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50W 10A Box Mod
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thejewk Offline
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Post: #1
50W 10A Box Mod
Hi folks,

As a preamble, I know Gords' brother and I just had a conversation with him about a recent mod I built, and I said I would make a build thread on this forum to show how I did it and what I used.

It's based on the Murata OKR T/10 chip which is a DC-DC step down board, and it can be purchased from here:

http://www.digikey.co.uk/product-search/...okr+t%2F10

As I said in the title, it maxes out at 50 watts or 10 amps, so there is a lot to play with.

I wired it up as follows, with pin 1 being the rightmost pin on the chip, and pin 5 on the far left.

Pin 5 goes to a 220 ohm resistor, and then to a 200 ohm trimmer potentiometer, then to ground.
Pin 4 goes to 510 connection positive pin, and the 510 connection negative to ground.
Pin 3 goes to ground.
Pin 2 goes to a master switch, then to a push switch, and then to the battery holder pos.

I made a solder join between the three ground wires and connected them to the batter holder negative.

In my application, Pin 1 was not used.  You can use Pin 1 as a control pin if you want to use a small tactile switch, but I think it needs to be a normally closed switch and you need a 10k resistor, maybe 15k, between Pin 1 and 3 to close the circuit again after you release the tactile switch.  I also have read that this introduces some drain across the circuit so you don't want to leave batteries in it long term if you do this.  Also, if you use a 5.6 v zener diode before the tactile switch when using Pin 1 it will set an undervoltage protection cut off of 6 volts which would be good for the sort of IMRs you need for this project.

I am using 2x18650s in this and would not recommend anything lower due to the load.  I am using VTC4s and they haven't even got warm.  Also, when using IMRs in series like this, it is important to make sure the batteries are rotated between uses, charged as a pair and kept exclusively for use in the mod.

I have tested it over the last 4 days and have got a full 3 days of vape time on the batteries, mostly running a Magma RDA with a 0.6 ohm dual micro coil build.

You want to use the 220 and 200 resistor and trimmer to specify the voltage range of the mod which in this case comes to 3.4-6 volts.  This means that if you want the full 50 watts you are going to have to dip into sub ohm territory.  For example, my 1.2 ohm single coiled Atomic, set to 6 volts, hits 30 watts max.  The aforementioned Magma build can go to 50 watts no problem and I encountered no hot components (other than the atty, which was very warm lol).

You need to make sure you have a decent battery sled too.  No shitty springs to heat up is a must.

Make sure you have chunky wire for Pin 2 and 4 connections because they are baring the load.

I haven't included a voltmeter in this build because I have a multimeter handy and have figured out my ranges quite quickly, but if you get one of the 2 wire voltmeters (like they have at Stealthvape) you could connect the neg to the battery holder, and the pos to an on/on or on/off/on switch, and then off to the atty pos and the battery poss from the switch.  This would allow you to see both the volts in the batteries and the volts to the atty on a select switch.

Here is the current build, which looks terrible and is in a massive plastic box.  It was the only thing I had kicking around.  I have an aluminium case I am brushing at the minute and a mahogany box I am building, so this is getting transfered to one of those shortly.  I am also going to replace the shorty 510 extender connection for an 'airflow adjustment cap'.

[Image: 13801576004_d14172c6f6.jpg]IMG_0239 by thejewk, on Flickr
[Image: 13801250063_1b9f5a1728.jpg]IMG_0238 by thejewk, on Flickr

If you order from Digi-Key, I recommend getting a £50 order together and taking the free postage option.  Takes 1-2 days shipped from America, but make sure you are there to receive it.

Any questions fire away.

Cheers
thejewk

Forgot to say, with no atty connected it reads 0.1 volt more than with an atty connected, so the drop is more than acceptable.  I tested the batteries under load, and they drop 0.3-0.4 under load as a pair, so you shouldn't be taking the batteries down lower than about 3.2 volts per cell unloaded.

