is this "kit" usable for VV?

[Kahuna]

I saw this on ebay today. I was thinking of making a 2x18650 VV modbox and wondering if this can be used.
http://www.ebay.com/itm/2-Set-LM2577-3A-Step-Up-ADJ-Switching-Regulator-KIT-H-US1-/190641223416?_trksid=p4340.m185&_trkparms=algo%3DSIC.NPJS%26its%3DI%252BC%26itu%3DUA%26otn%3D5%26pmod%3D190640704690%26ps%3D63%26clkid%3D6471600332066030096

 

[Killjoy1]

Yes, you can use it for a VV mod. If you search, you can even find the LM2577 (and others) already fully assembled for roughly the same price. I suppose a benefit of that kit as opposed to a fully assembled board is that you can configure it differently based on your particular space requirements

 

[Kahuna]

yeh, I might use a pre assembled board for my 18650 box mod, but I was thinking of using this kit to shoe horn it into a 14500 battery space in a 3xAA box mod.

 

[CraigHB]

Doubt you could make it much smaller than the ones you can buy ready to go. That's a booster so you only need one cell. It should do the job, but it's not the most compact way to go. That particular controller runs at a relatively low switching frequency so it needs a big inductor and relatively large capacitors.

The limit is 3A on input so you'd be limited to about 10W out. That's good for about 5.5V with a standard 3 ohm atomizer which is fine for most people. You could hit the drain limit with a single protected 14500, you'd need to run an IMR 14500 or a protected 18650 with it.

If you were thinking of running two cells in parallel, you'd do better running them in series with a buck (step-down) converter. You'll get much better results with that configuration, a lot more compact with much higher output capability. Plus, you can use a couple protected 14500s if you want.

 

[TomCatt]

I got one of the LM2577 modules from eBay and using a GTL 18650 "3000mAh" battery, wasn't able to get past 4.9V with a 3.2ohm clearomizer.

The LM2596 modules (buck not boost, so will need 2 batteries in series) on eBay are what I've been using. However, they are too large to fit in an AA slot. Here's one for $2 - LM2596 DC Step-Down Adjustable Converter Power Module | eBay

 

[CraigHB]

That doesn't surprise me. The specs listed for that boost controller indicate a max 3A input current which should relate to a max output of approximately 5.5V with a 3 ohm atomizer. However, switching converter design involves much more than just slapping some components on a circuit board and calling it done. These eBay modules are coming from China, designed and assembled by who knows. You pay your nickel and take your chances with them.

You'll probably have similar issues if you attempt to use a kit that requires laying out your own circuit board, unless of course, you know what you're doing. Even so, there's no guarantee the parts they're giving you conform to design requirements. Attempting to cobble the parts together wire to wire without using a circuit board will likely fail miserably.

 

[Kahuna]

thanks guys. I think I might just go the OKR-T/6-W12-C route. Mamu has picts on how the circuit is built and it looks easy and that regulator isn't crazy expensive. In the meantime since shipping will take a month a so, I will try out one of those pre assembled drop in Kis-3r33 DC-DC Step-Down 4A LM2596 power modules.
http://www.e-cigarette-forum.com/forum/battery-mods/246380-dena-vv-mod-denalis-lil-sis-step-step-how.html

 

[CraigHB]

That's going to be the best route. A buck converter is really the best solution. The only exception is if you really want USB charging and the convenience of a single cell. In that case, a booster makes it a fairly simple proposition. Though, you can still make a series cell mod with non-removable cells if you want. You just have to add a connector for a pack or balancing charger.