TrustFire 14500 from GB

[lemo]

Ok so I'm just getting into flashlights that take rechargeable lithium batteries so thought I would get some cheap ones from a well known Chinese website (GB).

I bought two TrustFire 14500 3.7V 900mAh Rechargeable Protected Li Ion Batteries.

One of the cells did not work at all and went straight in the bin leaving me with one left to test.



Please note that my testing methods are far from technical, but do provide a rough idea of the quality of a battery.

1. Measure voltage
Rated voltage = 3.7v
Measured voltage = 4.06v
So far so good. This measurement is constant with my other lithium cells rated at 3.7v when fully charged.



2. Resistance test.
Basically a test to see how well the battery will hold up to a heavy load from a flashlight. Apply a load to the cell for 10 seconds and measure the voltage drop. If the drop is high the battery will depleat quickly under load.
A guide (from my charger instructions) is that good cells should have a drop of 20-80 milliohms. Anything over 500 milliohms is only suitable for low load devices like digital clocks, remotes or the bin.
Measured drop = 234 milliohms.
This is the worst performing battery I have bought so far in regard to resistance. Please see that a two year old well used standard Duracell performs much better. I have just bought some 7dayshop cheapo AAA that measure a drop of just over 100 milliohms.



3. Capacity.
Fully charge, then discharge the battery and record the capacity in milliampere-hour.
Rated capacity 900mAh
Measured capacity 228mAh
This is pretty horrible. All other new batteries I have tested have had slightly more than their rated capacity. Even some decade old eveready batteries I have test close to the rated capacity.



Moral of this story is don't buy batteries at suspiciously low prices unless you know what you are doing.

These batteries have had good reviews so I am guessing I bought some fakes 

[dks]

The ones that look like yours and have the hologram, were considered good. I have some, bought a few years ago and they work OK.

However, 14500 sanyos  (salmon pink) are not that much more expensive nowadays, so I just buy sanyos.

The voltage you are getting should be about 4.2V, when fully charged.

Contact gear.. and ask for a refund. Ask for a refund on both batteries, as they may try to refund you only on the one.

[lemo]

Would cost me a lot more to return the batteries than they cost to buy so chalking it up to a learning experience.

I few people have recommended the Sanyos. Think I will give then a try.

[dks]

I doubt that they will ask you to return them - they will just offer you some money or store credit, which you can use to buy Sanyos.

Check the prices - sometimes it is cheaper to buy 4 individually rather than a 4-pack