Assistance with wiring a 1S BMS board

[Al Slitter]

Hello All;
I have an issue that I would like confirmation on, I have built a couple of emergency lights.
The layout is very simple consisting of a 18650 battery, a single battery holder, an on-off switch
a resister and 3 - 3Watt LED's wired in parallel.
I will charge the batteries after use using my 4-battery independent charger.
These leave me with one issue outstanding and that is the installation of a 1S BMS (Battery Management System). I purchase several of these boards and wired them up, the next test was to
verify that the 1S board would actually shut the light off when the voltage became low,
This test ended in failure so here I am trying to figure out why.
I wired the + / - battery poles to the areas marked B+ and B- as shown in the image below.
I then wired the leads to the LED's to P+ and P-.
As mentioned there was not charging leads needed to be installed as the charging of the batteries will be a manual process.
Has anyone got an idea where I went wrong?

Thanks in advance.

I am including an image of this board:

 

[BobK]

Watch this video.

The load is connected between B+ and P-.

Bob

 

[Al Slitter]

Thank you for the timely reply.
Just to make sure I have this correct let me state what I believe you are saying.
The battery is connected to B+ and B-, the LED's are connected to the B+ pad and the P- pad.
With this in mind I could wire the battery to the top of the chip and then wire the LED's to the bottom
of the chip using your explanation (load is connected between B+ and P-).
Am not sure of the logic here but if it works great.

Thanks again.

 

[Bluejets]

The battery is connected to B+ and B-, the LED's are connected to the B+ pad and the P- pad.

No, the battery is connected to B+ and B-
The Load is connected to P+ and P-

 

[BobK]

You have it correct.

The labeling of these boards is highly confusing. Logically, the board needs three sets of connections.
1. The battery (B)
2. The charge power input (P)
3. The load output

This would seem to take 6 connections, but the load connections are both shared.

1. The battery + is the same as the load +
2. The charger power input - is the same as the load -

It all has to do with which connections need to be switched. The battery - is switched to the P - by one MOSFET. And the load - is switched to the P- by a second MOSFET.

Bob

 

[BobK]

@Bluejets: That is the way he has it, and it is not woking. If you watch the video I posted, you will see why.

P+ and P- are the charger power inputs. Think what would happen if hooked up the way you show and you apply the 5V power in.

Bob

 

[Al Slitter]

No, the battery is connected to B+ and B-
The Load is connected to P+ and P-

That is exactly how I wired the board originally, however when testing the automatic shutting down of the battery
on low voltage it did not work. That is the exact reason for my request for assistance.

 

[Al Slitter]

@Bluejets: That is the way he has it, and it is not woking. If you watch the video I posted, you will see why.

P+ and P- are the charger power inputs. Think what would happen if hooked up the way you show and you apply the 5V power in.

Bob

Hello Bob;
Yes a bit confusing but your logic seems to be on the right path with the way the board is set up.
I also watched the video that you had included.

Thank you

 

[Bluejets]

@Bluejets: That is the way he has it, and it is not woking. If you watch the video I posted, you will see why.

P+ and P- are the charger power inputs. Think what would happen if hooked up the way you show and you apply the 5V power in.

Bob

Different board, that's why the confusion.
I also went by your video but the one the op shows is different.

https://www.ebay.com/itm/1S-3-7V-3A...188647&hash=item3d7cc78952:g:krsAAOSwzaJX60Fj

 

[BobK]

I know it is different, but it is almost certainly using the same circuit. You cannot possibly make it work by hooking up the load to P+ and P- if you are using it as a charger. That would put the full charging voltage on the load. The boards come in all shapes and sizes, but all of them seem to have B+ B- P+ and P-.

Bob