I needed to quickly test a 48v inverter just to make sure it actually works, so I grabbed four (4) 12v batteries to put them in series. The first battery is aAGM car starter battery (automotive post terminal), the second one is a solar AGM battery (1/4" inserted screw terminal) and the last twoare deep cycle AGM batteries (2 x 5/16" nut & bolt terminal). Again, this was just a quick test, just to make sure this inverter powers on.In my haste I started with the terminals opposite of me because they were harder to reach. First I connectedthe negative terminal of the car battery to the positive terminal of the next battery.Then I connected the positive of the car battery to negative of the next battery and that's when second battery's negative terminalgave a big ol'spark, it's1/4" screw broke off and part of the screw hole chipped off too. I figured my mistake was rushing and not paying attention to details likeconnecting the negative terminal first of the first/car battery instead of the positive terminal first. Then I thought maybe it was because the first/car battery pushed too many amps initially upon connection(hundreds of amps as if it was starting a car, maybe?) and the second battery's screw terminal just couldn't handle the current(side note:in previoustests with this second battery where I was using a 12v inverter,I could only pull 33 amps/400 watts before the voltage dropped significantly and the terminals got extremely hot). Then I realized I should know why and embarrassed I wasn't sure. I've connected batteries tens of times with no problems so far and obviously had some spark upon connecting to terminals, but never this big and this damaging.Any ideas why this sparked like this?
P.S. - I checked the voltage of both batteries in question after a couple of minutesand they still both had 12.6 volts, so I guess I didn't short them or destroythem...?
P.S. - I checked the voltage of both batteries in question after a couple of minutesand they still both had 12.6 volts, so I guess I didn't short them or destroythem...?