new 1 AWG to engine from battery bank

[KWKloeber]

The only critical circuit that I know of on my C34 is the Engine Starting.  With my skimpy AWG #4 tined wire - I touch the glow plugs for 5 seconds, and the touch the starter for 1 second and the engine STARTS!!  As I said before I made that wiring change in 1991? and have had NO problems since!!

Ron can you clarify the point you are trying to make?   Yes, starting would be one of the critical circuits, limited to 3% (or less) drop. 

But, you said that you had upgraded to 2 AWG -- This is consistent with what I said to Cliff: 'minimum #1 or #2 for the starting circuit[/u][/b].'

EVEN if 4 AWG on a starting circuit has 3% drop the key is, what happens when trying to start if the battery is down a bit?  That's when cable size becomes most important. 

Remember that V drop is along the entire (positive and negative) length.  @ 80a, a 4 AWG circuit with 5 feet of pos and neg cable is over 3% (not counting terminal loss.)  7 feet each of 2 AWG pos and neg cable is over 3%.  9 feet each of 1 AWG pos and neg cable puts you at 3%.

Certainly, 4 AWG is adequate for a separate charging conductor to the bank.


E11 - 11.14.2.6 Conductors used for panelboard or switchboard main feeders, bilge blowers, electronic equipment, navigation lights, and any other circuit where voltage drop should be kept to a minimum shall be sized for a voltage drop not to exceed three percent.

[Ron Hill]

Ken : The point is that even using the house banks #4 awg wire (no starting battery) -  if I can just touch the starter button for 1 second and the engine springs to life;  what ever voltage drop there is, doesn't bother the starter/engine one bit!! 

The key is - marine grade tinned wire and GOOD connections!!   

A thought

[crieders]

i looked for the tech article and did not see it. any chance you could sent to me or post?  last Sunday I looked over everything in prep for ordering what I needed and I was intimidated just figuring out where the new wires would hook to at the engine end and how to fish them to the location! But with all this good help, I intend to try.

[Jon W]

Hi Cliff, If you're talking about my write up; go to the Tech WIKI on this website, scroll down to Projects by Boat/Author, then click on Della Jean, Jon Windt. This will take you to a list of my project write ups. The first one is 1987 Catalina 34 MK1 Electrical System Upgrade. Click on that and you'll be taken to the write up with step by step text, photos, and spreadsheets. There's also a link in the introduction to the original post on the message board with lots of questions, answers, graphs, etc. Last I looked it was 19 pages and 69k views.

[KWKloeber]

Cliff

Note that if you have the OEM setup the Neg cable bolts to the bell housing. That's not the best location and should be moved to the starter bolt. Both are M8 bolts so you want a 5/16" lug on that cable end.

There is a diagram of the change to the Neg cable location here (bottom of the page):
https://groups.io/g/Catalina30/wiki/11336

The Pos cable is in the starter solenoid "B post" , which is also M8.

Of course, you need to also replace the cables to your battery selector switch.

Ken

[Ron Hill]

Cliff : Look at the old Mainsheet tech note in the Nov 1996 edition.  I list the electrical modifications made by 3 C34 owners.  Apache, Bay Tripper and Wiskers!  That should surely give you some ideas. Bay Tripper and Wiskers (as I recall) with for 4 Gulf Cart batteries while Apache did 3 group 27 Gel batteries.

Hope this helps, a few thoughts