Just For LM2596 Users

[SupplyDaddy]

Hello,

I am building a VV box mod using the LM2596 board power by two 14500's in series. I would like to be able to charge the batteries in the mod, can two USB charger boards be hooked up one to each battery while they are in series?

You could remove the USB connecter from one board and tie the inputs together and then wire each boards output to one battery.View attachment 363420View attachment 363421

You can use 1 each charger for the 2 batteries if you also use a 3 position switch. The switch can be used for Vape (on), Off, and Charge(on #2). This way, you can wire the batteries to the switch, and then the switch to the charging board and the LM2596 board. The switch will also act as your main power cut off in the Off position.

Send me a message if you would like details. I can also help find a switch for your sized box.

On another, related, note. I would suggest you get a Micro USB Charging board instead of the Mini USB you posted a pic of. Makes finding a cable a whole lot easier!

~sent from my galaxy mega using taptalk~

 

[RAMartinJr]

Do I have to switch each battery from the series to a board?

 

[SupplyDaddy]

You would wire each battery to the switch instead.

 

[RAMartinJr]

So it would be something like this:

 

[SupplyDaddy]

Egads! No. You have over complicated it. 1 switch, 1 usb board
http://m.instructables.com/id/SIMPLE-ParallelSeries-Select-Switch/

So it would be something like this:
View attachment 363667

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[SupplyDaddy]

I doubt this will be clear... I dont have my links on the phone and I won't be home for several more hours..

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[RAMartinJr]

I checked that link and I understand that the batteries will switch from series to parallel, but you tie the LM2596 and the USB battery charge board together on the output, the LM2596 should be okay, but wouldn't the charge board get damaged from the feedback when it's in series?

 

[SupplyDaddy]

No, the usb charger should just turn it self to over charge mode and refuse to pass any more charge onto the batteries. This is why we use the charging boards instead of the pass-through types (charge protection @4.2 volts verses constant input @5 volts). The board should be just fine.

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[SupplyDaddy]

Oh! And I'm stealing your diagram! Would love to be able to pump them out as nicely as you can!

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[RAMartinJr]

I have sketchup, autocad and a few other cad programs, but I recommend DeltaCad it is a simple easy to use cad program. Get a 45 day trial: Delta Cad - World's easiest CAD program, CAD software

 

[RAMartinJr]

Here is a corrected diagram. Share as you like.

 

[SupplyDaddy]

Here is a corrected diagram. Share as you like.
View attachment 363753

Nice! Thanks!

If you really feel like making the LM2596 work in the range it's going to be used with, I highly suggest replacing the built in 10K Trimmer Resistor with a 2K version. I've used both simple trimmers and a single turn Potentiometer with great success! Simply added wires to them to route them where I wanted them!

 

[RAMartinJr]

When I got my LM2596 I got two for the price of one, I wanted to take the chip off of one and piggy back it on the other to increase the current capacity. Have you tried that?

 

[RAMartinJr]

UT1205 posted this:
"Ok, curiosity got the best of me. I have several spare LM2596's so I decided to experiment with various pots.

I used my power supply and set the input voltage to the LM2596 to 8 VDC. This voltage stays constant through all the tests. The reason I chose 8 volts is that it is pretty close to the voltage of two 18650 batteries wired in series. Results are:

Ohms, Low Volts, High Volts
10K 2.0 7.9
5K 2.0 7.6
2K 1.3 5.5
1k 1.3 4.7
500 1.3 2.7

I intended to go lower but 500 ohms was the lowest pot that I had. This does prove what I thought that a reduction in ohms just lowers the "High" voltage. I have gotten use to the adjustments and 2K ohms works for me.

Hope this helps with your "build"."

Based on this I think I would prefer a 2.5K to 3K ohm multi turn pot so it wont be so sensitive and still get 5V under load.

 

[SupplyDaddy]

You will notice that UT1205 did that because of me earlier in the thread. I cant say on any other than the 2K, and for that I get different readings than he posted.
I'm currently on day 3 since changing my batteries out on my hammond LM2596 and I can still go up to 6.46(+/- .10) and down to about 2.34.
I know the 200 ohm versions won't work, but I may get some 1k's and try again.

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[RAMartinJr]

Are those loaded or no load readings? What batteries are you using?

Actually I wanted to build a VV device and really wanted to do a single 26650 boost/buck, but I never could find a decent circuit.

I have completely read through this thread two times from post 1 to here, but had never seen anything on the onboard dual charging circuit or piggybacking two LM2596's.

By the way what is the fascination with pass through devices, is it just to do away with batteries or just to tinker with an electronics project?

 

[SupplyDaddy]

Are those loaded or no load readings? What batteries are you using?

Actually I wanted to build a VV device and really wanted to do a single 26650 boost/buck, but I never could find a decent circuit.

I have completely read through this thread two times from post 1 to here, but had never seen anything on the onboard dual charging circuit or piggybacking two LM2596's.

By the way what is the fascination with pass through devices, is it just to do away with batteries or just to tinker with an electronics project?

Don't think anyone here is doing dual charging or dual LM2596's. No one has the need as there are alternates available. As to the pass thru stuff, Yep, you have it in both suggested answers.

On my device, with fresh batteries (Panasonic NCR18650A's total 8.47 volts via external meter) LM2596 set to 3.30v (using a 2k ohm Pot) on my built-in meter. my external meter says 3.35 No load. Drop on a 1.6 ohm coil and the built-in meter reads 3.27 when fired, flickering down to 3.26.

 

[Byovic]

Just built with this board capable of 5amp. Runs 1.2 ohm fine at 4.8. Tried buddies .79 today and held its own at 4.8. Awesome little boards http://pages.ebay.com/link/?nav=item.view&id=221527623906&alt=web

 

[jacosta951]

Was out of the game for a bit, i am very intrigued on how to piggy back two lm2596's to double the amps? Can someone elaborate? =)

 

[SupplyDaddy]

Was out of the game for a bit, i am very intrigued on how to piggy back two lm2596's to double the amps? Can someone elaborate? =)

No, because no one is doing it. The post above yours has the link to a 5 amp version. As long as you're going use a LM2596, that's about the best you're going to do.

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