This might be common knowledge but I was not aware of this. I recently had the coach batteries out. When reconnecting the wires I had a large spark when connecting one of the wires. I stopped and checked everything with meters and verified my photos that everything was going on the correct location. The second time there was no spark. Everything worked fine and I forgot about the issue. Then watching a video on the victron multiplus I saw that on larger inverters you need to precharge the capacitors by using a resistor to limit the voltage surge. To do this you place a resister on the positive lead and touch the restor to the battery connection for a few seconds. Once that is done you remove the resister and can safely connect the lead without sparks. While our systems are not large, if this eliminates the sparking I am going to try this next time I have the batteries disconnected.
Paul and Debbie
Hmmmm, never encountered that problem. My inverter is only 1000 watts. Maybe the spark was contained in my battery disconnect switch that I have on each battery. The cables are connected to an open post until you screw the switch knob in place. Would be hard to see a spark there.
Ah, the memories of charged capacitors. Not only are resistors used to slow the charge going into a capacitor but they are also used to discharge caps. Evil electronic techs would leave charged caps around for some unknowing fool to touch. Without a resistor to bleed off the cap, the charge would remain for a very long period of time.
I am very familiar with charged capacitors. When I worked in the field I serviced equipment in libraries that had caps charged to 320 volts DC that would stay there if you did not engage the safety interlock to bleed them off. Techs would often (usually only once) forget to verify they were bled off and then accidentally get across the terminals with a screwdriver. Instant very loud BANG, like a gunshot, in a very quiet library. Not so bad in the old days where the result was major embarrassment. With the world today, hearing that loud bang might cause people to hit the floor.
Retired electronic technician (45 years in the field)
2017 Greyhawk 29W
solar & many other mods
wife (maybe I should have given her top billing)