[LINK] Expert advise sought please...

[Tom Worthington]

At 10:13 AM 17/01/2008, Howard Lowndes wrote:
>-------- Original Message --------
>Subject: From Alex another NEW Idea to investigate
>Date: Wed, 16 Jan 2008 17:08:02 +0530
>
>... I want that every battery of each solar PV system we will 
>install over the next years ... to be registered ... monitor its 
>life cycle. ...

It might be simpler to just keep a central register, recording 
whatever identification there is on the batteries when they are 
installed and using that to identify them when they are replaced. 
This is on the assumption that the batteries are not going to be 
changed often and so it is not worth the effort and cost of fitting 
each one with a barcode, RFID tag or the like.

>any other suggestions ...

It might be worth looking at using "Low Self Discharge" rechargeable 
nickel metal hydride (NiMH) cells. These are commonly sold as "pre 
charged" rechargeable batteries.  They cost more, but are claimed to 
be able to be charged twice the usual 500 times 
<http://en.wikipedia.org/wiki/Nickel_metal_hydride#Low_Self_Discharge_Batteries>. 


I have successfully used the AAA size cells in a mobile phone 
<http://www.tomw.net.au/blog/2007/11/replace-your-battery-to-save-planet.html> 
and AAs in a string trimmer 
<http://www.tomw.net.au/blog/2007/11/replacing-batteries-in-string-trimmer.html>. 
These cells are very robust: I had to stand on the AAA cells to force 
them into the battery holder. I used the AA cells in place of larger 
sub-C NiCd cells in the line trimmer. I suspect these batteries will 
last much longer than regular ones, perhaps five to ten years in a 
solar lighting system.

More recently I have read of larger capacity low discharge C and D 
cells, but have not tried these and I am not sure they use the same 
technology 
<http://www.tomw.net.au/blog/2008/01/low-self-discharge-nimh-c-cells.html>.

The lower discharge rate batteries might allow the use of smaller 
batteries and smaller solar panels for home lighting, lowering the 
cost. The batteries could be combined with efficient LED lights, such 
as flexible LED tape, to provide light where it is needed and reduce 
waste. I have looked at using the flexible tape LEDs in a computer 
classroom 
<http://www.tomw.net.au/blog/2008/01/leds-for-office-home-and-classroom.html>.



Tom Worthington FACS HLM tom.worthington at tomw.net.au Ph: 0419 496150
Director, Tomw Communications Pty Ltd            ABN: 17 088 714 309
PO Box 13, Belconnen ACT 2617                      http://www.tomw.net.au/
Adjunct Senior Lecturer, ANU