Preliminary Wiring Diagram

[Snotter]

I am getting ready to add a 75 amp altenator and smart regulator to my morgan 41. I ripped out the old altenator, dumb regulator, and obsolete isolator. The boat has 3 battery banks: 2 house banks wired to a 1-2-B switch and a dedicated engine bank that is always connected to the engine. Attached is my preliminary design that omits many details that have yet been considered, but, conveys my current thoughts on how I wouild like to rewire the banks, altenator and starter. The basic design does not show fuses, which I plan to use judicially. I am hoping that flaws in my design will be pointed out by this community.

I have been toying with the idea of adding a 2nd battery combiner between the 1st and 3rd banks; however, since the altenator is always connected to at leat one battery bank, this may not be necessary. The attached design dictates that the 1-2-B switch be switched appropriately while the engine is running in order to charge the 3rd bank. Any thoughts?

 

[Stu Jackson]

Nice job

You're getting there. It is much like the diagram at reply #12 here: http://c34.org/bbs/index.php/topic,4949.0.html but you've done a couple of things that don't agree.

1. The alternator output should ONLY go directly to a battery and NOT to a switch, ever. The reasons are to avoid someone turning the switch off by always having a load on the alternator output (AO).

2. We may have discussed the use of a third battery earlier, but I forget the details and the reason. Easiest thing is to just combine them into one larger house bank, but if you don't want to, then just use either a simple on off switch to handle its charging or use the 1-2-B for that. The best place would be a wire off the PDP (where the AO goes to the house bank).

As shown on the referenced link diagram, the switches should be used to determine where power from sources goes, and not as wiring connectors, which seem to be what the "splices" in the wiring you show indicate. Remove those splices and show the wiring as it would actually be run.

I'm just not physically in a position to print out and annotate your diagram today, so I hope this describes it enough for you.

Good start.

 

[Ed Schenck]

What is the reason for the two house banks? My own system has all the same advantages but is much simpler. I have a 400ah house bank and an isolated starter battery. The two charging systems(alternator and Freedom 20) are connected to the house bank. A combiner keeps the starter battery topped off. That's it, one old battery switch(1979) and a combiner. The alternator and regulator are new. Do not understand the need for the complexity.

 

[Bill Roosa]

Only have 1 house bank

One larger house bank will not be drained as deeply and last longer than 2 smaller banks. then you just need one 3-way switch.
KISS

 

[Maine Sail]

Snotter,

As others have said lose the third bank. This is WAY more complex than necessary.

Wire the alt, and other charge sources, to the house and charge the start bank off the house via an Echo Charger, Duo Charger or an ACR (automatic charging relay).

If you are keeping a dedicated, hard wired starting battery a Blue Seas Dual Circuit Plus battery switch is an ok choice so long as you ignore the "combine" feature of it but it lacks the redundancy and features of a 1/2/BOTH/OFF switch. I like them on center console fishing boats but that's about it. If you already have a 1/2/BOTH/OFF it could still be a useful and excellent device if you wanted it to be when appropriately re-wired..

Unless there is some odd underlying reason why you have it, I vote to lose the third bank and simplify..

 

[RichH]

Parallel that house battery bank for the ultimate in simplicity!

If you 'must' keep 3 banks, Best is to connect B1 & B2 in parallel connection (using the "Both" on the batt switch OR direct parallel without the batt switch for 'simplicity') and apply another additional combiner from the alt. (or B2 or B1) to B3 Go to www.yandina.com --->combiners---->installation (manuals)

 

[Snotter]

All, I agree that 2 banks are all I would need; however, after considerable thought I've decided to retain the 3rd bank. Here is my reason. My 3 banks are configured as following: bank 1 has 2 12v tractor batteries that are now about 1 year old; bank2 has 3 deep-cycle, group 27 or 32 (I don't know which at this time) batteries in parallel that are about 1.5 years old; bank 3, which is currently hot wired to the engine, consists of 1 12v tractor battery which is about 2 years old. The batteries that I call tractor batteries are beasts. Bank 2 requires the most maintenance. When they (the 3 batteries in bank 2) goes belly up, I will replace them with a single tractor battery. Hopefully this will happen when the battery in bank 3 should be replaced so that I can combine bank 2 and bank 3. My fear in paralleling bank 2 with bank 3 all the time is that when a battery in bank 2 fails (bank 2 in my oppinion is the weakest link in the 3 bank system) it will destroy the batteries in bank 1. The batteries in bank 1 (and bank 3) are about 150$ a piece at Batteries Plus (the only place I can find them in north central AL). Also, I have an extra 1-2-B switch already. Too bad I don't already own a second combiner; however, they aren't expensive, in my opinion.

Stu, I drew heavily from the link you sited. Your opinion carries weight with me. When evaluating my schematic, think electrical continuity. After my research, and after I get all the wires, cables, connectors, adheasive backed heat shrink tubing, etc., I will wire the altenator output (actually, the output of the smart controller) directly (through a fuse) to a battery post in bank 1. Doesn't my diagram indicate that bank 1 will recieve altenator juice regardless of switch location?

I ordered Nigel Calders book on electrical systems (I forget the proper title). It should be delivered on Monday. I look forward to perusing it.

