Building a mod for battery life- suggestions needed

[Revmann]

I need some advice -

Looking to build a mod that will last me all day. I travel frequently and don't have much time to charge stuff. I currently juggle an ego twist and a madvapes VV box with the linear regulator. I am looking to switch to either a single 18650 VW or some type of dual 18650 VV using a switching regulator. I like vaping at 9 to 9.5 watts. I have been using 1.7 and 2 ohm carts and would not object to going a little higher in resistance if I could maintain 9-9.5 watts.

From a battery life standpoint (would be using AW IMR 2000 mah), which would be better? Is it safe to parallel two batteries for the VW mod?

 

[Rader2146]

You best bet is probably an OKR regulator at high voltage with 2x 1000mAh or better batteries.

• OKR for reliability and efficiency.
• High voltage because it draws let current to maintain you desired wattage.
• 1000mAh or better because users typically get a full day plus out of this setup and ~1000mAh.

With 2x 2250mAh Panasonic cells you should be able to stretch 2 days or more out of a charge. More if you spend a little more for the 3100mAh Panasonic NNP cells.

 

[WillyB]

Just build this and use a larger enclosure.

http://www.e-cigarette-forum.com/fo...ena-vv-mod-denalis-lil-sis-step-step-how.html

You amp load is quite modest, there is no advantage to using mAh challenged IMRs in a mod like this.

And don't fall for the Panasonic2900/3100 hype, middling performance and over rated mAh for actual vaping.

Note how quickly a Panasonic (bottom) drops voltage, even at a light 1A drain.

Dots at 3.5 and 3.25V. The Panasonic @ 3.5V manages about ~1600mAh, the Xtar (Sanyo2600) 2400mAh. That's 50% more, quite significant.

Paying more for sub par performance, from a manufacturer whose battery division always loses money, makes no sense.

Shipped from a US warehouse and priced right.

2pcs XTAR 18700 2600mAh $15.19 Fast Ship From US/UK stock | eBay

 

[Rader2146]

That's a good point on the discharge curves and usable voltage. I neglected to think about the dropout and min input voltage. Those Sanyo 2600s are pretty impressive and a good price.

 

[WillyB]

They really are.

One battery retailer has an Xtar battery but chose the 3100 Panasonic re-wrap, we don't need any more Panasonic re-wraps. Wrong Xtar.

Here's 3A test. Figure a 1.5Ω atty on a single tube PV at about 2.4A.

The Sanyo has a slight advantage as this one is unprotected vs. the AW/Panasonic which has a PCM.

Even if you drag your vaping down to 3.2V, once again the difference in vaping mAh/volts is quite significant.

Panasonic's mAh rating is based on a 2.5V cut-off, no vaper will ever drag a cell that low.

Here's another fav. Folks always like to say AW has 'accurate' mAh ratings and the Chinese always exagerate.

Here's a China Tenergy2600 VS an AW2600 Li-Ion (which costs a lot more).

The dots are on the 2A trace (a tad more than a LR Boge carto would draw). The dots are at 3.4 and 3.2V. It could just a sample to sample difference but the Tenergy noses out the AW by a hair. I have never seen such similar/identical looking tests at all amp loads. That AW very well may be a China Tenergy re-wrap.

 

[tsbrewers]

I had the same needs and went with a smartvapes altoid mod. I am using the panasonic batts and they are lasting me a good solid day and a half to close to two days.

Might have to look in to the Xtar batteries.

Brew