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Post by johnnyjames on Jun 25, 2014 13:54:34 GMT
That may not be a correct assumption. Stepping down (like this PV does) is a very efficient way to go and is also much easier on the batteries. Stepping down is always prefered to boosting in many situations. The Tesla, an electric car that uses huge banks of 18650s outputs 375V. A big advantage of a series battery configuration (7.4V) vs. parallel (3.7V) is that the series config provides a specific power at a lower current than the parallel, and thus the power loss is also lower. Maybe not perfect, but here's an example. In the US we run at 110V, but there are many cases where appliances/motors can be had that use 220V. Let's say you are going to install a 3kW motor in your house or shop and you can choose between a 110V or 220V motor. If you go with the 110V motor, it will draw 27A, therefore requiring a 30A breaker and 10AWG wire. If you go with the 220V motor, it is going to draw 14A, so you can install a 15A breaker and run 14AWG wire. Here's a pic from the 10A OKR stepdown assembly data sheet.  FWIW the lowly Vamo can only manage about ~14W with a single 18650 (boosting), but with a pair of stacked 18350 (stepping down), switched over to VV it can mange about ~24W with a 1.3-1.5? atty. Food for thought. |
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Post by johnnyjames on Mar 16, 2013 20:11:32 GMT
...im hoping to do it as a twin 18650 rather than a single i like the extra run time of twin batteries,i have a papa r and it goes 2 days before i need to charge the batteries And note these things will run full throttle with the batteries in SERIES. In step down mode (series) there is also less stress on the batteries, boosting puts extra stress on the battery especially as it drains down as it needs to progressively provide even more current to properly regulate. |
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Post by johnnyjames on Nov 19, 2012 21:36:33 GMT
FWIW the 'T' I got is a bit different. It's a left handed model (  ) Note where the wick hole is.  I don't have a pic of the top cap, but it is a bit more tapered at the top and fully polished (a shiny fingerprint magnet now). I noticed on an earlier post someone commented that with 28ga wire the coil heats up slower, but with all those thicker extra wraps needed get to at least 1.5Ω, because of all that extra mass, it will also heat up less. |
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Post by johnnyjames on Oct 22, 2011 22:01:31 GMT
See, I would have thought that the obvious choice for VV in this situation would be a Buck/Boost module such as the PTN04050CAH. I know Christophe had success using a similar module, but something he did with his meant that the voltage was offset by .5v (not sure what he did there). 2000Mah is always going to be enough to power a VV mod. I've had VV mods that run on stacked 300Mah batteries, so that's not the issue. Don't confuse mA, a measure of current, with mA h a measure of battery capacity. And in general a cell in a booster has to provide about 25% more current to obtain the same watts as a step down regulator. When feeding those 04050s (way under powered for today's atties with their 12W/2.4A rating) a battery can usually supply what is needed. It's current output is flexible. Larger cells and IMRs can supply 3+A if called for. With a 2A power supply (and you have to hope that's accurate) how much of that can actually get to the atty? In the real word those boosters are about 80% efficient, especially when a diode is involved to drop the final voltage plus of course the additional resistance a switch and the mod wiring adds. A quick example. Using Ohm's Law, 5V @ 2.5Ω we need 2A for 10W. But in this case we are boosting from a 3.7V source. So what do we need to get 10W from let's say 4V (a fresh cell). Ohm's Law tells us at 4V we need 2.5A for 10W. As the cell discharges at 3.6V it will have to now provide 2.8A to maintain that 10W. You'll note I haven't even figured in the efficiency loss of the booster/mod. |
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Post by johnnyjames on Jul 26, 2011 21:03:53 GMT
Thanks. The beauty of the clears is that you can get a real understanding of how cartos work. Here's one filled by top loading only.  I let is sit a day and vaped it for a few minutes. The air pocket never went away, I had to syringe it. With the Jumbo eGo DC the filler seems a little less dense, there is almost a gap between it and the shell. This is a good thing I believe. |
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Post by johnnyjames on Jul 26, 2011 19:45:14 GMT
... I haven't had ANY of the smaller ones (about 1.6ml?) blow on me, they scorch the little diapers wrapped around the coils after a while which tastes yuk and that's why mine have got retired. Although they don't look so pretty at times, the clear ones seem to be best for keeping an eye on what's going on with them. Well I've blown one coil in 3 so far, including the Jumbo eGo. I run them at a modest ~3.6V. And even though I try to keep them wet this has also happened twice.  The hole is in the filler, not the plastic. |
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Post by johnnyjames on Jul 25, 2011 22:30:27 GMT
I like them. And the draw doesn't seem to stiffen up like the normals.
