Battery Terminal Question

[seadooNY575]

I have a 96 sportster and in the past have had some problems with the battery keeping charge while left on the boat. My repair guy said that it was because I left the battery connected while not in use and that the electrical system would place a load on the battery even while not running. Recently I bought a battery tender and began to remove the battery while not in use to keep it charged. The last time I went to connect it, the boat would not start and after much frustration I realized that there are two negative terminals (one to the ecm/mpem) and one that goes to the engine. I discovered that if I connect the terminal from the ecm/mpem it will start, if I connect only connect the terminal that is connected to the engine it wont start and if I connect both it will start. It is my first boat and I dont ever recall both terminals being connected at once. Im assuming both need to be connected to complete the circuit to the electrical system but I am wondering if this may be the cause of my previous starting issues. Any help/advice is appreciated.

 

[fastboatman29212]

You CAN charge the battery while it is in the boat. I usually disconnect the positive and negative cables but have read on this forum that it's OK to charge the battery with them hooked up. NEVER, EVER JUMP START IT WITH THE CABLES HOOKED UP. Just unhook YOUR battery and connect to the loaner to jump.

Yes, I do believe the starting issues could have been related to the cables not being hooked up properly, but then again when i leave my boat sit for a couple months, the battery usually runs down too, so we may never know. Either way, trickle charger/battery tender is always a good idea when you are not using the boat for a month or more, and removing the negative cables will keep anything from drawing power from the battery.

 

[bigJake]

yes connect both ground wires to the battery