Bike Forums

Bike Forums (http://www.bikeforums.net/forum.php)
-   Electronics, Lighting, & Gadgets (http://www.bikeforums.net/electronics-lighting-gadgets/)
-   -   Choosing Rechargeable Batteries for Lights (http://www.bikeforums.net/electronics-lighting-gadgets/788657-choosing-rechargeable-batteries-lights.html)

matimeo 12-25-11 07:35 PM

Choosing Rechargeable Batteries for Lights
 
My current light setup uses AA and AAA batteries and I want to switch to using rechargeables to save money. I was turned onto the idea with the new "low discharge" batteries like the Sanyo Eneloops.

I got some for Christmas but they turned out to be the high capacity sort (2500 mah), but it looks like they're the kind that will lose their charge more quickly when left on the shelf or unused (they are Sony CycleEnergy High Capacity Batteries for the record).

So it seems like with the current battery technology you have to pick a tradeoff: higher capacity but more rapid self-discharge or a battery that retains its charge but doesn't have quite the same capacity.

I commute 10 miles a day for between 40 and 50 minutes in the saddle.

So the question is, as far as lighting on my bike go, which is the better choice? Using the higher capacity and just recharging them every weekend or the precharged type and not having to worry if they will lose their charge too soon.

Can anybody make an informed recommendation?

znomit 12-25-11 08:14 PM

NiMH self discharge is around 10% for the first day and then 1% daily after that. They still last a good while.
So comparing 2000mAh AA LSD with 2500 regular NiMH .... you'll take a few weeks to discharge that extra 500mAh.

Initially I ran eneloops in only my low drain devices but I've found them very reliable so am slowly replacing my energizer 2650s with them. I splurge for lithium primaries if I need a lot of power.

Note you can get 2500mAh LSD "eneloop XX" which trade the higher power for less recharge cycles.

a1penguin 12-25-11 08:30 PM

People on Candlepowerforums claim that Sanyo Eneloops are the best brand of LSD batteries. I've been happy with my AA and AAA Eneloops. The AAAs last forever in the original PBSF. I saw a news blurb on batteries and how environmentally unfriendly they are. The only non-rechargeable batteries I purchase are the 2032/2035 coin cell batts that are used in cycling gear.

If you look at battery levels and amount of light out of a flashlight, they ALL drop off quickly unless they are regulated. Most cheap lights are not regulated. The Lezyne Superdrive is reported to have large light level drops.

Doh! I use 9 volt primaries in fire/smoke/CO detectors and DMM.

matimeo 12-25-11 08:38 PM

Quote:

Originally Posted by a1penguin (Post 13640163)
If you look at battery levels and amount of light out of a flashlight, they ALL drop off quickly unless they are regulated. Most cheap lights are not regulated. The Lezyne Superdrive is reported to have large light level drops.

So are you saying that with rechargeables like the Eneloops the light will have poorer output compared to with alkalines (unless the light has something built in that regulate the amount of power it grabs)? Or are you just saying that when the battery starts to wear down it will drop more quickly than with alkaline?

Thanks you for the feedback- very helpful.

mechBgon 12-25-11 10:15 PM

Quote:

Originally Posted by matimeo (Post 13640173)
So are you saying that with rechargeables like the Eneloops the light will have poorer output compared to with alkalines (unless the light has something built in that regulate the amount of power it grabs)? Or are you just saying that when the battery starts to wear down it will drop more quickly than with alkaline?

Alkaline have higher initial voltage, so they could produce a brighter light if the current draw isn't too high. When the current draw goes up, such as when a regulated light starts pulling more amperage to keep the LED fed properly, alkaline may hit the wall very quickly. For example:

http://lights.chevrofreak.com/runtim...%20-%20max.png

Lithium primaries (non-rechargable Lithium) and NiMH are both much better at handling the high current draw, and hold out longer against this sort of load. Further info here if you're interested: http://www.candlepowerforums.com/vb/...runtime-graphs

Anyway, either type of NiMH is a good pick really.

matimeo 12-25-11 10:56 PM

Very interesting reading. I'm curious if those numbers would be similar in other types of lights as the referenced threads seemed to be speaking specifically about a certain light. I would assume it would more or less but I could be wrong. Impressive how much better performance comes from NiMh than alkaline.

prathmann 12-25-11 11:24 PM

Quote:

Originally Posted by matimeo (Post 13640385)
Very interesting reading. I'm curious if those numbers would be similar in other types of lights as the referenced threads seemed to be speaking specifically about a certain light. I would assume it would more or less but I could be wrong. Impressive how much better performance comes from NiMh than alkaline.

