Electrical System write up
Posted: Sun Apr 08, 2012 2:38 pm
I have seen very little on the forums about electrical systems and it has caused me many hours of grief figuring out, so I thought I would share. I bought this 50 AmpHour AGM battery on Amazon, the cheapest place I could find it. These have really good ability to hold a charge and won’t leak:
http://www.amazon.com/Universal-Power-4 ... 529&sr=8-1
The thing that has given me the most consternation is how to secure the battery upright in an acceptable manner. I kept having nightmares of getting into a squall and being glued to the helm, listening to the 30lb block wreaking havoc down below. I tried to build a small shelf out of wood, but didn’t like the outcome or the amount of space it took up. So, I decided to use two part foam. I didn’t need a lot, so I bought it from this model rocket vendor:
http://www.siriusrocketry.biz/ishop/ind ... cts_id=771
Most foam sold is for flotation and is 2lbs in density, which is not very dense. This foam is 6lbs density and just right for my needs. For foam, lower density means less air and harder foam. You can actually make high density foam less dense by adding a drop or two of water, but you can’t make less dense foam more dense. Anywho, I fiber glassed the inside of the boat box with some cloth to firm it up, then taped up a cardboard box inside to the dimensions I wanted the foam to fill to. Then came the foam. Here is a good website on how to use it. Follow his directions and it is pretty straightforward.
http://bertram31.com/proj/tips/foam.htm
It was fun and I actually ended up thinning it with 2 drops of water on the second pour. Temperature is important for the foam to expand and it was cold, so I used a lamp as a heater. I think it would have expanded more, even without the water, had it been warmer. It is easy to add layers and it bonds well, so I recommend several small pours which allow you to make up for areas where it expands too much in the middle. I think it would be a good idea to wrap the battery in wax paper and suspend it where you want it, then pour, so the foam would fill around a bit and give you a ledge to keep the battery in place, but I didn’t. Once to the level I wanted, I trimmed the foam with a bread knife and box cutter/chisel. It really turned out nice and bonds very well to the hull.
Final step in securing the battery was to screw in some padeyes where I will use a piece of webbing to snug the battery to the side of the box. I could only upload 3 pics, so you will have to use your imagination on that.
Next is the circuitry. First, I am not an electrician and I don’t recommend you do any wiring if you are not competent, I am just sharing what I did. If you don’t know anything about electronics (like me), the Don Casey book is good, but really too complicated for what we need. I struggled for resources, but figured it out with a buddy’s advice. I will walk through the circuits from the battery hot lead back to the battery ground.
I installed fresh switches and circuit breakers into the original Clark panel which I wanted to preserve. I chose circuit breakers instead of fuses; they sell them at WestMarine that fit into the panel. The hot wire from the battery goes to the first circuit breaker. I crimped the 8ga battery lead and a 10ga wire using a spade connector that fit the circuit breaker. The 10ga wire is a jumper and feeds the next breaker even if the first one opens. The second circuit breaker has the jumper from the first and its own jumper wire continuing the jump to the third circuit breaker. Each circuit breaker is then fed to its own switch. The switch in turn leads to a discrete circuit on the block terminal. The current only flows through a circuit if the amperage is within the circuit breakers capacity (it’s closed) and the switch is closed.
The hot wires from the switches come into the terminal block. If you didn’t have many devices, you could run the hot wires form the switches directly to the devices. However, I wanted to have space to expand and I don’t think it would be as tidy (safe) putting a bunch of spade splitters on the switch. The wires coming in from the right (pic below) are from the switches. The two wires leaving the top terminal from the left side feed the bow and stern lights. Both of mine are LED, so don’t draw much current, but I still used insulted 10ga wire, just to overbuild. The second circuit has a small speaker amplifier, a usb charger I homemade from an old car charger and the interior dome light (also LED). Instead of having three wires on one terminal, I used jumpers to connect three terminals to the same hot wire from the switch. These three terminals are now all the same circuit. The last circuit is for a cigarette lighter for temporary devices and I intend to add a depth finder and bilge pump later. Don’t be confused by its wires leading up when the others are going down. This is only because it would mount in the panel above it, where all the other wires are headed to other parts of the boat and are routed down.
From the hot terminal, the wires go out to the device you want to power and come back as negative wires. The negative wires are all attached to the negative bus on the left. A bus is different from a block. A bus is just a slab of metal, so everything attached shares the same amount of charge, unlike the terminal block where each circuit is isolated (unless you have a jumper joining them). So the negative bus is finally attached to an 8ga wire back to the battery.
