7.4V RC Battery Builds - Different way to vape. 150w + capable

[Shawheennn]

Im opening up this thread and reserving the next few posts for 7.4v related builds based off of RC batteries. In return I hope it creates some awareness for others as well as the opportunity for questions, learning and feedback in general. Hey, I just like these batteries. Cheaper, Safer, Better form factor, options. Of course this is mainly for vapers that will want to pass the traditional 100w barrier 3.7v builds give and enter safely into 100w+. Did i mention safer.. crummy 1850 batterties


anyways

Heres our first build to share. Things got a lil messy but its all good. I will offer links for ease of ordering for those who want to join and try something different. Ill try to keep up with steps and photos, feel free to ask anything i missed.

Hammond 1590G Black
IRL7833 Mosfet
15k 1/4w Resister
12mm or 1/2" Momentary button
Fatdaddy V4
16AWG Silicone Wire RED & BLACK (under 100w go 18awg)
XT60 Connector
Lipo Charger
1300mAh 52/65amp Lipo Battery - This 1000mAh works better but still tight fit, or a 800mAh gives you space for days.

TOTAL COST UNDER $60 WITH BATTERY AND CHARGER*

*I included bulk items too dgaf still cheaper

A 1590B build would give you much more room for bigger batteries but in reality these should last a while vs typical 18650 regardless of the mAh & with this easy connector you can have multiple spares to easily plug in.


Setup Everything & Necessary Liquid

Pokin holes into the box. Step down bits are legendary for this. The button was 1/2" and the Fat Daddy I drilled 7/32.

I snipped off the battery connector to shorten it but I'll show how I solder it for those new to the XT60 connector. Just put solder on it and apply wire lol

I cut a bit of the legs on the mosfet, do some creative resister bending and solder it

Adding the mosfet wires (to button, to battery neg, to fatdaddy tab). Remember, heatshrink is like wearing a nice sox with your outfit.

Get one wire ready on the button (the one that will get soldered to the wire going to the fatdaddy connector)

Fatdaddy time. Left some open on the wire so the switch can get attached to that wire

You should have this

sit for a second to think how tight this fit is and wished i made the wires shorter (i swear i calculated)

just stuff it yolo. Keep that charging cable (the white thing) easily accessible. thats all u plug in to charge.

Final product

Thats it for this one. Bunch of different ones to come. I hope u guys can see why I went this route. For the cloud chasers, this opens your doors to something a little safer. CHECK YOUR OHMS. no one better embarrass me trying to put a 5 wrap 24 guage wire on this & ask why it keeps melting your coils. For those who want to chuck clouds reasonably (130w or so) I would say 6 wraps on a 4mm bit using 26 guage should land u at .45 ohms or so. Just verify.

A tip on heating coils for those playing above 80w, do one coil at a time, fire, remove the coil and insert other one. pulse to keep those coils from melting.

 

[Shawheennn]

reserved

 

[Shawheennn]

reserved

 

[Shawheennn]

mine

 

[Shawheennn]

last one dibs

 

[zaroba]

A box battery for a box mod.
Nice


So, if I recall correctly from my RC hobbyist days...
amps x C = amp draw, so that 1300 battery has around a 50amp continuous?

 

[Shawheennn]

A box battery for a box mod.
Nice


So, if I recall correctly from my RC hobbyist days...
amps x C = amp draw, so that 1300 battery has around a 50amp continuous?

Exactly! @ 7.4v i doubt u cant reach this batteries capacity

 

[DIY FancyLights]

You can use much thinner wire to/from the switch, very little current goes through that. It can make it easier to fit everything into your case with a thinner wire to the switch and then to the MOSFET Gate.

 

[Shawheennn]

You can use much thinner wire to/from the switch, very little current goes through that. It can make it easier to fit everything into your case with a thinner wire to the switch and then to the MOSFET Gate.

Yes good tip to add. My 20 guage wasnt here yet and that is the one I wanted to use

 

[Slurp812]

Sweet looking Mod. That is how its done. You have some mad skillz. +1

 

[Caboose]

I've thought about building something like this, simply because of the capacity you get from lipo's and the quick charge rates. But without a voltage cutoff I'd consider this to be too high of a risk. lipo's are pretty volatile things, I don't know if you've ever seen one balloon up and go off from being drained too much but it's pretty spectacular. You could add a simple FET that would serve as a soft cutoff and provide an added layer of safety. Aside from that the safer alternative would be to use the LiFePo4 batteries, not quite as drastic charge and discharge rates but they are supposed to be a much safer battery.

 

[DIY FancyLights]

You think there is a market for a tiny PCB that could apply voltage cut-off to protect the batteries? Considering what I've done recently with a MOSFET, that should be possible if we feel there is enough interest ... we could even have surface mount modules built for us.