The better performance from NiMH vs. alkaline cells really only holds for high-current applications. So it's true for relatively high-power head/flashlights like the one tested, but not for low-power rear blinkies. Alkalines have much more internal resistance which wastes much of the power when you use them in high-power devices, but they work fine at lower power (and many people prefer them for rear blinky lights since they retain their charge for years when not in use and lose power gradually so you can notice the light getting dimmer over many days instead of rapidly fading away during a single ride.

I'd suggest either alkalines or the Eneloop style of NiMH for your rear flasher light and the slightly higher capacity NiMHs for the headlight. The rear light should last for quite a long time between recharges while you'd be charging the cells in the headlight much more often. Also not a bad idea to carry a spare set of charged cells along so if you notice a light dimming you can exchange the cells right away.

Scooby214 12-26-11 08:34 AM

I use Rayovac Platinum NiMH "low self discharge" rechargeable batteries. They last as long in my rear blinky as alkalines for me. When I used to run an AA powered front light, I also used the Rayovac Platinum LSD batteries with good success. What others have said is true in regard to alkaline vs NiMH batteries in low drain devices such as blinky lights. The NiMH batteries are only of any benefit in such devices if they are the low self discharge variety such as Sanyo Eneloops (great choice) or the Rayovac batteries (good choice) I'm using.

Where I get the greatest benefit from the NiMH batteries is in my digital camera. I get more than twice as many pictures out of my Canon PowerShot with my 2100 mAh Rayovac Platinum batteries than with alkalines such as Energizer or Duracell.

no1mad 12-26-11 08:56 AM

Nice to know the Rayovac LSD's have worked out for you, since that's what my wife got for me.

no motor? 12-26-11 03:25 PM

Using a smartcharger will extend the life of your batteries, allowing you to slowly charge them instead of shortening their life by charging them too quickly. Maha and LaCrosse were the 2 choices most people made when I got mine a few years ago.

AndreyT 12-26-11 03:40 PM

Experiment.

If you use your light every day, you might notice that having a higher capacity of ordinary rechargeables is more beneficial than having the better charge retention of LSD batteries. LDS batteries are better for those applications where the device is used only occasionally with extended periods of non-use. If you used your light only once a week I'd definitely recommend LSD batteries. But with everyday use I'd guess that ordinary high-capacity rechargeable batteries will work better.

In any case, try both and see how it works for your specific usage pattern.

AndreyT 12-26-11 03:48 PM

Quote:

Originally Posted by no motor? (Post 13642012)
Using a smartcharger will extend the life of your batteries, allowing you to slowly charge them instead of shortening their life by charging them too quickly. Maha and LaCrosse were the 2 choices most people made when I got mine a few years ago.

Um... The purpose of smartchargers is actually to charge the batteries quickly. The "smart" in "smartcharger" refers to the charger's capability to properly detect the "battery is full" situation and terminate the charge in time, without overcharging and overheating the battery. This specific capability is what makes it possible to charge the batteries very quickly without shortening their life. That's the whole idea behind "smartchargers".

If one plans to charge one's batteries slowly for some reason, one does not need to waste money on a smartcharger. An ordinary wall-wart trickle charger will do the job perfectly.

Burton 12-26-11 10:23 PM

Hmmmm ...... real world experience? I guess I`ve personally used a variety of AA and AAA format batteries in Alcaline, NiCad, NiMh, and the latest slow discharge rechargables. Currently have 3 smart chargers from MAHA, a couple standard chargers from Sony and a few from Energizer.

I`ll agree with most of whats already been posted. If you`re using these on a regular basis - as in every couple days - it really doesn`t matter what kind of rechargable you use. You`ll be draining them faster then they could possibly lose any significant amount of charge.

