OPUS eBay, round 2

Inverted 18650

Inverted 18650

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Jul 4, 2017
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Emailed this dude and bought 10 for $25 each. He says he has 26 left. If these check out and alls well, I will scoop up whatever he has left. If you plan on getting 1,2,3...whatever, $25 is better than $35-$38.

I want to open it up and change the gutsa bit, specifically so it cancharge at 1A in all four bays...maybe pump it up to 2A's, and tinker a bit more.
 
I've been wondering about the internals of the opus (opi?). There is a spring that connects the one terminal. Wouldn't that get hot during charging/discharging? Also, wouldn't that leak power along the way? I would think adding a second wire directly to the terminal from the pcb to minimize losses. Perhaps part of the reason some cells overheat, or even not charge all the way, is because of the spring(?)
 
That mechanism do affect yes. Especially the IR metering that sucks on them. By just pressing with something on the cell you can go from 300mOhm to 100mOhm :)
 
So adding a wire to bypass the electrical portion of the spring would help, then.
 
Charger heaven!! Vrooom!! Vroooom!!! Oh wait, not that kind of Charger :p
 
Maybe they are just empty shells :p It's great that they actually came in.
 
I actually like these a lot and as I said above, plan to buy the rest. I know I busted my brain for a couple weeks to make a usable Arduino version, but these are extremely user friendly and the functionality you get for the cash is hard to beat. I haven't hacked it yet but I can to take a look under the hood, see what micro they use, and see if there is a way to tap into a feedback loop in order to get 1A out at each tray and I'd be stoked.

I will also put the scope on it and see if it actually performs up to spec as well. I just made a DIY current probe (from Electron-Noobs channel) and think that would be a good project for it. But yep, stoked, I'll try to get the rest a bit cheaper and maybe flip a few....??

Damn I was thinking that looks familiar! Buts it's the springs for the tray, not the resistor...had to open
one up. There is a selector switch in here for max V. Guess I should read the manual 1st..that's probably the best thingI learned in school as I was study to get my BS. Read datasheet. And manuals, and directions. Very nontypical 'guy' stuff. But I still flat out refuse to ask for directions if I am lost and ALL THE GORCORIES MUST COME IN THE HOUSE AT ONCE!


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Same as viewing mikes video, you can see those springs are barely holding on. And they aren't even soldered on :-/ No wonder they give spurious resistance readings. I bet that right there would make a huge difference in their accuracy.
 
1A is possible in each slot without modifications, even though it will stop charging/discharging every now and then to let the circuitry cool down.
Replacing the fan might be an option.

The selector switch inside controls the maximum charge voltage. Normal 18650 Li-Ion cells get charged up to 4.2.
If you use LiFePo4 cells you can change it to 3.7V, since they have a 3.2 nominal voltage.
Some newer chemistries make use of 4,35V which is the third option.
 
Maybe it gets so hot because of those 4 huge resistors in there. I wonder, could someone take an opus, with the cover off charge cells at 1A and view it with a thermal camera to see where the heat is coming from, and how much?
 
Mine came with a 3A power pack so I need to swap it and see. I did notice that I can adjust all 4 up to 1A but my plugin won't support the draw, when I tried it the thing shuts down, unless it's a bad Opus? I plan to check it out thoroughly in the near future. And totally agree the little fan has to go.

Suppose I should searchYouTube for exists videos on the topic as well.
 
Inverted18650 said:
Mine came with a 3A power pack so I need to swap it and see. I did notice that I can adjust all 4 up to 1A but my plugin won't support the draw, when I tried it the thing shuts down, unless it's a bad Opus? I plan to check it out thoroughly in the near future. And totally agree the little fan has to go.

Suppose I should searchYouTube for exists videos on the topic as well.
Click to expand...

The 3A plug should be just fine, it's what they all ship with. It's 3A at 12V I think, so about 36W of input power. Charging1A per cell at 4.2V is about 17W. The difference is mostly lost to heat.

By 'shutting down', do you mean the current display reads zero? Or do you mean it completely powers off?

If the display reads 0mA, then I had the same problem. You basically just replace the fan with a better one and it fixes the problem. I posted a video about it if you want to search for it in my threads.
 
wat-tha! those the $10 ones ?
 
Excuse my ignorance but

Talk of hacking to get 1000 ma... I thought that I read that the 3100 is the same as the 3400?

If in fact that is the case, I believe you're able to get 1000 on all of them and actually get 1500 on the outside ones if you're not charging anything on the inside?

Am I misinformed?
 
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