I blew a component on my OPUS charger, my own fault. It looks to me to be a buffer for the charging current to the cell in bank #4. I was using alligator clips to manually charge 1 of 5 cells in a drill pack. I have done this many times, but this time the clip jumped off and briefly touched another cell. The charger went into a reboot cycle. What was encouraging at the time was that on each reboot, v2.0 appeared as usual. I took it apart and an sot23 component labeld “Xo4V” got warm instantly. I looked it up on Google and the only hits I get are on AliExpess. 5 pack for about $8, but no specs. To me it appears to be a buffer for the charge current to the cell in it’s slot. The slot will charge at up to 2A, so I don’t think this is a transistor but rather an FET. If I knew if it was P channel or N channel I could try to substitute something else, even non sot23.
BTW, after I removed the Xo4V the charger boots up and the other 3 banks work.
The red arrow points to the suspected bad component, the blue arrow points to the connection for the slider in the charging bay.
Now that I have removed it, the unit boots up and the other 3 bays work normally.
O -L, yes, I know of that link, but there is no info as to what this is. Besides, I don’t want to have to order and spend time and money waiting. I most probably have what I need on old circuit board sitting around here.
DaveEF, I would think that those last 2 numbers would not be important.
My guess is it’s an FET. If it is, then the source pin connects directly to the negative slider of the carrier.
I’ll see if I have a P channel and try it. Other than channel type, I wouldn’t think any other spec would be THAT important. Anyways, I’m not sure that’s what is wrong, if that doesn’t fix it then at worst I have lost 1 charging bay.
From this pic you can see that the Source pin of the FET is connected to the negative slider of the charging bay.
That would mean the the current flow (conventional current flow) would be going into the positive terminal of the cell and out the slider into the source of the FET.
So I would say that the Source is postive and the drain negative. That would mean P-channel, right?
When you first posted that device I immediately set out to order one, very cool. Then I stopped my self and said no. When I first blew this part, the first thing I thought was if I had ordered it I would have it right now and could put it to good use!
Now I ask everyone, how can I control my impulses when time and time again my impulses instincts prove out to be correct?
Here is a google translate that say that X04V is an N channel fet. N channel fets are “usually” what you call a low side switch. Presumably this fet goes from your negative battery slider to GND, thus a low side switch. If it was a P channel fet, then the switch would be a high side switch between the positive battery contact and the voltage source supply.
A good medium power logic level nfet would suffice, say in the 3-4A range should give plenty of overhead or safety factor.
Darn it, sorry about that the size discrepancy. It seems the SOT-323 might actually be shorter in length (same width) than a standard SOT-23. Hope it works out for you, maybe a little solder bridging required?