Second edit: this is not a mod for people who don't know what they are doing! be warned. I take no responsibility for you blowing your teeth out, etc. No reverse battery protection either so if you put batteries in the wrong way they WILL go thermal on the temperature front in 2-3 seconds.  Also note, don't try this on Efest red IMRs or similar, especially not 18350s, as they drop serious volts under load due to crappy internal resistance.
(This post was last modified: 15-04-2014 07:36 PM by thejewk.)
15-04-2014 07:24 PM
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18sixfifty (04-16-2014), apt323 (04-15-2014), Don (04-15-2014), gords1001 (04-15-2014)
JohnnyMac Offline
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Post: #2
RE: 50W 10A Box Mod
Welcome, thejewk!  Awesome build and very interesting.  I wouldn't mind trying something like this one day.  Any chance of getting better closeups of the circuit stuff?
15-04-2014 07:47 PM
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thejewk Offline
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Post: #3
RE: 50W 10A Box Mod
It's unfortunately difficult because everything is covered in shrink tube and electrical tape.  Let me have a go in paint and see if I can draw it for you.
15-04-2014 07:53 PM
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gords1001 Offline
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Post: #4
RE: 50W 10A Box Mod
Hi jewk, glad to see you here. I'm still at the fucking about stage of my dna20 build, I suspect the next one will involve lipo packs and some 300a mosfets. Thats a nice vv solution though.
15-04-2014 08:01 PM
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thejewk Offline
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Post: #5
RE: 50W 10A Box Mod
[Image: 13879569794_9d76266ffd.jpg]circuit by thejewk, on Flickr

(15-04-2014 08:01 PM)gords1001 Wrote:  Hi jewk,  glad to see you here. I'm still at the fucking about stage of my dna20 build,  I suspect the next one will involve lipo packs and some 300a mosfets.  Thats a nice vv solution though.

I am half working on an unregulated 18650 mod inside a battery case and I used a little tactile switch so used a MOSFET so I didn't need to worry about amp load on the switch and voltage drop but it was so bloody fiddly and I broke the damn thing.  The circuitry is sat on my desk taunting me.

There is also another chip with higher capabilities than this one, called the Naos Raptor, for 20a 120w, but it is a little bigger and needs capacitors to smooth it out.  That was about twice the price and out of stock when I ordered bits so I'll do one of those later.  I do have a 08100WVD though, which is getting chucked in another box at some point, or maybe a baccy tin.  
(This post was last modified: 15-04-2014 08:10 PM by thejewk.)
15-04-2014 08:04 PM
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apt323 Offline
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Post: #6
RE: 50W 10A Box Mod
Welcome

Nice and thanks for the pics and paint pic sounds like a sweet setup.

Do you have other setup that you have completed or some in the work, if you do post them up too!!!!1

Good
15-04-2014 08:19 PM
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gords1001 Offline
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Post: #7
RE: 50W 10A Box Mod
I've read quite a bit about the raptors. My problem is I have some 60a continuous drain 26700 cells and access to a lathe....I think we can see where thats going, I may have to turn my own hybrid dripper and see how that works out. I have got a good selection of high cap high drain lipo packs that would work well for a dc - dc converter mod too. My main project at the moment is a spring loaded 510 connector for use in box mods. I think I've got the suss of that, just need to grab a couple of hours away from the family to cut everything up and start building.
15-04-2014 08:21 PM
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Spasmod Offline
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Post: #8
RE: 50W 10A Box Mod
Welcome to TVF Jewk!

Wow that's some interesting stuff right there, I have to admit I'd not ever considered something along those lines. That looks like a pretty simple but powerful circuit which enables full control with fine adjustments too. I'm looking forward to seeing the finished project actually!

I'm glad you mentioned about the cell safety and how to ensure the highest possible way to avoid problems. I won't pretend I'd be 100% comfortable with in series IMR cells but that's just me being paranoid Smile

Have you considered a Lipo pack for this task at all ? I should imagine it wouldn't cost you a lot of room.

