Starting from Scratch

[knottybuoyz]

Hi Fella's

I'm starting from scratch designing the electrical system for our trawler project. I've read most of the books and followed the discussions here and elsewhere but having never done this before I'd like some input from all you experts. Attached is a drawing of what I've got so far, sans engine starting/control & charging sytems & bonding sytems.

The only legible format I can provide is Adobe PDF but can provide MS Visio or AutoCad files as well. I've spec'd out some of the equipment but not all and I'm sure requirements will change as this thing progresses.

Any help or advice is greatly appreciated.

Rick

[delmarrey]

I would say, when you do start the layout give yourself plenty of wire on the ends. Sure you'll be cutting away lots of short pieces but once you bundle them up they seem to get shorter. A small waste of wire it better then having to re-run.

I like the schematic! Very well laid out but I'm not that qualified to comment on the numbers.

Enjoy........................._/)

[DeepFrz]

Gord, I don't think your AC source selector switch is selecting the source. I don't believe that you want your AC hot to go to your battery charger when you are using your invertor. Or am I missing something.

Deep.

[knottybuoyz]

Originally Posted by DeepFrz

Gord, I don't think your AC source selector switch is selecting the source. I don't believe that you want your AC hot to go to your battery charger when you are using your invertor. Or am I missing something.

Deep.

Hey Deep

Nope it's totally isolated so the battery charger can only work on shorepower. The AC selector switches between the inverter AC and the shorepower AC. You could loop it by mistake but it wouldn't make sense charging the batteries from your inverter!

Rick

[knottybuoyz]

Originally Posted by delmarrey

I would say, when you do start the layout give yourself plenty of wire on the ends. Sure you'll be cutting away lots of short pieces but once you bundle them up they seem to get shorter. A small waste of wire it better then having to re-run.

I like the schematic! Very well laid out but I'm not that qualified to comment on the numbers.

Enjoy........................._/)

Hey Del

I need to draw it out somehow to "visualize" what I'm getting myself into.
Buying wire in bulk so there'll be plenty of leftovers for the next one! Opps hope Lori didn't read this!

Rick

[Pblais]

As shown you have 4 - 12 volt batteries wired as one single bank but you really don't indicate sizes and if one is for the engine alone. The battery combiner you chose only handles 3 banks, but you only have one bank drawn so you really don't need it That might be better speced out for some better discussions. Have you done computations for an energy budget to size the batteries? It's possible to use different batteries to cut down the number of banks. The type of batteries and how you place and handle them will make a difference in a lot of things not to mention cost.

Some little things you may want. Indicator lights for the bilge pumps. It's nice to see when they come on or sound an alarm. I would wire the the emergency pump to be set at a higher water level than the normal one and run from a float switch too. That way it kicks on when the little one is losing the battle. It shoudln't have to wait for you, but you can turn either on manually.

I would add manual switches to all pumps so you can do little things like pump when you want to when the level is less than the float switch. I would hard wire the pumps but make the manual switches run through the panel so you (or someone else) can't turn off the bilge pumps accidentally.

Battery monitoring is a real nice thing to have. Best thing I added to the last boat. You'll learn a lot and know when small problems are brewing by the battery usage. Smart charging would aslo require temperature sensors. There are units that combine the whole works monitor, charger, and inverter in one box. You may find you can reduce the size of the inverter by using more 12 volt devices and add some 12 volt auto style outlets. Cell phone chargers, laptop computers, GPS units and a lot of things like them. Inverters really waste a lot of your battery bank power. I would just be sure you really need all the "on the water" A/C power you may think you need. Smaller inverters would be cheaper and save power. You'll waste a lot of energy making AC power from DC. For a laptop computer it's more like 40% at best as you make AC from DC then make DC from AC.

Wire sizes on the windlass and thruster would be based on length of wire and that is something you have to compute based on the unit and the actual length of the DC lines. Controls from the deck and the bridge are nice too. Since they are low power it's not a lot to add.

Sounds like an exciting project.

[DeepFrz]

So, is it just the screwed up way you have drawn the 8367?

Deep

[Pblais]

So, is it just the screwed up way you have drawn the 8367?

