Planning the Electrics/Electronics - Domestic System Part 2

Just to get things clear, I have never done electrics before, so, if you have a squeamish disposition... look away now. 
   I'm treating this as a water system: the water goes out of the boiler (battery) hot, does its business, and comes back to the boiler cold. If it doesn't come back to complete its circuit it won't work.
     This is going to be done in modules so I can keep a check on things more easily

Module 1. Getting Power to the Wheel House.

Here we will have to safely deliver power from the battery in the aft locker:

to  the wheel house control console.

You may wonder why the battery isn't positioned at the console instead of at the stern. The reason is the starter battery needs to be near the outboard motor and both batteries are coupled and charged from the engine when it is running.

I have seen videos of people doing all the fancy electrical connections - that will be in the console- in uncomfortable positions, on their knees, lying down, and almost upside-down. With this and comfort in mind I made and inserted the panel, on which the electric magic will fit, to suit me . To start I will sit on the seat in the forecastle looking aft.

In front of me, like a music stand, will be the panel I have just made and glued in place.

Which, for those of you still disorientated, the new panel is in the back of this console.

Selecting the cable I need

I'll try to keep this simple because it's the only way I can understand it. I need to know three things:

i/  The voltage in the system = 12 Volt   (it's a 12v battery)  

ii/ The total Amps (see previous post for list of devices total amps)
                           =  10 amp x 2 = 20 amp
    (It's my idea is to double the total amps  - so I can add more devices later)

iii/ The length of cable from battery to console and            return = 40 feet (there is a 3% voltage drop dictated by length of                cable run)

With these three values I can use Table 1 (below) to determine the American Standard Gauge (ASG) cable I need. First, I go along the top of the table until I reach 20 (amps) then down the left column until I reach 40' row. Where they intersect is the wire gauge needed, 6 AWG, however, I've gone for a 4 AWG (1 size up) ... because I'd already ordered it after watching a Youtube video!!

Table 1

Table 1: Wire Gauge for 3% Voltage Drop at 12 Volts
CURRENT (AMPS)*
L E N G T H		5	10	15	20	25	30	40	50	60	70	80	90	100
	10'	18	14	12	12	10	10	8	8	6	6	6	4	4
	15'	16	12	10	10	8	8	6	6	4	4	4	2	2
	20'	14	12	10	8	8	6	6	4	4	4	2	2	2
	25'	14	10	8	8	6	6	4	4	2	2	2	1	1
	30'	12	10	8	6	6	4	4	2	2	2	1	1/0	1/0
	40'	12	8	6	6	4	4	2	2	1	1/0	1/0	2/0	2/0
	50'	10	8	6	4	4	2	2	1	1/0	1/0	2/0	3/0	3/0
	60'	10	6	6	4	2	2	1	1/0	2/0	2/0	3/0	3/0	4/

* Current (amps) determined by adding the total amps on a circuit.

To make it just a bit more complex, we don't use AWG in the UK so at Table 2 is a conversion chart from AWG to UK standards.

Table 2

American Wire Gauge (#AWG)	Diameter (inches)	Diameter (mm)	Cross Sectional Area (mm2)
0000 (4/0)	0.460	11.7	107
000 (3/0)	0.410	10.4	85.0
00 (2/0)	0.365	9.27	67.4
0 (1/0)	0.325	8.25	53.5
1	0.289	7.35	42.4
2	0.258	6.54	33.6
3	0.229	5.83	26.7
4	0.204	5.19	21.1
5	0.182	4.62	16.8
6	0.162	4.11	13.3
7	0.144	3.67	10.6
8	0.129	3.26	8.36
9	0.114	2.91	6.63
10	0.102	2.59	5.26
11	0.0907	2.30	4.17
12	0.0808	2.05	3.31
13	0.0720	1.83	2.63
14	0.0641	1.63	2.08
15	0.0571	1.45	1.65
16	0.0508	1.29	1.31

Materials needed to complete Module 1:

1 x red coloured cable (positive)     (5.19 mm dia)
1 x black coloured       (negative)

1 x double terminal

1 x inline waterproof 20 amp fuse holder
1 x inline waterproof 10 amp fuse holder  

4 x copper tube terminals

That's enough for now

Mooring Warps (ropes)

A few posts ago showed how I had bought the wrong sized hawse pipe, it being too small to take a shackle and splice on the anchor. At the time I said I would use the the small pipe for mooring warps.

Mooring Warp Lockers

When I built the aft lockers I did so to the original design which had left a small volume of the lockers unusable.

