So I’ve got this new charger. I changed the amperage to 1Amp while charging. While I looked up 21700 recommendations for what amperage to use. Online suggests anywhere from 1A to 3A… so I figured I’d charge it at 1A just to be safe. What do you all have for me to learn and what do you all recommend?
I usually choose something between 0.5c and 1c.
C means the capacity, so a 5000mAh cell can be charged with 2.5-5a. lower is better and if you have the time, keep on using 1A
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I’m almost never in any itchin’ hurry to charge cells, so stick to 1A or so, even on my Opus.
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Google the name of the cell and “specification datasheet” or similar. Manufacturers are very clear with reccomendations.
Slower is fine if you have the time - don’t leave cells unattended on the small chance there’s an issue.
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That does not mean you must have your eyes glued to the charger like a hawk, just keep a loose eye on the proces. Not leaving the house, etc.
FWIW: If I have enough time, I charge my 18650 cells with 0.5A and my 21700 cells with 1A.
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The overwhelming advice is to not leave charging batteries unattended, given OP is asking some “beginner” questions (which is fine, I did the same when I started!), I thought it worthwhile to include the above info.
Once information transmitted, people can decide their own acceptable level of risk (unless they’re my terraced house neighbours…!).
I put my charger on a heatproof surface in the kitchen, which is normally where I’d be hanging out anyway, this system works for me.
While we’re at it, I’d add:
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Don’t mess around with these lithium ion cells, don’t stick’em in stuff to see what happens unless you’re confident you know what the outcome is likely to be. Yes, you can physically jam 14500s into a TV remote, but it’s going to destroy it.
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Absolutely do not mix cells of sizes/chemistry/charge level.
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Its best practice to keep cells “married” /in a set it you have a light that takes more than 1 cell (especially in series). This will go some way in helping keeping the state of charge level i.e point 2.
4a) Don’t short the terminals (including trying to measure the length with a metal caliper!).
4b) be aware the shell of the cell is actually all connected to the negative terminal - if you damage the wrap near the top, there is an increased risk of accidental short given the proximity of the positive contact and the body shell.
- Don’t charge them if they are frozen (cold is fine, perhaps reduce the rate a little).
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“The overwhelming advice is to not leave charging batteries unattended,”
1000%,Just this past month I was charging up a Samsung 35E and went downstairs to watch some TV. Couple hours later I came back to a super hot cell. Too hot to touch. Immediately pulled the plug and left that cell outside. Next morning when it cooled down it read 3.96V. havent used it so far and most likely won’t.
I have xstar vp1 and portable enough that I sometimes bring to office and charge things up there so I can touch the cells periodically.
Hmm are there any fancy chargers with overheat protection?
Awesome! Thank you! Okay, I’ll just keep doing that then. Charging at 1Amp. So glad this charger is able to be tuned to different Amp outputs. I think it goes from .25Amp-3.Amps! Which seems wild to me! A wide variety. But I’m new to this sort of stuff
0.25 is good for small 16340 batteries, 0.5 is usually the choice for 14500 and 18350.
For 18650 the standard is 1A and 21700 you can charge with 2A no problem. Even the “low” capacity ones with 4Ah have zero problems with 2A
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Good information! Thank you!
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