If you flip it over to the left or right then you can have two inputs and one output. You only want one AC source. It's the inverter or the shore AC. later on if you added a genset you could switch that or some AC chargers will accept a modified square wave genset input. I think you want the shore charger to come off the main AC pannel as just another device. Then throw in an AC volt meter and polarity check to the panel so you don't energize any circuits until you know it's safe power. I blew up a shore charger that way An ameter on the load there would also be nice.

[knottybuoyz]

Originally Posted by DeepFrz

So, is it just the screwed up way you have drawn the 8367?

Deep

Oh I see it. I had to make up the 8367 which is basically a dpdt make before break rotary switch. There's two AC inputs, shorepower and inverter the diag shows them joined before entering switch. My mistake but I'll blame it on Visio auto-snapping them together .

[knottybuoyz]

Originally Posted by Pblais

As shown you have 4 - 12 volt batteries wired as one single bank but you really don't indicate sizes and if one is for the engine alone. The battery combiner you chose only handles 3 banks, but you only have one bank drawn so you really don't need it

Thanks for the input Paul. That's why I asked!! In the computer world there's a hard drive configuration called RAID, Redundant Array of Inexpensive Drives, what I'm using is an Redundant Array of Cheap Batteries! Local automotive deep cycle cheapies for the house bank. There will be 1 starting battery in a second bank but I haven't drawn that yet.

Originally Posted by Pblais

That might be better speced out for some better discussions. Have you done computations for an energy budget to size the batteries? It's possible to use different batteries to cut down the number of banks. The type of batteries and how you place and handle them will make a difference in a lot of things not to mention cost.

Spacing and the other systems not yet in place will be drawn as I go along. It's a learning process and definitely a work in progress. The batteries we have (Motomaster 103 Amp Hour Deep Cycles) in our current boat is what I'd use, they're relatively inexpensive and available and will last min. 5 years with proper charging. Cost around $450.00. Eventually I'll work out the "energy budget" but it might be nothing more than an academic exercise for this boat.

Originally Posted by Pblais

Some little things you may want. Indicator lights for the bilge pumps. It's nice to see when they come on or sound an alarm. I would wire the the emergency pump to be set at a higher water level than the normal one and run from a float switch too. That way it kicks on when the little one is losing the battle. It shoudln't have to wait for you, but you can turn either on manually.

Good ideas on the warning lights, I'm familiar with the mimic panels used on our ships and was planning something similar as a project later on down the road.

Originally Posted by Pblais

I would add manual switches to all pumps so you can do little things like pump when you want to when the level is less than the float switch. I would hard wire the pumps but make the manual switches run through the panel so you (or someone else) can't turn off the bilge pumps accidentally.

I'll add the manual switches and auto-switch for the big bilge pump. The aft pump is deep in the keel below the engine and the fwd one is about 10" higher underneath the cabin sole so we've got the level offset built in.

Originally Posted by Pblais

Battery monitoring is a real nice thing to have. Best thing I added to the last boat. You'll learn a lot and know when small problems are brewing by the battery usage. Smart charging would aslo require temperature sensors. There are units that combine the whole works monitor, charger, and inverter in one box. You may find you can reduce the size of the inverter by using more 12 volt devices and add some 12 volt auto style outlets. Cell phone chargers, laptop computers, GPS units and a lot of things like them. Inverters really waste a lot of your battery bank power. I would just be sure you really need all the "on the water" A/C power you may think you need. Smaller inverters would be cheaper and save power. You'll waste a lot of energy making AC power from DC. For a laptop computer it's more like 40% at best as you make AC from DC then make DC from AC.

Points taken. Monitoring is on my list of "nice to haves" for this boat. I'm thinking we'll use this boat the same way we use our current boat and I figure a 1000 - 1500 watt inverter would be plenty. The largest draw away from the dock will be the laptop. Not sure what it's power requirements are exactly but it and the fridge run fine on existing 700 watt inverter. We'd like to have a TV & DVD player for evenings on the hook. We have a few DC accessories and appliances and use them sparingly. The 12 volt coffee maker is a POS so it never gets plugged in. We'll put the 1000 watt microwave in but probably won't use it much away from the dock.

