In an attempt to get my new venture and my books in order, I ordered a new shed to use as an office. Getting electricity out to it is a nightmare, to get over this issue I chose to fit a solar panel and use Nicds as the storage medium (something I can get for nothing!). On my workbench, I have enough 3V6 1500mah batteries to make a 12v (actually around 15v fully charged) 10.5ah pack but I came to an issue after building my first 12v 1500mah pack, How do I balance charge this and how do I get a 3V6 tap that won’t cause issues.

To this end, I came up with designs for the following sub-packs.

Screen Shot 2017-10-28 at 21.10.14

As you can see, the above pack designs are of a different supply voltage.

Why 2 different voltages?

My lighting is supplied from 3V6 recycled Led lighting (ignoring the 240V side) but I also need 12V for the charge controller and inverter required for none 12V equipment!

One of my dilemmas comes from the 12V side. Do I build the packs as 12v packs which are easier to upgrade by adding more packs or, do I build the packs as 3V6 which require me to add cells to all the packs at the same time. The second dilemma comes from keeping them balanced charged.

If anyone knows the answer to this, please tell me which is the best construction method!