4.20v or 4.35v

dealgrabber2002

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I wanted to buy some 16650 batteries and asked the seller if this really has the capacity of 2500mah. He told me to achieve that, I need a charger that can charger at 4.35v.

How do I know if a battery can be charged at 4.20v or 4.35v?
 

ChrisGarrett

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I wanted to buy some 16650 batteries and asked the seller if this really has the capacity of 2500mah. He told me to achieve that, I need a charger that can charger at 4.35v.

How do I know if a battery can be charged at 4.20v or 4.35v?

Are they protected cells, or naked cells without a protection circuit/PCBs?

Apparently, while PCBs can be configured to stop charging at 4.35v, many are set for the more typical 4.20v level, since that's what most of the li-ions we use charge up to.

Charging up a 16650 2500mAh 4.35v cell with a protection circuit set to 4.20v, means the cell won't be filled up, resulting in a loss of capacity 100mAh to 200mAh. Not a big deal for many of us.

I have a pair of Redilast labeled Sanyo v.1 16650s with PCBs and while they're a 2000mAh-2100mAh 4.30v cell, I can only charge them up to roughly 4.20v. No real bother.

Put another way, if you're buying protected cells, generally don't worry about charging them up to 4.35v, but if they're naked, then you need a 4.35v (3.8v nominal) charger, like my Xtar VP2 and Liitokala Lii 100s and 202s.

Chris
 

hiuintahs

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16650 Sanyo UR16650ZTA 4.35V 2500mAh.

No harm charging up to 4.20v, but won't get the full 2500mAh capacity out of them. Not sure of what the difference is......maybe 10%.

I have an Xtar WP2H kicking around just for the 4.35v cells. It will do 4.20 or 4.35v. Has a switch on the side to select. Most of my cells are 4.20v so I don't use that particular charger very often since I have a variety of chargers.
 

Timothybil

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I have several lights that use 10440 and 14500 cells, and was not really happy with using my Xtar VC4 with its minimum charge rate of 0.5A. So I picked up an Xtar VP2 for its three voltage levels [3.6, 4.2, 4.35] and its three charge current levels [0.25/0.5/1.0A]. It would be my main charger except it doesn't do NiMH, so I keep both chargers around.
 

dealgrabber2002

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How do you know which battery can be charged at 4.35v? I have a few Samsung ICR18650-26D that I salvaged from laptops. They are around 23xx mah. Wondering if I charge it at 4.35v, would it hit 2600mah or above.
 

ChrisGarrett

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How do you know which battery can be charged at 4.35v? I have a few Samsung ICR18650-26D that I salvaged from laptops. They are around 23xx mah. Wondering if I charge it at 4.35v, would it hit 2600mah or above.

There are only a few cells that were in vogue a 4-5 years back. Both are 4.35v.

LG made the D1 and E1--3000mAh and 3200mAh 18650s. Sanyo makes the ~2200mAh and 2500mAh 16650s--4.30v and 4.35v respectively and the UR18650ZTA.

And I think that Samsung made/makes some--the 28G and the 30B.

You need to know the model and look here:

https://lygte-info.dk/review/batteries2012/Common18650IndividualTest UK.html

Go to the battery comparator and scroll down through the various tests and you'll see what's what.

You don't want to charge a 4.20v cell on a charger set to charge up to 4.35v.

No bueno.

Chris
 

WalkIntoTheLight

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How do you know which battery can be charged at 4.35v? I have a few Samsung ICR18650-26D that I salvaged from laptops. They are around 23xx mah. Wondering if I charge it at 4.35v, would it hit 2600mah or above.

Those cells aren't 4.35v cells. You can charge them to that high, but you'll kill them pretty quick by doing that. You'll maybe get a third the number of cycles if you do it, for maybe 10% higher capacity. Not worth it, IMO. Also, there may be safety issues with overcharging, though it's probably very unlikely to happen.

You have to download and read the spec sheet of the battery, to know for sure. Stay within all the bounds of the spec sheet. That's what it's there for.
 

StorminMatt

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The bottom line here is that ANY 4.35V battery can be charged to only 4.2V with somewhat lower capacity. If this is not a big deal for you, then go ahead and charge to 4.2V. The battery will probably even last longer for you of you do this.
 
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