Marine Electronics Forum - dual batteries

Question, I have a Nautic Star with a yamaha 150hp. When i bought it the mech showed me where I could plug in for a second battery. my question is this: how do I connect the 2 batteries to each other and would it be advisable to just run accessories off the second. Thanks in advance. Jim

assuming you have a switch you can hook it up so you can run either battery or both of them together. or if you want to leave it as it is you can parallel the batteries together and just have one big battery. Unless you get one of the fancy devices that allows charging of an accesory battery without draining the starting battery you will have a hard time running the accesories off one and charging it back up with the motor.

Just get the second charging lead, there are many posts on this. I have a starting battery and a house battery. I can isolate them or run them together with my battery switch.

http://www.thehulltruth.com/shipyard-isl-marine-engine-parts/178311-auxilary-charging-leads.html

thanks for the info will let you know how it turns out. have a day off thursday so I will try it then

running on "both" can damage the alternator as it is usually not sufficient to handle that much load at one time. run out on #1 stop shut off engine switch to #2 and restart engine and continue trip on #2
switch at intervals and you will have battery power when needed

likewise keep batteries charged with good marine battery charger while on land the charger should have circuitry to only charge when needed not a trickle type charger

Just get the second charging lead, there are many posts on this. I have a starting battery and a house battery. I can isolate them or run them together with my battery switch.

http://www.thehulltruth.com/shipyard-isl-marine-engine-parts/178311-auxilary-charging-leads.html

X2

running on "both" can damage the alternator as it is usually not sufficient to handle that much load at one time. run out on #1 stop shut off engine switch to #2 and restart engine and continue trip on #2
switch at intervals and you will have battery power when needed

likewise keep batteries charged with good marine battery charger while on land the charger should have circuitry to only charge when needed not a trickle type charger
I been doing this for at least 7 or 10 years without any problems ;?

X2


I been doing this for at least 7 or 10 years without any problems ;?


ditto - too small a batt will ruin a alternator but not too big of one -