I wasn't sure where this post should go, so let me start here and if I am wrong I hope it can be moved. I have been using for the last year or so on the lake a single battery. Well this year I am installing a new radio, and some other small things and I have always been a little scared about running the battery out on the lake. I have a 115 Mariner, so I was thinking there is already a spot for another battery to be held on the back of the toon. Is it easy to hook up a second? I know I should buy the switch that will allow me to use battery(1) or battery(2) or both. My questions is do I just get cables and run one battery to the other battery and then to the motor with the switch in the middle to have a choice to switch batteries? I don't want to over load my motor electrical or do any damage to anything. Thanks for the help.
What that diagram does not show is that ALL of your accessories should be connected to the COM terminal. You can then run with the switch on BOTH so both are being charged. If you stop to fish or party for a long period you can switch to BAT 2 (if that's the house battery) so you don't run the risk of draining BAT 1 (the start battery). when you are ready to go, switch back to BOTH or BAT 1, start the engine, switch to BAT 2 to charge the house battery or BOTH. Follow the wiring instructions that come with the switch. Note that every cable in the system must be the same gauge or larger than the cable going to the engine.
Following up on Silvertip's reply, It is also advisable not to charge both batteries at the same time if one is nearly fully charged and the other is low on charge. Batteries will take whatever power is available. If one is low, the charger will put out maximum charging power, possibly overcharging the other battery. Try to charge one at a time unless both batteries are close to the same level of charge.
We had the same problem, but instead of installing a second battery I installed the volt meter so it is always on. This way I can monitor the battery when the key/engine is not on. We have a system disconnect at the battery for when the boat is going to set more then a day or two.
We don't set more then an hour or two without running the engine and the engine is easy starting. Your situation maybe different if you float/party for longer periods of time.
Voltage regulators monitor "system" voltage, not individual batteries in a dual battery system. If one battery is fully charged, the battery that is partially discharged will suck current for the full battery until they are both equal. During the charging cycle if the regulator senses normal voltage it will regulate accordingly. There are many trucks, cars, and boats running dual battery systems, they don't have a switch so both are charged at the same time and the system works just fine. That is exactly why the switch has a BOTH setting - so you can start on both or charge both. If you did happen to run a single battery very deeply, set the switch to that battery so that 100% of available power goes to that battery. It will not harm the charging system to run on BOTH. If it did, you would see law suits up the ying yang.
Pontoon 2nd Battery set-up
Linear Mode
