I have a problem with this type of battery together with this charger.
First of all, look how many modules for power we have, we have BMSs, chargers,
boost converters and so on, so which one to use? But these two together, I use them all the time
for my homemade projects and they work great together providing steady voltage and protection
and I already have an awesome project on how to make such a charger with a boosted output as well.
The link for that video is below. Anyway, the problem that I’m having is the current output.
You see, these batteries which are lithium ion batteries of 4.2V, they could easily deliver
more than 10 amps of current. But when used with a protection charger module like this one based
on the TP40 56, the current output is limited at 2 amps which is not enough for a lot of my projects.
And what if I want to use two batteries in series and I still want to charge them using
a USB connector? That’s another problem. So in this video I will study what options we have to
get a USB charger, battery protection but also a decent current output at the same time. I will
show you different modules, BMSs, chargers and what NOT to do. So guys, let’s get started.
What’s up my friends, welcome back. So why do I like this charger? Well, for the same as
you probably do. Is simple to use. It has a USB connector and it doesn’t require anything more.
I don’t want to use a separate power adapter, I don’t want a power supply with a specific voltage
connected, I don’t want all kinds of battery connectors of different shapes, and for sure
I don’t want several modules, regulators and converters connected to the battery when I make
quick homemade projects. But the problem of this module is the current output. What if my project
requires more than only 2 amps of current? Well, let’s start with 1 Lithium Ion battery with a
maximum voltage of 4.2V and minimum voltage of 3V. A charger such as this one, will make sure
these values won’t be overpassed. When charging, it will stop the process when 4.2V is reached.
And when we apply a load, it will cut off the output when the voltage is below 3V.
But this also has a current protection with a maximum output of 2A.
So you might wonder, why not connect the load directly to the battery and not at the output
pins of the module? In that way we would have no current limit, right? Well, yes, but we also lose
the undervoltage protection because the charging module can’t control the output voltage anymore.
So basically the battery will fully discharge and that will definitely destroy the battery.
Actually we could buy directly this other module which is kind of the same but without
these two ICs, so it has no current limit. But using only the TP4056 IC, we would only have
overvoltage protection. That means the battery will stop charging when 4.2V is
reached. But we don’t have undervoltage protection anymore, and that’s very bad, so that’s a NO NO.
So basically this is what I want: A USB 5V input easy to use, the TP4056 to charge the battery to
4.2V and then we need undervoltage protection. To get that, also with decent current, we could use
a dedicated BMS. We have different types of BMSs and I will make a full video about this
topic because I think is important and needed, but that’s for a future video. But basically,
one characteristic of any BMS is the amount of cells it is design for. 1S, 2S, 3S and so on.
For the first example, I want to use only 1 battery cell so we need a 1S BMS,
such as this one here. This is made to work with output current values up to 10A,
So basically, what I want is the combination between the TP40 56 and a BMS of 10 amps.
Like that we have overvoltage and undervoltage protection, 10A current output and it could
be charged at 5V from any USB connector. Exactly what I want but I can’t find such a product on the
market, so if you know one, comment below. I’ve searched for modules on AliExpress and one that
was a bit better was this one. It has a USB type C connector which is used for both input or output.
But on the back you can also solder a USB type B connector for output. The current out is of 3.1A
which is better but still kind of low compared with the maximum current output of the battery.
So this module is better but is not exactly what I want. But it does have a battery level
indicator with some LEDs, a button to turn on or off the output together with a boost converter for
increasing the output to 5V. So is a great module if you don’t need more than 3 amps of current.
We would also have this other module which also works for charging and discharging a lithium ion
battery but again, the maximum current is of 2.5Amps so is the same as before.
Or this one which can only charge the battery but it doesn't have protection.
So let’s fix this charging module. This is the schematic. The current protection is controlled
by this IC, the DW01. By looking at the datasheet, we can’t get a straight forward current limit.
Basically, the IC measures the voltage drop at the CS pin over the sense resistor, which usually
is of 1K. And since this threshold is preset, the limit depends on the internal resistance of
the control MOSFETs, which are these two here and these control the flow of current from the
battery. So, we need to select other MOSFETs than the ones the module is using. Actually, the small
1S BMS also has the DW01 IC but it uses two bigger MOSFETs, So we can use the same for our PCB.
Basically we get the TP4056, we add the DW01 and we change the MSOFETs to withstand 10 amps.
I finally made this schematic. I’ve passed to PCB and this would be the final design.
I haven’t received the boards yet but you could use this design if you want.
The links for the GERBERs files are below on electronoobs.com
I don’t know why I can’t find such a design online already. It seems like such a good idea, right?
To make the test, I connect the TP4056 module with USB input to the 1S BMS like this.
The battery is connected at the B+ and - pins and the load is connected between
the B+ pin and the C - pin. Th e charger is connected in parallel with the load.
Like this we can charge the battery with a 5V USB connector but also protect the battery.
Actually, some Li-Po batteries already have a BMS board connected to the input, as you
can see with this battery. But the Li-On cells don’t have one, that’s why we need to add it.
So not the battery charges without problems. And then I can draw a lot more current then only 2A.
So, problem solved. Anyway, finally, what if you want to use a 2S pack or 3S or more than that,
but you still want a USB charger? First of all, for that we need a balanced BMS connected
to + and -, but also to the middle point between the batteries. But now, we can’t use that USB
charger anymore because its maximum output voltage is 4.2V and we now need 8.4V, 12.6V and so on.
You could find DC adaptors with exactly that voltage, but I prefer the USB connector of 5V,
because is so common, compatible and easy to use. For that I found this module.
Is has a different driver and also a boost converter to elevate the voltage to exactly 8.4V.
But since it doesn’t have a balance protection we need to add a BMS at the output. So the final
connection would be like this. And this module comes for 2S, 3S and even 4S battery packs.
So it would be great to have just one PCB with this converter together with the BMS part so
we would have an all in PCB, one charger, USB connector and also protection with high current
output. So guys, I hope you now have a better understanding of the battery charging process,
protection and the modules we have out there. For me it seems such a good idea
to have both USB charger and also high current output on the same module, right?
Soon I will also post a full tutorial on BMSs, boost converters, types that we have and when to
use one or another. So stay tuned for that. Check more information on electronoobs.com
Consider giving me a like or comment below. Thanks again and see you later guys.