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December 01, 2020, 11:11:09 am

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Samsung 18650 cells

Started by FlyinBrian, October 02, 2020, 10:46:31 am

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FlyinBrian


https://www.fogstar.co.uk/collections/batteries/products/samsung-25r-br-2500mah-20a

I bought a few of these to test for using as receiver/servo batteries. I have always thought Samsung to manufacture quality batteries.

I connected pairs of them in series to give a nominal 6.6 volts, after charging I discharged at 1.5A and was most disappointed to find the capacity is only a couple of hundred mAh at this discharge rate.

Anyone have any ideas why?, they claim to be able to discharge at up to 20A and to be 2500mAh
Basic Research is what I do - when I don't know what I'm doing!.

PDR

What did you charge them with?

PDR
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meharibear

Any "best before" date on them?
Inside every old person is a young person wondering what happened.  (Terry Pratchett)

RobC

Are you charging them on a LiFe setting instead of the Li-ion setting?  That would only charges them to 3.6v when they should be charged up to 4.2v according to that link.
flying's easy - it's getting it back down in one piece that's the hard part

Chippie

I think they should be balanced too.... :-\
But deffo charge them to 4.2volts...
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paulinfrance

I also got a couple, but the best ones came out of my old computer pack.
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RobC

You'll also need servos rated to at least 7v, ie HV ones
flying's easy - it's getting it back down in one piece that's the hard part

FlyinBrian

Thank you for the input guys.

I can not see any best before date.

I always thought these cells were 3.6 v charged DOH!

PDR I used my Hobby king (Reaktor) charger.
https://hobbyking.com/en_us/turnigy-reaktor-250w-10a-1-6s-balance-charger.html?___store=en_us

It has a Li-ION setting but when I set it and press start the display alternates between LiFe and L-ion. I think my Graupner charger has a dedicated Li-ION setting so I will give that a go.

There is no balance lead on these they  come as individual cells, I guess I could fit an XH balance lead.
Basic Research is what I do - when I don't know what I'm doing!.