hello friends...
I have a battery pack arranged in 4S1p configuration. It is connected to a BMS as well. The output from the BMS is connected to an amplifier board and a LED driver. While using the battery pack to power the amp, everything works fine and I have no trouble. But, when I power the LED driver (with amp turned off)which drives a few led strips, it works for around 5 minutes or so and then suddenly turns off. The small digital voltmeter attached to the output terminals of the BMS also goes dead. After waiting for around 10 mins, the BMS is back to normal and could be used to power the LED driver till the problem is repeated afte the next 5 min. So what would be the reason for this?? I'm very sure that The led strip wont consume a current more than 400mA ,so i think there won't be an over load issues for the BMS.

 

if you are powering 12V strips with your 14.4V battery, it might well be drawing a more current than you expect.

Typically 12V strips have 3 LEDs in series at 20mA. So a 60 LED strip will take 400mA. You said "strips", how many?

Bob

 

if you are powering 12V strips with your 14.4V battery, it might well be drawing a more current than you expect.

Typically 12V strips have 3 LEDs in series at 20mA. So a 60 LED strip will take 400mA. You said "strips", how many?

Bob

From the output pads of the BMS(P+, P-), a buck/boost module set at 12V is connected and the LED driver is powered from the output of this module. The BMS is rated for 30A. Actually 400mA was an estimate round value. To be precise there are 15 set of LEDs (each set having 3 LEDs each) So 300mA. So its not a problem right ??Also, the amplifier that I'm powering with the this battery is 25W+25W amplifier board. So for a nominal sound level I'm sure that the amplifier board will take at least 1A of current. But the BMS has no problem with that load of the amp.

 

Put an ammeter between the battery and the buck converter.

I now suspect a wiring error.

Bob

 

Put an ammeter between the battery and the buck converter.

I now suspect a wiring error.

Bob

Yes I have done that. for a medium brightness , the driver only consumes arround 250 mA of current. One could connect an buck/boost converter directly to the output pads of the BMS right ?? I was wondering that if the buck/boost module have any sort of reverse current or something which tricks the BMS to shut down.

 

Uneducated stab in the dark here. What is the maximum supported output from the BMS? How much current is the BMS outputting when your LEDs are connected? Does the BMS auto turn-off when not in use (when current is below a some threshold)? If yes, is it possible your LEDs aren't drawing enough current for the BMS to think that the outputs are in use, and it's auto turning off?

 

Uneducated stab in the dark here. What is the maximum supported output from the BMS? How much current is the BMS outputting when your LEDs are connected? Does the BMS auto turn-off when not in use (when current is below a some threshold)? If yes, is it possible your LEDs aren't drawing enough current for the BMS to think that the outputs are in use, and it's auto turning off?

The maximum output current of the BMS is 30A. While the LEDs are connected the current draw is around 230mA. I guess the BMS dont have than auto turn off function because even when the amplifier board is in stand by mode it doesnt turn off. The problem is only with powering the LEDs.

 

What is the current draw when the amplifier is in idle? I guess the easy way to check is disconnect everything from the BMS, connect your volt meter and see if it powers off after a while.

 

When the amplifier is idle, the current draw is 0.06mA. I disconnected everthing from the BMS and conneced the voltmeter but, it doesnt power off after a while

 

I founded out the problem. Powered an amplifier module driectly from the BMS and powered it with a buck/boost module connected to the BMS. It is found that by using the buck/boost module, the BMS turns off a while. So Its clear that the PWM signal of the module is casing some trouble to the BMS and to turn it off. But I dont know how to sole this. Any idea for it??

 

I would try an additional load on the battery, something in parallel with the buck
boost converter.

Bob

 

Maybe some capacitors on the outputs to try to filter out the noise. Can you put a scope on it and see what the noise looks like?