Personally I stopped using Alcalines altogether simply because I`ve never had a rechargable leak and have had poor experiences with too many Alcalines. Batteries are cheap - some equipment isn`t.

Intelligent chargers let you select a charge/discharge rate for each individual cell according to cell format as well as charging each cell individually. They also cost about $100. A regular charger charges batteries in pairs and kicks off when the firts one is full. Which is fine as long as they were both discharged to the same point. And if you use them in pairs and charge them in pairs, there really shouldn`t be an issue.

But suggest you avoid `rapid chargers`. Anything that charges an AA cell in one hour generates excessive heat and really kills the expected life of a battery. 1,000ma is a good rate for an AA and that translates to between 2 and 3 hours for an AA cell.

I usually carry an extra set of batteries with me but I`m running quartz headlights and neon rear flashers. If you`re using LEDs you shouldn`t need them - just figure out the optimal time frame to put in fresh batteries. You can recharge those at any point - they don`t have to be completely drained.

You will notice that the voltage output from rechargables is more stable than Alcalines so the light won`t dim as the batteries drain. Thats actually a big plus!

Litespeedlouie 12-27-11 02:02 AM

My experience with Non-LSD Eneloop cells with high capacity ratings is that a they tend to lose their capacity fairly quickly. You end up with less capacity than an Eneloop and it still self discharges quickly. I only use Eneloops for AA and AAA applications except for a few clocks and and an outdoor thermometer where I use lithium AAs to withstand the cold. Eneloops also seem to not have the leakage problem of alkalines. YMMV.

cehowardGS 12-27-11 09:18 AM

I am a newbie, with that said, I am running cheapo lights. Also, I am running cheapo Asian rechargeable batteries. I have a quick charger on both ends of my commute. I have a 20 minute commute in the morning (dark), and 20 minutes on the return leg of the commute and it is dark too. Also, when the it gets light out, I put the front lights on blinking. So far no problems. Later on and if I move up to more expensive lights, I will get more expensive batteries. From what I have read, Sanyo has the best. They cost more too. My cheapo rechargeable batteries are rated at 1500 to 1850 on the AAA, and 2500 to 3000 on the AA. Like I said, so far so good.. ;)

Digital_Cowboy 12-28-11 01:01 AM

Here's a question for those using rechargeable batteries. Particularly the LiIon and NiMH variety.

How often/frequently do you recharge your batteries? Do you recharge them as soon as you get home from your ride/commute, once a week, once a month, when they show a significant drop in voltage? Do you keep a charger at work to recharge them while you're working? Do you carry a spare set so that if you're on a particularly long ride/commute you can swap them out while on the road?

Also what kind of charger(s) do you use? Do you have one "massive" charger that charges a large number of cells or do you have several smaller chargers that charge a small number of cells?

A10K 12-28-11 02:21 PM

DC, I run a 2AA light for my headlight, and use the white Eneloops for them (2000mah). I always carry a spare pair with me and only replace the batteries when the flashlight gets critically low/dies. This ensures that the batteries are almost fully discharged when they are recharged, which prevents memory effect long term (although this is more an issue with non-Eneloops). NiMH's, unlike Li-Ions, don't fare well when frequently charged small amounts, and this will over time reduce the number of cycles they can go through.

I have a cheap Energizer charger that charges up to 2 sets of batteries, but in pairs only (so 4 total). This isn't the optimal solution, since it can't compensate for slight differences in voltage/capacity, but I always use my batteries in pairs, so the same two always get used together, to minimize any differences between them. I have a USB charger that will charge 2 at once, but since it only delivers 160mA, its really only for emergencies as it would take over a day to charge a pair of Eneloops.

I'm currently working on building a light to take Li-Ions, but those are a whole different animal and the consequences for improper charging/battery matching can be severe.

davidad 12-28-11 06:59 PM

Sanyo 2700's have a good reputation. If you are using them every day then recharging as necessary then they might be better for your purpose. The advantage of the Eneloops is the ability to hold a charge for months before useage.

