Li-Ion Charger IC for $1.66

[LED_ASAP]

If DAT2ZIP can make a quick trip to his sales rep and get some samples that would be great. But please do this as a private group buy and not just add to the Sandwich Shoppe---the S&H charge from there is pretty high, too /ubbthreads/images/graemlins/icon3.gif If he can not find enough time to organize this group buy, I would suggest some one in the US volunteer to do so (yeah, the international shipment from Linear is high; and it just doesn't make sense for me to buy a whole lot, facing the taxes, and shipping most of them back to the US /ubbthreads/images/graemlins/icon15.gif )

The next logical thing would be to have some one organize a group buy for various sized and shaped Li-Ion cells to use with these IC's---maybe even those flat ones that have welded leads instead of regular buttom terminals. Then we can envision some self-contained lights that have the charger built right in, leaving only two contact points for an external power source, maybe as simple as the USB port on your computer /ubbthreads/images/graemlins/naughty.gif

 

[dat2zip]

OK, I got confirmation that I will get the samples. I don't have a target date. It would be prefereable if I keep a few and send the rest to someone like maybe CM or someone who could handle the group distribution.

This is not part of the shoppe.

Just let me know what I should do with the parts or who to send them to. I have requested 10 and plan on keeping a few.

I can request to will call them next week but the delivery time is one day from the sales office to my house so unless there is some urgent need for them the extra day probably won't kill anyone.

I will post when I get a delivery date or when they show up on my doorstep.

I would be interested in any other group buys on batteries if any crop up.

 

[Klaus]

Wayne,

seems the last Li-Ion group buy was kind of disheartening - people are still waiting for some sizes and some others had high failure rates it seems - so possibly it would be better to wait a little bit how that works out. I will be visiting some places in Asia related to Li-Ions (being used in Notebooks) later this month and maybe (just maybe) can arrange a contact for Li-Ions for us - we´ll see how that works out.

Klaus

 

[shiftd]

[ QUOTE ]
Klaus said:
Wayne,

seems the last Li-Ion group buy was kind of disheartening - people are still waiting for some sizes and some others had high failure rates it seems - so possibly it would be better to wait a little bit how that works out. I will be visiting some places in Asia related to Li-Ions (being used in Notebooks) later this month and maybe (just maybe) can arrange a contact for Li-Ions for us - we´ll see how that works out.

Klaus

[/ QUOTE ]

that is GOOD news, klaus /ubbthreads/images/graemlins/grin.gif

at first i feel sorry bec i missed the groupbuy, but looking at the post feedback, i think i would not miss it after all. Looking forward to the news from you /ubbthreads/images/graemlins/grin.gif

Btw, wayne. I am in this one too. Please put me for one. /ubbthreads/images/graemlins/grin.gif

 

[Phaserburn]

Klaus, that sounds very promising, going to the source. Good for you and thanks in advance! /ubbthreads/images/graemlins/thumbsup.gif

 

[CM]

OK, I guess I'll handle the distribution. I want to limit the quantity to two pieces each (sound fair I hope). So far I have in

Klaus
Bart
KK
LedsAs...

I think the sample quantity will all be spoken for with these guys. If there's not enough, someone will get a single quantity or none. In any case, a group buy may still be in order.


Re: battery group buy. I'd prefer if we had a domestic source. Most sources are based in the far east, there is one that has a domestic office. It's

http://www.sabahoceanic.com/lithium.html

Their sizes are kinda limited, but we don't have to pay exhorbitant low quantity surcharges. They do charge $12.00 for shipping which we can amortize through the group.

 

[highlandsun]

I've ordered a laptop battery from Sabah before; they're OK to deal with and they have the latest Panasonic LiIon 18650s which is a good thing. They don't offer LiIons in AA or AAA size which was my original motivation for ordering direct from China.

As far as I know, the 18650s, 18500s, and AAs we received from Hyper have all been up to spec. We had problems with 17670s, which they already advised us were not a popular item in their lineup, so I'm not going to hold that too much against them. They tried to talk me out of ordering them, now I know why. The only sticking point is the AAAs, which of course is all I wanted in the first place; I only ordered the other sizes as a favor for the folks tagging along on the buy.

If anyone is seriously interested, we can get 1000 Minamoto LiIon AAs for $1720.00, plus $168 express shipping. That's $1888.00 total, $1.89 per cell. 1000 AAs from Hyper is $2610.00 total. 1000 18650s from Hyper is around $3200.00. Now you know the kind of markup that Sabah Oceanic is passing off to you.

Also for comparison, the Minamoto AA is a flat top, the Hyper AA has more of a button top. Minamoto is 19g, Hyper is 26g in AA. Minamoto spec'd at 650mAH, tested to 775mAH. Hyper spec'd at 750mAh, tested to 777mAH. (Essentially equal performance.)

 

[LED_ASAP]

Mmm, I didn't realize those Li-Ion AA's have such a low capacity---even considering the higher voltage they offer, that's still lower per-volume energy density than a regular alkaline AA /ubbthreads/images/graemlins/confused.gif Did I miss something?

