My first BLF post

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SecaRob
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Location: Ohio
My first BLF post

So I was drawn to this website by the "other" and have decided to make my first post regarding my recent purchase.

 

I have been tinkering with the hobby and noticed that I was accumilating a number of lights that would use the 18650 so I took the plunge (on a BUDGET of course).  Ended up picking these http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=390280052926&ssPageName=STRK:MEWNX:IT . 

They arrived today and I took a quick check of the voltage,  battery "A" was at 3.8 and battery "B" was at 3.7.  Charged them for 2 1/2 hours using the included charger and ended up with 4.2v for "A" and 4.1 for "B" (hot off the charger).

I went ahead and let them sit for 5 hours and a re-check shows 4.05v for "A" and 3.98v for "B". 

Decided to run them both for 1/2 hour

Battery "A" in my Solarforce XPG starting voltage 4.05 ending 3.72

Battery "B" in my Skyline 1 starting volatage 3.98 ending 3.8.

 

What are your thoughts on the quality of the batteries based on the above.  Also and more importantly how do I move forward with these batteries as far as a break-in period?  Should I place them back on the charger or should I go ahead and run them down???

Thanks in advance

Rob

 

jekostas
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Those are some really big voltage drops for a 5 hour rest

SecaRob
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Location: Ohio

I thought they seemed kind of high but comming hot off the charger I was not sure. 

old4570
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Big drops ...  

Perhaps cells quality , perhaps charger , or a combination of both ..

Unfortunately you purchased some of the worst cells available .. In regards to internal resistance [ cell quality ] ..

Anyhow , let us know if you plan on investing further , and hopefully we can offer you some good advice in regards to charger's and batteries .. 

 Always remember , the easiest thing in the world to do , is to expel hot air from your lungs and through some vocal chords ..
The resulting sound may , or may not be worth listening too ….

 

Budgeteer
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That charger is far from decent quality if it is the same as DX sells (i did read all of the chargers reviews). Most of them (probably all) don't do CC/CV. And by what you said the cells are surely bad. For one they should not even be hot off charge. The self discharge is awful. It seems they were stored at ver low voltage for quite some time...

The capacity i would guees also be low to support my educated guessing. And finally those cells are not playing nice with moderate discharge current. Best used for low drain devices. My 2 cents.

My advice would be to top them and do a discharge test in some light not drawing more than 1A. If you get results around 1100mAh by calculating the outcome... dispose them and ask for a refund. The charger is probably ok, the cells are not.

kragmutt wrote:

They're gonna send you a green redcat with a black LED.

fishinfool
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Aloha and welcome to BLF SecaRob!

Don wrote:

"But as I said long ago, you are more likely to be killed by a dead fish dropped by a seagull in the Sahara Desert than by a lithium ion

sb56637
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Hi SecaRob, welcome to BLF! We're glad to have you.

Budget Light Forum ...where Frugal meets with Flashlight!

SecaRob
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Location: Ohio

Thanks for the welcome and responses.  I may have been a little mis-leading when I said "hot off the charger".  The batteries were actually still a room temperature after the 2 1/2 hour charge.  What I should have said is that I checked the voltage 5 seconds after removing them from the charger.

So after sitting overnight here is where they stand

Battery "A" is up to 3.86v from 3.72

Battery "B" is up to 3.87v from 3.8

I think I will go ahead and put them back on the charger for maybe 4 hours?.  These batteries appear to have the protection circuit on the bottom so I should not have an issue with overcharging correct?

 

Don
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Welcome SecaRob.

Should be OK, but do keep an eye on the cells' voltages. Don't let them get above 4.20V

 

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

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