Friday, September 17, 2010

Batery protection - An implemented idea

Already, somewhere in this blog, I mentioned my solar panel and the homebrew battery charger/regulator. This setup gives power to the 12v equipment in the shack while I don't finish a 12V power supply project I have, then it will be used for backup.
For now it has been running un-protected, that means I have a direct cable from the battery to the equipment without any interrupt point, that is not safe and I know it.
There are many ways of protecting a battery and the most used one is a fuse, why? Because is fast acting. There are also switch's breakers specially made for DC systems, those are expensive and the fuse option means you have to have some spare ones.... but... there's always a but, the AC protection switch breakers work the same way a DC one do, in fact I think the only difference is the isolation characteristics, that's my theory which was confirmed from a talk with a former school teacher. He didn't looked at me with surprise when I told him my idea... he just mentioned to get one with a fast acting curve ("shot" time versus circuit current).

So, on to buy a 230/25A protection switch (cost 3.45 Eur), which must be a fast action one but really don't know (didn't care to confirm), but I will let you know if I have any future problem. Anyhow for now this is just to have a break point.

The other terminal of the battery will probably get a car fuse if I can get in the scrapyard some car fuse holder (car fuses are relative inexpensive). The best of both worlds in each line.

I you look at the photo, the color code in the cable doesn't match the standard 12V system (Red and Black) but this cable was free (scrap from a datacenter I worked on) and really, you should know this, electrons are color blind!

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