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Old Mar 22, 2003, 04:30 PM
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Summerville, SC
Joined Mar 2003
19 Posts
Cheap Radio Shack Chargers and L-I's

A nearby Radio Shack is a wharehouse clearence center. I just bought a a/c cell phone charger/discharger which charges ni-cad, nm-HI and Li-ion. for $5.00. It claims to balance and condition the cells. It has two slots, one for phone, one for spare batt. It states on the back that the phone slot output is 4.6-5.6v at 1100mah and the battery slot is 7.3-8.9v at 495mah. Can this be converted for "our" use ? If so where can I find some direction? Also for sale was a basketful of cell phone batt. Mostly Ni-mh and Li-ion. They wanted $10/pack regardless of size/output etc. Good price ? or should I look around here?
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Old Mar 22, 2003, 04:55 PM
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Broomfield, CO 80023
Joined Dec 2002
354 Posts
I don't know anything about your question, but I'd like to connect as I'm in Summerville also.

Give me a call at 851-0678

JOhn C
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Old Mar 23, 2003, 07:06 AM
RIP "Long Shadow Flyer"
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Upstate New York-- Rochester, NY USA
Joined Oct 2001
732 Posts
I am not sure about your charger conversion, depends on what you are planning on charging. Nimhs and Li-ions have very different requirements.
I have locked in on 6 cell packs for my Nimh, about a year ago I picked up a bunch of close out 7.2v wall chargers from Radio Shack, they put out 150mA, a 1200mAh Nimh battery pack takes about 8 hours to charge. A long slow charge (1/10C) is better for Nimhs.
Recently due to a post on this site picked up some "blow out" Li-Ion NOKIA cell phone batteries at Best Buy for only $1.99ea. Was going to build the cheap charger discussed on this site, but the kind clerk at the store showed me some "blow out" cirarette Lighter chargers he had for the Qualcomm Q phones ($.97). I bought all 6 that he had. Cat. #273-1229A. I have hooked 4 of them to a 12v supply and charge 4 batteries at a time. These work great with the Best Buy batteries....
I think the batteries at $10 a pack are a bit expensive for "blow out" items... Keep an eye on The Electronic surplus market, soon there will be a lot of cheap li-ion, and Li-poly batteries.

Here are some currently aviailable:
http://www.sciplus.com/category.cfm?subsection=13

28985 6V NIMH BATTERY $2.75 / EACH I have made packs from these batteries... http://home.rochester.rr.com/carlvogt/batteries.htm

Have not used these myself, but check other posts on this site..
http://sales.goldmine-elec.com/prodinfo.asp?prodid=3430

Hope this Helps,
Carl
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Last edited by crvogt; Mar 23, 2003 at 07:16 AM.
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Old Mar 23, 2003, 08:49 AM
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Summerville, SC
Joined Mar 2003
19 Posts
Carl, Thanks for the help. I guess you dont think the charger I got will work with Li-ions?

John, I live in Newington and fly at the elementary school,
My name is Cal 871-0133
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Old Mar 23, 2003, 11:50 AM
RIP "Long Shadow Flyer"
crvogt's Avatar
Upstate New York-- Rochester, NY USA
Joined Oct 2001
732 Posts
Not sure if your charger is ok for Li-ions or not. IMPORTANT!!! Read the many posts on charging LI-ion batteries, they are fussy on charging and may be Dangerous if not properly charged,,,,, The typical voltage is 3.7per cell with the max voltage for Li-ions 4.2v per cell, or 8.4 for a 2 cel pack. Only If the output can be held below the max, when the pack charges it could work. Be Careful!!!!

Carl
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Old Mar 23, 2003, 05:04 PM
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Summerville, SC
Joined Mar 2003
19 Posts
The box claims it will charge and condition li-ions. I'll read the threads and see what I can find out.
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Old Nov 12, 2008, 04:17 AM
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658 Posts
Use that RS charger for 2s (7.4v) packs. It should be perfect, but not for a 3s (11.1v) pack as you need 12.6v output for a 3s. $5? Good deal! READ the booklet that came with it and try to discern if it is a "cascading current charger", where the VOLTAGE out is constant BUT the CURRENT output goes DOWN when they near top off. And FYI: They are glorified car battery chargers to begin with, because car batteries are charged with varying current output chargers.

Now as to these BATTERIES you're getting ripped off on: Go to Home Depot and look through their battery disposal collection box and look for the NEW sealed/unused phone batteries which the store disposes of because they are past their sale date code. That is IRRELEVANT if they are sealed in the package and never used. I picked up (6) 1200mA NiMH packs from there!
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Old Nov 12, 2008, 04:24 AM
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658 Posts
For a 2s LiPO pack (7.4v), that charger needs to be 8.4 volts output. NO LOAD by the way. Since it's ONLY .5 amp output, you're gonna be waiting awhile regardless.

Example:

2s LiPO pack @ 1000mAH: with 8.4v @ 495mA charging input...

1000 / 495 = 2.02 Hours!

2s LiPO pack @ 1000mAH: with 8.4v @ 1200mA charging input...

1000 / 1200 = .83 Hours!

Okay, so ya got a DEAL then? For the SAME MONEY you could have got one of these.
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Last edited by heli_ebook; Nov 12, 2008 at 04:33 AM.
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