Chargers, batteries and confusion...

Hi,

Confusion reigns here and I have done a lot of searching. If you're feeling tolerant maybe you can supply some advice.

I was searching for an inexpensive charger and I think I found one here:
http://www.dealextreme.com/details.dx/sku.936 It got a ton of good reviews.

I will be using it to keep an Ultrafire C2 fed. But I keep reading about protected and unprotected and CR123a and RCR123a and 16340. Are 16340s the same as the CR123a battery? (and I won't even get into 18650 with and without nipples and spacers and blobs o' solder).

From what I have read a pair of CR123a batts. will give me a longer runtime than a single 18650. True?

Would someone tell me the best type of rechargeables I can buy that will give me the best throw and runtime while still being safe for use in this light? It is regulated (from everything I've read here).

Here are the battery specs:

- Takes both 2xCR123A and 1x18650 batteries
- Accepted voltage input 3.6V ~ 9V
- Note: this light's the battery compartment does not have contact spring on the positive node. So protected 18650 cells (those with recessed positive node) will not work with this light without a small spacer.

I'm sure there are also quesions which I should be asking which I am not. Sorry.

If there is a reference thread somewhere which explains this please point me towards it. Believe me, I have looked.

Thanks,

Mike

Just have to do a search for 18650 or c123a and it'll pop up a lot of threads.

From what I've read the pair of c123a will run brighter but at a lot lower runtime. I read one example was a power draw of 3.5(v? mA? don't remember) on a single 18650 and 4.3 on a pair of c123a.

Also there was something I read about if one of the c123a runs low it can cause the other battery to run hot and possibly explode. Don't know how often this happens, probably not too often.

I went ahead and stuck with 18650 since I like longer runtimes. Especially when I'm taking my flashlight on a hiking trip.

Hi mick53,

Yes, 16340 is the same as RCR123a.

Two RCR123a cells in series will be brighter than one 18650, but with less runtime as guy121 already said. The reason is partially due to less current draw with the 18650 (and that is the reason for decreased brightness), but also because one 18650 stores more energy than two RCR123a cells. The capacity of one RCR123a is about 650mAh. Don't believe advertisements that claim more than that. In testing under reasonable loads you will not be able to get 900mAh out of one RCR123a (some cells claim that much). A protected 18650 will typically deliver 2200mAh, so you will get an extra 900 mAh of capacity compared to two RCR123a cells if you want to look at it that way. Unprotected 18650s can deliver even a bit more, but using unprotected Li-ion cells can be much more dangerous.

If you do decide to use two Li-ion cells in series, please don't use unprotected cells - this is dangerous as guy121 mentioned. I had a problem with this when I was first getting into this hobby where one cell reverse charged the other to -1.25V. I was lucky it didn't explode.

I recommend you go with an AW protected 18650 and the charger you linked to. That will be a fine way to begin.

CPF has a forum for electronics and batteries. Please search that forum.

This was posted in the wrong forum, and is closed. There's no need to move it, as it's a commonly asked question in the correct forum.