[C320-list] Another battery-related question

[Jeff Hare]

This should work. If the 1-2-both switch is acting like an on/off then the new battery probably wasn't hooked up quite right.

In proper hookup, both battery negatives should be connected directly together. One heavy red from one battery positive should go to the "1" post of the switch, the second heavy red should go to the "2" post on the switch. The "C"ommon post of the switch goes to the starter and the "house" power panel.

The 4awg red cables are usually shore power charger and windlass power. 

Check carefully for the 3 foot section of black 2/0 gauge cable that is the key ground between both batteries. If the prev owner only had one battery, he may have also disconnected that jumper and left it in the compartment somewhere. You need that.

-jeff
-jeff 

Dean Vermeire <dean at vermeire.us> wrote:

Hi Jeff,

I'm familiar with the wiring that you've described. Makes perfect sense.

In my case, there was only one battery to start with. Both positive 
cables, as well as the two heavy ground cables and the smaller ground 
cable were connected to the one 4D battery. There was no jumper.

When I replaced the 4D battery with a group 27 battery, I found that I 
had to connect all cables the way I had found them, which sounds 
obvious. What surprised me was that I couldn't have one battery 
connected to just one set of cables with the switch set to that battery 
and have the engine start. Basically, the two battery switch really 
only acts as an on / off switch when both sets of cables are connected 
to only one battery.

On 9/6/2011 10:14 AM, Jeff Hare wrote:
> We can only speculate here without some pictures of the wiring you're referring to, but what may have happened was that you didn't get all the grounds connected.
>
> The starter/engine ground connects via heavy cable to the aft most battery, then a jumper continues to the forward battery. The forward battery typically has the windlass ground attached also. Is it possible you didn't get the heavy ground between the batteries connected? All grounds need to be connected.
>
> Jeff
>
> Dean Vermeire<dean at vermeire.us> wrote:
>
> Hi Folks,
>
> You'd think that all possible questions have been asked by now, but I
> came up with another this weekend. When we got out to the boat for a
> nice long weekend and were ready to head out, the engine would not
> start. The batteries just didn't have enough juice for it.
>
> This is the first time I have had to get at the batteries on this boat,
> so please forgive the stupidity here! When I got at the batteries, I
> found that there was really only 1 there - a 4D truck battery (which
> others have recommended lately). That's fine. Nice to know. I ran
> over to the marina store (the only place open on Sunday) and bought a
> Group 27 Deep Cycle battery. I will probably put in a 4D again, since
> the battery tray fits a 4D perfectly.
>
> When I hooked up the new battery. I only connected one set of battery
> cables. I put the switch on "1". The radio, instruments, VHF, etc. all
> worked fine, but the engine did not turn over. Not even a click. I
> switched the cables on the battery and put the switch on "2". Same
> thing. Finally, I put the cables the way I had found them, with both
> sets of cables hooked to the one battery. I probably put the switch on
> "All", although I don't understand what difference it would make. The
> engine started right up.
>
> The boats I have had in the past had two batteries. I made it a habit
> of switching to just one battery once the engine was off, to make sure I
> would have enough power to start up again later. Having both sets of
> cables on one battery seems to be contrary to that idea.
>
> So, why didn't the engine have power when I had just one set of cables
> on the battery and have the switch set to that battery number?
>
> Humbly,
> Dean Vermeire
> Moonstruck II (#847)
>
>
>