 

[torq5252]

DIY, I would LOVE a very tiny PCB for low voltage cut-off, or even just a led gauge indicator. I'm converting a bunch of fried iStick 50 watt mods to Unregulated mosfet builds and there is very little room to play. No way can I get one those little voltmeters in there. They don't really open up easy, or take a sled so they have to have onboard charging. Just getting the charging board and mosfet into them is so tight I have to pull the female micro usb connectors off and wire them so the board fits vertically. I was looking at buying cheap Ego sticks to cannibalize the boards for the lighted indicator switch and "low battery protection", but they're a crap solution, really. I'm totally eyeballing your little mosfet boards and when I use up these 3034's I have I'll probably hit you or D4500 up for some tiny stuff..

 

[DIY FancyLights]

DIY, I would LOVE a very tiny PCB for low voltage cut-off, or even just a led gauge indicator. I'm converting a bunch of fried iStick 50 watt mods to Unregulated mosfet builds and there is very little room to play. No way can I get one those little voltmeters in there. They don't really open up easy, or take a sled so they have to have onboard charging. Just getting the charging board and mosfet into them is so tight I have to pull the female micro usb connectors off and wire them so the board fits vertically. I was looking at buying cheap Ego sticks to cannibalize the boards for the lighted indicator switch and "low battery protection", but they're a crap solution, really. I'm totally eyeballing your little mosfet boards and when I use up these 3034's I have I'll probably hit you or D4500 up for some tiny stuff..

 

[DIY FancyLights]

The microFET's we sell are half the thickness of the 3034's, and only 0.1" longer then the case + tab if you remove all of the leads. That allows them to fit into some very small spaces while gaining the through hole convenience, There is even room on the board for a resistor to help light a LED while firing.

I'll take some time to look at possible solutions for low voltage cutoff & a low power warning LED and post what I come up with.

 

[DIY FancyLights]

The microFET's we sell are half the thickness of the 3034's, and only 0.1" longer then the case + tab if you remove all of the leads. That allows them to fit into some very small spaces while gaining the through hole convenience, There is even room on the board for a resistor to help light a LED while firing.

I'll take some time to look at possible solutions for low voltage cutoff & a low power warning LED and post what I come up with.

How small do you consider small? First draft of a possible circuit with two thresholds, the first one is intended to light an LED when you get that low. When you get lower the other one either prevents firing or lights a second LED. In theory maybe even both but I won't make any bets until I can do some math and test values to make sure both could work on the lowest level.

Just playing with possible ideas I got all that to fit on a 0.8"x0.4" board, but that's only a first draft and untested ... just a basic concept for now. In theory a fin tip soldering iron, magnifying class & tweezers could assemble them. The smallest parts are 0805's even though I could have used smaller one.

Since it's such an early concept I'm not posting the schematic, but I did send D4500 a copy to look at.

 

[torq5252]

That would definitely be small enough for my application. Is that with the LED's on the board? I could make that work, but for myself (and I'd bet most modders) leaving them to be attached with a through hole so they can be wired to any location would be helpful.

 

[DIY FancyLights]

Currently it's one LED through hole connection at each end of the board, but I would want to play around with the design more. I totally understand why people will do things differently, which is why I'v been doing little modules instead of all-in-one solutions.

 

[DIY FancyLights]

I just rearranged the board so both sets of LED holes are at one end. The other end has power, 2x GND, a a control off board (to Fire, PWM, or MOSFET as desired). If the fire button is on the control line leading off the board, then the LED's will be able to light as long as power is available. But, I expect most people will probably wire the Fire button to power the board so the LED's only light while you are trying to fire. But, different people have different ideas on how to use things like this

Board dimensions are still 0.8"x0.4". Four holes on each end on 0.1" spacing currently.

 

[DIY FancyLights]

I keep playing around with the board & features and I think I have an interesting minimal configuration using one IC, one cap, 2 voltage dividers using 2 resistors (1% or better tolerance) and then two resistors for LED's. One voltage divider has an optional 0805 capacitor location also if smoothing is needed. The board is still 0.8"x0.4", and 8 to 9 parts. PL1 & PL2 are the outputs to the LED's, PL3 is the power connection.

The threshold for each LED is independently adjustable, and the outputs need not be for LED's, but that is the intended usage. The minus side of the LED gets grounded out when you are below the threshold, the resistors are connected to the plus side. To help with other wiring, there are a couple spare ground & power connections.

I'm looking on arranging prototype PCB's for testing in the near future. Instructions, including how to set the thresholds with the dividers will be getting written up as well.