dougmc

i.e. circuitry? Your trust is misguided.

Your laptop explicitly has a circuitry to look at every cell and refuse to overcharge any particular one. Your cell phone only has one cell and therefore there's no need for any sort of balancing circuit.

The Magicshine has no balancing circuit whatsoever. I do believe it has some protective circuits on each cell, but they're pretty fragile and unreliable.

Iowegian

The 7.4V battery controller IC's that have specs on the web now seem to have a balancing function built into them now so perhaps newer packs will have balancing circuitry. I can't tell if my gen1 MagicShine pack has balancing as I can't find the exact spec sheet for the IC anymore (thought I found it once...). There is a wire to the center tap of the battery pairs but if the pinout on this IC is the same as the ones I can find on the web now the balancing function is disabled since the 2 pins that would be doing the balancing are tied together. In any case, my pack is quite out of balance so if there was balancing circuitry in place it didn't work well.

Iowegian

Hope I'm not boring everyone but I was looking into the battery protection IC's a little closer and found something that may explain the 'balancing' problem with cheap cells. This spec sheet for this particular chip indicates that the 'balancing circuit' operates only when one cell (or pair if a MS) exceeds the overcharge voltage. Then it appears that the circuit goes into a balancing mode that drains current from the higher voltage cell(s) to the lower voltage cell(s) until a) the cell voltages are the same or b) the higher voltage cell(s) reaches the 'overcharge release voltage' which is about 4.013V (depends on temperature). Based on this, it seems that if the cells were close to the same 'health' and they both ended up near the same voltage when the first cell reached the charging cutoff voltage, the balancing circuit could equalize the charge level every time. If one cell was much weaker, the charging would stop when the stronger cell hit the limit and the balancing operation would attempt to equalize them but terminate before the cells were at the same voltage. Repeated failures to balance could then be cumulative and the pack would terminate charging at a lower and lower voltage as the voltage difference between the cells increased.

Or maybe I'm just reading the spec sheet wrong. It's a bit unclear and appears to have been translated to English from another language.

dwmckee

I have a p7 rechargeable also but for what you want I strongly recommend you look at the two watt (500 lumen) Blaze two watt light from Planet Bike. It sells for around fifty bucks and uses two AAs. It is really bright even in daylight and is a lot smaller lighter and less clunky on your handlebars because it was designed for bikes. I have had a guy on a bike flag me down to see what my light was because it was so bright at half a mile away. Despite my brighter P7 light this is what I prefer for touring. The beam is designed for biking and the double AAs mean that when they run down on a tour I can get replacements anywhere and not have to carry a charger. Excellent light! Outstanding brightness with cheap readily available batteries and small and lightweight.

https://ecom1.planetbike.com/planetbike/media/3045.jpg

Researching all of the P7 lights on DX and looking at all of the battery options and all of the charger problems and all of the comments about how to fix the switches and heating problems and quality issues and it just goes on and on. The little planet bike light is simple because you just buy one model and drop in a couple of AAs and it works perfect forever. Batteries last over twelve hours on brightest too. If you do not want to research and become an expert on deal extreme lights and spend hours comparing and gambling that the one you pick won't be defective then just grab the blaze. I own both and honestly the little blaze is the way to go. It is bright enough to actually see the road ahead too, not just for being seen. Not as bright as a P7 but for occasional use when you stayed at a friends past dark (like the original post said). One last thing is that these nice p7 lights are tempting to steal so you cannot leave it on your bike. The blaze does not look like something anyone would want to steal. You just leave the blaze on your bike all the time and the day you stay too late it is there ready to go to work. The day you need your p7, it will be at home somewhere doing you no good at all because you cannot leave it on the bike.

dougmc

It's not 500 lumens. The one watt version is around 50 lumens, so I'd expect the two watt version to be around 100 lumens.

The P7 flashlights are around 400 lumens on high. This one isn't actually P7, but BIN-M (or is BIN-M a type of P7?) which is similar but newer and a bit more efficient for $20. You can buy two of those and a pack of batteries for the price of the PB Blaze 2w. Throw in $18 more and get two more batteries (spares!) and a charger. Well, you'll also need a $1.50 mount. Might as well get two, as you've got two fully functional lights.

And don't delude yourself about the Blaze -- thieves know it's a good light, and absolutely will steal it. Yes, it's better built than the flashlight I gave above -- but it costs nearly twice as much and puts out much less light.

If you want a cheap bike light, get this or this. The light they put out is comparable to the original PB Blaze 1w, though taking 3xAAA rather than 2xAA is certainly a minus, and they're not as rugged as the Blaze. These are less likely to be stolen than the Blaze as well, but they're still pretty likely to go.

hopperja

While I don't plan to use it as a bike light, I just got a Jet Beam BA20 flashlight. It's about the size of my Fenix L2D Premium Q5, runs off 2 x AA batteries, and puts out a manufacturer claimed 270 lumens. It was estimated by one reviewer on CPF to put out 255 lumens. Remember, the Fenix is said to give about 180 lumens. I just got it and have compared it in my backyard at night with my Fenix. It is noticeably brighter than the Fenix. It's another option to consider for those looking in the sub-$50 category. Fenix's warranty is 2 years while Jet Beam's warranty (through the dealer I linked) is a year.

