iforgotmename

I went to a local battery company to see about a rebuild and he said that there was not a protective circuit in the pack. Seems like that could be a problem. I had him take it apart to give me a rebuild quote, which was $60. I looked for a replacement cell and they seem to average around $40. For the extra $20 I'll probably just have him build me one with the extension cable that came with the light. As far as the light goes one eveniung I had a car slow down to tell me how much they liked my tail light. The next day I actually had a guy pull over and wait to ask what kind of head light I have so he could get one. If it's just a battery problem the light is still a good deal in my opinion.

iforgotmename

link?

Richard Cranium

Hey folks - batteries aren't rocket science.

I could go all "legal" and spell out what and why Geoman quit selling - but the simple facts are some products have liability issues and if the manufacturer/distributor doesn't have the insurance - they ARE screwed.

I've played with four sets of MS lights, one light burned out - but all four batteries appear to be of good quality.

So what. Some ****er bangs his battery - starts a fire and BAM - no more Geoman sales - so what.

electrik

Damned ****ers!!

dougmc

https://www.dealextreme.com/details.dx/sku.19770 $6.35 for two unprotected cells.
https://www.dealextreme.com/details.dx/sku.5790 $8.01 for two protected cells.

I have not torn my pack apart, but I'm guessing it's made of the two protected cells (with four cells total.) (The protection here refers to a tiny circuit that stops the cell from being discharged or charged too much. It sits at the end of the cell and is pretty easy to miss.)

If I were to make my own packs, I'd probably buy the unprotected packs ($12.70 total), solder two cells in parallel, then another, then put those in series, adding a balancing tap in the middle while I'm at it, and then I'd use my balancing R/C charger to charge it. I'd also scan DX's site for a 2s protection circuit, one that will cut off at >8.4 volts and <7.2 volts or so -- not essential, but a good idea. It's also possible that they sell something that does balancing as well -- if so, that would remove the need to use my balancing charger at all.

darkrider2

Some of what I am reading about rebuilding MagicShine packs is scaring me. Li-ion packs are a bit of rocket science. First, the MS packs do have a balancing circuit in them that assures each pair in the 2x2 pack is not overcharged or over discharged. However, because there are pairs in parallel, it is VERY important that all the cells in the pack are closely matched in full charge voltage and capacity. Otherwise the packs will quickly degrade. This is one of the main problems with the older MagicShine packs. So unless you have a battery analyzer and a large batch of cells to pick from I would not advise building your own pack. Now you could easily build a 6 or 7 cell NiMH pack and have something easier to manage and safer.

Cyclist0383

The cheap cells (ones from DX et al) are often recycled cells from laptop packs. There are several well documented threads on this over at CPF. People have taken the wrappers and nipples off of DX cells and found where they had previously had been soldered in a series.



https://www.candlepowerforums.com/vb/...5&postcount=21

balto charlie

Didn't know this, thanks. My first use of lithium batt. I have always been a NiMH or lead kinda guy.

balto charlie

I'm liking these batteries less and less. I doubt that I'm going to hang around watching my battery evry evening. Most evenings I could turn it off before bed but on nights when I roll in late I plug it in and go to bed.

So:
I guess I should put in in a "fire ' proof container when charging connected to some type of surge protector plug?

OR make a pack of NiMH. Will I get 2.5 hours on 4 AA NiMH 2700ma?

I'm not going to baby sit my batteries,just ain't gonna happen.

colleen c

You can charge them on a fire resistant surface or on top of a tile floor. If you don't have those, you can place a piece of Sheetrock, several piece of Tiles for flooring or even a left over Wonder Board will work fine. Make sure the surrounding and whatever above is clear of flamable material. I used to leave my charger in top of my Marble floor until the cat kept messing around with the battery/charger. I broke down and bought a $25 fireproof lock box from Amazon and do all my charging there. You can also put a timer on you charger and set it for several hours as a safeguard. I also store my 18650 battery individually in home made 3/4 PVC pipe so that if one does vent by itself, other cell will not catch fire. I heard of others using surplus Ammo box lined with Sheetrock. At worst case, an old heavy pot or even an old slow cooker pot will work if it comes down to that If you do charge 18650 cell(not pack), get a Pila charger. I got one and it is so much better than my DX, Cytac, and an unkown brand charger from Ebay. Those China made charger has an OCV of 4.23v and tops off the battery at 4.22. Way to high and is overcharging them. The cytac from 4seven is better but not as good as a Pila.

