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Old Apr 11, 2002, 05:35 PM
Hornet Basher
College Station, TX
Joined Jan 2002
460 Posts
How can I charge li-ions w/o an expensive charger??

I have some 45g 1600mah li-ion cells But the protective circuit is for 14.4v so I can't use it at 7.2 (or maybe I could If I doubled up the cells what voltage would I use? Is it like 4v per cell x 4 cells 16v?) Anyway, is there any charger that is cheap (like 10$?) for charging the cells w/o a prot. circuit?
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Old Apr 11, 2002, 06:35 PM
Dimension Engineering
Akron, Ohio
Joined Jan 2002
1,705 Posts
If you're got a bunch of connectors handy, there's one thing you can do

Obtain a qualcom charger and at least one qualcom pack

remove the protective circuit from th qualcom pack

take the protection curcuit and wire connectors to the + and - battery points

put individal (not paired) conectors on sets of two cells (take your pack apart) in series. charge each of these separately, then put the packs in series and into your plane. Proceed to fly.

take you about 4 hours per charge though
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Old Apr 11, 2002, 07:14 PM
Hornet Basher
College Station, TX
Joined Jan 2002
460 Posts
what voltage would you charge a li-ion battery at (4, 4.5??)?
Would the protective circuit on the batteries regulate the voltage?
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Old Apr 11, 2002, 09:13 PM
"Simplify, then add lightness"
Raleigh,NC
Joined Nov 2000
2,701 Posts
I would strongly suggest that you get a proper charger before using these cells. They can explode violently, or vent large flames if not handled properly. The protection circuit board is not part of the charging circuit, it's function is to prevent damage through excessive charge or discharge. The cells are not simply charged at a constant voltage. They require charging at a constant current, until the cell voltage reaches a certain level, and switching to a constant voltage, sensing to make sure that an over discharged cell is not charged, and a cutoff so that they are not constantly trickle charged. There are circuits diagrams on the web that meet some of these requirements. If you have the skill to build one, you should be able to search the archives and find them. If not.

http://www.hobby-lobby.com/chargers.htm POT010 $25
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Old Apr 11, 2002, 09:29 PM
Registered User
Surrey, BC Canada
Joined Apr 2000
649 Posts
Could not agree more with the last post. Li-Ion cells are VERY,VERY fussy about the charger they are attached to. So much so that they have and can be very explosive. The correct constant voltage and the correct constant current must be used.

Having said that, when the correct charger is used, they are just like any other cell that we use.

Robert.
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Old Apr 11, 2002, 11:12 PM
Fish & Fly
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Tyler, TX USA
Joined Jul 2000
1,406 Posts
Listen to Jeffs555.

That little $25 Hobby-Lobby Li-Ion charger (made by Potensky, for 2 cell packs) works very well.
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Old Apr 11, 2002, 11:17 PM
Registered User
Bleriot's Avatar
Joined May 2000
2,837 Posts
Howdy Ya all! , try www.homefly.com 1,2 or 3 cell LiOn charger for $45 shipped. Best Regards
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Old Apr 11, 2002, 11:33 PM
Dangerous
Spaulding's Avatar
LA
Joined Nov 2001
871 Posts
Oh fooey. Just hack into any old li-ion camcorder charger and you are golden!
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Old Apr 11, 2002, 11:41 PM
Registered User
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Joined May 2000
2,837 Posts
Quote:
Originally posted by Spaulding
Oh fooey. Just hack into any old li-ion camcorder charger and you are golden!
You're overlooking the fact that not everyone may be as comfortable"Hacking into" electronic equipment as are thou and may be a "Plug and Play" hobbyist. Best Regards
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Old Apr 11, 2002, 11:54 PM
Dangerous
Spaulding's Avatar
LA
Joined Nov 2001
871 Posts
Oops. I meant to say, "just kidding". Plug and play with li-ions, now that is something to try! Hey, I thought someone was going to videotape a li-ion cell blowing up? Did that guy blow up with the cell?
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Old Apr 11, 2002, 11:58 PM
Crash Master
Gene Bond's Avatar
Indianapolis, IN
Joined Sep 2001
16,632 Posts
http://thomas-distributing.com/mh-c2000.htm
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Old Apr 12, 2002, 12:11 AM
Dangerous
Spaulding's Avatar
LA
Joined Nov 2001
871 Posts
Yeah that 2000 looks like it needs some hacking to work for any pack. I have been considering the c777plus for awhile because it is more suited for r/c packs and would not require much hacking. It is double the price as the 2000 and it takes a long time to charge li-ions(limited to 400mah).

http://thomas-distributing.com/mh-c777plus.htm
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