Need help designing 5v Mod Circuitry

[justaguy0]

Hey guys,

So i've been ultimately trying to develop my own 5v mod and need some help in coming up with the wiring diagram to make this work the way I want to. Ultimately, after I make a rough draft, I'd like to create a PCB to a size of a my choice that I can have manufactured through my work.

Essentially I've already got the essential components, but first some questions. I've heard that if possible, running 2 of the UltraFire Li-Ion Protected batteries in parallel is better than running in serial. I'm not sure why, but thought I'd ask if anyone has a good explanation?

What I'd like to do, is similar to the "detonator" 5v mod, only I'd also like to add a USB Charging option. I was thinking a 3.5mm stereo jack connection that a 3.5mm stereo jack can plug into and be removed easily with the other end a USB connection. That way I can charge it, use it as a USB Pass-Thru, and disconnect it and walk freely with it at the same time.

I'm having trouble figuring out how to wire this all though. I already have the 2 UltraFire batteries, the TI Regulator, switch, led, 510 coupler (nerf's), switch, and I've got plenty of 3.5mm and USB connections laying around. Not sure if I need to wire in some resistors here, or something else for the "charging" aspect.... I guess i'm looking for some help here.

Can anyone lend me a hand with some of the "electrical" design?

Thanks!

 

[j0ker]

Parallel will give you 3.7 volts, series will give you 7.4. Of course the parallel setup would last much longer.

If you design to charge from USB, you'll have to design a charging circuit to fit into the mod. Won't be easy in a Detonator mod. If you google search "Lithium Ion charging circuit" you'll find an abundance of circuits you can build. If you feed power straight to the batteries, you WILL have an explosion. The circuit is meant to monitor batteries and shut off charging once the batteries reach capacity. You might consider do a little research on lithium batteries. They can be dangerous if you don't know what you are doing.

 

[j0ker]

Here's the site I was trying to think of that will help you understand batteries a little better.


Welcome to Battery University

 

[justaguy0]

Yea that's why I was looking specifically for a "USB Charging Circuit" for Li-Ion batteries No explosions wanted here... lol.

So is there "Anyway" I can wire some li-ion batteries in parallel to still pull 5v AND incorporate a USB Charging Circuit? Is there another battery I could go with?

 

[Paranoyed]

Isn't the TI regulator actually designed to step up the volts from the input source to the desired output level?

 

[justaguy0]

by the way... just for reference. I'm talking about 2 Protected UltraFire 14500 900mah Li-Ion Batteries.

 

[j0ker]

The only way you will get 5 volt is through 2 batteries in series, regulated or 1 or 2 batteries parallel with booster. There are other options but I'm only answering your situation having 2 batteries.

 

[justaguy0]

Well i guess I'm still stuck then. I'd really like to design my own, and have it wired more safely than something in series. I'm open to other options, but really looking for someone to help me with the wiring diagram for what I'm trying to do. If there's a known charging circuit I can incorporate somehow, or if someone has done that before, I'm really all ears.

 

[j0ker]

justaguy0, take a look at this.
Electronic Crafts | Main / Address
Scroll down the page till you see "Battery Charger", it shows you how to use a MAX1555 chip to create a charger. It's very tiny and should be able to be scaled to fit most any mod. This is what I'm going to be using real soon. There's also some links to where you can purchase the chip but make sure you a break out board. A break out board will make it much easier to use in your application.

Hope that helps. Good luck! Send me PM if I can help further.

 

[justaguy0]

Hey Joker, that might work... or at least we're closer. It looks like the 1555 max chip has a 100mA max charge current when used with a USB. So how will that effect charging a 900mA battery like the UltraFire 14500?

Also, the chip supports charging of 1 li-ion battery only. Looks like max input from USB ranges from 3.7 - 6V max.

Wiring 2 14500 Li-Ion batteries in series doesn't even really seem possible here. However, maybe 1 Li-Ion 6V battery outputted by a TI Regulator for 5V? Do they even make a decent battery like that? I'm really not a fan of all the "in-series" wiring everyone seems to be doing. I'd feel more comfortable with either a good capacity 6V, or something wired in parallel.

Thoughts?

 

[Paranoyed]

Just if you get the free samples of the TI RN series voltage booster you can step up the volts from 1 3.7 to 5.0. I am going to do this build in a 3AA batt holder. I am also going to add in the charging circuit from the DigiPower JS1-V3 from Radio Shack. This way I will have a slightly larger nico stick with charging and 5v capabilities. I am also thinking about getting another JS1-V3 and wiring a 14550 to the batt connects then wiring the atty connect and switch to the 1 and 4 pin of the dissassembled male USB plug. If I am thinking correctly this will give me the 5v and USB charging without the TI even being used. All I have to do is find the right box.

 

[j0ker]

It looks like the 1555 max chip has a 100mA max charge current when used with a USB. So how will that effect charging a 900mA battery like the UltraFire 14500?

