Added Charging Circuit(for modding lights with charging) OP Updated ME4057

Flashlight Modding and DIY Parts
1

It seems like integrated charging has been showing up on more and more lights such as the convoy BD0 series of lights. This is a great feature, but makes it hard for modding as a driver change typically means the charging feature will be sacrificed. This leaves the feeling incomplete especially when there is a hole in the body where the charging cable used to go.

I think it would be nice to get some discussion going that would help us modders advance and be able to offer our own charging circuit to compliment our beautiful drivers. I don’t know enough to complete the project on my own, but I believe some discussion will make it possible.

For now, it took the circuit from the cheap tp4056 charger board that can be found all over eBay and ali and wherever, and I transferred the components over to a new layout that could potentially fit in some of the lights discussed above. I will post my drawings here to get some discussion going. This board could be potted onto a driver in the correct position.




Topic points:
Will this circuit work as layed out above?
Will our drivers require a firmware change in order to integrate with this circuit?
Are there extra components needed to integrate?
Can reverse polarity protection be added to the circuit?(I believe there is room, but how)
How to make a board that can be adjusted to fit different lights?

Edit:

As a result of the feedback on the above circuit I redesigned a board using the ME4057 charger. This IC has solid specs and includes reverse polarity protection, recharge, and overtemp protection. The new design is below. Please give me your feedback!

I would like to bring a design to oshpark but i am unsure how to do so. In fact, what you see below is as far as I have learned of the design software DipTrace. I do not know how to prepare the design for printing. I don’t know what to do with the different layers such as silk mask or even how they are edited. So I’ll be studying up on that if anyone wants to give some pointers.

Anyway, here is the new design. It is on a 17mm board but could be sanded to 16mm without trouble to the circuit.





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Reserved

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Honestly, I would strongly advise against basing designs around 4056 chips. The original / genuine tp4056 has not been available for quite some time, it’s been pushed off the market by cheaper counterfeit 4056 clones. HKJ only tested the original tp4056 NanJing Top Power chip (with stylized TP logo).

Now it’s just a bunch of different 4056 counterfeit clones. Imho trusting these 4056 clones is dangerous. Never know which one you are going to get. Don’t know if it will do proper cc/cv, terminate properly / tickle charge. Even if it seems ok you can’t count on these chips not to fail in a dangerous manner at some random time in the future. I received a few 4056 clones and they didn’t do proper cc/cv at all. One just applied straight 4.28v. I’ve seen someone report that their 4056 clone appeared fine to begin with then later it randomly started overcharging. Can’t be trusted. Especially for a charger built into a flashlight. You really don’t want a cell to vent inside a sealed metal pipe.

Microchip Technology makes some popular, easy to find, easy to use li-ion charge controllers. MCP73833 does up to 1.2A. The original NanJing tp4056 maxed out at 850mA according the HKJ’s test (it’s specs lie, claimed 1A). If you don’t need as much current then the MCP73831 does up to 500mA in a nice small SOT-23 package. You can build it into really tiny spaces.

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This looks like an orsm start to something big. Thanks for taking the initiative. :+1:

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Hmmm? I chose this one because it has been tested, it’s the simplest circuit, and it can be found for cheap. The original tp can still be found and it seems the tpower clone works well too. But the source is everything and you are right that most can’t be trusted even when asked about the chip. I will look into some other chips and see if there are any good ready made circuits for them.

6

For easily available parts (and alternative to TP4056) you could base it on the Xtar MC1. They’re getting pretty cheap and are known to be reliable. I forget what chip they use, but someone identified it as a common one.

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Thanks. I’ll take one apart later today and see if the circuit is simple enough. I think I have one arround here somewhere :wink:

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TP4057
Doesn’t have a solid CC phase, current begins dropping right away. This isn’t harmful but it is slow. HKJ’s review (2x tp4057 were used in the original ml-102). There are certainly better choices, but still, a couple tp4057 might be safer than random 4056 clones. There is a decent chance they are also cloning the tp4057, but the 4056 chips you know are random clones.

Microchip Technology chips (as well as many others linear li-ion charge controllers) use extremely simple circuits. Two caps, current set resistor, optional indicator led. Circuit and component values are in the datasheet. Adafruit and sparkfun also have chargers using those common Microchip Technology chips. And they provide open source Eagle files for their boards.

I haven’t seen anyone chart the charge profile of any of the 4056 clones.

You have a recent, reliable source for the original tp4056 NanJing Top Power chips (with stylized TP logo)? Please share?

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Looking forward to seeing this come to fruition. A BLF driver with built in charging would be sweet! Think of the mods and/or scratch builds that can be done!

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Adafruit’s MCP73833 open source Eagle .brd and .sch files GitHub - adafruit/Adafruit_MCP73833_PCB: USB LiIon/LiPoly charger

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Honestly it wouldn’t be hard to do, the hard part will be making a generic driver/charge combo board that will work in multiple hosts. The OP looks like a separate little charger board that you would stack on an existing driver, which might be the best route. (definitely the most versatile.)

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Ok, I misunderstood. A combination driver/charger is what I thought the target was here. I thought the design in the OP was meant to just be a starting place for design.

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I agree, that would be awesome, it’s just more specialized than generic. Using EagleEye as an example, If we made a board that fit the driver pocket and charger cutout/port in an X6R (which we sorta did), it wouldn’t work at all in an X5R, and vice versa.

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Looking into the MCP73833

15

As a result of the feedback on the above circuit I redesigned a board using the ME4057 charger. This IC has solid specs and includes reverse polarity protection, recharge, and overtemp protection. The new design is below. Please give me your feedback!

I would like to bring a design to oshpark but i am unsure how to do so. In fact, what you see below is as far as I have learned of the design software DipTrace. I do not know how to prepare the design for printing. I don’t know what to do with the different layers such as silk mask or even how they are edited. So I’ll be studying up on that if anyone wants to give some pointers.

Anyway, here is the new design. It is on a 17mm board but could be sanded to 16mm without trouble to the circuit.





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It looks good! (Says the guy who doesn’t know anything about what he’s looking at :person_facepalming: ) You should contact Texas_Ace about using Diptrace and uploading to OSH Park. He uses Diptrace for all of his designs.

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Don’t worry. I pretty much feel the same way. I have to say I was a bit embarrassed/nervous to post this considering. :slight_smile:

I’m working on trying to edit the silk screen labels now

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Anyone have a link to a good tutorial for uploading to oshpark?

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Sorry, no Oshpark experience to help you out.

But a question: if I think about a light with build-in charging that I would like to upgrade, I think of the Supfire A2 (bad UI, low PWM). And in that light I would think of another approach: I would leave the stock board in, but cleared from components except for the micro-USB socket. That way the socket is fixed in its original correct position and I start with a big worry less. What I then need is an upgraded driver (a 17mm bistro driver would fit easily) and a minimised charging board that can be attached to the socket with wires, and looking at the number of components needed, that can easily be 10mm diameter (it does not even need to be round). Yet another approach could be starting from a one-sided driver (could be a bistro driver again, why not?) and add the charging components on the underside (it will be used floating so the battery side is not in use).

Just thinking out loud without the skills to contribute anything to an actual design :innocent:

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Those are great observations! I have a couple a2s and feel the same way. I’ll look at it more and see if an fet +1 single sided version of TAs boards might hold this circuit. Also, certain lights that do not have charging, such as vg10, might be able to hold a board with a dremeled hole for the charge port. Lights without charging stock might be better candidates for the board as it is above. So I’ll also put together a board without the micro USB. This way it could be wired to any charging port desired.