haplorrhine

Did anyone order that flashlight because I put the link up? The price rose $4.
I'm just curious. I remember when a book's price rose immediately after my purchase of it.

Burton

You haven't convinced me that what you shorted out wasn't a polymer Lithium Ion cell in a 16850 format - hence still a Lipo.

ItsJustMe

It had a liquid (gooey) electrolyte, therefore it was not Lipo, by definition.

haplorrhine

What science concerns battery functioning? Is it a subdiscipline of chemistry?

ItsJustMe

Google seems to say people who work on battery chemistry are simply called battery chemists. I have a friend who worked in the lab under the guy who invented NiMH, I'll ask him, but I don't think there's a specific name for that.

sknhgy 

Hmmm. Wonder what I'm doing wrong. I buy the pre-charged NiMH Energizer AA's and they won't power my Dinotte 200L on high after a week in the saddle bag.

joewein

Don't buy the Energizer NiMH, get some Sanyo eneloop. They are some of the best low self discharge NiMH cells. I do use eneloop for AA and AAA form factor applications, but for my front light I've switched to a dynamo hub and a Lumotec IQ Cyo, which works great even for 300 km brevets.

For my smart phone I currently use a 18650 cell based USB pack for backup power (this covers 20 hour brevets too). I use relatively inexpensive Trustfire 2500 mAh protected cells, which have worked well for me so far. I'd stay away from Ultrafire.

2manybikes

Eneloops wont do that.

Are you leaving them connected to something?

Richard Cranium

As some have mentioned - 18650 - is a battery format. So when thinking about choosing bicycle lighting think in terms of how you will use the lights - not just battery specs or lighting power.

Many of the long time forum readers have multiple styles of lights are that over powered and redundant because they understand that different situations will require different lighting.

Recently I used Blackburn "click" lights - they use the tiny CR2032 battery. But they are perfect to get me down to the Pizza place and back safely. On my race-ready road bike.

cehowardGS

Richard, ya know we love ya around here, with that said, I would LOVE to see a picture of your race-ready road bike!!

Richard Cranium

You can see it by clicking the "sig line" - the last time I rode it was on April 23rd - I wanted to see if I was still in shape since I have given up on "real training" and consider my self a long distance tourist. I rode 41 miles in 2:02, never got up over 21 mph average.......

The hybrid bike was used on an overnight ride two weeks ago - covering 230 miles in 48 hours - with a bike/load weight of nearly 50 pounds! (too many lights batteries and clothes - as well as binoculars and other doo-dads for outdoors.......)

sknhgy 

I beg to differ. All my experience has shown that even the new rechargeable AA's won't hold a charge needed to power a strong bike light for more than about a week. 18650's will hold a charge over a span of months. I use both. The difference is quite apparent.

dougmc

Maybe you had the wrong new rechargeable AA's. The Eneloops (and other low self discharge rate batteries) are great and well worth the small premium they cost.

Now, that said ... a single NiMH AA battery contains about 2.4 WHr of power, and an 18650 battery about 9.0 WHr. The 18650 is a good deal larger, and Liion and LiPo are known to have higher power densities than NiMH, so this shouldn't suprise anybody that a 18650 can provide more energy -- though 4 AAs would give it a run for its money.) But when it comes to the discharge rates when the batteries aren't being used ... both the Eneloops and the LiPo/Liion (I'm not sure which) 18650s are excellent, and both will have over 80% of their charge even after several months of not being used.

That said, 18650s are damned convenient, inexpensive and perform well. The single 18650 cell flashlights make great bike lights -- put two on your bars (using one most of the time), keep two batteries in your bag as backups and you're ready for pretty much anything short of riding all night (and you'd even be ready for that if you avoided the high light modes.)

dougmc

That's a good link -- lots of real world testing.

However, I came up with a different conclusion from it than you did. The conclusion I got from it was that "the 2600 mAh Ultrafire cells I've been getting from DX for $4 each are pretty good". Sure, they measured them at 80% actual capacity, but most of the other cells weren't much better but cost a lot more.

To me, this says to avoid the 3000 mAh rated and larger Ultrafires. I'm surprised that they'd really cut open old laptop packs and make crappy batteries from them, but the evidence seems pretty strong. But my experience with the 2600 mAh batteries is very good, and this page seems to confirm it.

ItsJustMe

You could be right. I gave up on using AA cells for lighting a couple of years ago. 18650 is the only way to go even if you use cells right out of the charger. AA cells are just weak in general. I only really use AA cells for stuff like camera flash, digital audio recorders, etc. where they seem to have a good charge even after sitting for a month or two, but I don't use them to exhaustion so they could be discharged more than I think. I have a charger that will tell me how many mAH is left in a cell if I wanted to do experiments, but honestly I don't really care that much.

haplorrhine

I don't think I'll need slow discharge because I have three flashlights now. I can mount them all and use them in combination when the batteries are running low. Unfortunately, I haven't tried this yet because I haven't been on the bike in far too long. I normally ride at every day or every other day, which is another reason for me not needing slow discharge very much.

Burton

My only conclusion is that you're not riding regularly. A 'strong' bike light will drain ANY battery format in a matter of hours (or in some cases minutes) so regardless of format or chemistry - the batteries used by any commuter won't have a chance to self-discharge. They'll be discharged by the light instead. Any other differences in run-time will be entirely because of capacity.

Thats not a guess - I have a pack of Imedion AA's that I use to run a 900 lumen headlight and aside from the extra weight - it does as well as lithium ion. The only difference relative to most users on this forum is that I run 10W / 12V LEDs which require a lower amperage draw than 10W LEDs at a lower voltage. Thats a lot easier on AA batteries. (or any other format for that matter)

BetweenRides

Here's another link for you: https://budgetlightforum.com/node/2619

I have several UF cells, a few are ok, a few are total crap. It's not a question of if you will get a fake as much as when. Why play the lottery? DX, DD, KD and countless eBay sellers have been caught selling fake UltraFires and TrustFires - not worth it when you can get good quality cells from reputable dealers for a few dollars more. You will also find that most UF cells will not power a good regulated flashlight in high mode - I think it is due to higher internal resistance. My UFs will work fine in quite a few flashlights, but if I try them in a quality light (Such as Balder BD-2, Solarforce M6, Thrunite T30), they will not power them in high at all or will very quickly drop down to medium or low. No way would I ever use UltraFires in a 2x series multicell light - very hard to find two that are balanced.

Glad you have had good experience, but in today's marketplace, counterfeits seem to be rampant.

JPMacG

https://www.rcgroups.com/forums/showthread.php?t=719116