Speed controllers for use with Lipoly ?

[wonwinglo]

I was speaking to a modeller at the weekend about my lack of success with Lipoly batteries,I told him that the manufacturers/distributors had informed me that the reason my batteries had failed was they had discharged too low,he immedietly said that I was not using the 'correct' type of speed controller which came as some surprise especially as the whole set up had been supplied by someone who was into electric flight in a big way,it appears that there are dedicated speed controllers just for use with Lipoly batteries,these speed controllers require initial set up depending on the number of cells,current drawn etc he showed me a set of instructions for the said controller and it was a very complex procedure,I then asked him if the distributors knew about these units and he said no ! so it appears that they are selling the wrong speed controllers for use with Lipoly,little wonder they are failing in this way !

Can anyone throw any light on this as there appears to be a difference of opinion on the way Li-poly batteries are used in conjunction with speed controller units,it makes sense that if the scu is draining the batteries flat then this is where the damage is being done,I also noticed in one of the American mags where a auxiliary unit is being fitted to avoid battery discharge so it appears that they are trying to make a fix for a bad job here ?

Have the manufacturers discovered a flaw in the way the batteries are being used/mis-used ? and if so why are they not letting the modeller know about this problem,instead of letting us blow them through ignorance which is not entirely our fault ?

Would anyone like to comment on this shortcoming please as I am reluctant to spend more money on batteries that quickly fail in this way?

[Guest]

Hi Barry, I did respond to your post but it seems to have gone AWOL!

Anyway, re. dedicated ESC’s I recently bought one along with all the rest of what I needed as a first time electro user.

The ESC is an Athena and I don’t know if it’s for LiPo’s only but it does have ‘LiPo low voltage auto protection” so I’m assuming it’s safe.

I’m completely new to the electric side of flying and I agree that manufacturers need to provide more info as to what will work with what.

I, (think/hope!), I’m lucky in that my local model shop are always ready to help, otherwise, in spite of all the info on tinterweb, it would be a bit of a nightmare knowing what to buy.

I watch this thread with interest.

Steve.

[Greyhead]

I’m not into this electric “new technology”, I have a simple speed 400 / NmH set up (as well as my Lasers), but my brother uses lypos etc. and had an interesting experience recently.

His speed controller has the low voltage protection but on one occasion he only disconnected one of the battery leads before packing the model away. Somehow the connectors managed to touch and when he tried to charge the battery again it was ruined because it had been fully discharged. It appears that the low voltage protection doesn’t disconnect the battery; it only stops the motor, the logical assumption being that once the motor stops you will be landing quite soon thereafter well before the battery is discharged.

He has since modified the connectors and I bet he makes doubly sure they’re kept safely away from each other.

[wonwinglo]

Polarity protection is especially important with Lithium type batteries,one small touch and the wires will burn fiercly and certainly wreck the battery.

Battery elimination merely provides enough reserve battery power to power up the receiver,it is a good policy to land as soon as the revs drop to avoid any more battery drain even if the prop is spinning over.

Golden rule is allow battery to cool down,then charge fully as soon as possible,a small top up charge before setting out flying again is adviseable.

Dont forget always use the correct ESC (Electronic Speed Controller ) to suit the set up being used,get advice from a specialist supplier on this point.

It is good to see that the Chinese sellers on E-bay are selling excellent combo deals ie Outrunner or Inrunner Motor/Battery/Correct ESC so all you have to do is build your model around the supplied units.