Re: Supermaramu wire sizes?

Dan Carlson

Thanks for the follow up Bill,  I did read about Scott on Tengh rewiring with 2x50mm2 for his 5000w inverter.  I believe others have installed the 3000w with the 100A wire. Can't recall the size inverter that Delos installed or if they rewired.  

I did a double take on the resulting wire size from your calculations and I redid them myself and cross checked on a different calculator before I realized that the wire length should be entered in meters not feet.  This results in a wire size of 50mm2 or 1AWG (actually 42.4mm2) for a 4 meter wire.  That is why I wanted to confirm the wire sizes.  My guestimate is that the 100Amp charger has a 50mm2 wire as it looks close to the size of another labeled 50mm wire on the boat.  Then the existing 1800watt inverter looks slightly smaller, like it has a 35mm2 wire and the wire to the inverter looks even smaller, perhaps 25mm.  The wire to the alternator is just a bit larger than the 100A charger, so that could be 70mm2, which would be appropriate for the 175 amp.   The wire to the bow thruster (longest run and highest current @ 300-400A) looks like a 4/0AWG length of have which is between the standard sizes of 95mm2 and 120mm2.

I'm pretty comfortable with the calculations, and I am really just looking for confirmation on the existing wire sizes.

Best regards, Daniel Carlson on sv BeBe, SM#387

On Sat, Nov 23, 2019, 1:52 PM CW Bill Rouse <brouse@... wrote:

Yes, the Amels that I have seen have increased the size of the wiring.

You might want to look at this:
3000 watts = 13.64 amps of 220 volts:
So the short answer is, assuming that the 24 volt wiring for the 100 charger watt was designed for 100 amps. You should NOT use that wire because you should expect a maximum of around 140 amps. Not good! So, replacement is going to be required. Since replacement is required, calculate the wiring size needed for the inverter/charger using an online is one:  
I am not sure about the length of the cable run...I used 12 could be 15 feet.

The result above shows required wire is 120 mm2 = 12.4mm diameter, which is about 1/2" diameter

Hope this helps.

CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 

On Sat, Nov 23, 2019 at 11:30 AM Dan Carlson <carlsdan61@...> wrote:
Hi Bill, yes I'm well aware of the different cable sizing standards.  But was looking for the reference data for the actual cables in the SM.  

The existing cables are well shielded and have shrink wrap covering right up to the terminal lug so the actual wire is not accessible for direct measurements. 

I am just trying to understand the sizes with respect to the various loads.  Several of boats have talked  of replacing the original Dolphin 100A with a 3000watt Victron Multi or Quatro and I wanted to understand the impact in terms of current load and voltage drop potential.  

Regards, Daniel Carlson

On Fri, Nov 22, 2019, 7:04 PM CW Bill Rouse <brouse@... wrote:

I am sure that you know this: In Europe the wire is sized in square mm. 

You might want to measure the diameter of the existing wire, calculate the area of the cross-section in square mm, then if you need AWG, use an online conversation chart to get to AWG. Here is one: 


CW Bill Rouse
Amel Owners Yacht School -
720 Winnie St
Galveston Island, TX 77550
+1(832) 380-4970

On Fri, Nov 22, 2019, 5:32 PM Dan Carlson <carlsdan61@...> wrote:
Hello SM owners,

Does anyone know the original
wire sizes for the following:
1) 100 amp charger to battery switch
2) 30 amp charger to battery switch
3) Battery switch to bow thruster

The wiring does not appear to be labeled. And I'm not a good judge by eye.

I'm in Panama right now trying to search the forum from my phone with my cell connection isn't working for me.

Thanks and regards, Daniel Carlson on SM #387, sv BeBe

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