Don't confuse mA with mAH. mA is the amount or current flow and mAH is capacity(time). The 100mA charge really only determines how fast the batteries will charge. How much time that will be we can see when we first charge it. My guess would be no more than 2 hours but probably much less. If you set up an all day PV, probably won't matter since you will probably put on charge overnight.

Also, the chip supports charging of 1 li-ion battery only. Looks like max input from USB ranges from 3.7 - 6V max.

I notice that too. I'm going to read a little more on the spec sheet to get more details as to what exactly the mean. I'm not sure why it would matter how many batteries you were charging. USB is around 5 volts so the input range would be fine..

Wiring 2 14500 Li-Ion batteries in series doesn't even really seem possible here. However, maybe 1 Li-Ion 6V battery outputted by a TI Regulator for 5V?

When batteries are in series, you add the value of each battery for total voltage, when in parallel, the voltage remains the same. The difference is, parallel will give you more time, longer lasting PV. Series will give you more voltage. To complicate this even further you can do series/parallel and get more voltage and time. That would require at least 4 batteries. I can draw up an example if you not sure what I mean.

All in all it might require having 1 MAX1555 for each battery. I ordered four for myself but I would like to attempt charging 2 and see what the results will be. I will probably do that to test before building the ciruit into a PV. I'll post my results. It won't be real soon but hopefully in the next couple weeks.

Keep in mind, I'm no expert, I haven't worked at circuit level in several years and college was even further back . Others may have better info, so please share if you do.

 

[justaguy0]

Thanks for the info Joker,

Same here, I haven't done circuitry in quite some time. I'm probably going to use Eagle or ExpressPCB to design it and prototype it. I'd like to see an example schematic you're thinking about to see if it lines up with what I'm thinking.

I thought about the 2 max chips running series / parallel. That may end up being the way to go.

If you run 2 14500s in series, you're talking about 7.2V that you'd have to use a TI regulator to limit output Volts to the atomizer at 5V. So then capacity wise, you'd have probably, 2 more 14500s in series, and the pair of both them wired in parallel.

On the input side, looking at the maxim schematic. I'd probably leave the DC connection alone, not even use it. I found female Mini USB connectors (5-pin) I could order. Question is, do you happen to know which wires / pins on a mini USB - USB actually contain the power / ground? I'm thinking this is a 2 wire connection needed only.

If you use the maxim IC, it doesn't appear that you'd really have to wire in any extra resistance anywhere... except perhaps on the LED indicator?? not sure about that.

More thoughts?

 

[j0ker]

I need to build my idea in a simulator but I just haven't had the time yet. I probably will though.

The mods I been building for myself have been 3.7 volt, I personally don't care for the 5 volt. I do have a 5 volt unit and when my KR8 cartos come in, I'm going to see how they do at 5 volt.

In USB pin1 is power, pin 4 is ground.

As soon as I put some stuff together, I'll be sure to share design.

 

[justaguy0]

Thanks joker, I'll share my progrss as well.

 

[Fenix-T]

I've got some questions if you guys don't mind,

1. (2) 14500's in series with TI regulator

vs.

2. (2) 14500's in parallel with TI booster

Which gives the most vape time between charges? Which one would produce better vapor?

I've got samples of both on the way so I'm trying to figure out which would be the way to go.

 

[radwor]

I'm pretty sure the reg set-up would last longer. I wouldn't boost with any less than 4 14500's or 2 18500+ w/o caps. AS for vape quality side by side the reg seems a little bit warmer, but both are good.

I've got some questions if you guys don't mind,

1. (2) 14500's in series with TI regulator

vs.

2. (2) 14500's in parallel with TI booster

Which gives the most vape time between charges? Which one would produce better vapor?

I've got samples of both on the way so I'm trying to figure out which would be the way to go.

 

[Fenix-T]

I understand how the vapor would be warmer, but I'm confused about how the life would be longer with the regulated. In parallel it would have the 1800mah.

I think alot of my confusion is that I'm not sure how the regulator works. Does it take the extra 1.3v and waste it as heat? Or is it working smarter than that?

 

[radwor]

Fenix, there are others on this forum more familiar with the working of the two.
I would get on Ti's site or google and check it out. I think they both use switching for efficiency, but the boost uses on board inductors and caps.
I think the reg is more efficient, but I'm no expert so if you need more GL.

I understand how the vapor would be warmer, but I'm confused about how the life would be longer with the regulated. In parallel it would have the 1800mah.

I think alot of my confusion is that I'm not sure how the regulator works. Does it take the extra 1.3v and waste it as heat? Or is it working smarter than that?

 

[j0ker]

14500's in parallel would only be 3.7volts and the regulator would not be necessary. The reason for regulator with 2 14500's in series is that it would be around 8 volts with batteries fully charged. The regulator is to regulate the voltage from the series batteries down to 5 volts. A 14500, as well as most lithium batteries, produce around 4 volts on a fresh charge.