I feel bad. All I care about is that it works.
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These Nitecore Scharger’s been ruining my wraps on my new 21700 40T’s
What’s a decent charger that handles 21700’s good. and Any that have like special recovery features? ne one?
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Freddie, I thought of the Efest LUC V2 and V4 (which are advertised as being able to charge 21700s) - but The Mooch’s review of the Luc V4 (and V6) states this is not so. A Google Patreon web-site search-string:
“site:patreon.com 21700 charger mooch”
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Thanks I’ll figure it out. Just ticked off… First the nitecore SC2 charger got too hot and started cooking. (Dont ever get the SC2) It ruined one of my new 21700’s Then the SC2 says it takes 21700’s doesn’t and is ruining all the wraps. So yea if IMR doen’t take care of this $hi7 I’ll never buy there again. Anyhow the only saving grace is I did buy 21700 wraps and insulators. 
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Seems to be popular to make this untrue (or “stretched”) claim (and also true for other Nitecore i-Series):
When I looked at chargers, I found quite a few reports of Nitecore models overheating, batt fire/explosion “critical reviews” (particularly on Amazon pages). On the other hand, a friend of ours has a Nitecore and reports that it has worked without issue for years. The Efest LUC Series evidently do not get nearly as hot as some of the Nitecores. Have bought a couple of LUC V2s (one recently as a back-up spare), and they seem solid, with adequate display, and run “cool” (when charging two 18650s at 500 mA current each).
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No the SC2… 2nd one that’s smoked a component on the board and fried out, made the mistake of getting 2 of them before reseaching. It’s a documented fact by a few others as well. I know the LUX 4 is awesome. it just dont do 21700s
Rather have 2 x 2 bay chargers than 1 x 4 bay that way if 1 breaks im not without something.
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That’s been my philosophy. My needs are minor (typically 1 or 2 18650s charged solo at 500 mA each day). I figured that it might be wise to acquire a back-up of a good thing (before Efest might discontinue LUC V2).
This person performs and reports on chargers and such things with a great deal of in-depth test data:
https://lygte-info.dk/info/indexBatteriesAndChargers%20UK.html
Not sure how recent some of the chargers (and published reviews) may be - but it might be helpful to you ?
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Two options for you:
- Opus BT-C3100 (v2.2)
- Xtar Dragon VP4 Plus
I’ve owned both chargers, and both handle 21700’s without issue.
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Yes I also have the Dragon and am pretty happy with it,
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I got 2 of the Opus and can confirm.
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BT-C3100 (“adaptively” controlled) fan-cooling looks pretty slick. How well has that fan held up over time ?
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Mine developed a slight wobble around the 2 year mark (give or take), but never stopped working, nor got louder.
My unit died about three years of age though.
Replaced it with the Dragon to try and see if I liked the continuous charging better than the method used by the Opus. But it’s been too early to tell.
I definitely prefer the smaller footprint of the Opus (hands down), as well as the voltage under charge display. But the Dragon runs cooler and silently.
So there’s some give and take to be considered.
I wish Opus would develop a model with their footprint, functions, and display, but with the CC circuit, and quieter cooling. Alas… Until such time, these are the two best of the bunch (at the price-point) IMO.
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I got an older opus an a newer one, in the sense of the fan exhaust. the newer one definitely have a better exhaust system. much quieter, at the very least. the other one have a very loud fan, but it doesn’t affect the charging. both managed to keep the batteries cool.
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A very good safety measure, that (keeping charging battery cell temperatures lower, as opposed to higher):
Note: Initially incorrect linking from the text quoted directly above has been subsequently corrected.
This interesting paper has excellent graphics of electron-microscope images of Li-Ion batt cell innards.
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NiteCore SC2 Review:
https://lygte-info.dk/review/Review%20Charger%20Nitecore%20SC2b%20UK.html
The reviewer published (presumably Nitecore’s) compatible battery list - that does not include 21700s:
In addition to possible temperature concerns (and the tales of woe), I decided to avoid Nitecore:
… because their info displays (except on their most expensive models) are crude compared to Efest:
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@Raven-Knightly
One of the first 2… had to RMA for the same issue. This time Im not spending $8 to send back a bad charger I got for $11 and some change/ So they can send me the same fire and battery saftey hazard charger as a replacement. 
I may want to stay away from anything with the 12V step down transformer built into it. And stay with USB or a 12v wall plug type transformer
Moochs post
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My Efests (like just about everything these days) have tiny wall-warts that are highly efficient switching power supplies. As a result, that circuitry (existing either out-board, or on-board) generates very little excess heat (at a 1 Amp charging load, anyway). However, the switching supply circuitry that converts 120 VAC to DC volts being external to the main package will result in somewhat better heat-dissipation characteristics.
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I’ve never had anything but 18650’s, and use the Nitecore i4’s to charge them, so I have no input for the 21xxx cells and heat. I just wanted to say that I’ve always had an external fan on them whenever they are on, and it’s always kept the cells and charger at room temp during the charge cycle. I’m 4 years into the i4’s and haven’t had any failures or cell issues due to charging. Just a PSA, sorry, back to your regularly scheduled thread.
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