what am I missing so I dont have to wait another month for a part from china

[satelliteguy]

Ok when I first started vaping about a month ago I ordered some 18650's from ebay

4 x 18650 3000mAh 3.7V Protected Rechargeable battery - eBay (item 270557741453 end time Mar-29-11 02:54:15 PDT)

and a charger

18650 Rechargeable Battery Travel Charger GTL Li-ion - eBay (item 280557735903 end time Apr-02-11 06:00:17 PDT)

So I spent about 15 bucks for 4 18650's and a dual charger, when I first ordered them, I wasnt sure what I was going to use them for but I liked the idea of lots of vape time,

I read up on the evercool mod, ordered the free samples from ti, and the free parts came in from ti, but after building my first nicostic and being really horrible at soldering, i've opted not to go that route, and just went ahead and ordered this chip as it was mentioned in another thread,

DC-DC Converter Board regulator In:3-30V Out:1.3-18V - eBay (item 300536835340 end time Apr-13-11 19:32:29 PDT)

So then I found this today to hold the 18650's and the chip,and ordered it,

18650 battery case 2 x parallel connection DIY case For Sale

its coming from china so I figure i've got three or four weeks till it comes in, i've got the 510 battery connector from mad vapes, and a button switch from mad vapes (not real happy with how hard I have to mash the button to make it work on my nicostick and remote control mod)

Yes I know it says parallel but it looks like it would be easy enough to put the batteries in series

So the question is what is a good switch to order, I'm not real concerned with having a on/off switch as I didnt put it on my nicostick and no serious problems so far, but I would like a switch that works better than the button switch i've been using.

and am i forgetting anything? I think I have all it takes to make a 2x 18650 vv mod. except a decent switch

another question is about the wiring in series, according to what I read online if you wire in series you increase the volts but not the mah, but if you wire in parallel you increase the mah and not the volts, so am I still going to have just 3000 mah?, I ask because I'm not going to be running at 7.2v, I think I have found my sweet spot with the boge lr cartomizers, which is around 3.7-3.8 volts cause I love the nicostick when I pop in a fresh battery, and does anyone have a clue how long the two 18650's can hold the fresh battery feeling with that chip?

 

[Java_Az]

Looks like a ok battery case if you can wait the 3 to 6 weeks it takes to get stuff from china.

It is true that when you wire in series the mah stays the the same unlike when wired in parallel where it doubles. But dont let the numbers fool you. 3000mah @ 3.7 volts is not the same as 3000mah @ 7.4 volts. 2 amps at 3.7 volts is 7.4 watts 2amps @ 7.4 volts is 14.8 watts. Now since your not going to be vaping at 7.4 volts and your going to be using that switching regulator your actually going to be getting back that mah you think you are losing. Let say you adjusted your output to 3.7 volts to vape a 2.2 ohm atomizer. Your output amps should be 1.68amps. But since your input is 7.4 volts you will find that on that side of the regulator your only putting in 0.84 amps . Real world it would be a little bit more since the regulator is not 100% efficient. That switching reg you have i think is around 90% efficient. so add 10% to it it would be 0.93 amps. So if you did vape off two batts in series regulated down to 3.7 volts the whole charge on the batteries you would really end up with 5400 mah with a regulator thats 90% efficient. Sure you have to pay the price of efficiency but it gives you the freedom of being able to to adjust your voltage for a better vape.

The above was based on if those batteries your getting were actually 3000 mah. Real world tests they are going to be closer to 2200 mah or lower. But i wont get into the china overrating the hell outa there batteries tonight anymore then what i have already said.

 

[satelliteguy]

thanks, thats what I was wondering, i'm shooting for all day vape plus some...

 

[Java_Az]

thanks, thats what I was wondering, i'm shooting for all day vape plus some...

you should get at least two days off of it depending on how much you vape and how high you set the voltage maybe longer.

edit: Just looked at the data sheet the board uses this chip http://www.national.com/ds/LM/LM2596.pdf not as efficient as i though. Your going to get about 80% on that board i believe. Still should last more then a day though.

 

[Gummy Bear]

Did you find anything that says what the dimensions of the case is? In the space above the batteries you'll need 45mm x 38mm x 10mm for the chip plus the space the switch takes up.

 

[satelliteguy]

why of course I am completely winging it, upon eyeball inspection it officially looks pretty close, if the chip I bought from ebay doesn't fit, i've still got parts for the evercool mode, which I can make fit, if i can get my soldering done without ruining everything.

 

[Java_Az]

Evercool chip gets up to 96% efficiency. Should avarage out to around 92 to 93% threw the discharge cycle of the batteries. That adds up to quite a bit more mah then what you would get out of the other chip. Get you some old broken electronics and practice away at soldering. Also some good youtube vids on the do's and don'ts of soldering. "practice makes perfect" they say.

 

[satelliteguy]

on a side note since I have 4 of the 18650's, would this dohickey work to create what I want (steady 3.8 - 3.9v) off of a single 18650?
DC-DC Converter Auto Boost Buck Power Voltage regulator - eBay (item 220740465531 end time Mar-17-11 19:51:47 PDT)

would be nice to have a smaller mod.

 

[Java_Az]

Yeah it would work with regular ohm atomizers. If you use a LR atomizer you will be pushing the reg passed it's max rated output of 2 amps. Would still work with LR's but it wont last very long be for it fried. 80 to 85% efficient so chop 20% off your mah rating. Also might find the regulator not working before battery protection kicks in. Minimum input is 3 volts most protection kicks in around 2.75 volts