LX - LCBST Li-ion output test

0:00 hello again the same old project and let's talk a little bit about this little fellow here lx- lcbs or better said a battery charger board DC to DC stepa boost module with TP 456 we can apply a voltage from a lithon cell and we can boost it up to 28 volts so it's a perfect solution for a 9 volts battery inside the multimeter and many many other devices so this little device have three different parts we got this part here as a battery charge controller then we have this part here with this

0:46 circuit which is a battery protection or cell protection in fact and up here we have the Boost converter let's start with this one very classic cheap uh TP 45 6 it's a low cost leth ion uh IC controller it supports constant current charging mechanis constant voltage for single lithium cell what's important here we have this resistor which by default it's uh 1.2 kilms and that makes the circuit charging the cell with 1 amp 1,000 milliamps uh changing the value of this resistor here we can have uh charging currents from 50 milliamps to 1

1:32 amp of course let's say if if we have a 10 kiloohms over here we're going to have around 130 milliamps of charging this circuit is doing a perfect job there are a few LEDs here showing when it's red it's charging when it's blue finish the charging you know it's a very intuitive uh device all right let's go to the next one which by the way was the main con concern or the main uh question mark now let's talk about the cell protection circuit because I've been asked about that in my case it's a circuit named m k g or C I think it's G to F but um in

2:23 some literator I could find it under hm 545 four and we have the data sheet about this you know uh this circuit it's uh doing all the protection necessary for the cell it's disconnecting the cell once it reach 2.5 volts over charging the cell over voltage the cell in fact it's easy to find information about the circuit uh on the internet and of course the next part it's this one here here this is the Boost the Step Up converter so this is um Mt 3608 here on this particular board we

3:10 have another Mark like 86 28 or something anyway so this circuit it's responsible with stepping up the voltage and it's working uh to a high frequency I think it's 1.2 mahz doing all this uh Step Up conversion and it's going up to 2 Ms okay so we have Mt 3608 1.2 mahz 2 AMP step up converter 2 amps that feels a lot for me you know it's going up to 28 volts operating input voltage from 2 volts to 24 it have a current limit at 4 amps that means a

3:56 lot you know I have doubts about that but uh the or orinal have really really nice uh characteristics so behind the board we have this two contacts here and a t letter you know a t symbol if we check the schematic somehow the battery or the cell minus goes to the ground what that means in the moment when a cell have its own protection board let's open this guy and let's see what I'm talking about so this is uh a Sony cell from a mobile phone and theoretically we should have a

4:43 board here with a protection circuit and of course there we are you see this is a protection board applied by the manufacturers of this uh cells in this case we don't need to use the onboard cell protection because the battery or the cell itself has already this protection incorporated in this situation we have to short these two contacts just holder a piece of wire if you use a simple cell like this one this one got absolutely no protection nothing this needs to be

5:29 applied with the protection on board so don't short this if you use Simple cells like this or like any other cell you know as long as they don't have Incorporated protection boards okay now I've been also asked if there is any protection to Short Circuit at the output let's take a look and let's do some experiments about that we need some WI s soldering iron battery plus I have the green color on this okay plus goes here in the meantime until I'm

6:15 finishing the the setup here let's put it to charge we should see some red LED and by the way as long as we are here let me see the charging current we have the charging light and now it's charging with 0 0.38 almost 0.4 amps almost two watts of charging okay nice let me see about the standby current we have a kind of 200 microamps this is the standby current of this device and that means almost nothing it can be on standby for months or something okay so that's the output

7:01 wire 20 volts let's power on we have 7.38 volts okay let's put it higher let's say 18 volts you see what's happening if I'm just shortcutting these guys I recover yes so look here this is very very nice we have a of course it's getting a little bit hot okay short look at the protection you see nothing wrong happened here nothing

7:49 wrong once again it was interesting first time the current went up but uh in a split of a second and now it's not growing anymore you see so we are in short now at the output of the converter and we have like 30 milliamps but evidently nothing wrong happened to the Circuit so I can say it's safe to have a shortcut at the output doesn't heard the device nothing wrong happens we should do another experiment and that's about

8:37 polarity of the cell let me change the polarity maybe I should use a kind of fuse this is minus now so I reversed the circuit now I'm using a resistor of 22 ohms to see if anything happens okay let's go well that hurts we have 130 milliam so people I'm pretty sure and the resistor is getting hot so I'm pretty sure that first protection circuit will be burnt if you reverse the polarity let me check with a

9:25 lower now this is a 10 ohms 280 milliam you know something people don't try that getting hot for sure with this kind of amps a battery can supply the input circuit will be blown okay let's try this this is a bare piece of wire we should see it burning oh 4 amps oh I can feel the smell already let's make it longer for higher

10:14 resistance let's see it's burning you see that 3.28 amp yeah this one is hot too so probably the diode inside there is doing the job maybe a kind of 0.5 amps fuse it's a good idea maybe but now that's the question is still alive battery evidently you saw that I didn't push it too much but um we have four amps easily but I can say that I played safe will it be alive what do you think

11:00 good question let's see it's alive is it of course it is this is a huge load let's see if it's able to light this that's the output we have 19 volts no way no way it's way too much of course but like I said before short circuit at the output protection it's working great and I don't need anything more is it charging it's not charging anymore says the battery it's

11:46 full how much voltage do we have on this battery huh I'm a little concerned about the accuracy of this multimeter here 4.11 so uh you know the the module it's considering the cell full so it's not charging anymore okay let's see the output yeah 17 point it's safe to short the output nothing happens my concern is about reversing the input polarity the cell polarity that will destroy the protection for sure well like usually I really hope it's useful and uh don't forget subscribe to my channel press

12:32 like like always that will help me a lot and uh any question don't hesitate comment write them down I'll be happy to answer in the meantime have fun bye-bye