Hi all,

i have bought a cheap DC/DC converter (24v to 19v, 15A, http://www.current-logic.com/shop/index.php?main_page=product_info&cPath=5&products_id=319 ). When i attach a 24v battery pack to the converter input i get sparks. Is there any way to suppress these sparks when i attach the converter?

 

It is the capacitors charging when first connected that creates the large inrush of current which makes the sparks you see.

If you connect one terminal only and temporarily connect a 3 or 5 ohm resistor between the other terminals, the caps will charge slower and you will not have such a big spark when you remove it and connect directly.

Not any easy way.

 

Three 9 volt batteries makes 27 volts.
Perfect for your 24 volt system.
Put three in series and attach wires so you have a 27 volt pack.

The high internal resistance of the rectangular batteries will prevent destructive sparking while the caps charge.

Leave it connected for 5 to 10 seconds then hook up the real battery pack.