Max charge rates for 18650's (hi-max) (x-tar 2600)

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xxllmm4
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Max charge rates for 18650's (hi-max) (x-tar 2600)

Hey everyone.

I just got out my Imax B6 charger for the first time, I have had it for a couple years for my RC car but never tryed it on single cells. Funny I had it all this time and never thought of charging singles with it.


Anyway whats the max charge rates for the Hi-max 2600 and the Xtar 2600? I have herd its actually good for the Lithium batteries to be charged near their max charge rates ocassionally.

 

Thanks
Jason

Don
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You should be OK up to 2.5A. Personally, I prefer to charge them at about half the rated capacity. Only charge them one at a time unless you want to set up balance charging. This isn't important if you are only using them in single-cell lights, but it is quite important in multi-cell lights that the cells are as closely matched as possible - the higher the current, the more important this is.

 

But don't bother about this if they'll only be used in single cell lights. Balancing can be extremely slow so I only do it these days for the lights that use more than one 18650 or when I'm doing tests and want the cells to be identical for testing.

 

I'm not sure if you can still find Magtrix connectors on eBay - the guy who owns the patent used to sell them there. They are basically magnets on wires and are amazingly useful for charging cells. A quick search on ebay.co.uk didn't turn them up and the patent was owned by a British guy.

 

A bunch of small magnets are very handy for charging more than one cell at a time too.

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

xxllmm4
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Don, thanks for the info. 2.5A seems crazy considering I'm coming from a 650mah "quick charger" lol I figure I'll charge it like your saying at about half that. The magnet connectors look like the perfect solution for charging / discharging a varity of batteries.

 

One other question, do you need to balance charge if your going to run your batteries in parallel? 

mfm
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Some manufacturers recommend a maximum charge rate of 0.8C which in your case would be 2A.

Don
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xxllmm4 wrote:

Don, thanks for the info. 2.5A seems crazy considering I'm coming from a 650mah "quick charger" lol I figure I'll charge it like your saying at about half that. The magnet connectors look like the perfect solution for charging / discharging a varity of batteries.

 

One other question, do you need to balance charge if your going to run your batteries in parallel? 

 

Not really, as long as you don't charge them too quickly - they will equalise as long as they are reasonably close in voltage to start with - say less than quarter of a volt. I'd not be happy trying to charge wildly differently charged cells in parallel.

 

These are the magnet things. I still have that D NiCd cell - it is now 27 years old and still holds its rated charge though the internal resistance is a bit on the high side nowadays.

Magnet on stick

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

okwchin
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I charge my RC LiPo cells at 1C, and im quite happy to do so becasue they are high performance cells with low cell resistances, so they never even feel the slightest bit warm at 1C charge. (during discharge, they get warm after a 10-20C discharge rate).

On the other hand, these lithium cells we use in flashlights are no where near the same, with a much higher internal resistance. When I charge my Trustfire Flames at 1C, they get warm!, and im not comfortable/ dont think this is good for the cells. I tend to charge at 0.5-0.8C max depending on how urgently I want the cells done. Usually a 2-3 hour charge, due to the high internal resistance of these cells. 

The 18700s from XTAR/himax im not familiar with, but im hoping their somewhat better. I have some XTAR 2600s on the way Smile

 

I series charge on my hobby charger setup, using the balance lead connector. I charge between 1-4 cells on my battery carrier. 

Parallel charging is fine, as long as the cells are Very well balanced initially. If you dont have well balanced cells to start off with, you will be discharging one into the other, and without any current limiting!, so a fully charged cell will be shorting out through a discharged cell, possibly pushing many many amps depending on the performance of the cells and the voltage difference.

"like everyone else - I’m looking for my next “last” flashlight" -  ohnonothimagain