battery chargers

Dumb question maybe but how do battery chargees workd,i dont mean how to hook it up,more like how does the needle work,does it go from right to left when charging?If so,this makes no sense for me cuz everything we do we go from left to right.Btw,it's an Einhell battery charger,german product.I'm...

i have a SELMAR BATTERY CHARGER TURBO 12 it doesn't work any more after charger my car battery that i find out that is has a short circuit so i think is that what damage my battery charger :'( So i open it then i found that the Bridge Rectifier SB151 is cracked and it cause a short circuit, i...

I need to get two new 7ah 12V Lead Acid batteries for my 1000va Belkin UPS as they are shot after 3.5 years of use. They clearly need replacing as the UPS just shuts of immediately on power loss and the batteries are very hot and slightly swollen out. Ones even resting around 6V. They are...

Looking for a charger for a 24v 3G cordless hammer drill, that's not gonna break the bank. Any ideas please ??