Are cheap Li-ion batteries safe?

Hello, I am new to all this flashlight stuff. During a blackout I realized we have no flashlights around the house so I bought 3 lights and a bunch of batteries, but after reading the forums for abit, apparently there are bad battery combinations and that they might explode? So yeah, is there anything wrong with my setup?

These all claim to be protected.
I ordered:
2 Grey Ultrafire 18650 2400 mAh from DX
3 Red with White Ultrafire 18650 3000mAh from eBay (Pretty sure these are fakes) - 99%+ reviews so it shouldn't be too bad
2 Grey Trustfire 14500 900mAh from eBay (Not sure if fake) - Same
2 AW 14500 750mAh from Lighthound - Should be fine considering how expensive they were...
2 Xtar 18650 2600mAh from eBay - Also extremely expensive from authorized Fenix dealer

Charger is an Xtar WP2 II dual charger with 4.2V cutoff so if the fake ones don't really have protection they wont explode??? Hopefully.

The 3 lights are:
Fenix TK15 337 Lumen - Runs single 18650
Ultrafire 1000Lumen XML T6(Should be fake, bought it for $14) - Runs single 18650 - I'll probably be leaving this one in my car with 2 CR123a batteries for emergencies.
Xeno E03 400+ Lumen - Runs single 14500

I plan on keeping the Xtar and AW's in the flashlights to be used moderately. I am pretty sure they will be fine, I'm not worried about them.
Now about the other ones, it will be when I just want to play around with them etc. and because I don't really care about the longevity of the battery, I will probably be discharging them pretty fast. I've heard there some safety precautions such as, recharge the batteries once they start to dim, watch them while recharging and checking their voltage(I don't have a volt meter so I probably won't be doing that). I really don't want them to explode, especially since those lights will draw a lot of current off them, making it more likely? I don't know. What will cause them to explode? How to prevent them from exploding? And, will drawing such a high current from the cheapies damage the batteries or more importantly the flashlights? Also, the WP2 II charger has 2 independent charging channels so does that mean I can charge 2 separate types of battery at the same time? ie. one 18650 and one 14500 at the same time? Thanks~

I'm new to all this too. My first battery charger arrived today, Xtar WP2 ii, and I stumbled onto your thread here whilst searching the forum for advice on how to use it (can't make head or tail of the instructions even though it's a very simple piece of kit). A few weeks ago I posted a similar question here and a couple of the guys were very helpful. Check out the links near the end of the thread, especially this one:

Hope this helps.

Single cell lights are no problem. You have a good charger. You have good batteries and some cheaper ones. I don't see you having problems. Just check the voltage of the batteries.

Don't over charge, or over discharge and you will be fine.

If your plan is not to heavy test cheap batteries with your dreamel etc cheap not protected have just lower capacity

but protected batteries maybe are more safe if of good quality, btw ever take litio with pcp to prevent short cuts.. who said explosions? xD

would be great have LiFePo4

Tipologie di batterie Piombo Acido NiCd NiMh LiCo (LiIon o LiPo) LiMn (LiIon) LiFePo4
Anno di commercializzazione 1956 1990 1990 1992 1997 2004
Sicurezza Buono Buono Buono Pessimo Quasi buono Eccellente
Prodotto Green No No Si No Si Si
Carica a temperature elevate Buono Buono Mediocre Quasi buono Pessimo Buono
Effetto memoria No Si Ni (molto ridotto) No No No
Tensione nominale 2V 1.25V 1.25V 3.7V 3.7V 3.3V
Densità di potenza (mA/g) ND ND ND 140-160 105-110 160
Densità di energia (Wh/Kg) 30 57 80 167 110 115
Potenza di Start Up (W/Kg) 300 400 600 900 500 >2500
Cicli di vita (scarica 1C) 400 500 500 >500 >500 >2000
Vita in servizio (uso giornaliero) 1-2 anni 3 anni 3 anni 2 anni 2 anni 5-6 anni
Efficienza di carica 60% 75% 70% 90% 90% 95%
Tempo di carica (ore) 8 1.5 4 2-4 2-4 0,25-1
Autoscarica (mensile) 20% 15% 30% 10% 10%


sry for the italian

as long as you don't abuse them

usually just a a waste of money to buy them

One of the best pieces of advice I can offer newbies or anyone for that matter is to not skimp on good batteries. We all have probably done so, and thought they ought to be alright when we did so. But I would suggest sticking with good protected cells like Trustfire 18650 flames like from Manofont to make sure you get good one and not fakes, Hi-Max 2600MAH batteries or Xtar 18700 2600MAH batteries. That's the cheapest route I would go and still these should be safe. Yes you can buy the even better higher end batteries like the protected Panasonics and such if you want too. The other piece of advice is to invest in a good multimeter. By good I would suggest this one for the price.

I always try to be near my charger and watch it when I m charging my batteries. And I also now try to check the voltage so that I know the batteries are good after they say charged once I pull them from the charger. The chargers I have usually will charge anywhere from 4.13 to 4.23 volts depending on which one I use. Another good piece of advice is to pull the batteries from your charger once they show charged or in my case when the green light comes on. This will keep them from overcharging which can be dangerous. But buying a good charger is also a plus so this doesn't happen.

Welcome to BLF Panda. I would consider investing in a decent charger. Or at least make sure you have a WP2 that works properly.


Data is ok

But, are these realy new, or used?

Ok, I bought one for test.
Geniune crap cell J)
Only 1200mAh at 1.5A. But interesting it hold voltage very well. 3.40V till 1050mAh, then quick drop to 2.90V.
Maybe new smaler cell inside 18650 body?