IN the case of the magicshine, they use commonly used cells. They seem, though, to buy them from people who don't believe in quality control.

Perhaps they are getting the cells that failed QC? :innocent:

In many industries, it's normal to group production into lots, and sample a small fraction of the lot. If too many of the sample fail inspection, the lot is condemned or otherwise disposed of. In some cases, that means selling it a discount. Given the wildly variable quality of the few things I've bought from DX, it wouldn't surprise me that's a very common practice among their suppliers. I'm not opposed to that when it's done above board.

Ok, it sounds to me that what we want out of MagicShine is 4 good batteries with a holder that allows us to pop out each battery for recharging. Then the battery holder is both hooked up in series and in parallel to make it work in unison.

This reminds me of the old days of my Marantz tube amp and preamp. I think it was the 7c and 8b. Everything had to be matched. I bought Telefunken tubes from Germany. Even the 12AX7's.

That would be ideal. BatterySpace sells 4 x 18650 holders with integrated protection circuitry for $20. Honestly, if you're charging each cell separately, you can get away with using fairly cheap cells, and if one dies, it's easy to replace, so you could use the $4 cells from DX and put together a whole pack for < $40. Of course, then you need a separate charger, but the 2 cell 18650 charger that I bought for about $7 from DX works well. I might buy two of them if the charge wasn't fast enough or just because I'd forget to swap them and get to the end of the day and have only 2 charged cells.

I think if I had it I'd probably still charge the whole pack as a pack maybe 2 out of 3 times, and charge the cells individually 1 out of 3 times. That would equalize the cells frequently without the hassle of removing the cells.

My cheap trustfire 18650 outlasted my MS pack most likely because they are individually charge and series charge like the MS pack.

Technology sooner or later will fix these bugs. Currently there is 3000ma 18650, however if they ever can make a 4400ma 18650, then two in series can run a MS with the same volts and runtime. To solve the series charging problem, a balancing charger can be use as an option assuming the pack is wired for that. This probably will allow the battery to last the 2-3 years of useage. Until then, we'll have to grin it and bear it.

I also think a eight pack will be much better than the four pack if the pack will get depleted down to 50% depletion. Not sure if this is a fact, but I think the pack will maintain better balance of the cell if it get recharge at 50% instead of a full drain. So that means I will have to recharge a 8 pack after 3 hours use.

One thing I am looking into is those SST 50 flashlight. They run on a single cell and gives out just as much light as a MS. Only drawback is the 1 hour runtime. I might be hacking into one of those flaslight and add an external pack of 3P1S to get 3 hours of runtime. Since they are not in series, charging and keeping them in sync should be less of an issue. Just a thought.......

It's already solved them. It just involves spending money, and the magicshine is all about being cheap. It's perfectly possible (and widely done) to build a charge controller that charges the batteries individually, but it's more expensive, and you really should use cells that are properly matched, which costs money. Maybe if costs of good quality Li-ion cells come down, they'll buy first rate ones. But since there's a big market for cheap over quality, maybe not.

Then why not apply good old fashion American marketing, a-la Sears Roebuck? They could offer, good, better, best. Do you really think Craftsman tools are "best"?

They're the best that Sears sells...

Oh yeah, I just did another "test." I ran two MS 900s on MS batteries for the same time frame at the same power at the same time. And then I charged them using identical chargers and charging times.

I monitored the battery voltages and charging rates periodically. Both batteries drained and recharged identically. One battery I have owned for several months and has been drained to "auto shut off" about five times as well hours and hours of short term use. The other battery was being used for the very first time.

So -in my case - I have a battery that has been run over 100 hours and appears to act like a brand new battery. Or I have a brand new battery that acts like it has been run over 100 hours - gee whiz.......

If you do a little research on the MagicShine light, you will find that its made in an Industrial Zone in Shenzhen, Guangdong. You'll also find that this area also makes batteries.

I've been using a Magicshine for about a year. I put it away over the summer with longer daylight hours. When I started using it again a few weeks ago, my light was intermittently going out -- a problem that seemed to arising from the connectors between the light cable and battery cable. I emailed Magicshine, and they sent me a coupon for 50% off a new light unit and/or battery. I decided to replace both the light and the battery since I wasn't sure which connector was faulty, and it wasn't a bad deal for $45. I am glad that I made the switch because the new light unit has 5 settings (high, med, low and two blinkie settings), plus the cable is shorter. The cable on my old unit was ridiculously long and I had to fold it up.

My old unit and battery still work and might be useful to someone if they have the know-how to replace the cable connectors.

tarwheel - I'd be interested in your old light. Send me a PM if you decide to sell it.

tcpasley

Reduce, Reuse, Rebicycle

Regarding connectors dying, I find it's worthwhile to put some electrical contact grease on anything that might possibly be exposed to the weather. It used to be that every time I've gotten a new car, I pull off all the electrical connectors and spray contact grease in there. I never had an electrical problem.

These days car makers spray the grease in at the plant.

Also, if you have a faulty connector, you can buy a 1 meter extension cable which has one female and one male connector on it, and replace both of them in 10 minutes with a soldering iron and some electrical tape. DX sells these cables for $3.60 I think. I bought a couple just for spares and so I could put the battery in the bottom of my pannier if I wanted to. I also picked up some spare Y cables also < $4.

I think the manufacturers in China will make just about anything you want them to make. They can make batteries as good as anyone else, I mean quality and features. In fact, they make certain components for the aerospace industry. Its all about the specifications and the testing afterwards.

With the knowledge right here in this forum, a engineer type with business sense, can actually get something going. The Sears-Roebuck analogy was meant to be a figurative expression of how the American consumer tends to think: good, better, best. If the Geoman organization would venture out this way, their strategic planning, I think it would be even more successful.