Voltage drop on one battery bay

[Jimmeh]

I have a Lost Vape Traide 200 and have recently been getting less battery life than I am used to. I stuck it on the device monitor and whilst all of the three cells are reading about the same voltage at rest, when I fire the mod two cells are dropping down to about 4v, the third is dropping to around 3.85v. I have rotated the cells in the device and shows the same cell as dropping more than the rest (so the individual cell is not to blame, just that bay in the device). What could be causing this and how can I resolve it? FYI - the board was disassembled to have the case cerakoted and was then reassembled. Seemed fine after that (was about 2 months ago) but in the last week I seem to be hitting low battery much sooner.

[dwcraig1]

Look to see how they got the voltage for cell #3 to #3 on the balance tap. I have not been inside the LV 200.  Wismec used a tiny resister there to jump Batt + and #3, others just solder bridged it or bridged it with wire. Your problem lies in the connection to the battery tap. (appears to anyway)

Look for cold solder joints on the balance tap.

[Jimmeh]

So an update - I haven't done anything to look at this, but the mod is non-functioning this morning. Screen turns on, and is dim, shows 0% battery and just says check battery when you try to fire. Screen brightens when connected to USB.

When I connect with three full charged batteries, I am seeing the following:

Cell1:  3.2V

Cell2: 3.42V

Cell3: 1.8V

When I connect to device monitor without any batteries I am seeing the following:

Cell1: 0.0V

Cell2: 1.0V

Cell3:3.07V

USB Voltage: 4.847V

 

@dwcraig1 - Do you still think what you described might be the issue? Or are we looking at something deeper here? 

Edited September 17, 2018 by Jimmeh

[dwcraig1]

this is the front side, you will be wanting a look at the other side. 3, 2 ,1, gnd

Here's how is wired, electrically anyway

[Jimmeh]

Since my last post I have worked out where everything is. I am trying to avoid de-soldering the board at this point to get it out, but can see that the fuse looks okay. There appears to be a resistor between B+ and 3 but can't see it properly. I will have a go at taking it apart tomorrow night and see if I can see anything obvious. 

 

[Jimmeh]

So I disassembled and took a look at that connection which looks fine but the component next to it, which I believe is a mosfet, looks like it’s blown. Picture attached. I assume I have a dead board?