POLL: Your favorite Chinese knife?

[HKJ]

@B42

I know the 2A ~ .5C is better for the battery but 3A is under 1C and should be able to accept that charge …shouldnt really damage a 4200mAh 26650 battery until 4.3A should it?

That depends on the actual battery, then 1C charge rate is rule of thumb, not a specification or a law.

[Jinx]

@B42

@Jeansy

I agree 2a is enough but more would be nice, who knows what’s around the corner and the ability to rapid charge if really needed would be nice.

That’s how I thought about it too, plus I know the 2A ~ .5C is better for the battery but 3A is under 1C and should be able to accept that charge …shouldnt really damage a 4200mAh 26650 battery until 4.3A should it?

IMO, damage at 1c will be minimal, it would be interesting to see cycles compared between 0.5 & 1c.
Above this damage will get progressively worse, ie on the 4200mAh, 4.3 amps would be so close to 1c I doubt a difference would be noticed

[B42]

@HKJ

@B42

I know the 2A ~ .5C is better for the battery but 3A is under 1C and should be able to accept that charge …shouldnt really damage a 4200mAh 26650 battery until 4.3A should it?

That depends on the actual battery, then 1C charge rate is rule of thumb, not a specification or a law.

Right, I figured it was somewhat standard for the chemistry and based on that? But I guess there is no telling with the Chinese cells what is inside as to chemical composition and how they really stand up unless you tried it.

[HKJ]

@B42

@HKJ

That depends on the actual battery, then 1C charge rate is rule of thumb, not a specification or a law.

Right, I figured it was somewhat standard for the chemistry and based on that? But I guess there is no telling with the Chinese cells what is inside as to chemical composition and how they really stand up unless you tried it.

Not only Chinese cells, the Panasonic 2900 and 3100mAh cells are 0.3C charge current. The new 3400mAh cell has been upgraded to 0.5C.

[kreisler]

@HKJ

No, 2A for a slot is enough. With 18650 I nearly always uses 1A. With 26650 the 2A current is fine for standard charge, many of the 26650 batteries could accept 3A or 4A for a quick charger (i.e. with slight damage to the battery), but I have not seen a need for that.

Making higher charge current in a charger will also make it more expensive, especially if you need PFC correction (Required at higher power levels).

Thanks HKJ for your valuable input, your technical view is as always highly appreciated.

Since you like the 2A, i have voted for 2.0A now too!

:p

[Chloe]

@HKJ

Making higher charge current in a charger will also make it more expensive, especially if you need PFC correction (Required at higher power levels).

PFC = installing more capacitors? If so I can see how it would cost more.

[HKJ]

@Chloe

“PFC”:http://www.energy-in-motion.com/PFC.html = installing more capacitors? If so I can see how it would cost more.

That is not enough today, a full compensation requires an activate circuit that will regulate the current draw.

Here is some more explanation (It is technical): http://www.fairchildsemi.com/an/AN/AN-42047.pdf

[kreisler]

@HKJ

That is not enough today, a full compensation requires an activate circuit that will regulate the current draw.

my PC power supply, engineered in Gemany, has it.

active PFC:

kreisl wins :p

[HKJ]

@kreisler

@HKJ

That is not enough today, a full compensation requires an activate circuit that will regulate the current draw.

my PC power supply, engineered in Gemany, has it.

It would be illegal in the entire EU, if the PFC was missing or you would have a very low power PC.

[kreisler]

@HKJ

It would be illegal in the entire EU, if the PFC was missing or you would have a very low power PC.

So what would you think about an integrated power supply (no power adapter!) in a dream charger with 4×3.0A output, say ~50-60Watts. Should it have active PFC too? :)

[HKJ]

@kreisler

@HKJ

It would be illegal in the entire EU, if the PFC was missing or you would have a very low power PC.

So what would you think about an integrated power supply (no power adapter!) in a dream charger with 4×3.0A output, say ~50-60Watts. Should it have active PFC too? :)

As I wrote above, I do not know exactly where the limit is today.

[Jinx]

@kreisler

@HKJ

It would be illegal in the entire EU, if the PFC was missing or you would have a very low power PC.

So what would you think about an integrated power supply (no power adapter!) in a dream charger with 4×3.0A output, say ~50-60Watts. Should it have active PFC too?

No stick to normal external PSU Dinoboy. The ability to run off of 12v battery bank is useful and also failure of PSU doesn’t mean scrap charger also :cowboy_hat_face:

[kreisler]

@Jeansy

No stick to normal external PSU Dinoboy. The ability to run off of 12v battery bank is useful and also failure of PSU doesn’t mean scrap charger also :cowboy_hat_face:

Oh, 12V input is kinda standard with most modern chargers. Nitecore i4 was exceptional with both 12V input and built in power supply unit.

Right now i am charging 2x18650 in the Nitecore i4 starting off 3.80V (slot1 and slot4 occupied) and the back of the charger is really hot by now. Maybe the heat production has something to do with the built-in PSU? Output is only 2x0.75A (nominal) but wtf does the charger get so hot?

The two 18650's are slightly warm, nothing to be concerned about, i guess.

It's time for a new, better built charger. The dream charger.

[Chloe]

Do you have any other mains leads you can use instead, or a 12V power supply?

[B42]

“BatterySpace.com/AA Portable Power Corp. Tel: 510-525-2328 - Powerizer Battery Official Site These are high drain with 1500 cycle repeatability. Made for cars and scooters. I’m using them for my HD2010. 18A constant draw rate at 3000mAh capacity. $9.50 ea.”

These are listed with a charge rate of 1C…so we do have one confirmed that could easily take a 3A charge rate. I know 1C is a guideline, 26650’s are the only reason I say 3A charge rate at least for the 4-6 channel dream charger

[kreisler]

@Chloe

Do you have any other mains leads you can use instead, or a 12V power supply?

that's a tricky question i think! ;)

[Jinx]

Yes another advantage to external power supply is heat generated in the rectifier will not be conducted to the cells. Possibly a much bigger problem for a NiMh charger as it may monitor the temperature delta, as all good chargers do, to terminate correctly.

[kreisler]

@Jeansy

monitor the temperature delta, as all good chargers do, to terminate correctly.

on the one hand I believe that temperature delta is the correct classic way to terminate charging. on the other hand modern dream chargers have a full-fledged big CPU inside, quite similar to PC CPU's, and one could program the CPU to simply monitor the exact voltage and then terminate the charging when the target voltage, e.g. 1.470V has been reached. So the CPU controls the charging process directly through the actual voltage instead of monitoring the classic temperature delta.

Was a hot long day today, if i am talking **i* lemme know and i'll try to cut the ***p ;)

[Jinx]

Temperature would not be the primary termination method, usually voltage as you say (although delta V looks for a slight dip in voltage at correct termination, it’s applying CC). The temperature is a back-up method but still this fails, at least I’ve seen reports of chargers missing termination.

[kreisler]

@Jeansy

Yes another advantage to external power supply is heat generated in the rectifier will not be conducted to the cells. Possibly a much bigger problem for a NiMh charger as it may monitor the temperature delta, as all good chargers do, to terminate correctly.

Excellent point. This heat conduction problem was observed in some less popular Chinese C9000-like charger by Opus Instrument Co., Ltd, the inexpensive BM210 charger now marketed by the Danish Japcell brand:

http://www.amazon.com/review/RRZI4G772IAVR
http://www.amazon.com/review/R30IYBU06GPMKC

XTAR designers and engineers need pay special attention to the efficient removal of heat into the right direction. Not into the cells!