Really cheap true cc/cv usb charging board

[Kenjutsu]

@rizky_p: Do you use the Arduino and the LiPo gauge just to monitor the charging process and give feedback on the LCD?

 

[alltoclear]

Hi guys, any idea how we could mod this board's full charge voltage to 4.35v so that i could use it to charge a Lg D1 cell?

 

[Illum]

Probably not alltoclear

Only charger I know that outputs 4.35V is MCP73831-3


Been using this with nice results.
http://www.adafruit.com/products/1304

The inherent problem with linear chargers... is heat from voltage drops.

 

[hiuintahs]

Edit: post deleted

 

[Bullzeyebill]

If I thought it was worth the investment, then I'd market my chargers (I've got 2 designs.....one USB fixed value using the LTC4053 and the other discrete design utilizing a buck regulator with both voltage feedback and current to get the CC/CV charge process. That one has a pot where I can set the termination voltage to whatever I like.

Start your own sales thread when you are ready. Custom mods such as this can be displayed on CPF, not in this thread, but in Custom BST. This as long as you are not a manufacturer, per se.

Bill

 

[rizky_p]

@rizky_p: Do you use the Arduino and the LiPo gauge just to monitor the charging process and give feedback on the LCD?

Sorry for the late reply. Yes i use the max lipo gauge to read the voltage as i have them lying around, or you can just use analog input from one of the arduino pin and some voltage devider. The max chip communicates through IIC interface with the arduino. In recent changes i also add current monitoring using alegro hall sensor and report the current back to lcd.

 

[Matthew86]

Hi,

I'm using a DX version of this board. The problem is its termination appears to be at <50ma and at 4.25v or so.
I've tried a 0.5ohm resistor in series when charging and that seems to drop the termination voltage to safer levels.

The question is whether that's a safe modification and whether it could create issues in the constant current phase of charging?

 

[BringerOfLight]

Hi,

I'm using a DX version of this board. The problem is its termination appears to be at <50ma and at 4.25v or so.
I've tried a 0.5ohm resistor in series when charging and that seems to drop the termination voltage to safer levels.

4.25V is still safe, but not good for battery lifetime.

The question is whether that's a safe modification and whether it could create issues in the constant current phase of charging?

Yes, it's safe to do. The TP4056 will normally terminate at C/10, so you have a 500mA board, right?

At 500mA, your 0.5Ohm resistor will drop 0.25V. So if the TP4056 targets 4.25V, it will already ramp down the charge current (enter the CV phase) at 4V battery voltage. The charge time will be a fair bit longer.

4.25V is well within the TP4056 specs (4.137V - 4.263V). You may want to play the chip lottery and get a 5 or 10-pack of those boards. I have one that charges to 4.165V.

 

[RoGuE_StreaK]

I think I recall some fake or "alternate" chips out there, which may or may not be part of what you are seeing. I've just tried a quick search and can't find anything to back this up, so not sure what the situation was.

 

[Matthew86]

...The TP4056 will normally terminate at C/10, so you have a 500mA board, right?

At 500mA, your 0.5Ohm resistor will drop 0.25V. So if the TP4056 targets 4.25V, it will already ramp down the charge current (enter the CV phase) at 4V battery voltage. The charge time will be a fair bit longer...

Yeah I noticed that. Its a bit of a pain but Ive been switching to the resistor after the voltage hits 4.2.
Its a 1amp board but I found out the apple USB source has only been outputting 0.5amp, strangely today it looked like ~0.1amp termination.:thinking:

...4.25V is well within the TP4056 specs (4.137V - 4.263V). You may want to play the chip lottery and get a 5 or 10-pack of those boards. I have one that charges to 4.165V.

That is the plan I think.
Cheers

 

[tomasi02]

Home made charger:

1.

2.

Is the wiring for #2 ok?
Sometimes led is not on on the second slot, when charging only one battery.

 

[Illum]

Can anyone confirm that the battery output pins are high impedance when the battery is connected but input supply turned off?
My charger boards should be arriving soon and I plan on integrating them into systems involving a permanently connected battery

 

[thijsco19]

If I leave this TP4056 based charger board connected to a Li-ion/Li-Po cell, without input power, will it drain the cell?
If yes, how quick?
(I believe my question is similar to Illum's question..?)

Oh, this charger works for both Li-ion cells and Li-Po cells, right?
NVM the last question, I don't see reasons why it wouldn't work with Li-Po type cells.

 

[HKJ]

If I leave this TP4056 based charger board connected to a Li-ion/Li-Po cell, without input power, will it drain the cell?
If yes, how quick?

The one I tested had a current draw of about 1uA, that will drain a battery in 40 years.

 

[thijsco19]

Thanks!
That is what I was hoping to hear. Add a protection pcb to it and it should be relatively safe.

 

[CuriousOne]

The real gem for linear battery chargers it Linear's LTC1185 chip:

1. It is big, in TO-220 case, so no special soldering skills required, actually, you can just wind wires across it's legs.
2. It requires very few external componens.
3. You can set individually both charging voltage and current (up to 3A).
4. It has low drop circuitry, so even from USB 5V you can charge 4.35V cells at high currents.

It has two drawbacks:

1. Since this is LDO, not charger IC, it has no charge completion indication.
2. Quite expensive- around $9

I've built more than 10 chargers with it, all work just fine.