Tiny Lithium rechargeable batteries for toys.

  Diemmess 17:41 PM 03 Sep 12

I indulged myself in one of those miniature helicopters. Incredibly cheap for the fun this has given me. The whole thing including a 150 mah Lithium battery built into the machine was something just under £17.

The battery is recharged either by a built in lead to the Tx batteries or by (you've guessed it) a USB port on the PC, also connecting cable supplied. (USB plug glows orange when only USB plug is in and later when the battery is fully charged).

Flight times have slipped badly recently, one takeoff and the briefest of flights before it ceased to climb again.

Guessed the battery was failing and Ebay had a source in PRC. This time, delivery took 10 days and cost £1.79 including postage?

I had dared to do this because of a very useful tutorial on the net. It was very fiddly but scary because the new battery showed no volts at all before wiring it in.

Makers recommend40-50 minutes to charge, the new battery took nearer 60 mins, but is back with at least 5 minutes of flight possible.

So, that's the background

Q1 Is it expected to have a no-volt reading on a new battery which hasn't been charged?

Q2 Did I wreck the first battery by leaving it charging for maybe a couple of hours while I did something else? No sign of heating either in use or when charging.

Q3 Do Lithium batteries develop a memory like NiCads used to do?

  Ventad 16:04 PM 15 Sep 12

Have a read of this click here I used to leave my laptop Li-ion battery plugged in but switched off when charging completed, (previously I used to unplug) but my charge quickly went down hill, and then I read a University paper on the net saying even though it is switched off but still connected a chemical reaction takes place which finally destroys the battery life, now with a new battery the charger is now quickly turned off and unplugged once charging is complete.

  Diemmess 17:16 PM 15 Sep 12

Thanks ventad.

The new battery is still behaving, so I watch the charge very closely and stop charging as soon as the warning LED glows. That has presumably done the trick.

In more sophisticated kit, the charge current is reduced almost to zero once the battery is full, but what can you expect with such a delightful toy @ £14.95 including airmail from China.


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