Actually I have both …when I git the new ones for the INN i got myself and a couple employees some lol…
That makes 2 of us …
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Yeah, that’s exactly the reason my 21700 batteries are unused atm.
I have the same nitecore and just use the 18560s.
I noticed the difficulty of getting the other ones in and decided not to take the risk.
If the day comes that I have some money to spare, I will go for the one you just recommended.
I’ve got an Opus but haven’t used it after reading some horror stories about those 
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what’s wrong with the Opus? I have 2 of them and they’re still going strong after almost 3 years. (well, one of the slot had it’s fuse blown. but everything else is fine.)
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That’s what gives me the willies. If I remember correctly it was @SmilingOgre who had a mishap with his Opus.
I haven’t used it since.
It gets kinda hot too and I’m a coward. The last is basically the only reason I need 
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I’ve got two as well @delltrapp, and as mentioned above, someone (maybe Ogre), posted a pic of the back of the circuit board with corrossion ?? Can’t remember who it was, but when I saw it, I took both of mine apart, and both were clean and clear, and after years of service. I was thinking it would be perfect for @fidalgo_vapes, because not only does it love 21700’s you get the handy extra features to repair battieres, AND the bonus of seeing exactly how many mah’s they are taking upon charging. I’ve had no issues with any of mine, and even bought a spare JUST in case.
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Dovetailing on the Opus, I think the only issue I had was a noisy fan (bad bearings), and replaced it. That’s about it, and most times mine are full with either 18650’s, 20700’s, or 21700’s, and they’ve NOT had an easy life, that’s for sure.
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my OPUS is just fine. i bought a backup x-star X4, well, just for a change. it is not that good of a charger. yes, it works, but i would not buy it again.
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The newer opus(bt c3100 v2.2) is better than the older version, because the fan actually works. Like @SessionDrummer said, the fan of the older version is loud, but the newer version is quiet. As for the rust, mine still clear. A bit dusty, though.
But, yes, it’s better to have peace of the mind.
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ABSOLUTELY. Peace of mind for sure. Im going to have to SEARCH for that older thread, wherein someone (maybe they lived at the beach maybe), posted a pic of the circuit board, right where the slider tabs inserted, and there was a lot of corrosion. Looked kind of scary. I immedicately tore mine apart, only to find clean circuits and traces. To be fair, the OLD fan DID used to get on my nerves.
Regardless of which BRAND of charger I use, I ALWAYS have mine sitting on an alluminum plate just in case something gets hot, or acts up. I never recommend charging while you’re NOT home, or especially on flamable furniture. ALWAYS best to have on a protected surface, and WHILE you are present, hehe.
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I think it was @anon36682625 that toasted his Opus. Mine has been fine. If I remember correctly he had a battery go into thermal runaway while in the Opus. Total flame on.
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I use an old Efest LUC V6 charger for 18650s and 20700 batteries. 21700s will fit too but they’re really tight. I got a cheap 4 bay charger from Liion Wholesale that I charge 21700s in. Its called Enook Alien E4. It does the job well. It uses a micro USB cord which a lot of people don’t like but I’ve never had any trouble with it. I might buy a nicer all in one but have been using 2 separate chargers for a couple of years now.
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I’ve had no issues with my Opus and 21700s. I run refresh and standard charging cycles with a full 4 batt load and it works very well. The internal fan will come on when refreshing 4 batteries, but the device is never warm to the touch. My old nitecor would getting pretty warm recharging 4 batteries at once.
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I might just do that 
I have that AND two fire repellent blankets draped over it 
Safety first 
Now I remember, he was very happy his dog wasn’t anywhere near it when it happened.
You were the one feeling guilty about it because you had recommended it in a review 
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Ya this feature really caught my eye
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@fidalgo_vapes I’m just glad you are okay. And, it gives you the opportunity to buy something new. Sometimes I want to buy something new and have to come up with a semi-legitimate reason for getting it. You REALLY have a reason to buy a new charger. Take care, and again, glad you are okay.
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I use my nitecore 8 battery stand up charger with no issues for my 21700 and 18650 bats. Sure the 21700 fit snug but no issues besides that!. 
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Beyond all of the extra features the the Opus offers like cell balancing, repair, etc., I always love that I can check how many mahs each cell has taken after a charge.
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the newr OPUS is very nice. i modified mine to make it easier to get the batteries out.
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@WVance Welcome to the forum. And it’s always great when you find something that works for you. I still use an intellicharger i2 and I only use 18650 batteries. It’s not fancy, but it gets the job done. For safety, I blow it out every few months with compressed air. It still works after 5 years of use.
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