 

[CM]

Howard,

What do you use the AA and AAA's for? I was gonna order some originally but didn't know where to stick it. (OK, guys, KNOCK IT OFF! /ubbthreads/images/graemlins/grin.gif )

CM

 

[CM]

As promised, I made a mockup of an LTC4054 charger. This one will charge a single cell at 714mA (1.4k program resistor) It doesn't have a real part in there, I just tacked on a SOT-23 tiny logic chip in there for illustration. The circuit's ready to go as shown except for the IC. When I get the chip, I'll just replace the IC, hook up wires to supply and battery holder and I have a CC-CV Li-Ion charger. I'll hook up a LED charge indicator later, it's set up for that. (Sorry for the fuzzy image, macro setting doesn't work very well)

CM

 

[highlandsun]

I'm using 6 of them in 3 MiniMags with InReTech white, blue, and green adapters. With two AAs connected in parallel I get 4 hours runtime on a full charge for each light.

LEDasap - no, they don't come anywhere close to alkaline primary cells but that's not the point, since they're rechargeable. They have only marginally higher energy density than NiMH, but the advantage of the higher voltage is still significant. For example, if you have 3 2200mAH NiMH batteries in series, on a full charge you'll get ~3.9V @ 2200mAH. 3 LiIon AAs in parallel will give you ~4.1V @ 2250mAH. Also, given their low self-discharge, I don't have to think about recharging them more than once every 6 months if they sit unused.

Another point - the Maha 2200mAh NIMH cells just came out recently, and they cost $17 in a 4-pack, about $4.25 each. I ordered these AAs from Minamoto a year ago, and they were only $3.20 each delivered to my door from Hong Kong (in bulk they would cost half that...). I've been happily using them in various projects for a year now, while most people are still debating whether to jump at these new NiMH cells.

When (if) I get the AAAs I plan to convert my Mag Solitaire to a Luxeon. (With help from LEDasap in fact.)

 

[shiftd]

dang, i missed on this. /ubbthreads/images/graemlins/frown.gif
CM, if you get spare, put me down for a couple, ok? /ubbthreads/images/graemlins/grin.gif

 

[kingkong]

I open an old Compaq laptop battery(LI-ON), and it has some 1860(1760??) cell on it. I will try to charge this when get the IC.

Cuong.

 

[CM]

shiftd,

If you miss this, there may be a group buy brewing /ubbthreads/images/graemlins/smile.gif I'm trying not to hog the samples so I'll need more than what I've allocated for each of us. Regardless, for 1.66 each, they're durn cheap even with the shipping. Just think, how much did you spend on LED's in the past month? /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif

OK, shiftd is next in line.

CM

 

[shiftd]

[ QUOTE ]
CM said:
shiftd,

If you miss this, there may be a group buy brewing /ubbthreads/images/graemlins/smile.gif I'm trying not to hog the samples so I'll need more than what I've allocated for each of us. Regardless, for 1.66 each, they're durn cheap even with the shipping. Just think, how much did you spend on LED's in the past month? /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif

OK, shiftd is next in line.

CM

[/ QUOTE ]

That is great news /ubbthreads/images/graemlins/grin.gif
yep, this is a great valued one /ubbthreads/images/graemlins/frown.gif
so sad that i missed this one

 

[Klaus]

/ubbthreads/images/graemlins/bowdown.gif CM,

circuit looks really nice - whats the big one on the left side - the cap ? In regards to AA LiIons I had the same feeling - the Sanyo 2100ma NiMhs have the same energy density and I can get some around 2.xx bucks - and charging and handling them is a no-brainer - still the higher voltage will certainly come in handy for certain applications, like an ARC AA, Infinity or MMM LS single cell mod. But the LiIons especially in the larger sizes have a much bigger appeal to me - and the L4 just cries for the 17650s - and two 17500s are a nice fit for any UBH or 3-123 body as well. Still thinking about the old bored out fat AA2A LS ARC pack for one 17500 too - need to be careful not to discharge too low though.

Klaus

 

[B@rt]

Thanks CM, /ubbthreads/images/graemlins/thumbsup.gif I'll be looking forward to any further info. /ubbthreads/images/graemlins/wink.gif

 

[CM]

That big part on the left is a 10uF tantalum cap.

I made the ckt using a double sided copper clad board and I cut the pads using an X-acto knife. It's a very simple pattern to cut for DIY. The pinout of the SOT-23 facilitates layout--thank you linear. You could even deadbug an IC on a breadboard, but you need to make sure you keep the supply voltage around 5V since this is a linear IC and it will dissipate power.

 

[Klaus]

Thanks Chris,

hmmh - any specific reasons (besides on hand parts) to use such a large 10uF part with Linear using just an 1uF in all the example designs ? This is what made me wonder as I thought a 1uF cap would be quite small and yours looked so large (just talking about the cap though) /ubbthreads/images/graemlins/grin.gif

Klaus

 

[CM]

Klaus, I had 10uF on hand so I just used that. No reason other than that. I agree the part is large but it's not going into your pocket so size doesn't matter. (OK, again, knock it off you guys /ubbthreads/images/graemlins/grin.gif)

Cris