Please help with DC wiring

[Jeunesse27]

Starter & OB should come off "C" post of batt switch. As is now you have no isolation of start battery from starter or outboard.. If one of those starters should hang up yoo'd be glad you had a switch. Also a requirement if you want to wire to safety standards. Don't forget over current protection for batteries..I also don't see wire gauges?

P.S. I just finished a few months of testing the new Balmar Smart Gauge and hands down it is the most simple battery capacity meter out there. Battery monitors are great but only as great as how you use, program them and track changes in your batteries... The Smart Gauge is truly plug and play....

Thanks MS! The diagram is a work in progress, today was mainly learning how to use TurboCAD. I will do some reading on gauge selection and fuses and will update the diagram to reflect that, any comments always appreciated

 

[Jeunesse27]

Just noticed now that not all the items are visible when I saved to PDF, I'll try and see why tomorrow.

 

[Jeunesse27]

This is my dc panel I have on board, plan is to remove the battery switch from it and in its place put a battery monitor either like the victron or balmar. The switch is then going to be placed under the chart table near the batteries so that the starter wires are as short as possible.

 

[Stu Jackson]

Why do all that work? It is a recurring misconception that switches should be moved closer to the engine "so that the starter wires are as short as possible." If there is any concern about the distance, simply increase the wire size. On our C34 I'm sure the engine is further away, but most likely we use the same #4 wires. My starter has been working just fine since 1986. Maine Sail suggests increasing the wire size, based on his experiences with his C36, but I believe it to be adequate.

If it was my boat, and the engine started just fine, I'd leave the switch where it is and install the monitor elsewhere.

I'm just trying to save you unnecessary work.

 

[Jeunesse27]

Less money spent on wire... My catalina 30 is from 1974 I believe, its serial number 0027 so everything on that boat is pretty old and things haven't been as standardized as you'd find on catalina 30's in the 0300+ serial numbers.

 

[weinie]

If it were me, I'd save some dough by forgoing the battery monitor. You need to see how you will be sailing the boat and what your power demands are. And even then, if you find your battery running low, you know you will have a reserve battery to get your diesel started and get everything charged up again.

If you want to be "off the grid" you can also mount a small solar panel (with controller of course) to make sure your batteries are topped off for the weekend. It's cheaper than those battery monitors and while you are sailing, it also puts in what your electronics take out (more or less, depending on cloud cover).

 

[Jeunesse27]

If it were me, I'd save some dough by forgoing the battery monitor. You need to see how you will be sailing the boat and what your power demands are. And even then, if you find your battery running low, you know you will have a reserve battery to get your diesel started and get everything charged up again.

If you want to be "off the grid" you can also mount a small solar panel (with controller of course) to make sure your batteries are topped off for the weekend. It's cheaper than those battery monitors and while you are sailing, it also puts in what your electronics take out (more or less, depending on cloud cover).

Yes but how exactly am I going to know how much my DC loads draw?

 

[weinie]

Yes but how exactly am I going to know how much my DC loads draw?

Estimate!!!! It's not hard at all and you can be reasonably close with a quick calculation.

For instance, my Autopilot draws 5 Amps if the drive motor is running all the time (which obviously it is not). So if I have my AP on for 6 hours, I will be using 30AH MAXIMUM. That is by far the largest draw on my boat while sailing. I know my house bank is just shy of 200 AHs I know I have about 170 AH left (or about 70 AH to get my bank down to 50%).

My other electronics use much less and that can be calculated as well. I even have an electric head which draws a full 16 amps. However since it only gets flushed for 10 seconds max each time, it only draws .03 (10/3600 x 16) AH per flush!!! 10 flushes will only use .3 AH!

 

[Jeunesse27]

Fair enough, so a simple ammeter will do the same then.

 

[weinie]

Fair enough, so a simple ammeter will do the same then.

Not necessary! Just look in the manual of your electronics to find out how much current they draw. Then multiply that number my how many hours that item will be in use for.
A 5 Amp device will draw 5 amps over a give period of time. If you plan to use it for 10 hours, you will need to dedicate 50AH from your batteries.

For lights and radios whose power usage is indicated in watts, you can use the following equation:

Power (in watts) = Current (in Amps) x Voltage (12 volts obviously)
In other words, a 10 watt light bulb will require 10/12 = 1.2 Amps. If you leave that bulb on for 3 hours, you will use 1.2 x 3 = 3.6 AH.
Then make a list of current draw and how long each will be on for during a typical day.
Do another one for a typical overnight cruise.
Calculate the AHs you will need for both situations.
With your big batteries and that huge charger (assuming you plug it in each night) you will never run out of juice unless you are running power hungry refrigeration.

ETA: edited for clarity

 

[Jeunesse27]

Not necessary! Just look in the manual of your electronics to find out how much current they draw. Then multiply that number my how many hours that item will be in use for.
A 5 Amp device will draw 5 amps over a give period of time. If you plan to use it for 10 hours, you will need to dedicate 50AH from your batteries.

For lights and radios whose power usage is indicated in watts, you can use the following equation:

Power (in watts) = Current (in Amps) x Voltage (12 volts obviously)
In other words, a 10 watt light bulb will require 10/12 = 1.2 Amps. If you leave that bulb on for 3 hours, you will use 1.2 x 3 = 3.6 AH.
Then make a list of current draw and how long each will be on for during a typical day.
Do another one for a typical overnight cruise.
Calculate the AHs you will need for both situations.
With your big batteries and that huge charger (assuming you plug it in each night) you will never run out of juice unless you are running power hungry refrigeration.

