wonwinglo

Following up from my previous comments on Li-poly cells some new information has come to light following some research on this subject-
Li-poly cells can easily become damaged due to being discharged too low,what happens is the BEC will come in at a set voltage governed by the requirements of the receiver and above all the way the speed controller will take the current from the Li-poly itself,this is where I went wrong and it now appears that a dedicated speed controller set up is available to get around this problem.
The SCU required are what is termed lithium friendly and are so designed that the voltage can be set higher to avoid any discharge of the Li-poly cells,this may require some careful settings to be installed prior to use but it is the only answer to avoid expensive cell damage.
One unit that fulfills these requirements is serial number 4460915 which should prove adequate protection for small electric motors run on Li-poly cells such as the popular GWS powerplants.
It cost myself dearly prior to this knowledge that I feel the manufacturers should have provided to avoid the damage that ensued to my batteries,the notes above should provide the knowledge required for other modellers to avoid a repetition of this problem.

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'And there I was oil on my goggles from a broken pipe,then I looked at the altimeter,all I could see was the makers name !'
www.wonwinglo.scale-models.net/

duncan

....and they CAN be very dangerous.

wonwinglo

Yes so I understand Duncan,I always charge up in a pyrex dish placed over the cells,just in case they explode,what we could do with is a more user friendly battery type with less hazards,in Sweden they have developed a wafer thin cell but at the moment the cost is too high to put it into production.
I purchased a special charger that checks the cell count,amperage etc under no circumstances use a standard charger as they have been known to explode with the incorrect charge rate.

__________________
'And there I was oil on my goggles from a broken pipe,then I looked at the altimeter,all I could see was the makers name !'
www.wonwinglo.scale-models.net/

duncan

The current edition of Aviation Modeller International( Oct.`04) has a very well written article by Simon Cocker on the subject of Li-Po cells. Their use,dangers,benefits,charging etc all explained in easy to read manner. As he says "a new way of thinking" is required, but certainly the way to go for electric flight. Other users might like to bone-up on their use too.

duncan

Even more on "new batteries". RCM&E Oct 2004 issue has a very informative article by guru Nigel Hawes on the subject. Two of the photographs should make the disbelievers of the dangers take note. A new way of thinking required in handling these.