I was trying to make a portable PSU with LTC3780 Module and a 12v 7Ah lead acid battery. But I am thoroughly disappointed by the module. Infact my past experience with this module is not good. This module is like a glass ball, with little improper use and it smokes and gets destroyed. I do not expect a 10amp buck boost converter to behave so unreliable. Off late I felt the module has lot of features but not able to handle high currents efficiently. Many may disagree.

Now the project took interesting turn when I connected the module with a 0-30v digital voltmeter ammeter unit. With no load attached, I was just trying to set the low voltage cutoff pot and I saw that the voltmeter module started smoking. My connection was alright with no short circuit. I triple checked. I read somewhere that the LTC module limits current on output's ground line so input and output ground must not be shorted. I ensured that and I attached my ammeter terminals to the +ve side of the output. My voltmeter's yellow wire is connected to +ve of output. However worth mentioning that I am powering the voltmeter module with a 7805 connected to the same battery input. I am wondering, if somehow due to the lack of common ground the voltmeter is shorting out internally when trying to measure current and voltage together. Has anyone came across this?

If needed I can share a circuit diagram.

Edit: I changed the connection a bit and now there is no smoking/overheating. The voltmeter module works fine, the wire of it smoked. However now the LTC module doesn't produce above 1.3x volts. The input is still around 12.9v. Wondering if something else smoked and the LTC module is gone as usual. Never had anything different with this module. It's frustrating!

Here is the schematic

 

If needed I can share a circuit diagram

hi sri,
On your posted diagram, show all the ground connections.
E

 

If needed I can share a circuit diagram.
...
I changed the connection a bit.

You changed the connection 'a bit'? How are we supposed to make any sense of that? Sharing a circuit diagram should be the very first step you take.

 

Since you are getting only 1.3x volts output from the module, the feedback circuit or one of the MOSFETs may have been damaged. Check the continuities of the MOSFET or the diodes with a multimeter.

 

You changed the connection 'a bit'? How are we supposed to make any sense of that? Sharing a circuit diagram should be the very first step you take.

Sorry for responding late. I didn't have access to my computer to create the schematic. Here is how my design looks like now:

 

hi sri,
On your posted diagram, show all the ground connections.
E

Shared the schematic

 

Since you are getting only 1.3x volts output from the module, the feedback circuit or one of the MOSFETs may have been damaged. Check the continuities of the MOSFET or the diodes with a multimeter.

The output changes between .7 to 1.3v when I adjust the voltage control pot. So the output voltage is not fixed. It gives below the rated 1V lower threshold which is also strange. But I'll check the MOSFET as suggested by you.

 

IT CAN NOT EVER WORK THAT WAY!! For those voltmeter-ammeter packages the operating power circuit MUST BE ISOLATED from the circuit being measured. This is often a bitter reality with some meter products: Isolation is mandatory!!