A final note about the stereo system. I think music is required on a boat; listening to Buffet or reggae while sailing is not optional to me. So, I bought a very small amp made for motorcycles/snowmobiles. I think it is something like 25watts per channel. Then I got two 3” polyplaner speakers and will attach them to the bridge over my hatchway where I am running my cleats for singlehanded set up. Instead of using a head unit, which would suck more power, I have repurposed an old 12v phone charger. I cut the wires that led to the cigarette plug and soldered spade connectors that attach to my terminal block. Then, I cut off the end that led to the phone and soldered it to an old USB cable. There are online guides to this process. Finally, I bought a Bluetooth receiver from Monoprice for $20 that is powered via the USB cable. I then can send tunes to the Bluetooth receiver from my phone in the cockpit, which in turns sends the signal via a standard 3.5m male to male headphone cable to the amp. The amp is powered via its own dedicated lead on the same circuit.
Hope this helps someone!
Kuriti
http://www.amazon.com/Universal-Power-4 ... 529&sr=8-1
The thing that has given me the most consternation is how to secure the battery upright in an acceptable manner. I kept having nightmares of getting into a squall and being glued to the helm, listening to the 30lb block wreaking havoc down below. I tried to build a small shelf out of wood, but didn’t like the outcome or the amount of space it took up. So, I decided to use two part foam. I didn’t need a lot, so I bought it from this model rocket vendor:
http://www.siriusrocketry.biz/ishop/ind ... cts_id=771
Most foam sold is for flotation and is 2lbs in density, which is not very dense. This foam is 6lbs density and just right for my needs. For foam, lower density means less air and harder foam. You can actually make high density foam less dense by adding a drop or two of water, but you can’t make less dense foam more dense. Anywho, I fiber glassed the inside of the boat box with some cloth to firm it up, then taped up a cardboard box inside to the dimensions I wanted the foam to fill to. Then came the foam. Here is a good website on how to use it. Follow his directions and it is pretty straightforward.
http://bertram31.com/proj/tips/foam.htm
It was fun and I actually ended up thinning it with 2 drops of water on the second pour. Temperature is important for the foam to expand and it was cold, so I used a lamp as a heater. I think it would have expanded more, even without the water, had it been warmer. It is easy to add layers and it bonds well, so I recommend several small pours which allow you to make up for areas where it expands too much in the middle. I think it would be a good idea to wrap the battery in wax paper and suspend it where you want it, then pour, so the foam would fill around a bit and give you a ledge to keep the battery in place, but I didn’t. Once to the level I wanted, I trimmed the foam with a bread knife and box cutter/chisel. It really turned out nice and bonds very well to the hull.
- 2.JPG (22.2KiB)Viewed 48373 times
Next is the circuitry. First, I am not an electrician and I don’t recommend you do any wiring if you are not competent, I am just sharing what I did. If you don’t know anything about electronics (like me), the Don Casey book is good, but really too complicated for what we need. I struggled for resources, but figured it out with a buddy’s advice. I will walk through the circuits from the battery hot lead back to the battery ground.
I installed fresh switches and circuit breakers into the original Clark panel which I wanted to preserve. I chose circuit breakers instead of fuses; they sell them at WestMarine that fit into the panel. The hot wire from the battery goes to the first circuit breaker. I crimped the 8ga battery lead and a 10ga wire using a spade connector that fit the circuit breaker. The 10ga wire is a jumper and feeds the next breaker even if the first one opens. The second circuit breaker has the jumper from the first and its own jumper wire continuing the jump to the third circuit breaker. Each circuit breaker is then fed to its own switch. The switch in turn leads to a discrete circuit on the block terminal. The current only flows through a circuit if the amperage is within the circuit breakers capacity (it’s closed) and the switch is closed.
- 4.jpg (50.44KiB)Viewed 48373 times
- 3.jpg (66.58KiB)Viewed 48373 times
A final note about the stereo system. I think music is required on a boat; listening to Buffet or reggae while sailing is not optional to me. So, I bought a very small amp made for motorcycles/snowmobiles. I think it is something like 25watts per channel. Then I got two 3” polyplaner speakers and will attach them to the bridge over my hatchway where I am running my cleats for singlehanded set up. Instead of using a head unit, which would suck more power, I have repurposed an old 12v phone charger. I cut the wires that led to the cigarette plug and soldered spade connectors that attach to my terminal block. Then, I cut off the end that led to the phone and soldered it to an old USB cable. There are online guides to this process. Finally, I bought a Bluetooth receiver from Monoprice for $20 that is powered via the USB cable. I then can send tunes to the Bluetooth receiver from my phone in the cockpit, which in turns sends the signal via a standard 3.5m male to male headphone cable to the amp. The amp is powered via its own dedicated lead on the same circuit.
Hope this helps someone!
Kuriti
. Mine has an inset designed into the fiberglass to accommodate the wood, which you wouldn't have. You would need to figure something out, but you could also cut the hole bigger than mine, which would be nice.