I hope I didn't just fry my new cells...help?

Okay guys. So, just bought 4 Eagtac 3400 18650s. I put them on the i4 intellicharger, and for some reason these took like 4 or 5 hours to from what seemed like completely empty to a full charge.
That seemed longer than usual, but these were brand new cells from IS.

The problem is, I kept them on the charger while I was in the room, just to make sure I was monitoring them. Around 3 am, I noticed they were almost done, with 2 of the 3 flashes on all 4 cells....getting closer...

Then, I fell asleep!

I noticed at 8 am that the batteries were still charging in the charger and I had forgot to take them off.

While they were charging the whole night while I was waiting for them, the charger was very hot, but I wouldn't say too hot. Just very very warm to the touch.
When I went to pull them off the charger just now at 8, I noticed the lights were still on the charger, but the charger was nice and cool.

Please tell me guys, did I just ruin a brand new set of 80 dollar 18650s? Or did they stop charging when full, and the charger just stopped charging them itself, thats why it was so cool?

I am worried now. Bad. Took me a while to get the funds together for these batteries after paying some good money for a new TK75vnKT light. So please, let me know if I killed my new batteries, or if they are fine and I am worrying for nothing. Or perhaps they won't last long now since I made this stupid dangerous mistake? The charger was cool like i said, so I am REALLLLLLLY hoping that it just kind of cut them off, and didn't overcharge or ruin the cells.


Any help or advice will be greatly appreciated. I have been so excited for this day for a while now, just to screw up like this makes me sick. I really hope the batteries are still perfect. This is obviously the first charge, but I need these to last a long time as they are very expensive, for me anyway.


Thanks guys
Dave

Not sure what model i4 you have, HJK's review of the V2 shows good cut-off and no 'trickle charging'. A 3100mAh 18650 was charged in 6 hours, 4*3100mAh were charged in 11 hours.

Only way of telling is by measuring the voltage of the cells, if you don't have a voltmeter- get one. You don't need the most expensive model, just something to tell you what the voltage is. Above 4.20V is overcharged.

Get a digital multimeter and check the voltage! My I4 charges cells up to 4.23V. In a full complement of 4 cells rated at 2900 mAh takes roughly 8 hours to fully charge from 3.7 V, a pair in separate channels takes 4-5 hours for me.

Your charger and batteries are OK. I have an i4 intellicharger as well, and I normally charge my batteries overnight. The charger will stop charging when the batteries are full. Look at the manual

Ive had two of the i4 V2 chargers for a few years, and they've always terminated the charge properly. If your charger is nice and cool, they, more than likely, terminated the charge for each channel, when the charge was complete. All should be good. Just be sure to measure the voltage on the batteries.

If your set of four 3400 mAh batteries charged as quickly as 5 hours, they must have been already partially charged. The i4 charges at only 375 mAh, when all four channels are used simultaneously.

I just picked up two of the D4 chargers, and they are amazing.

Enjoy your new batteries!

Okay, so they were probably charging closer to like 6 hours. Maybe a bit more. It is the V2 I believe.
And, I am going to the store right now to get a voltmeter, so I will report back in a few.

Great to know my cells and charger are still ok. Be back in a bit...

Ok, just got home. Bought a Southwire Autoranging multimeter, as I need a good one for other stuff like working on cars.
So, this has two Voltage settings.

One with a squiggly line, and other setting has a solid line on top of a dashed line. Didn't come with a manual for some odd reason.

I think the solid/dashed line is the DC setting? And, i should get around 4.17 to 4.19 on each cell, AFTER taking off the charger, correct?

Thanks guys.

dave

Okay update. My new MM reads the 4 cells in fine condition I think, but the readings are not all the same even though they were all on the charger the same time, i4 4 bay charger again...
4.176
4.184
4.191
4.187

Seems ok but unsure about the readings being different.

And, I would think my i4 should charge up to 4.23v just like everyone says, but mine are coming up short. The charger probably has like 15-20 cycles on it, and the cells are brand new from IS. So, does this all sound right? Or am I missing something?

