Mod/build question for the mre techy minded.

[UkUsa]

I made myself a rough and ready usb power supply for my 901. Today i was looking through our spare parts tubs at work and found some leds, switches and a good supply of possible battery boxes.

My question is, or should that be questions are -
1 - What rated battery power should i be looking for to run a 901 atomizer efficiently wihtout burning it up?
2 - I'm guessing volts bewteen 4 and 5 would be preferred.
3 - I've been seeing a lot of talk about milliamps. What is the general consensus on that?
4 - Anyone thoughts about using a cellphone battery?
5 - How/what components would be needed for it to be able to charge while plugged into a usb?

I should of got the dimensions of the enclosures i found, tomorrow i will. At a guess i'd say the internal dims are .75" x 1.75" x 3.5".
What i'm thinking is battery pack plugged into a usb port. This would have a socket to plug the 901 batt leads into. When away from the comp i could take it with and have a batt pack.

I know APC makes pretty much what i'm looking for but i think i could make something lots cheaper since i have a lot of the parts just gathering dust at work.
Besides isn't half the fun actually making the thing .

Any tips or links to useful posts would be appreciated. I have watched Madogs magnum vid and read a few other mod threads so i am confident i could build something easy enough.

Thanks in advance ...

[Trumpybloke]

G'day UK
Few points for your consumption lol
-bigger capacity batteries the better
-li-poly or li-ion batts sometimes come with built in charge discharge protection.. USE this type of battery if you arent confident dealing in non-protected cells ( which may in exceptional circumstances vent ( or blow up !!! )
- less voltage to the atomiser, less strain on the components , they are designed to run on 3.5 to 4.2 V I wouldnt drive them over 5.5 V but thats just me.
- Around 1,000 mA is needed to get the atomiser humming , make sure anything you incorporate into the design , wires, switches, and of course batteries can deliver and cope with this .
-chargers must be specific to battery type...ie NiMH to NiMH , Li-poly to Li-poly. etc

My rough suggestions are , at least a 1000. mAh battery ( this gives a 1C discharge .. it shouldn't heat up or degrade below manufacturers specs at this rate ) and the best voltage cut-off charging system you can find or afford .... pay super close attention to anything that might enable a short... you really dont want one of these burning up in your pocket !!!!

[youfillintheblank]

I've had good luck with NiMH batteries. 4 aa size, I think the ones I'm using are 2300mah. They provide lots of power, and last a good 2-3 days for me before the voltage drops enough to warrant recharging. I don't like NiCD as much, I know they churn out more power upon use, and kinda leave a burnt taste to the vapour. And to use effectively you have to drain them totally before recharging. Lithium Ion is good too, after all, that's what's in our e-cigs, but they're pricey and you don't have as much play with the voltage....they come in 3.0v and 3.6v and that's it. I've used 2 3v cells recently and they worked great, I'm surprised they didn't overcook the juice like the NiCD batteries did. As for me, I'd never use a Lithium polymer battery, I've heard and seen what they can do if overcharged accidentally...

fffffffffffffffffffffffffffffffffffffffBANG!!!

[Trumpybloke]

Ummmm its more the li-ions that go bang .... li-polys are far safer and tend to swell rather than explode

[youfillintheblank]

really? Okay, since I get the impression that you're big and tough and ride a motorbike I believe you.

I was watching people intentionally blow up Li-Po batteries. The fact that they sell, or come with special bags to guard against explosion made me wary

"Okay, here charge this battery, but wait, put it in this big thick heavy bag first, cuz if it explodes you might die. Have fun!"

Ummmm its more the li-ions that go bang .... li-polys are far safer and tend to swell rather than explode

[Trumpybloke]

edit -- li-poly's go fizzle splurt and maybe a bit of flame... Li-ions go... " Oh Poo I think my hand fell off !!! "
LOL
They both can go bang but I have been dealing with both types of batteries for may years in high charge discharge environments ( I play with R/C planes ) I have experienced a Li-ion BANG lol and seen li-poly fizzles

Interesting aside ( special note to your homeland security here , please look the other way ) Just after Sept 11 I was involved in importing a large quantity of QCP 800 Li-ion batteries from the States to here ... well there was a wee problem with the order not leaving the USA ... I was given a phone number to ring .... so being the good little fella I am , I did ..... a voice answered with the name of a facility in Langley Virginia ( you figure it out LMAO ) and I was then interviewed by an agent for about 15 mins ... during which he asked was I aware of the potential for these units to be used as timed primer explosives for a large nitrate device.... I asked him how that worked , and he went into quite some detail..... I had a great laugh with him and said " Thanks , I always knew of their explosive potential , but you've done a great job of alerting me to how its done !!! "
Kinda ironic !!!

But yes all batteries have the potential for harm under uncontrolled discharge .... treat them nice .... but I'd rather have a runaway Li-poly in my pocket than the same capacity Li-ion doing a thermal runaway

Oh and the charging bags are a great marketing thing , totally unnecessary but the scare factor makes people wanna buy em .... kinda like intellicig hype LMAO