colleen c

Depends on what light you are using. NiMh has a nominal volt of 1.2 although mime sit at 1.3 to 1.4v. Four cell is only about 4.8v and a light like a MS will not even turn on. You will need probably 6 MiMh to get about 7.2v which should be fine for the MS (I'm guessing). They do sell 6 AA battery holder at Battery Space. At 2700 mah, it should run 1.5 hours. To get the same potential as a MS pack, I think you will need 12 NiMh wired 2ea of 6 in series and parallel them?? That's why LiIon is here for a while.

dscheidt

You can buy four battery shaped objects for 16 bucks. You may, or may not, get a lithium battery. It might work. It might not.
DX doesn't give a flying leap about quality; neither do their suppliers. If you do get four working cells, you won't get four cells that are well matched, and they're even less likely to stay matched after a dozen charge cycles.

It's exactly that sort of crap cell that's causing problems in the magic shine (and lots of other POS cheap chinese electronic junk, too.)

no motor?

I have heard from Geoman QC again, and they said they are going to get me a replacement battery when they are available. I replied to the original address after getting an email that showed my address as the source, did you try that?

tuxbailey

I will give it a shot.

MarvelousMark

MS may not be recycling batteries or doing something deliberate to decrease the performance and reliability. Lithium-Ion batteries are fickle. Unlike NiMH or NiCD, L-Ion will lose their charge over time whether you use them or not. So they'll die in 2-3 years anyway. And the charge curve seems more like a charge cliff, where suddenly the performance drops off, not tapers off.

MS could have screwed up the batteries by violating two rules: 1) Storing them at a full charge (they ideally should be at a 40% charge level and 2) Storing them at high temperature. So they could have a bad run of batteries because they had them in a hot warehouse all summer.

Richard Cranium

Huh?

I find your remarks poorly stated and inaccurate. The only statement even close to true is that the implication that "heat" damages batteries. Li Ion technology is favored for it's low self-discharged character.

You are confused.

Richard Cranium

And I've already run a MS on low mode using 4xAA for an all night ride. I used three sets of throw away Alkaline from the dollar store. They cost three bucks.

dougmc

"Battery shaped object". Clever.

I've bought quite a few 18650 cells from DX. One was indeed bad -- the other 15 or so were just fine. DX replaced the bad one with no trouble -- I got a new pack (so I got a free cell out of the deal.)

I've only explicitly measured the capacity of a few cells, but the ones I did measure all worked out to be 2500 mAh (the rated capacity) or a bit more. Even the ones that I didn't measure have performed similarly in flashlights, so I expect that they too would perform similarly if I tried to measure it.

You must buy different batteries than I do. Mine have been great.

tuxbailey

I also got a reply from them about battery replacement once they get the new ones from the manufacturer. Considering that hasn't failed, this is pretty good, proactive customer service.

dscheidt

you've got better luck than I do. Battery shaped object is entirely accurate from the cells I've seen from DX. allegedly protected cells with no protection IC at all. Cells that have zero capacity after a dozen cycles.

By your own numbers, they've got a 6% DOA rate. That gives you about a 75% chance of being able to build a battery pack that works, since you need four working cells. You really need four cells that have very similar properties, which you're even less likely to get. We don't know what failure rate Geoman have been seeing in their packs, but I'd bet it's a lot less than 25%.

dougmc

I've never gotten any batteries from them that were not batteries. (I did get a PSP charger that was an exact copy of the Sony version, except that it had no electronics in it whatsoever about a year ago, however.)

The one cell that was bad wouldn't even charge. Since I want similarly charged cells when I make a pack, they get charged first. So the odds of a working pack go up towards 100% again, as I'd notice a totally bad pack before I made it.

(Since I solder rather than using a spot welder, the odds are likely higher that I'll ruin the cell myself than it'll be bad before I get it.)

As for the cells matching, their capacity can be off 10% without much trouble -- the balancing and protective circuit will take care of it (though your pack will have the capacity of the lowest rated cell if it's all in series, it gets more complicated if they're in parallel too like the Magicshine pack). All of the ones I measured were within about 3% of each other.

Dunno. Hopefully the packs at least get a smoke test before they're shipped.

Richard Cranium

This thread has gone beyond the "bogus" limit - back away from your keyboards and leave your mice alone - and nobody gets hurt...........

balto charlie

Thanks. I will use an old ammo box from my canoeing days. I'll charge them on my basement floor. Shame as I have a nice wooden table set up for everyday charging. I could also build an asbestos box for the top of the table

no motor?

Yeah, that's what I think too.

kudude

If they come through