Each locker has three bulkheads, the one nearest the camera, a rear locker bulkhead and then - just behind it - the main transverse bulkhead that goes right across the boat. The blurry picture below shows a close-up of the rear bullheads on the starboard locker.

When the top went on the locker the space between the bulkheads became sealed in. I thought that if I accessed this lost volume it would make an ideal locker for a mooring warp.

First a hole was cut out in the bulkhead. Then a hole in the deck .

Next the warp was fed into the locker from the top, and the end pulled through the bulkhead for securing to an anchor point.

Finally, the hawse pipe was fitted and the warp fed through it.

This now means that instead of 12 metre coils of rope waiting for someone to fall over them, the mooring warp lives in the locker - previously a lost volume.

Planning the Electrics/Electronics - Domestic System Part 1

Soon it will be time to install the electrics. Let’s start with the various application types of batteries. There are two types:     

  Starting batteries are designed to provide a big jolt of electrical power (or amperes) for a short period of time, then be quickly recharged. 

  Deep-cycle batteries (or House/Domestic/Leisure electrics battery) are built to supply a limited number of amps over a longer time and then be recharged more slowly. 

I will use AGM (absorbed glass mat) Batteries, explained below. 

The Domestic Electrics/Electronics
 At this stage I will ignore the Starting battery side until I have the Outboard Motor: the motor I will choose specifies the exact battery it needs.

   I will begin with the 'domestic/leisure' side of the equation: that is the battery that powers all the devices like lights, bilge pump, etc. Therefore, I will need to list the devices I mean to use and the power they will draw in Amps.

Most devices have the Amperage printed on them, if not you can use the table I add at the end of this post.

.
Calculating Ampere Hours Required (Ah)

         Device                         Amps          

1.   Bilge Pump                      3

2.   Dragonfly-5                     0.8

3.   Cockpit Light                   0.1

4.   Nav Lights                       3.7  

5.   2 Windscreen Wipers       2.0

6.   VHF  Radio                      1.2

                                       ________

Total Amps                           10.8  

Although it is unlikely that all the devices will be operating at the same time, especially continuously for 10 hours, we must cater for the maximum use for 10 hours - which we calculate thus:

                  10 x 10.8 = 108 Amp Hours (Ah)

So we need to find a (domestic/Leisure) battery capable of supplying at least, say, 110 Ah.

Battery Choice

I have selected a battery, Cost £160 (US$210), it's the:

12V 120AH LEOCH ADVENTURER AGM LEISURE BATTERY (LAGM120)

 Which satisfies the Ah I need.

It is a Absorbed Glass Mat (AGM) battery which is  dry-cell, with the battery acid being encapsulated in fibreglass sheets. In comparison to flooded batteries, AGMs offer increased levels of reliability and versatility – with no free acid, they can be mounted in any orientation and are better able to handle vibration.

See Link> https://www.alpha-batteries.co.uk/120ah-leoch-agm-leisure-battery/

Battery Location on Boat

The battery will be stowed in the aft starboard locker, the one nearest us in the picture below. Retaining straps have already purchased and will be shown during fitting.

This battery will need  special charging equipment.

Charging  the Battery -Ashore:

Costing £65 (US$85), I selected the charger shown as an accessory to the above battery.

12V 10A 7 STAGE CONNECT & FORGET AUTOMATIC BATTERY CHARGER WITH UK PLUG

See the Link for details> https://www.alpha-batteries.co.uk/catalog/product/view/id/598/s/12v-10a-connect-forget-leisure-battery-charger/category/148/

Ah Table

The Anchor System Part 5

You will see from earlier posts on here that the hawser pipe I'd used was too small, I therefore had to buy a larger one. Being polished stainless steel and a better quality meant it cost a lot more, that's life.

Using the new hawser pipe as a template I marked out the enlarged hole I would need to cut. I then drilled a series of small holes around the proposed hole shape. This would make it easier for the jigsaw as the thickness of the sprit, deck-planking and deck are over 2 inches.

Using the jig saw I cut out the hole.

There was a bit of fitting using a rasp until the hawser pipe fitted snugly. The pipe was turned upside down for me to apply sealing strip. The pipe was reinserted and screwed down tight

The warp was then inserted into the pipe and fed through to the chain locker.

When I got to the chain shackle and warp eye I felt a relief that they went through the pipe easily - which had been the problem earlier

I was pleased to see the offending parts lying in the chain locker.

Finally, the chain was all fed into the locker and the anchor fitting snugly into the self-launch bracket on the pulpit.

I'm really pleased to see another system in place and completed. The anchor will live in this location although I will add a few shackles to hold it in place whilst at sea First Time I've Used That Phrase so it's getting closer!!