where to begin? right i have 4 lead acid 12v batteries for a model boat (baitboat to the anglers present) and i have various things etc that i connect to it, Solar panel charger, mains charger, battery tester etc. It was using a tamiya style plug on both battery and related chargers etc but the connection is crap with these things - a dead battery is reporting fully charged after 5 mins when this cannot be the case - the tamiya connectors are giving false information - a slight 'wiggle' is reporting not connected or fully charged. This is obviously no good to me as i might be sending a £400 piece of equipment to the other side of a lake with no means of getting it back and so I've purchased jack plugs, male and female like these the wire looks a bit flimsy to me but trying to solder jack plugs manually has proven to be impossible to me as the gap between live and neutral is less than a mm and my soldering skills aren't that good, this is why i got the ones with leads already on. My question is this, would i be better putting the male on the batteries and the female in the boat / charger / tester / solar charger or the other way around? also, is it better to allow the batteries to be run down to dead or nearly dead every once in a while as some of them rarely get used or if they do get used, only periodically and then recharged, or to keep them topped up and not let them get too low TIA!