Thanks for sharing and giving us all some inspiration Drinks
15-04-2014 08:29 PM
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thejewk Offline
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Post: #9
RE: 50W 10A Box Mod
(15-04-2014 08:19 PM)apt323 Wrote:  Welcome

Nice and thanks for the pics and paint pic sounds like a sweet setup.

Do you have other setup that you have completed or some in the work, if you do post them up too!!!!1
Sure man will do, just not right now lol.

I have made so far:
2x18350 KIS3R33S VV box, maxes out at 19ish watts
2x18650 woody with the same board
1x18650 unregulated as a test, too much voltage drop for me

In progress:
1x18650 unregulated in a battery case for portability

Coming soonish:
Something using this: http://www.ebay.co.uk/itm/3-5-to-30V-100W-Step-Up-Converter-Boost-Power-Supply-LED-Voltmeter-DC-DC-LTC1871-/121227471730?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item1c39b86b72
Possibly a vapestation with a couple of hoses attached with attys on the end, mains powered.  Need to do research.
Another OKR T/10 going into some mahogany.
An 08100WVD in an aluminium Hammond 1590B

I'll make some threads over the coming week and post pictures.

@ Graham

If you get some sprung connectors done, I'll take some off your hands if there are any going.  Sounds great.  I am using the 510 extenders from Stealthvapes at present which are OK but not great.  I have ordered some clone top caps from fasttech to try out too. 

(15-04-2014 08:29 PM)Spasmod Wrote:  Welcome to TVF Jewk!

Wow that's some interesting stuff right there, I have to admit I'd not ever considered something along those lines. That looks like a pretty simple but powerful circuit which enables full control with fine adjustments too. I'm looking forward to seeing the finished project actually!

I'm glad you mentioned about the cell safety and how to ensure the highest possible way to avoid problems. I won't pretend I'd be 100% comfortable with in series IMR cells but that's just me being paranoid Smile

Have you considered a Lipo pack for this task at all ? I should imagine it wouldn't cost you a lot of room.

Thanks for sharing and giving us all some inspiration Drinks
My pleasure mate.  

I was initially concerned about 'stacked' IMRs, but after using them in various mods for a few months, I see no problems that careful monitoring and sensible behavior can't avoid.  Keep them balanced with external charging, rotate, don't over use and don't over stress.  Nowadays I am more worried about the terrible mech designs that are coming out left, right and centre with crappy springs that can short to the mod tube, ill fitting delrin insulators, etc.

I wouldn't be against using lipos, but the problem is charging them.  If you use a step down board you need to go in above what you want to come out, so it means series cells, whether internal or external, and that mean no USB charging and with no easy access way to charge them externally without disconnecting them.

I am definitely going to have a play with some lipos, but it'll be multiple small cells in parallel to give me a high amp drain, low voltage drop and kick arse battery life.  Link those up with parallel mosfets and you will have the mother of all unregulated mods.

Disclaimer:  Most of the things I have made and am talking about here are a result of many conversations with many forum people, and I wouldn't have got anywhere without the help of brilliant people like Boltar, doobedoobedo, Guill, breaktru and Stig, amongst others.  I recommend researching their builds as they know a crap ton more than I do.  I hadn't even looked at a soldering iron before last December.
(This post was last modified: 15-04-2014 08:42 PM by thejewk.)
15-04-2014 08:32 PM
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gords1001 Offline
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Post: #10
RE: 50W 10A Box Mod
For lipo charging its really best to look to the rc market, you need to include in the assembly a pos neg and balance port if your charging in situ, or use a deans connector or banana connectors and just pull the pack like you would in a plane.

The advantage is 5000mah charged in an hour or so, but it means buying a thirty quid charger and acquiring a 10amp capable 12volt supply. I definitely like lipo packs, they're capable of dropping seriously silly current without a sweat and give high capacity into the bargain.
15-04-2014 08:56 PM
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