ETA: edited for clarity

Yes I understand all the math and am familiar with it, however those calculations are based on best case scenario where all the wires are in good condition. I am still using some of the original wiring for lights that are embedded in the deck (What where you thinking Catalina Yachts???), an ammeter (and voltmeter) in that case would also let me know if a particular circuit has issues. For the $40 price tag it's worth it to me.

 

[weinie]

The battery monitor won't really tell you if you have a problem with the wiring. If you are concerned, test each circuit with a multimeter and confirm that you are getting 12 volts at each device. If you have a large voltage drop or no voltage at all, then you might have a problem. Otherwise, if the wire is not chafed and the terminal connections are not corroded, I'd leave it in place! As long as the wire is appropriately fuse protected you are safe.

As far as the battery wires are concerned, as Stu said above, catalina may have undersized the wires but mine seem to be fine and I've had no problem starting my motor. Once again, just make sure they are not chafed, have good, clean terminal connections and are fuse protected at the battery itself.

I'd be more concerned with the AC side of your electric if you plan to use it. Your original outlets may not be grounded and if original, certainly don't have GFCI protection. It's also recommended (though I haven't done it), to replace the single pole master AC breaker with a two pole one.

 

[Jeunesse27]

The battery monitor won't really tell you if you have a problem with the wiring. If you are concerned, test each circuit with a multimeter and confirm that you are getting 12 volts at each device. If you have a large voltage drop or no voltage at all, then you might have a problem. Otherwise, if the wire is not chafed and the terminal connections are not corroded, I'd leave it in place! As long as the wire is appropriately fuse protected you are safe.

As far as the battery wires are concerned, as Stu said above, catalina may have undersized the wires but mine seem to be fine and I've had no problem starting my motor. Once again, just make sure they are not chafed, have good, clean terminal connections and are fuse protected at the battery itself.

I'd be more concerned with the AC side of your electric if you plan to use it. Your original outlets may not be grounded and if original, certainly don't have GFCI protection. It's also recommended (though I haven't done it), to replace the single pole master AC breaker with a two pole one.

Thanks for the suggestions. I did replace the AC outlets to GFCI outlets (2 on board port/startboard), the main AC is still original but I do have a dual pole one in my goodie bin... I am upgrading the starter and ground cable to new 1/0 wire to start with, I will then check the condition of all the heavy gauge wires I have to see if any of them are still in good useable condition and either get new wire of use what I have.

 

[Jeunesse27]

Wish they made something simpler, live a set f dies that can be used with a table wise or hydraulic press...
http://shop.sailboatowners.com/prod.php?12660/Correct Crimp Heavy Duty Crimp Tool

Anyone try one of these?
http://www.ebay.com/itm/SDT-K05-1GL...ts-8awg-1-0-awg-w-rotating-dies-/191078540949

 

[woodster]

Wish they made something simpler, live a set f dies that can be used with a table wise or hydraulic press...
http://shop.sailboatowners.com/prod.php?12660/Correct Crimp Heavy Duty Crimp Tool

you can have your cables made by Genuinedealz or you can buy the parts and fittings from him and he will loan you a crimper on your shipment and all he ask is you pay the return freight goggle him and contact him to confirm ...

regards

woody

 

[Maine Sail]

Wish they made something simpler, live a set f dies that can be used with a table wise or hydraulic press...
http://shop.sailboatowners.com/prod.php?12660/Correct Crimp Heavy Duty Crimp Tool

That is the best value in a crimp tool for battery lugs going. You simply can not buy a better crimp tool for the money. You do not need the ratcheting version.. Buy it, use it, then sell it here in the classifieds....

If you are looking to save money forget the second charger. Hundreds of customers with "calculated" Ah daily loads, yet to see one that is even close... The batt mon is good money well spent the second charger is just a nice to have..

 

[Solstice]

That is the best value in a crimp tool for battery lugs going. You simply can not buy a better crimp tool for the money. You do not need the ratcheting version.. Buy it, use it, then sell it here in the classifieds.... If you are looking to save money forget the second charger. Hundreds of customers with "calculated" Ah daily loads, yet to see one that is even close... The batt mon is good money well spent the second charger is just a nice to have..

I can vouch for the FTZ crimper. Based on Maine Sails' recommendation I Bought one last year and it is worth every penny! Also highly recommend Genuinedealz for all your wiring needs...

 

[Jeunesse27]

How's this? I included the wire size (Might still change all 1/0 wire to 2/0, price is negligible and I'm starting from scratch anyway). I haven't worked on fuse sizes yet. I know the fuse is supposed to protect the wire, so because my starter motor will never be pulling the amount of amperage that the 1/0 cable is able to deliver I should be ok with 150A~200A?

 

[Stu Jackson]

Nice diagram. You seemed to have picked up computer drafting quite quickly.

1. Suggest you use a positive bus bar, like your negative one, to avoid overloading the house bank battery post.

2. It may have been covered here earlier, but I'm confused about the outboard and seemingly inboard engine(s). Could you please clarify?

3. Had you considered just using an I/O switch instead of the second 1-2-B switch fro the reserve, based on the wiring diagrams I think I provided a link to earlier in this topic. See page 2, reply #27.

Nice job, good luck.

 

[Jeunesse27]

1. Just working on a revision right now to add fuses and +bus bar.

2. The inboard is a diesel M25 and I also have a yamaha 9.9 High Thrust outboard hanging off the transom for emergency use. Our previous inboard was an Atomic 4 which was extremely unreliable and we had to add an O/B, the new M25 (rebuilt by me with help of professional heavy duty mechanic) is very reliable but we are still hanging on to the O/B for now. I have used it one before when all my battery banks died and couldn't start the diesel, easy done because I can pull start the O/B and let it recharge the batteries enough to start the inboard. Essentially using it as an emergency generator, LOL...

3. I have 3 of these 1,b,2,off switches so I want to use them and not have to buy more stuff.