Folks should know they are particular about connectors though.
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Post by johnnyjames on Jul 10, 2011 21:42:24 GMT
Its certainly not the case with the 1.5ohm Boge cartos Lindsay,they perform faultless and give a far superior vape to any other cartomiser, including the dual coils.I dont think the dual coils are anything special at 3.7v,they need 5v to perform for me  It's interesting how opinions very so widely, but many times it's in the fine details. I was long time Boge 2Ω user at about ~4.6V with PG juices. Bought some 1.5Ω and flat out didn't like them. The SmokTech 1.5Ω DCs I really like and mostly because they work so well at ~3.5V. Oh Well. |
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Post by johnnyjames on Jul 10, 2011 21:22:57 GMT
That 2.6A supply is quite nice. The switching types (cooler running) are always of a higher quality than the 2000mAh (2A) unregulated little USB things offered at shops. For what it's worth unless you need it 2 pieces I would wire it direct to the PT. My first mod from a few years ago. No frills, just max performance. No extra connectors, thin USB cables etc to add resistance.   Hardwired your PS should run any atty from 2Ω and up at a full 5V. Hopefully that's what you really want. |
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Post by johnnyjames on Jul 10, 2011 20:49:34 GMT
Well I few observations. It's basically a pressure thing. Obviously the hole (most folks in the States use demeled slits) has to be sized right. I may have to try a hole, but 1mm sure sounds small. Is that just one hole? Back to the pressure thing, With the CE2s when in the tank they are never really perfectly sealed/air tight like with the DCs. Once you fill and start pressing in the grommet/washer the pressure will have to push the liquid through your hole. It has to, whether the hole is big or small. With a fresh empty carto, the first time, don't pre-fill the carto. Install it, fill your tank and just drip a few drops on top. Then slowly push your rubber in place and as soon as you can hold it horizontal then let it sit awhile. Probably the best bet is simply a port, that can also be used for filling. There are a few ways to do this.  The yellow dot is where a small hole can be placed, What this one will do is allow air to escape until the very end till your rubber finally covers it. The red dot is good but will need a removable plug of some sort. I'm sure you can think of many ways to make a little plug. The red line is where I usually cut my slit. |
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Post by johnnyjames on Jul 10, 2011 4:45:34 GMT
If I may ask, what are the black top/bottom plugs made of?
Thanks
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Post by johnnyjames on Jun 12, 2011 21:07:11 GMT
I've got all the bits I need to make a box mod, but I'm still looking for a case. Needs to be fairly large to fit all the bits - 2s 800mAH LiPo, I don't know what you mean by LiPo, but you should a pair of 3.7V cells. |
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Post by johnnyjames on Jun 12, 2011 20:59:14 GMT
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Post by johnnyjames on Jun 8, 2011 1:41:38 GMT
A clean and well tinned tip is very important. You should also tin any bare wires. As far as the the atty shell clean it well, some fine sandpaper or steel wool. If the connector is the silver shiny type, file it till you see brass.
I like and use type RMA rosin flux.
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Post by johnnyjames on Jun 6, 2011 20:02:56 GMT
Nice, but you are underestimating the voltage (3.7V) a pair of 18650's can provide, at least if you had some better cells. Those cells are a poor choice, high resistance and major voltage sag. Note in this 2A drain test just how much those UF3000's sag (brown trace) with voltages always and well below the competition. And for me at least, any capacity under ~3.4V is pretty much useless. |
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