Personally, I like the AA batteries because I can use Eneloops, which everyone seems to agree are outstanding batteries. My Fenix (back up bike light), DiNotte 140L, work flashlight (BA20) and work camera all run off AA batteries. This simplifies things for me.

Shadowex3

Eneloops, if they are remotely as beefy as their ratings and heftiness suggest, are indeed kickass batteries.

speedlever

The JetBeam BA20 looks nice but the output is described as 2 modes. I don't see a strobe mode, which is what I like to use for rides at dusk.

dougmc

Eneloops aren't "beefy". Their mAh ratings are mediocre -- 2000 mAh when batteries claiming 3200 mAh are available. (Note that the really high mAh rated batteries tend to suck in other ways, even if they do achieve their rated capacity, which is iffy.)

However, their low discharge rates are totally worth it. Charge it today, use it six months from now -- it's ready to go. Low internal resistances as well.

Do you mean hefty as in heavy? Their size is limited by the AA specifications, and I haven't noticed them to be significantly heavier than other rechargeables.

hopperja

Low and High. No strobe, you're right. But, I've been using it at work for the past week and it has been awesome! I won't be going back to my Fenix for work. Now, as far as biking is concerned, I see the value in a strobe mode (even SOS) for dawn/dusk road riding. I just think it's an excellent compromise light (ie, no strobe, but good output at a great price, using ubiquitous AA batteries).

scoatw

What's the runtime on the Jet Beam on what kind of batteries ?

hopperja

Well, the CPF review I referenced earlier reads 92 minutes to 50% with 2xAA Eneloops. I have not done any runtime tests, but I'd guess the CPF review is accurate.

Shadowex3

I'd rather have middle of the road mAh ratings from a reliable battery that isn't going to literally fall apart on me (I'm not kidding, some have) than higher ratings from something less trustworthy.

oneofpr

Around one dollar, uses 1 AA battery with one bright led, bought a faucer o-ring on Home Depot, attached over the handlebar. Commute to downtown Jax with no hassles.

Cyclist0383

I just picked up a Solarforce XL-M Drop-in and host. It's noticeably brighter than the MC-E from Shining Beam it's replacing, and has a lot better through. All together including shipping it was $46.48 from https://www.solarforce-sales.com, which is the retail end of Solarforce lights.

Personally I think that Solarforce lights are one of the best deals around as they are sturdy inexpensive, and simple and cheap to upgrade as they use a P-60 drop-in.

davidad

How much current does it draw? I have a 501B 5-mode form DX and it draws 1.44 amps and doesn't get too hot.

Cyclist0383

Around 3 amps with a fully charged AW 2600 18650.

davidad

Don't run it too long on high. There is too much heat and not enough Al. in the light to get rid of it.

Cyclist0383

I already wrapped the drop-in in aluminum foil to help with heat sinking. I think that and the air flow from riding should be enough to keep it cool. If it dies on my due to heat I'll update this thread.

dougmc

Are you sure of this? I've never had a problem with my P7 lights, even on high. Not when mounted on bike, anyways.

I've had them get hot when I used them as a flashlight -- but on a bike there's a 15 mph breeze blowing over them, and I've never found mine to get more than say ten degrees warmer than the outside air, even when on high. Perhaps during the day with 100 degree temps and the sun heating it as well it would be a problem (and get up to 120 degrees F or so) -- but normally you don't need your light then, or if you do, it's on flash and the average power is low.

And wrapping it up aluminum foil sounds counter productive. Yes, aluminum is a good conductor of heat, but your foil won't be well connected to the light itself (heat transfer works much like electrical conduction -- good joints make a difference) and so overall I'd expect it to keep the light warmer rather than cooler. Still, with a 15 mph airflow, I think it'll still work fine either way.

Shadowex3

That's not going to be a good connection for heat transfer, you're doing a better job of insulating it than anything else.

davidad

I used foil on a p-60 module I got from DX and it drew over 3.3 amps on a fresh battery. With the foil the 502B body I installed it in got so hot I couldn't touch it. The modes quit qorking after a 15 minute run and before I returned it it wouldn't stay lit.

Cyclist0383

The folks over at CPF would disagree with you. They seem to know what's what in the world of lights.

Cyclist0383

That means the foil is doing it's job as it's transferring the heat from the drop-in to the host. The quality of DX drop-ins is a whole different matter. I stopped buying them a few years ago when I had the LED literally fall of a brand new drop-in. The best drop-ins I've bought are from CPF member Nailbender. He makes some quite nice ones.

socalrider

I would like to know what kind of runtimes you get with the drop-in in high mode.. I have a couple of XML's lights on order but could use a couple of dropins for some older lights I have laying around.