[NOOB] Choosing my first set of 18650, few questions

Hey guys, I am sorry because I am sure that this question is asked all the time and trust me, I have searched and read so much my brain is going to bleed.

3400 Protected Panasonics

Are these the right ones? Is that a fair price for 3400ma batteries?

I have a solorforce light that can utilize two 18650s in series, I was told that these batteries would need to be paired up and always used and charged together as a married pair, once separated they could not be paired again. Is there any actual truth to this? My research is indicating there isnt.

Ive read that if you plan to keep the light in your car, you should swap the 18650s for non rechargeable CR123s in the summer time since they are safer. Is this correct?

Lastly, Im ordering a charger. This seems to the be the popular choice, is there a better one you might recommend instead?

Nitecore I4 for $16.00

I know this has all been asked before, but I also know how important proper care is when working with Lithium batteries and want to make sure I order the right pieces.

What follows is my opinion — I’m no expert, but have been around for a while, hopefully learning as I go.

Panasonics are good, as are Sanyos and LGs. Protected is a good idea. 3400 might not be necessary, as one usually gets slightly better bang for the buck with 2900s or 3100s. Depends on whether you want the ultimate in runtime. I haven’t ordered batteries from China/HK lately, so am not sure if shipments are getting through easily these days. You might look at illumn.com or mtnelectronics.com if you’re stateside (both will tell you what cells are inside the wrapper).

I’ve always understood that you should match charge levels and capacities when using batteries in series. If you don’t have a multimeter, it would help to have one for checking voltage.

I don’t have a researched opinion about car heat/lithium ion, except to say that I’ve got spare batteries stashed in both vehicles all the time.

The nitecore charger is fine. (Cheaper at illumn than amazon.)

You are making two good purchases, that is the battery that I buy, and at the same place.

I just remembered, check your measurements to make sure that those batteries will fit your light, they are a smidgen larger than some batteries, and while they fit everything I have, I read that they won’t fit some lights.

If you can swing the money try to buy this charger— http://www.gearbest.com/chargers-batteries/pp_71596.html

If you can’t, then the charger you are buying is very good, and with a generic car adapter that you might already own, it works in the car, a great charger to have.

I’m only slightly less noob then you.
“Once separated they could not be pair again”, to me just does not sound right and does not make sense to me.
I’ve also been looking at the Nitecore I4 for my nephews and so far can’t find anything better, for the price.
Might as well get the Panasonic 3400, price is good, except if they turn out to be fakes.

Here is a supplier located in San Jose, California and it will cost you a little more.

As far as I know Fast-Tech sells genuine batteries, most of those battery reviews are probably from members here.

TheJoe, I have the Opus BT-C3400 version and it’s been working great.
I’ve used it to bring used (laptop battery pulls) 18650 back to fairly good capacity.

These are the best in my opinion (if you want the best instead of the cheapest and if your flashlight accepts longer protected batteries):

Panasonic CR18650B 3400mAh 3.7V Gold Plating Rechargeable Li-ion Battery with Seiko protection board.

Use coupon “BLF” to get a discount.

BT-C3400 Battery Charger Analyzer Tester Li-ion NiMH NiCd Lithium ion V2.1


You might be able to buy both for a few dollars cheaper but I hope you make more than minimal wage and would not want to waste your time surfing the Internet for hours to save a few bucks.

From my personal experience, in the long run, better quality items would likely serve you longer and you would get more satisfaction from using them even though they cost a bit more than from saving a few dollars on cheaper items only to regret such purchases later.

In that pricerange I’d go with the Xtar XP4c. Higher charge current.

While you’re at it, you might as well consider cells from MTN as well…
The PF and BD are higher drain cells, so depending on what you want to do with them you may wish to consider that. For truly high drain applications you won’t be able to use protected cells.

If you keep your cells paired up the way you’ve seen recommended it will be a good thing. It’s quite possible to not do that and still be OK, but you’ll have to take additional precautions. Keeping cells in sets that are used together is not a bad practice.

EDIT: as long as I’m here, I may as well point out that NCR18650B and other similar cells from Panasonic may not keep their voltage up as long as other cells under load… so you may get a longer, unregulated, tail on single cell lights with linear drivers such as the common Nanjg-105c. Take a look at HKJ’s battery comparator to see what’s going on there. Cells you may want to look at in the comparator are the LG D1, Panasonic NCR18650B, Samsung ICR18650-28A, and Sanyo 18650 2600mAh (UR18650FM). Be sure to select the correct discharge current when comparing and unselect anything you won’t be using to avoid confusion.