At whitworths yesterday i thought i got all the info on the "how to" and what goes were etc, but once on the boat i wasnt really sure.
my switch has 0, 1, 2 and 1+2. On the back it has , batt 1, batt 2 and feeder.
ive connected red cables to batt 1 and 1 connections on back of switch. Do these go to each positive of the 2 batteries?
Im to believe the two batteries have a negative crossover between the 2 neg terminals?Heres where i get confused. where do my charging wires from my outboard go? 1 pos and 1 neg.
I think the ww guy said the neg goes to the feeder screw on the back of the switch.
from where on the batteries or switch do i connect to the main circuit of the boats switch?
Currently , with one battery , i just have a pos and neg lead from the brass bars behind the switchboard leading to the batt terminals.
I guess my question is : how do i connect 2 batteries to the switch board?
Im confused! i feel if i do it wrong it will bypass the switch which is pointless!
thanks Graham. The instructions and the WW guy said you run neg lead between the two negs of the 2 batteries...THese guys dont do that, but this video makes more sense.
When they refer to "Neg common Ground" would this be the same spot where i had the neg from the 1 battery (with 1 batt system) going on the control panel? (behind switch board)
Technically speaking the "negative common ground" is the actual battery negative terminal in a one battery system. The switchboard ground technically speaking isnt, because theres a small voltage drop along the cable connecting it to the battery terminal, though in practice if its a good solid cable it probably doesnt matter.
When using two batteries you can connect together the negatives of the batteries. That join then becomes "negative common ground". Then run a lead from that join to the engine and another lead from that join to the switch box.
Just use nice heavy tinned cable (of a higher capacity than the load and the circuit breakers) and after crimping it solder it. Many argue about that but I always do.
In the picture below you can see the cable joining the battery negatives (black), then a cable going off to switchboard (top one) and another to the engine block (bottom). The red ones go to the battery switch. This is big mess 
. Since then I tidied it up and rewired it all. But it might give you an idea!
think i get it. so i can just put the neg from the engine directly on the terminal for the motor battery, and link the 2 negs up of the 2 batteries?
But i see from your diagram you are connecting the neg from motor batt also to the neg common ground/switchboard?
Yes, that should do it. Technically speaking again, the connection between the two battery negative terminals is your "negative common ground" not the place you marked although in practice it shouldn't matter. Ideally make the connections on the boat like a star where the "negative common ground" is the centre and the points of the star are the outboard, switchboard etc. In other words all the devices that connect to the "negative common ground" which is the connection between the negative terminals of your battery have their own personal cable.
Thanks Trek .Currently, with 1 battery, there is a neg lead from the battery to the back of the switchboard. So are you saying that i do not need this anymore with the dual/switch set up?
Select to expand quoteSectorsteve said..
Thanks Trek .Currently, with 1 battery, there is a neg lead from the battery to the back of the switchboard. So are you saying that i do not need this anymore with the dual/switch set up?
Trek said the switchboard is one of the points in the star, so Trek said that you do need the neg lead from the battery to the negative bus bar at the back of the switchboard.
It is necessary to install a fuse or circuit breaker sized to protect every circuit on the boat (on the positive as close as practical to the power source side of the circuit), with the possible exception of the starter motor circuit (since you can release the starter button).
Select to expand quotesomeday said..Sectorsteve said..
Thanks Trek .Currently, with 1 battery, there is a neg lead from the battery to the back of the switchboard. So are you saying that i do not need this anymore with the dual/switch set up?
Trek said the switchboard is one of the points in the star, so Trek said that you do need the neg lead from the battery to the negative bus bar at the back of the switchboard.
It is necessary to install a fuse or circuit breaker sized to protect every circuit on the boat (on the positive as close as practical to the power source side of the circuit), with the possible exception of the starter motor circuit (since you can release the starter button).
thanks someday.
Every circuit has a fuse. Im only using batteries for lights, nav gear, fridge as ive only got an outboard but my outboard is set up to charge batteries.