Originally Posted by Pblais

Wire sizes on the windlass and thruster would be based on length of wire and that is something you have to compute based on the unit and the actual length of the DC lines. Controls from the deck and the bridge are nice too. Since they are low power it's not a lot to add.

I'm sizing the wire based on estimated runs according to the ABYC 3% voltage drop charts. Also memorized Gord May's "Ohms Law & You" article! We'll run the windlass from the wheel aswell as deck controls. I don't know exactly which windlass yet so I've just doodled in the main conductors. The thruster will be directly below the battery bank with a total run of <6' so wattage of whatever thruster we buy will determine eventual conductor size.

Originally Posted by Pblais

Sounds like an exciting project.

Just a bit of background on the boat. It's a Jacques Mertens designed 28' trawler built in "Stitch & Glue" composite method.

http://www.bateau.com/proddetail.php?prod=TW28



We'll use it for weekend & evening cruises up and down the St. Lawrence River with the occasional 3 week vacation trip through the other nearby inland waterways such as the Rideal, Trent Severn and Erie Canals. Our season is relatively short, May to October and we're hoping to extend that a bit with the help of a propane fired cabin heater and global warming.

We are currently discussing some modifications with the designer and are hoping to stretch her 30" in the midship area for a larger main cabin allowing us to put in a full queen island berth and move the galley up. In total she'll be 30 1/2' long with a 10' beam and 3' draft. One small diesel, 40 - 50 hp with a 1000+ nautical mile range.

I expect the total cost to be somewhere between $65K & $72K. Compare that with new production boats in similar sizes and features and it's about 50% of the price. When you can't afford to buy what you want you build it! Something I've wanted to do all my life.

Thanks for your interest and input.

Rick

[DeepFrz]

Looks like a great project. I wish you all the best in building her and will watch on with envy.

Cheers, Deep

[Pblais]

Sounds like a nice project. I grew up on Lake Ontario and lived a block from the Erie Canal too. Some nice boating May to October.

You might want to take the four batteries and divide them into 2 banks then use a (1,2, both, off) switch so if one battery goes south you can un hook a pair from the bank. Thats the risk with flood batteries. In one bank you can lose it all for one cell gone bad. If you watch the batteries close you can avoid the trouble of losing the whole lot.

For laptops get a 12 volt adapter it saves a lot of power. If you get the urge to go for a big screen TV the plasma TV's take more power than a fridge run off the inverter. For video I'm now running a 15 inch LCD TV off a CD player that also outputs video from a DVD. A small inverter can run it fine. You just need to think small and it can stay simple. Avoid the temptation to use a Microwave away from the marina and you'll be OK.

When you get closer to being ready send a message to Rick for the final review.

[knottybuoyz]

Modifications:

1. Split battery bank into two w/1,2/1+2 switch
2. Doodled in engine w/alternator & starter
3. Drew in starting battery
4. Removed primary grounding wires for clarity
5. Drew in and wired manual bilge pump capabilities
6. Fixed AC source selector switch

Somehow it seemed like a lot more work than that!

To be done:

1. Draw in lights & sockets
2. Draw in solar panel & charge controller
3. Work out the materials list
4. Move some things around for clarity

Back to the books to see what I've missed.

Rick

[Pblais]

Rick,

Looks like something that could actually work!.

You might swap the ON/OFF switch from the starting battery to a 1,2,both Off. That would let you choose 1 - starting battery or 2 House bank in case the starting battery gives itself up.

You set it up so when the engine switch is set to 2 the house starts but the starting battery still charges. You really won't need the BOTH position, though I did one time when all the batteries were about shot. Just had enough to crank it over but the next time I tried to leave the dock nothing.

[knottybuoyz]

New battery configuration using 6 volt deep cycles split into 2 banks for house & thruster/windlass.

Emergency cross connect between starting & house batteries added.

I'm thinking Paul's recommendation for battery monitoring is going to be more important with this many batteries. Thoughts? I've got lots of space for this many and weight isn't a consideration, they'll be low in the boat just below the drawn waterline. I may start with 2 & 2 and add more if needed.

Where do you wire in the feed from the solar panel controller? Just ahead of the battery combiner?

Any help or suggestions are appreciated.