Scooby214 12-28-11 07:49 PM

My Rayovac Hybrid NiMH batteries for my taillight get charged every couple of weeks. That is with daily use in the morning before sunrise. They are not fully drained at that point, but I want them charged before they become critically low or die (since the light is behind me and I wouldn't know when it quit working). My headlight is a Serfas True 250, with a lithium ion battery, and it gets charged nightly. It gets about two hours of use, with a one hour commute in the morning and the return trip home in the evening. I always have plenty of charge to spare, but prefer to start off each day's commute with a fully charged headlight in case I decide to take the scenic route to work.

A10K 12-29-11 12:29 AM

Quote:

Originally Posted by davidad (Post 13649477)
Sanyo 2700's have a good reputation. If you are using them every day then recharging as necessary then they might be better for your purpose. The advantage of the Eneloops is the ability to hold a charge for months before useage.

I'm not sure how they compare to Sanyo's Eneloops, but the Eneloops also have the additional advantages of more recharge cycles total (1500 vs 200-300 for regular NiMH's) and more consistent capacity over their lifetime. I just got some of those Rayovac Platinums for a small flashlight and some rechargeable phones, and I don't know how much the Rayovac's address those issues. The memory effect is actually a bigger issue for my, because I've already run into what I consider the end of the usable life for my Duracell/Energizer rechargeables; they last much less than they used to a year or two ago.

BetweenRides 12-29-11 08:31 AM

In my experience, Duracell/Energizer rechargeables are crap as far as useful life goes. They do not live up to billing. Eneloops for me next time for around the house duty. I'm glad I've made the leap to 18650 for big flashlights. Li-Ion batteries are pretty amazing.

no motor? 12-29-11 02:23 PM

Quote:

Originally Posted by AndreyT (Post 13642058)
Um... The purpose of smartchargers is actually to charge the batteries quickly. The "smart" in "smartcharger" refers to the charger's capability to properly detect the "battery is full" situation and terminate the charge in time, without overcharging and overheating the battery. This specific capability is what makes it possible to charge the batteries very quickly without shortening their life. That's the whole idea behind "smartchargers".

If one plans to charge one's batteries slowly for some reason, one does not need to waste money on a smartcharger. An ordinary wall-wart trickle charger will do the job perfectly.

Guess the definition has changed over the years. Smartcharger used to refer to the ability to avoid overcharging and overheating the battery back when NiMH AAs were more commonly used. I can see where the faster charge time might come in handy though if you weren't recharging them overnight or while you're at work, but how often is that going to happen?

Pluto 12-29-11 07:15 PM

I find it necessary to do a lot of my riding in either early morning or late evening with lights. I started out using AA rechargeables and would recharge after each ride. The downside was that on longer rides, say an hour, I would have to switch to a spare light or spare batteries. I've made the switch to a Four Sevens 123 tactical light that can be programmed for two different outputs. At the highest setting, I can get 360 lumens OTF for 1.8 hours of continous use, or greater time by dialing back the output. 123s require a separate charger and the batteries are more expensive but the light is smaller and lighter than my other AA lights. This seems to work for me. I added a second 123 light for my MTB.

billyel 12-30-11 12:52 PM

Quote:

Originally Posted by Digital_Cowboy (Post 13647035)
How often/frequently do you recharge your batteries? Do you recharge them as soon as you get home from your ride/commute, once a week, once a month, when they show a significant drop in voltage? Do you keep a charger at work to recharge them while you're working? Do you carry a spare set so that if you're on a particularly long ride/commute you can swap them out while on the road?

Also what kind of charger(s) do you use? Do you have one "massive" charger that charges a large number of cells or do you have several smaller chargers that charge a small number of cells?

I use two LiIon [18650] batteries in a light with expected runtime of just over two hours on high. My commute is ~25 minutes/day so I charge it every other day to ensure (ideally) I will not need to switch to my backup light or install non-rechargable backup batteries. The light allows me to rotate the head between high/low, so I'll turn it down when waiting, etc. to extend functional runtime. In spite of temperatures being between 25 and 35 I've had no capacity problems.

I have a single dual-bay charger [LINK] that takes 3-4 hours to fully charge. If the batteries are cold I'll let them warm before starting up the charger.

vol 12-31-11 01:16 AM

How long is the charging time usually to charge an AAA from weak (when the light is not bright any more) to full? (I have never used rechargeables)


All times are GMT -6. The time now is 09:10 PM.