Sony 30A 18650 warm when charging?

[Lucky1384]

Just noticed that the first time I'm charging my new VTC4's, they're warm to the touch and so is the charger. I don't get this with my Panasonic 18650's, so is there anything to worry about? The best way I can explain the heat is it's like a nice temperature for bath water to be at, like a nice relaxing warmth (sorry, only analogy I could think of ). It's probably as warm as the average laptop power supply. Any other battery I charge stays pretty cool.

Ive switched the charging current from 1A to 0.5A. Will this just take longer to charge with no ill effects? Is 0.5A recommended above 1A or vice versa? I want to treat these batteries right!

 

[MorpheusPA]

Gentle warmth generally isn't a concern--runaway heating is a concern. Many batteries warm up a bit while charging because of internal resistance, where some of the charge energy is thrown away as waste heat.

There's certainly no problem with charging your batteries at 0.5 A if you prefer, the only consideration is that it'll take around double the time compared to charging at 1 A.

 

[Lucky1384]

Thanks Morpheus They seem to be cooler at 0.5A and I have no problem waiting. I'll be keeping an eye on them for the first couple of charges

 

[porkchopbun]

Funny, I had the same exact issue when I first charge my VTC4 at 1A...I was .....did I get some bad ones...
then I decided to be more patient with .25 A, it took longer, but I had no issues since...if I'm in hurry, I'll do .5A and it gets little bit warm...

 

[MorpheusPA]

Thanks Morpheus They seem to be cooler at 0.5A and I have no problem waiting. I'll be keeping an eye on them for the first couple of charges

That's always wise! If you'd reported lots of heat, I'd say there's a problem...but gentle warmth I actually expect from any battery being charged at any reasonable rate.

Does your charger have thermal detection? I never consider it smart to rely on it, but it's nice if it does--it'll cut charging if the battery gets too hot.

 

[Lucky1384]

That's always wise! If you'd reported lots of heat, I'd say there's a problem...but gentle warmth I actually expect from any battery being charged at any reasonable rate.

Does your charger have thermal detection? I never consider it smart to rely on it, but it's nice if it does--it'll cut charging if the battery gets too hot.

It seems to. I have the same charger at work for other uses and my less than smart apprentice decided for some reason to short out one side while a single battery was charging on the other. Both LED's just turned green and shut charging down until I pulled the short and charging continued. Yes he did get a severe telling off!

 

[MorpheusPA]

It seems to. I have the same charger at work for other uses and my less than smart apprentice decided for some reason to short out one side while a single battery was charging on the other. Both LED's just turned green and shut charging down until I pulled the short and charging continued. Yes he did get a severe telling off!

Fortunately, that's harmless. The charger is amperage-limited, so it can't burn itself out easily. And undoubtedly it has short protection even if the charging module doesn't detect that there's no voltage differential across the leads.

Still, I wouldn't make a habit of it...

 

[emus]

I'd use a DMM to verify charger is charging around 4.2 v; if charging much higher it is a big problem. I charge all my batts at 0.5A and I've never noticed a batt warm on charger. I would charge in a metal box or in a location where batt fire wouldn't cause house fire.

 

[MorpheusPA]

I'd use a DMM to verify charger is charging around 4.2 v; if charging much higher it is a big problem. I charge all my batts at 0.5A and I've never noticed a batt warm on charger. I would charge in a metal box or in a location where batt fire wouldn't cause house fire.

That's wise, and checking a new charger (and verifying it occasionally) is a good idea.

Most batteries I charge actually get slightly warm, particularly when charging at more than 0.5 C (about 1 A in this case). At 0.25 C you might detect warmth if you happen to observe closely. 1 C produces moderate warmth (2 A), and anything above that is not recommended.

Those amperages are for a 2,000 mAh battery. I see conflicting capacities for this particular battery, so I'm not sure what the capacity is--except that it's at least 1,500 so 1 A is a safe setting and around 0.67 C maximum.

Lithium batteries have low internal resistance, but not zero. For real warmth, charge a NiMH. I could put those in gloves and use them as hand-warmers.

 

[Lucky1384]

It is only a moderate warmth, and I only charge them 15 feet from me in the kitchen with the doors open for as long as I'm at home. I've no reason to doubt that they're the stated capacity. They're from a trusted supplier and receive excellent reviews stating super long life. I get a day or almost a day regularly from 700mAH 18350's, but use 18650's for lower resistance coils (at least half resistance). If they last me a couple of days running sub ohm I'm happy!

 

[gofastman]

If memory serves, those batteries can handle a charge rate of 4 amps. I would guess most of the heat you are feeling isn't actually being produced by the cells, but rather conducted out of the charger. That said, I charge at 250mah the vast majority of the time.