And another exploding ecig

[Tubbyengineer]

This thread shows the internals of each, http://www.planetofthevapes.co.uk/f...notices_425/36495-usb-pc-charger-dongles.html

m0th, this is the Pic I was talking about...

 

[mental2k]

I know in amateur electronics circles lithium cells are generally treated with a respect which approaches fear in a lot of cases (having said that there's plenty of madmen who know what they're doing and produce awesome hacks too). I was trying to find an article which had a few teardowns of cheap chinese import chargers, but I can't find it. Here's one that might be interesting Buying cheaper electronics and not saving money .

With wall warts I'm lead to believe they tend to scrimp on the ground isolation side of things. My rule of thumb is, treat lithium cells like grenades and the chargers like pins. If you deduct raw materials, design and manufacturing cost, packaging and shipping to the UK, ebay and paypal fees and the profit someone has made on it, how much do you trust a charger that costs about the same as 2 first class stamps!

 

[m0th]

@m0th, this is the Pic I was talking about...

i did see that and wonder if it was the one you were on about.

 

[Tubbyengineer]

i did see that and wonder if it was the one you were on about.

Now you see why I consider them to be the work of Satan - or Linda McAvan...

 

[gords1001]

Just to be clear.

Yes applying more than 4.25vdc can be bad for most li-ion/li-po cells (there are cells that charge to 4.35vdc max). However. You cannot just randomly apply any potential current you wish. All cells have a c rating, their maximum charge and discharge ratings are factors Of this c rating, so you will see maximum discharge 2c or 5c or in some lipo cases 25c or more. You will see maximum charge rate 1c or 5c etc. You shouls though, if you dont have access to the ratings, always assume charge at 1c discharge at 2c.

This is why people suggest sticking to a 500ma supply. It eliminates one of the charging state issues in the wvent of charger failure. Yes you can still apply excessive voltage, that will make the cell unstable, but excessive current will make the cell fucking hot and that is the big concern here.

So could the idiots that keep saying a two amp power supply feeding a little puny cell is fine please fuck off till they understand what they are talking about fully? Kthanks

 

[Dennis]

Just to be clear.

Yes applying more than 4.25vdc can be bad for most li-ion/li-po cells (there are cells that charge to 4.35vdc max). However. You cannot just randomly apply any potential current you wish. All cells have a c rating, their maximum charge and discharge ratings are factors Of this c rating, so you will see maximum discharge 2c or 5c or in some lipo cases 25c or more. You will see maximum charge rate 1c or 5c etc. You shouls though, if you dont have access to the ratings, always assume charge at 1c discharge at 2c.

This is why people suggest sticking to a 500ma supply. It eliminates one of the charging state issues in the wvent of charger failure. Yes you can still apply excessive voltage, that will make the cell unstable, but excessive current will make the cell fucking hot and that is the big concern here.

So could the idiots that keep saying a two amp power supply feeding a little puny cell is fine please fuck off till they understand what they are talking about fully? Kthanks

You'd think that kits would come with their own chargers that don't go over the max C rating, regardless of power supply.

 

[knome]

You'd think that kits would come with their own chargers that don't go over the max C rating, regardless of power supply.

As gords1001 said, it is the "in the event of charger failure" that has to be taken into account re safety.

 

[Maxcat]

Just to be clear.

Yes applying more than 4.25vdc can be bad for most li-ion/li-po cells (there are cells that charge to 4.35vdc max). However. You cannot just randomly apply any potential current you wish. All cells have a c rating, their maximum charge and discharge ratings are factors Of this c rating, so you will see maximum discharge 2c or 5c or in some lipo cases 25c or more. You will see maximum charge rate 1c or 5c etc. You shouls though, if you dont have access to the ratings, always assume charge at 1c discharge at 2c.

This is why people suggest sticking to a 500ma supply. It eliminates one of the charging state issues in the wvent of charger failure. Yes you can still apply excessive voltage, that will make the cell unstable, but excessive current will make the cell fucking hot and that is the big concern here.

So could the idiots that keep saying a two amp power supply feeding a little puny cell is fine please fuck off till they understand what they are talking about fully? Kthanks

I agree with you in that charging above a cells maximum c rating is not good practice but using a 1 amp iphone supply with a 4.2v regulated connector to charge a 650ma ego (1.53c) should not be any worse than using an Xtar charger at 2 amps to charge a 700ma 18350 cell (2.85c).
There does not seem to be a rash of reports of 18350 cells venting.

From what can be seen in the majority of these ‘exploding e-cig’ reports are the use of connectors allowing 5 volts to the battery which even at a maximum 500ma current causes the battery to vent.

 

[Danny K]

I agree with you in that charging above a cells maximum c rating is not good practice but using a 1 amp iphone supply with a 4.2v regulated connector to charge a 650ma ego (1.53c) should not be any worse than using an Xtar charger at 2 amps to charge a 700ma 18350 cell (2.85c).
There does not seem to be a rash of reports of 18350 cells venting.

From what can be seen in the majority of these ‘exploding e-cig’ reports are the use of connectors allowing 5 volts to the battery which even at a maximum 500ma current causes the battery to vent.

This one vented as it kept supplying the current even at 500mA !
Mainly because that isn't the correct charger.

Don't mix and match use only approved chargers and use a bit of common sense.



Sent from my GT-N7105 using Planet of the Vapes mobile app

 

[gords1001]

If you can actually find a data sheet on some 18350 imr cells, you'll likely find they can be charged at 5c, most imrs are up around there (kinda scary tbh) but xtars also have current selectors, how many people, who actually use 18350 cells, actually charge them on the 1a setting rather than the 500ma setting? Even one cell in an i4 only sees 700ma or so.

Then look up some specs on icr cells, they have a far lowrr charge rate, and most of these little firebombs are, I'm pretty sure, icr cells. Big difference.