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Looking for a LIPION charger...

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Looking for a LIPION charger...

By madcat207
-  Tue Mar 14, 2006 12:16 pm #11037
Hello!

Recently, i came across a spare battery back that was not being used ( and was considering using on a future GPS Data Logger). It is in great condition, and looks to be usable. The one problem is, i have no way to charge it. The tails have never been soildered, so they are nice, but I have no specific hardware to charge it otherwise.

I looked around, and so far, have come up pretty short on actual boards for this. Any advice guys? Would i need to make something from scratch, or is there a product i am missing.

Thanks!
-Daniel

By madcat207
-  Tue Mar 14, 2006 1:31 pm #11040
I did see that, but admittedly, I am not too sure how i woul duse it. I have only a basic background in actual circuit design, so i am not sure what i would really need to do to make it work.

By Philba
-  Tue Mar 14, 2006 2:30 pm #11043
look at the datasheet. It has an incredibly simple circuit for the this chip. Except for soldering an SOT, this would be as easy as falling off a log.

No battery temperature monitoring, though.

By geekything
-  Tue Mar 14, 2006 3:40 pm #11044
I just ordered a few of these, and will be making my own chargers. They are by far the simplest IC I've seen for this application! USB charging is a very nice bonus for my application.

I really don't think you need to worry about the lack of battery temperature monitoring -- they do temperature monitoring of the die itself and then ramp down the charge current. Also bear in mind the manufucaturer doesn't think that thermal shutdown will *ever* occur with USB as a source (and I tend to agree).

I'll post pics once I get this project off-the-ground!

-marc

By madcat207
-  Tue Mar 14, 2006 4:25 pm #11047
geekything wrote:I just ordered a few of these, and will be making my own chargers. They are by far the simplest IC I've seen for this application! USB charging is a very nice bonus for my application.

I really don't think you need to worry about the lack of battery temperature monitoring -- they do temperature monitoring of the die itself and then ramp down the charge current. Also bear in mind the manufucaturer doesn't think that thermal shutdown will *ever* occur with USB as a source (and I tend to agree).

I'll post pics once I get this project off-the-ground!

-marc
Marc-

Any help you could post would be great. I hate to sound so amerature-ish, but the community is nice here, so I have come out of my shelf. Anyway- anything you could suggest. Or- if you would be even willing to sell one, i would be a willing buyer. :)

-Daniel

By geekything
-  Tue Mar 14, 2006 4:45 pm #11049
Daniel,

Sure...I'll share what I can come up with. I was planning on making a little board that'll charge via a DC jack or USB and has alligator clips for charging the LiIon/LiPoly pack. Then doing the "reflow skillet" assembly ;-)

-marc

By madcat207
-  Tue Mar 14, 2006 5:29 pm #11052
geekything wrote:Daniel,

Sure...I'll share what I can come up with. I was planning on making a little board that'll charge via a DC jack or USB and has alligator clips for charging the LiIon/LiPoly pack. Then doing the "reflow skillet" assembly ;-)

-marc
Marc

Thanks! I greatly appreciate it! 8)

-Daniel

By Philba
-  Tue Mar 14, 2006 9:40 pm #11065
I almost posted that the die temp monitoring solves the battery temp monitoring issue but it doesn't. Over temp situations should suspend trickle charging completely. the maxim device only proportionally reduces the charge rate after the die temp reaches around 70C. I don't think that really buy you much beyond short circuit protection. Everything I've read recommends suspension of charging (fast charge or trickle) when the battery reaches 40C (some say 50C).

I agree on the USB powered limitation but powered from a wall wart could be an issue.

By madcat207
-  Wed Mar 15, 2006 11:45 am #11092
Philba wrote:look at the datasheet. It has an incredibly simple circuit for the this chip. Except for soldering an SOT, this would be as easy as falling off a log.

No battery temperature monitoring, though.
I did take a look at the datasheet, but as i said, i have only basic expereince (i mean, i took an EECE class a while ago, and learned only about simple logic gates- And/Or/Mux/Etc.). And while i am sure it is easy once you know how, it is still a little confusing starting out.. Not to mention, i dont think i can solder anything that small... :?

By geekything
-  Wed Mar 15, 2006 6:30 pm #11116
Philba wrote:I almost posted that the die temp monitoring solves the battery temp monitoring issue but it doesn't. Over temp situations should suspend trickle charging completely. the maxim device only proportionally reduces the charge rate after the die temp reaches around 70C. I don't think that really buy you much beyond short circuit protection. Everything I've read recommends suspension of charging (fast charge or trickle) when the battery reaches 40C (some say 50C).

I agree on the USB powered limitation but powered from a wall wart could be an issue.
I think you'll find that as the battery gets warmer (dissipates heat), the load for the charger IC will increase, and as the load increases, the die gets hotter. :)

In other news, I've made an Eagle part for the MAX1551 if anyone wants it, PM me.

-marc

By Philba
-  Wed Mar 15, 2006 8:25 pm #11122
even with trickle charging? I'm not so sure. It's a pretty barebones LIION charger IC.

By madcat207
-  Thu Mar 16, 2006 8:47 am #11141
geekything wrote:
Philba wrote:I almost posted that the die temp monitoring solves the battery temp monitoring issue but it doesn't. Over temp situations should suspend trickle charging completely. the maxim device only proportionally reduces the charge rate after the die temp reaches around 70C. I don't think that really buy you much beyond short circuit protection. Everything I've read recommends suspension of charging (fast charge or trickle) when the battery reaches 40C (some say 50C).

I agree on the USB powered limitation but powered from a wall wart could be an issue.
I think you'll find that as the battery gets warmer (dissipates heat), the load for the charger IC will increase, and as the load increases, the die gets hotter. :)

In other news, I've made an Eagle part for the MAX1551 if anyone wants it, PM me.

-marc
Im not sure what you mean by Eagle part, but i am still interested in this whole thing... :D

By geekything
-  Thu Mar 16, 2006 10:58 am #11148
madcat207 wrote: Im not sure what you mean by Eagle part, but i am still interested in this whole thing... :D
Eagle is a freeware PCB layout package from Cadsoft in Germany (http://www.cadsoft.de).

If you wanted to make your own circuit boards, you'd use something like Eagle.

I made a part for the MAX1551 IC so that Eagle "knows" about this chip.

I'll have a circuit finished fairly soon.

-marc
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