya the best.....you asked for guidance, which has been offered....so do what you will my friend....

 

[vshadowheart]

All of this wouldn't be an issue at all if I just used one battery right? And if I am only using one battery and I don't have a boost circuit could I just basically hook a protected 18650 straight to a switch and atomizer to vape with, isn't that basically what an ego brand battery is? Maybe toss the charger board (I already bought it) into it and have a rechargable ego battery?

 

[bapgood]

I agree with retired and Lucent. You seemed awfully worried about blowing things up, which generally is kinda hard to do following all the good info out there. However you are creating a situation that is far from the norm and safe.

There is an entire thread on lm2596 builds.

 

[LucentShadow]

Firstly let me say thank you very very much for all the help.

Interestingly enough I intended to buy some boost circuits and hit the wrong link and ended up buying 10 step down circuits. When switched over to vape mode the parallel positive path would be broken, leaving only the series path going through the switch, and when in charging mode the batteries would only be connected to the charging board as a parallel connection.

To be clear, the diagram shows the two battery negatives connected at all times. That is a problem in a circuit where the batteries need to be in series when in use.

It looks as if the positives are connected at all times as well, on one side of the switch, with the other side of the switch connected to the charger. This would also be a problem.

The charger should also be isolated when in vape mode.

The batteries cannot have those extra connections when the batteries are put back in series. The only way I see to meet all of those conditions is to have all four individual charge connections opened by separate (possibly ganged) switches when in vape mode, and those need to be opened before the batteries are put back in series.

While I'm not an electronics engineer, I was a certified electronics technician with over a thousand hours of electronics theory training, and I can say with certainty that the above circuit is unsafe, and will not work. This is why I said earlier that it is not a realistically buildable circuit. It can be done, but it'll need to be well more complicated than that, to be done correctly.

I'd advise charging the batteries individually, as retird said.

If you went with a boost circuit, this becomes a rather easy problem. Just isolate the battery from the boost circuit while charging.

 

[retird]

http://www.e-cigarette-forum.com/forum/battery-mods/259577-just-lm2596-users.html

 

[LucentShadow]

All of this wouldn't be an issue at all if I just used one battery right? And if I am only using one battery and I don't have a boost circuit could I just basically hook a protected 18650 straight to a switch and atomizer to vape with, isn't that basically what an ego brand battery is? Maybe toss the charger board (I already bought it) into it and have a rechargable ego battery?

You could, indeed, make a 3.7v passthrough mod by leaving out the buck circuit and just using one battery. You can probably find a circuit for that here.

 

[vshadowheart]

Thanks for all of the info, I think I am going to pick up a couple of boost circuits. I am working my way through the Just for LM2596 threads, I think I am up to page 50 something lol.