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Sky Sharkster
10-31-2005, 02:36 PM
Has anyone tried these? A flier at our club brought out a 3 cell pack and some loose cells from http://www.power-motion.com/shop/. These are "Saphion" rechargeable Lithium Ion made by Valence Technology (www.Valence.com> in Texas but for some reason only available from Power-Motion in Great Britain. These are made with phosphate, apparently to avoid the volatilty of the "Ion" cells that has been widely reported.
Valence has posted the following figures;
Charge Voltage 3.65V standard 4.2V Max
Nominal Operating Voltage 3.2V @ C/5,>2.8V @ 10C
Nominal Rated Capacity 1100 mAH @ 10C
Discharge Method (Standard) 11.0A (10C)
Max Continuous Discharge 16.5 A (15C)
Max Pulse Discharge (30 Seconds) 27.5 A (25C)
Discharge Cut-Off Voltage 2.0V
Impedence (Initial 1kHz AC) < 20 mOhm)
Charging Times (Standard Charge) 2.5 Hours
Rapid Charge > 90 % Capacity in 1/2 Hour w/ 2200 mA (2C) charge
Cycling Life Characteristics > 1000 Cycles to 70 % Capacity
These are conventional round cells but much bigger than AA's, the dimensions are 18mm diameter X 65mm Length (11/16" X 2-1/2") and weigh 39 grams per cell. Power-Motion sells 3,4,6 and 8 cell (various s/p configurations) packs starting at $ 33.99 USD. Note that the 3.2 Voltage is lower than Lipos, 3 cell voltage is 9.6V, exactly the same as an 8 cell NiMh or Nicad, also they are only available in 1100mAH capacity for now. They also sell single (tabbed) cells for $ 8.50 each USD plus S + H.
Just a note on performance, hardly a scientific test, Dave H from Rocky Mountain Electric Flyers brought the pack and cells out and I Buddied him on a brushless E-Starter using the 3 cell pack. The power at launch seemed about like 8 cell NiMH, plenty of power but not ballistic, later an ROG was off the ground in about 15 feet and a quick throttle-back was required. The first minute or so was fine at 1/2 throttle, later a slight winding-down of power was noticed and it took 3/4 throttle to maintain "fast cruise" flying. The first flight lasted about 6 minutes and a check showed 70 % capacity remaining. The next flight lasted 10 + minutes and didn't reach cut-off. Between flights Dave was using the "Rapid Charge" 2C rate and each took less than 1/2 hour. Last flight (the ROG) lasted over 8 minutes and we only needed 2/3 throttle near the end, the cells seemed to "settle in" and put out more constant power 'til the last minute or so. Before landing Dave practiced a couple of landing approaches and had plenty of "juice" to climb out and go around again. The cells were barely warm but it was a cool day, 50 degrees or so.
As I mentioned, this was not a scientific test but I was impressed with the performance, even looped the plane twice from level flight about 5 minutes into the last flight. I plan to buy some single cells and will pass along the results. Also Dave has 4 single cells and plans on making a 4 cell pack. He did have to enlarge the battery compartment since the packs are so big.
Always something new in Electric, ain't it great! Ron.
www.rmeflyers.org (http://www.rmeflyers.org)

batman
10-31-2005, 07:46 PM
I was going to give them a try but still can't justify spending the money when the round cells work out so much cheaper.

watt_the?!
10-31-2005, 09:22 PM
good discovery mate!

i called them today and they claim no thermal runaway as their greatest strength....i.e. no reactive oxygen explosion and self fuelled fire in the event of damage or misuse.

still the tradeoffs seem to be weight and cost as usual.

weighing somewhere in between nimh and lipo and costing more like the lipo might be a problem at least initially. Demand and supply always corrects this though as we know.

compatibility with current ESC and chargers is also an issue me thinks.

Time will tell.

Tim.

ROGUE BULL CRAFTERS
08-30-2006, 06:03 PM
After a search on Google, looking for rechargeable batteries to replace 3 volt CR123 lithium batteries, I found the BatterySpace.com website. I have digital cameras that I use in my job as a desktop publisher and they eat batteries like mad. On some jobs I can take a couple hundred or more photos of products I must illustrate later. I rely on the batteries of the camera to be usable for the whole day and still work when I need to download the pictures to my laptop computer. I also use Surefire lights that eat 3 volt lithium batteries. After reading the extensive knowledge based articles and customer reviews on BatterySpace.com, I still had questions as to the use of higher voltage Li-Ion (3.7 V) batteries in my digital camera and Surefire lights. The knowledge based articles stated that the higher voltage (3.7 V) of the rechargeable Li-Ion batteries can cause the bulbs to burn out on some flashlights. I had noticed that the standard bulbs that come with the Xenon Flashlight is a 6 volt bulb. There is a note on the Xenon flashlight web page that states you can order rechargeable RCR123 Li-Ion batteries to make this a rechargeable light. I wrote an email to BatterySpace.com to question the higher voltage usage in this light and also on my Surefire lights. To my surprise, the next morning I had received an answer as to the usage of the rechargeable RCR123 Li-Ion batteries and a solution to the higher voltage of the batteries in the Surefire flashlight. The tech representative stated that Battery Space.com tests their Aluminum Xenon Rechargeable Flashlight with the rechargeable RCR123 Li-Ion batteries and it works just fine. Also, they stated that I could use the rechargeable RCR123 Li-Ion batteries in my Surefire 6P if I simply discharged the fully recharged 3.7 voltage down to 3.0 volts before installing in my Surefire light. Searching farther on the web site, I found the Aluminum Xenon Rechargeable Flashlight + 4 Pcs 3 V RCR123a Li-Ion + Smart Charger combination package for just $29.95. Wow, this is less than half the price I paid for a Surefire 6P flashlight with standard CR123 Lithium batteries. The cost of CR123 batteries is staggering if I add up how much I have spent over the last year. Knowing that I can recharge the RCR123 Li-Ion batteries over a 1000 times is the greatest thing since sliced bread. I just ordered the Aluminum Xenon Rechargeable Flashlight + 4 Pcs 3 V RCR123a Li-Ion + Smart Charger combination package for just $29.95. I placed the order at 4 pm the night before and this morning I already have a Quantum View UPS tracking number. My order has been processed immediately and my Aluminum Xenon Rechargeable Flashlight + 4 Pcs 3 V RCR123a Li-Ion + Smart Charger combination package is on its way. While shopping the BatterySpace.com web site I also noticed that they sell RC radio and in flight battery packs. Their batteries are a much better value than other resellers that I have priced. If the customer service at BatterySpace.com continues as it has been already, I will be back to make additional portable power supply purchases.

Rogue Bull Crafters
Wilderville, Oregon

flypaper 2
08-31-2006, 12:18 AM
Been using Li-ion from the Makita drill. Just a little over a 100 bucks at Home Depot up here in Canuckland. 18.5 volts 3 AH. Takes 25 Min's to charge on a 109 charger at a 5 amp charge rate. Barely noticeable rise in temp. Heavier than Lipos but will take a higher charge rate and about half the cost for the same MAH rate. Can take the heat from drawing to much amps when experimenting with props. A good alternative for old farts on a pension :D These are the same dimensions as mentioned above bit are 1500 mah. Ten cells in a pack stripped down weighs one lb. I use two packs in an 8 lb, 6 ft. span Eastbourne Monoplane. Cruises around at half throttle for about 12 Min's. Motor is Himax 50. Equal to a 50 size glow engine. Glad some Mfrs are numbering their motors as equivalent glow.

planekiller
08-31-2006, 09:37 PM
ive heard of these and thinking of getting some overlander.co.uk sell them