Any other device with li-ions has protection on the battery. Mobile phones, laptops. Even tablets & other devices with li-ions not meant to be user removable have protection attached to the cells. Battery manufacturers will tell you protection is required / not optional. Since cells are often made into multi cell battery packs they are sold bare as components. The end battery distributors that should add protection want save every cent & don’t care.
Overcharge protection needs to go with the battery. Overcurrent protection can help if a loose battery shorts in transport. Have you seen how some chinese sellers use to pack batteries for shipping?
Flashlight manufacturers are just stupid & don’t care when a light can’t fit the batteries. If those lights started getting less sales I bet they would learn how to measure a battery tube quick enough.
I could not measure the amps of my bike light without cutting the wires, but because this battery was completely dead after 1 hour and 30 minutes i thougt there was someting wrong with the Magicshine bike light.
This battery http://dx.com/p/water-resistant-rechargeable-8-in-1-18650-battery-pack-for-bicycle-light-black-238274 should have a capacity of 7000mAh, but it is only 2640mAh.
There are 6 16850 batteries in the pack, 2 decent 18650 batteries have more capacity than the 6 batteries in the pack…
I have posted a review on DX, but i don’t think they will show it on the website…
I did nog get an answer to the RMA
Now i have bougt a Fenix BT20 and some high quality 18650 batteries (Eden 3400mAh = Panasonic), i don’t want no more unreliable batterypacks from chinese manufaturers.
Well, I guess I’ll find out … I’ve been using Tenergy protected 18650s
in my Xin TD NW and HD2010 lites with no prob so I guess we’ll see …
Are the Panny 3400mAH longer or wider than standard protected 18650s like the tenergy 2600 mAH batts?
The standard 18650 length is 65 mm — the 65 in 18650. 69.4 mm is the length of Panasonic 3400 mAh protected by Fasttech. TrustFire Protected “3000mAh” length is 68 mm by Dealextreme.
No need to cut wires if you have a meter with a DC clamp. I use a Craftsman 82369 from Sears that sells for about $60 or less. Open the jaws and put one wire inside and the meter shows the current down to about 10ma accuracy.
An AC or DC clamp meter can only measure the current if it is over 1 of the 2 wires, if the 2 wires (+ and -) are in 1 cable it is impossible to measure the current by putting the clamp over the cable.
When is a battery considered empty in regards to testing for capacity? How does anyone know all battery manufacturers are using the same stop point? Do most li-ion batteries have a common voltage point(3.0V, 3.1V, 2.7V, 2.5V…etc) where a significant drop-off can be observed?
All lithium ion batteries have a cutoff voltage that should be published in their spec sheet. Don’t expect this info from *fire brand batteries, but you should be able to find it for Panasonic, Sanyo, Sony, LG, Samsung, etc.
A Panasonic NCR18650B can be discharged down to 2.5v and this is the discharge voltage they rate the capacity of 3400mAh at. A Sanyo UR18650F can be discharged to 2.75v and this is the voltage they rate the capacity of 2600mAh at. As a general rule, you shouldn’t go below 2.8v. Most protection circuits kick in at 2.75v. HKJ tests all of his lithium ions down to 2.8v.
The industry standard discharge current for testing battery capacity is .2C, which is the battery capacity in amps multiplied by 0.2. So in the case of a Panasonic NCR18650B, which is 3400 mAh, .2C would be 3.4x0.2= .68A, so you would set the discharge current to .7A.
