Lipo batteries
 

I'm not a smoker, but have noticed the increasing number of discarded disposable electronic cigarettes on the streets.
These contain a rechargeable 3.7v 500mAh Lipo battery. They don't have the control circuitry, but these are very cheap, five for £2-3 on eBay for instance. Just need to find a use as they are an intermediate voltage.

Re: Lipo batteries
 

Li-po batteries are basically all the same when in comes to voltage. They will read 4.2V when fully charged by a charge controller chip, and need to be recharged before the voltage drops to about 3.2V.

Poundland mobile phone 'battery packs' intended for use at things like festivals are a good source of low capacity lithium batteries.

A couple of cells will power a 9V transistor radio pretty well. Don't forget to include a fuse somewhere though.

Re: Lipo batteries
 

Found an E-cig in the road, had been extensively run over but yielded several very odd screw threads, and a metal-case power resistor of about 2Ω

Re: Lipo batteries
 

The ones I found had the battery and a combined pressure switch and LED indicator. The presumed heater remained in the front of the casing, but I chose not to investigate that part further!

Re: Lipo batteries
 

Very wise - I had forgotten my desperate efforts to clean the ghastly stuff off my hands, spanners, worktop...

Re: Lipo batteries
 

I actually use one.
The stuff in them is water based even though it looks like oil.
The cheap batteries have a poor number charge cycles and many come with a charge regulator that is variable in quality built in.
The charging can be made safe with a small number of external components and better quality batteries can be fitted in the 18650 ones.

Re: Lipo batteries
 

New 18650s are easily obtained (along with a range of USB-powered chargers) from:

https://www.fogstar.co.uk/ *

FWIW, I've dismantled several 'duff' notebook/laptop batteries over the last couple of years and have found that these often yield perfectly good 18650s. Care is needed in refurbishing them (a judicious application of 120-grit abrasive paper smooths down the sharp edges once the spot-welded interconnecting strips have been pulled off ... and I choose to apply replacement heatshrink sleeving as the original often tears where the cell is glued to the plastic housing). These are a good companion to the single-cell LED torches that are also available from the above supplier - a practical and inexpensive gift with the added feel-good factor of having recycled/repurposed something that might otherwise have gone into the local transfer depot ...

Guy

* No commercial connection, just a satisfied Customer.

Re: Lipo batteries
 

I also scavenge 18650s from discarded battery packs - drills, cordless vacuums etc. I replace the heatshrink with ordinary vinyl adhesive tape if it's damaged. You can buy 18650 holders cheaply on eBay.

Re: Lipo batteries
 

Just looking at those holders (wasn't previously aware), I wonder what the max current is that you could draw from them? I suspect it may be quite limited?

B

Re: Lipo batteries
 

It certainly wouldn't be wise to draw several amps through them. You really need a specialist battery pack with built in battery management for that sort of job. The cheap holders are fine for things like radios or LED torches.

Re: Lipo batteries
 

I have an ancient, but good as new, 12V Bosch drill which I converted from NiCd to 18650's about a year ago and that has worked out really well. I put a fuse in the drill circuit and that has burned out (10A) just once under a very heavy load.

B