 

[Stu Jackson]

Yup, it did look familiar. With all the "T" fittings on your diagram, it is difficult to know how you are physically gonna wire it, that's why I suggested the corrections. And since wires only have two ends, that's why - 'cuz what you draw should equal what you physically install and will avoid confusion. Then go back and re-read my earlier suggestions. Maine Sail and I generally agree on systems, and most of the folks have suggested simplicity, but I think I remember your earlier reasons for keeping three banks. If that's the case, then use one switch as a simple on/off switch for #3 when charging and if #3 is your reserve bank, then you rarely need to ever turn that switch on 'cuz the reserve bank is almost always fully charged because there's so little coming out of it. A combiner's just an automatic switch and you can do it just as well with the switches you already have in hand.

 

[Maine Sail]

Snotter,

I am going to guess that the "beast" batteries are either 8D's or 4D's. When it comes time to upgrade you may want to consider a bank of 6V golf cart batteries. Pound for pound, dollar for Ah's and sq in size to sq inch size they are the most bang for the buck. Four 6V golf cart batts will yield about 450 Ah's and two 4D's (same basic foot print size wise) about 320 Ah's...

 

[Snotter]

Maine Sail, would you happen to know what my batteries are rated at? Pound for pound, you are probably right about bang for the buck; however, in defense of the big batteries, they are incredibly robust, and, because they are so big, they don't need constant watering. Moreover, that there is no way to use those friggen rectangular caps that cover 3 cells at a time, it is a safety feature that the screw on caps are spaced so far apart. (A couple of weeks ago I got sprayed with battery acid in my eyes because a rectangular cap flipped off towards me. Fortunately the burns missed my corneas. My eye doctor made me promise to buy goggles.) I will re-evaluate my choice for batteries when I see how long they last. However, between my 4-stage Dolphin charger and the 3-stage smart controller that will be connected to the altenator, I suspect my batteries will last a long time inspite of the fact I run the refrigerator 24/7. I keep meaning to build an AC power supply dedicated to the refrigerator. The will help extend the batteries and cut down on the need for watering all those batteries.

Stu, I plan to post a more detailed wiring diagram prior to when I begin wiring things up. I will anotate where the actual wires go in that diagram. I want to do things right since my old ferrous battery charger almost caused a fire when it failed. As I mentioned previously, I am an advocate of fuses in line of all 12 v wires supplying a charge to the batteries.

If anyone wants the .ppt file that corresponds to my jpg, email me through sailboatowners.com with an email address that accepts .ppt attachments.

 

[Maine Sail]

Maine Sail, would you happen to know what my batteries are rated at? Pound for pound, you are probably right about bang for the buck; however, in defense of the big batteries, they are incredibly robust, and, because they are so big, they don't need constant watering.

Not unless you know the brand and whether they are 4D or 8D or another size. When people refer to tractor batteries they are usually talking about 4D's or 8D's so I took a stab.

Most 4D's that are deep cycle, not starting or dual purpose 4D's, are about 160 Ah's each. Dual purpose 4D's, which are more common, are about 135 Ah's +/-..

 

[Stu Jackson]

You can email me a copy by using the contacts pm on the site. Would enjoy helping. The BIG monster batteries are a pain to replace, which is what MS is getting at. Once you get them off the boat, you'll never ever put anything like that on again, even if you've already bought them and have them on the dock right next to the boat, ready to go in. Just 'cuz they don't bubble or dry out doesn't mean they're fine. Check the cells with a hydrometer.

 

[Snotter]

I cheated when I replaced my batteries--I hired a yard worker.

 

[Snotter]

Here is draft #2 that incorporates the changes that Stu recommended. Stu, notice that I moved the connection of Bank 3's switch to the C post of the main 1-2-B switch. I felt that the change would result in more flexibility.

current return paths, fuses, and more delail will be added in future drafts.

 

[Stu Jackson]

Yup, it does

Looks good, putting it on the C post gives you the flexibility to determine which of the Bank 1 or 2 parallels with B3. Still suggest you label them House B1 & 2 and reserve bank B3.

Also, please # the switches so we can refer to them properly. S2 to B3 operationally remains OFF almost all of the time unless B3 needs a charge.

 

[Snotter]

Good suggestions Stu.

I've updated the diagram.

 

[paulj]

Snotter

All grounds to one common ground......


paulj :troll:

 

[Snotter]

Snotter

All grounds to one common ground......


paulj :troll:

No--don't want stray currents eating away at my under-water metal parts. However, some common grounds must be accomodated when it is not practical to do otherwise.

 

[Don S/V ILLusion]

No--don't want stray currents eating away at my under-water metal parts. However, some common grounds must be accomodated when it is not practical to do otherwise.

For a thorough explanation of the need for a single common ground, there are discussions of this issue in virtually every boat electrical book. Suffice it to say that multiple ground paths provide the biggest cause of stray current corrosion. Ideally, you want only one common ground buss properly connected to the engine block.

 

[Maine Sail]

Ideally, you want only one common ground buss properly connected to the engine block.

Amen!

P.S. Snotter what software are you using to draw your wiring diagrams. I am looking for a simple software for a non-computer type of guy and I've yet to find it..?


Sorry for the hijack question.. Now back to your regular scheduled programming.