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Old Jan 09, 2002, 06:28 PM
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Neptune Beach FL USA
Joined Nov 2000
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Lithium Battery Charger??

Does anyone know where to get a lithium-ion battery charger that will charge more than two cells? One that has a variable voltage output. I need one to charge 3 or more cells in series.

Thanks John Moler

Email me at: johnmoler3@yahoo.com
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Old Jan 09, 2002, 08:32 PM
Our Daddy and Heli Junkie
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The Orbit V6 will do up to 9 3v lthium cells.


http://www.orbitronic.de/model/e_produkte.html


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Old Jan 10, 2002, 05:04 PM
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Thanks Fred.
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Old Jan 11, 2002, 08:51 AM
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Pensacola Regional, Florida, United States
Joined Jan 2002
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I'm really interested in buying an Orbit for my charging needs. I know it allows you to charge litium ion but does it allow you to charge them as cells only (removing the safty circuits)?

I already have a sony charger that I'm going to modify with connectors, but Im assuming it will only work with the specific battery it was designed for (7.2v 1100 mah).
I just reciently purchased some 7.2 600mah lithiums for my stick and am nervious about charging them with the same charger. I'm thinking of creating some connectors and quick wiring them in series to allow for the added amperage of the sony charger. Will this work?
Another idea is to leave the safety circuit in the 600mah cells and charge them with the sony charger with no other mods. The safety circuits are for current limitation right? If so the charger is designed to shut off at the right voltage so I should be ok???

Also does anyone have any experience with a lite stick s and the 1100 mah cells? Will it fly leasurly? I think it would as they aren't much more weight than the nicad supplied with the flight pack...

I could avoid all of these headaches if the orbit allows charging different lithiums (mah) without the safety circuits.....
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Old Jan 11, 2002, 10:40 AM
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Sunnyvale, CA
Joined May 2001
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Hi rakm. Yes, the Orbit does allow you to charge lithium cells without the safety circuits. The current is adjustable, and I regularly charge 830mAh and 1400mAh cells at 1C. All of my packs are made up of 2 cells, and the Orbit charges them just fine. Note that it cannot however determine the voltage on each cell when charging them like this; this could be a problem if the cells charge/discharge at slightly different rates (you may end up over-charging one of them). I put a tap in the middle of the pack and for the first charge I charged each cell individually. After every couple of flights I check the voltage of each cell to make sure they're exactly the same. So far they have been, but they're ever different I'll just charge each cell separately again to get them back to the same level.
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Old Jan 11, 2002, 11:00 AM
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United Kingdom, Bracknell
Joined Nov 2000
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BTW the 2001 versions of the Schulze ISL 6 series chargers also charge 1-3 cell Li Ion (10.8V) or 1-3 cell Tadiran (9V). See:

http://www.schulze-elektronik.com/isl6-e.htm

The Orbit is cheaper though.
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Old Jan 11, 2002, 12:02 PM
nothingtosay
Vaasa, Finland
Joined Oct 2001
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Its waaaaay better to charge 1cell at a time. If the other cell(s) is unbalancer, you might hurt them!
I mean that if the voltage drops too low on the other cell like this:
--> 1.Cell voltage is 2,7, an 2.cells voltage is 3,0!
so it overcharges/discharges the 1.Cell!
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Old Jan 11, 2002, 12:29 PM
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With the low draw used on Lithium cells, plus only using 2-3 of them. And you NEVER discharge a lithium past 2v.

Charging them in series should present no issue at all.
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Old Jan 11, 2002, 01:11 PM
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Pensacola Regional, Florida, United States
Joined Jan 2002
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First of all thanks for the informative responses. I'm really leaning to the orbit now because charging the individual packs without the added circuitry is VERY appealing to me. Is the link above the only place to purchase or are there other sources?

I have to agree with Fred. The reason I say this is because I'm sure the sony charger, fit for commercial consumption, doesn't check each cell. Unless the circuitry built into the battery packs protects against this.

