charging 18650's and charger question

[nasa779]

im just curious.... can i use a NDFeB magnet to "connect" a alligator clip to a + or - end of a battery? im just trying to find a way to charge any cell with a charger im looking at..... after hearing bad things about the 139 charger

also has anyone tried the Cytac Dual Bay Fast Charger 139? is it safe to use?
im also eyeballing a electrifly triton jr

 

[SilverFox]

Hello Nasa779,

I think you would be much better off going for the Triton...

Tom

 

[nasa779]

what about the magnets as charging leads?

 

[SilverFox]

Hello Nasa779,

What is the resistance of your magnets, and how does that resistance compare to the internal resistance of the cell?

The Triton historically has been sensitive to charge lead and connection resistance. When the resistance goes up, the final charge voltage goes down.

With that said, magnets are very convenient and are used a lot. Just be aware of their limits.

Tom

 

[Brian321]

Hello Nasa779,

I think you would be much better off going for the Triton...

Tom

+1, I have a triton and it is awesome. I use a quick clamp to hold the batteries. If you want pics let me know.

Brian

 

[nasa779]

i actually bought a dynamite passport ultra... and the leads have maybe .1ohm of resistance but thats not under a load..... it may change resistance under a load if my charger throws 1-2 amps through it.....

by the way im charging 2200mah aw 18650's and im curious to know what i should be charging them at... rate wise... ive been charging at about 1C but tomorrow im going to do it right and discharge them and charge them at .18C (if thats the proper rate) i dont know any better at this point so what rate should i be charging/discharging my 18650 2200mah AW's at for...

1. a slow charge...
2. a fast charge...
3. slow discharge...
4. fast discharge...

 

[SilverFox]

Hello Nasa779,

If you are in a hurry, charge at 1C.

If you have time, charge at 0.7C.

Tom

 

[jasonck08]

I usually use magnetic charging leads for charging, but I think I did have to calibrate my Turnegy Accell 6 to boost up the voltage a little bit to account for the added resistance. The max you ever want to charge standard LiCo cells at is 1C. I usually try to charge at .5C-.7C because I think this will increase cycle life.

 

[nasa779]

what about a discharge?

and also i had a 4 day old aw18650 2200mah
and when i got it i discharged it to 3v then charged it at various rates between 500ma and 2.2A (playing with new charger) redischarged it today and that went fine..... i wanted to give it a nice slow constant charge from my passport ultra and it read that the batt was a "open circuit" and as a "short" ... leads are fine everything is good but when i metered my batt it read between .14v and -.20v yet i only discharged it down to 3v

 

[nasa779]

 

[SilverFox]

Hello Nasa779,

Put it on your charger, charge for 30 seconds and then measure the voltage again.

Tom

 

[nasa779]

i cant... the charger wont let me because it sees a "short" in the circuit... i RMA'd it

 

[benckie]

can you use these just solder on a plug of your choice to suit your charger and charge lead.

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=180685158510&ssPageName=STRK:MEWNX:IT

or these

http://www.batteryspace.com/Li-Ion-18650-cell-series-Battery-Holders-with-PCB-installed.aspx

cheaper international shipping for the above on flea bay