Im going to test everything now with my new DMM!!!

dave

d.weglarz13 said:

Okay update. My new MM reads the 4 cells in fine condition I think, but the readings are not all the same even though they were all on the charger the same time, i4 4 bay charger again... 4.176 4.184 4.191 4.187 Seems ok but unsure about the readings being different. And, I would think my i4 should charge up to 4.23v just like everyone says, but mine are coming up short. The charger probably has like 15-20 cycles on it, and the cells are brand new from IS. So, does this all sound right? Or am I missing something? Im going to test everything now with my new DMM!!! dave

Click to expand...

Not all DMM's are calibrated with perfect precision and unless you spend money on it, your DMM will probably be off by a little! 4.18v could be 4.20v.

Consumer chargers are not precise instruments

Ditto for consumer-grade chargers: they don't typically have precise-enough components, QA and/or calibration to distinguish 4.18V vs. 4.20V.

Re: Consumer chargers are not precise instruments

great. Thanks again.

Re: Consumer chargers are not precise instruments

I hate to say it but this thread was somewhat amusing.

Due to the nature of the li-ion battery, I don't think a charger exists that would overcharge them unless it was defective or a home brew.

I've been using a cheap ebay special charger for years and my batteries are all quite happy.

Well, since you've now invested in a multi meter, you now know your charger is correctly cutting off.
So you now know you can trust charger unattended if you wish.

You may also be interested to know that your batteries have an integrated protection circuit that will prevent them from being overcharged in the even that your charger did malfunction. This could explain the discrepancy of the rated cut off on the charger and the voltage you measured as it's entirely possible that the battery circuit cut off the charge before the charger did.

On a side note. New batteries ship with a storage charge in them. They were something like 70% full when you got them and will likely take much longer to charge in the future. This makes the trust you've gained all the more important as it may not be feasible to monitor the charge in the future.

Re: Consumer chargers are not precise instruments

Conte said:

I hate to say it but this thread was somewhat amusing.

Due to the nature of the li-ion battery, I don't think a charger exists that would overcharge them unless it was defective or a home brew.

I've been using a cheap ebay special charger for years and my batteries are all quite happy.

Well, since you've now invested in a multi meter, you now know your charger is correctly cutting off.
So you now know you can trust charger unattended if you wish.

You may also be interested to know that your batteries have an integrated protection circuit that will prevent them from being overcharged in the even that your charger did malfunction. This could explain the discrepancy of the rated cut off on the charger and the voltage you measured as it's entirely possible that the battery circuit cut off the charge before the charger did.

On a side note. New batteries ship with a storage charge in them. They were something like 70% full when you got them and will likely take much longer to charge in the future. This makes the trust you've gained all the more important as it may not be feasible to monitor the charge in the future.

Click to expand...

Or just god-awful design, iirc there was an ultrafire charger that used to 'trickle charge' cells after 4.20v.

Over-voltage cut-off on these cells is claimed to be 4.25 - 4.3V, so I doubt the range of values is due to cut-off.

Re: Consumer chargers are not precise instruments

Conte said:

Due to the nature of the li-ion battery, I don't think a charger exists that would overcharge them unless it was defective or a home brew.

Click to expand...

Au contraire, there are in fact many cheap dangerous Li-ion chargers. For example, on eBay one can find for sale "Li-ion chargers" that connect to an auto-accessory (cigarette) port and simply pass-through 12V (very dangerous!) It's not clear if these were mismanufactured, mismatched, or what, but they are wrongly being sold as Li-ion chargers (they plug into a dumb cradle, i.e. one with no charging IC, so feed their 12V input directly to the cell).

Re: Consumer chargers are not precise instruments

Again, learning a lot here so thanks.

Question. Does the 12v adaptor for the i4 also fit the D4? Just curious, and ALSO is it safe to use in the car like that through the cigarette lighter? OR does this mean I shouldn't mess with the 12v accessory cord at all.....

Thanks, figured it was worth asking.

dave