Back to the other question, does anyone know if the built in circuitry in the packs will protect against the charger putting out to much current. The way I've read it is the charger limits the voltage and the circuitry limits the current. Is this correct? If so then I could feasably use the sony charger thats designed to charge 7.2 1100 mah to charge 7.2 600 mah cells, providing I charge through the batterie packs circuitry...
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Old Jan 11, 2002, 02:12 PM
"Simplify, then add lightness"
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Joined Nov 2000
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Rakm,
The circuit on the top of the battery is purely a safety circuit, it is not part of the charging circuit. The safety circuit board monitors both current and voltage during charge and discharge. It monitors each cell individually, and disconnects the cells if it detects over voltage, under voltage, or over current. The cell phone chargers contain the constant current / constant voltage circuitry to charge the cells in series, and do not monitor each cell individually. The safety circuit is the only thing to prevent damage or possible explosion if the cells become unbalanced. If you charge cells in series without the safety circuit, be extremely carefull and don't charge them unattended.

Jeff

PS The safety circuit is not a current limiter. A limiter would let the current go up to the limit and then maintain that current. If the safety circuit limit is reached, it will totally disconnect the cells.
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Old Jan 11, 2002, 02:42 PM
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Pensacola Regional, Florida, United States
Joined Jan 2002
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So that sounds like the sony cell phone charger is exactly the same thing as the Orbit when it comes to that particular battery 7.2 volts 1100 mah. It will maintain the correct current and stop charging at the correct voltage just like the Orbit, and it wont check the individual cell for overcharging, only the entire circuit, just like the Orbit??? So if I check, with a multimeter, each cell before charging and there the same, I could remove the safety circuit? Can cells get unbalanced while charging, or only on the discharge?

Im not saying it's in the same class as the Orbit, just for that particular application the sony charger will do the same thing. Now if I can get it to charge safely the 7.2 600mah's, Id be happy...
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Old Jan 11, 2002, 03:05 PM
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Rochester, NY
Joined Mar 2001
226 Posts
I have used the "sony charger" to charge my 600mah lit ion pack. I left the safety circuit on the pack.

It seems to work. I've charged several cycles so far. The LED goes red to green etc.

I didn't check the charge current (maybe I should). I suspect it is charging at above the recommended rate. Maybe the cell life will be cut short.
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Old Jan 11, 2002, 03:16 PM
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Pensacola Regional, Florida, United States
Joined Jan 2002
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Is your sony charger the one made for the 1100 mah cells? Thats good to hear that it works with the 600's. I'll try it out and put an ampmeter in the circuit.

Hum??? How long does it take to charge them from start to finish. I know it takes around two hours on the 1100's so does that mean it's charging at approx 550ma? If so then thats still within 1c for the 600's also.......

Am I looking at this right or am I way off here. It looks to me like this charger would work on 7.2 volt li-ion at 600 or above mah.
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Old Jan 11, 2002, 04:27 PM
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Mincha Victoria Aussie
Joined Dec 2000
461 Posts
This is taken from the WEStechnik site -- Gonna get one myself
(Walter if you are reading this it better be for a good price lol)
http://www.idnet.de/homepage/scholl/...ch/Battery.htm
Automatic charger for Lithium Batteries

What is the benefit of beautiful Batteries if you can not recharge them?
This new charger for Lithium Mangandioxid Batteries was exclusively developed for WES-Technik. This Microprocessor controlled charger is easy to use. It detects the number of cells (1-3) and their condition. If the cells need to be recharged the charger starts automatically charging 430mAh or 780mAh cells according to the manufacturers specs and switches off, once the cells are fully charged. The input voltage is 8 14 V from any source available. The charger guarantees maximum liefetime of your Lithium cells. Simply connect the JST plugs of your Li-cells to the JST socket of the charger.

price 89 DM


One Of JMP's I believe .
Walter Scholl gives excellent service and prompt Mail order
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Old Jan 11, 2002, 04:39 PM
DNA
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NE Ohio
Joined Jun 2001
3,311 Posts
Aussie,

The Lithium manganese dioxide cells are NOT the same as
Lithium Ion cells. The now discontinued Tadiran cells were the
lithium metal or lithium manganese cells. The specs and voltages are
completely different and the charger for lithium metal cells should
not be used for lithium ion cells.
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