What is the function of the parallel switch?

[brico]

Can someone enlighten me as to the function of the parallel switch? Is it meant to be used to isolate only one battery bank for starting the engines or something else? I have the spring loaded toggle switch Port/Starboard which I believe isolates each so only one is used to start either of the engines, otherwise both banks are used to start each engine if the switch is in the middle, e.g. not used/engaged.

[oscarvan]

It is designed to temporarily connect another battery bank to your start bank to help crank the beast if the start bank is undercharged. Now whether you tie in the other start bank and/or the house bank I don't know on the Hatts. AFAIK the start banks are NOT connected in the normal state.

[bobk]

My start banks are not connected except when the parallel switch is engaged. Its an emergency feature.

Bobk

[Outfitter]

I parallel start my engines every time. It is easier on both banks to use em all.
Zak K
Black Hat

[Pascal]

Problem with using the parallel switch every time is that you won't know when your banks are getting weak.

Hatteras used a solenoid controlled by the switch which is more convenient than a manual parallel switch. It has two position so it can use either bank to power the solenoid

[SKYCHENEY]

Port bank starts port engine. Stbd bank starts stbd engine. To parallel, you push the switch to the good bank and crank. This will temporarily connect both banks together.

[brico]

Thanks for all of your replies. I have one 8D - 1155 CCA starting battery connected to the Starboard distribution box and two deep cycle 8D -1600 house batteries connected to the Port distribution box. I never start my engines from late September to early May unless I've had the block heaters warm them up so they always start instantly and minimum cranking therefore I believe I should be OK with starting both with my starting battery for which it is designed but with current setup I am not sure I can start both with starting battery unless I use parallel switch (I think so) . Using deep cycle batteries to start engines is not really good thing to do on regular basis, neither is using starting batteries as house batteries on longer but lower rate of discharge on regular basis. If parallel switch does not isolate but actually couple both banks (in my case one starting and two deep cycle) I am damaging my deep cycle batteries using them to start the engines.

Let me know if this line of thinking is wrong.

[scottinsydney]

Referring back to SKYCHENEYS comment, it seems to me that pushing the battery combining switch port or starboard has the same effect. ie. the batteries are combined to start either engine. I have a 1984 61MY. What don’t I understand? Why push left or right?

[Pascal]

You push the switch to the side of the good battery. If one of them is dead trying to activate the solenoid with that bank will not work.

[kingsley_oasis]

Pushing parallel switch selects which battery set supplies hold coil voltage for parallel solenoid. Mine is in starboard engine room. If you had very low voltage on one side it would be insufficient to pull solenoid in. Best to select side with good voltage which you plan to start from.
As a side note on my 61CMY the parallel switch is not rated for the current being supplied to solenoid. Parts appear to be as per Hatteras drawings. Found out when switch stuck and smoked. Design is intermittent use so replaced with same Cole Hersee switch.