Installed Perko switch with single engine/two battery(cranking battery and house battery)

Tried to post several times on this site over the last day and had no success. Anyway, hooked up Perko battery selector switch on my boat. All seems well but had a few questions. The two batteries are located forward under a hatch and one is mounted on port side of center stringer,other is mounted on starboard side of center stringer. The port battery is the "cranking" and the starboard is the "house". Installed the Perko switch as according to the directions for (single engine-two batteries). Like I said all is well, but need some reassurance that things are right. As I stated in my previous post, both batteries are isolated from one another and after looking at the thing closely, I remembered that everthing such as (bilge pumps,exaust blower fans,power trim motor etc.) are powered by the house battery. The only thing powered by the cranking battery is of course the ignition switch,coil,gauges,and running lights. Great care has been taken with connections to cranking battery. It has been fished through electrical conduit under floor and secured to stringers in engine compartment for safety. It has heavy gauge battery cables from battery to starter and also heavy duty ground to block. After installing, I turned switch to #1 battery which is cranking battery and all was well. (yes I hooked drive up to a hose) Next, I switched battery to #2 which is the house battery. I attempted to crank engine and was not able to get enough amperage to start engine. It clicked and tried to turn but did not have enough juice to start. I immediately stopped doing that because I did not want to damage any wires or heat anything up. Now, question is this: Should the engine fire up with Perko switch in the #2 selection? Now wait, when I switch to the "all" selection on the Perko switch, the starter spins like a raped ape and she immediately starts right up. Question again, Is this the way it should operate? Don't mean to ask silly questions but wanted some assurance as to whether things are working correctly. Also, I figured I would mention that when the Perko switch was turned to the "Off position, everything on boat was dead. Thats good right? I figured I would start with the Perko switch and yes I decided to install switch under hatch in front of batteries because it states that the wiring should be kept as short as possible in the directions. I know at this point it is a primitive type of system but figured with a little effort on my part, will have to remember what selection I am using when on the water. Now, finally was wondering if when selector is on "all" position: Will the house battery get charged, because switch is bridging or linking power from both batteries? That is what I really need to know. I did not use a voltage tester yet on the house battery but alternator is putting out around 14.5 volts according to gauge. Note: The house battery never had any charging system hooked up to it at this point except a battery charger once or twice to keep it from going flat. The batteries are both less than 6 months old. Maybe I am ok at this point with the charging of my battery system? Or do I still need to install the isolator setup after the fact? I will have more information for you guys tomorrow for sure, getting late and have to get back home at this point. I think I got a good start at it and like I said I tried to post several times on the site and it was locking up.
said enough for now, any additional comments or suggestions would be greatly appreciated.
P.S. This was what I was going to post previously to you guys so let me try again:
http://www.boatfix.com/how/Ele2.html * Look at figure (D). It is the first one on page.
As always, thanks guys for all the support! Tom

1) using a charger, fully charge both batteries and make sure the neg. posts are connected to each other
2 )pos1 for starting battery, test start ok, battery cables and battery ok
3) pos 2, house, test start, no go. check cable connections from battery to switch.
4) quick and easy way, install a 2 battery isolator across the battery switch, c to c, 1 to 1, 2 to 2.
no matter what you select the other battery will be isolated and charged.
Most have the bilge pumps wired to the main battery,either at the battery of off the "C" terminal of the battery switch
I agree with all those diagrams except the twin installation. 1 motor shoud be dedicated ,meaning nothing on it except 2
batterys, the other motor can have the isolator and the house battery.

Tom, forgive all of my underscoring and bold text. I'm doing this to point out critical areas of concern. Key Words, if you will!

Just to be clear, we'll see several types of battery bank switching methods being used on our boats.
On/Off only.... were multiple switches may be used to control independant battery banks. These may have an additional combining switch capabilities.
Combining Switches..... usually more complex..... but share a portion of both On/Off and MBSS methods.
Battery Selector switches.... whereby one switch is able to connect between two battery banks, including offering a combining ability! One switch per engine.... usually!
The latter often being refered to as an MBSS.... (main battery selector switch)...... "select" being a key word here, and one that plays an important role in my explanation below.


Tom, that's a good basic schematic, however, it does not show the actual MBSS rear terminals. This becomes somewhat confusing for some people. Furthermore.... if your alternator is still OEM configured, it will deliver the charge via an interface with the engine harness.... not as shown in this schematic, (although this will work also).
(I think we discussed this in your other thread)

There's nothing wrong with this per se'......, but an ACR could replace this Isolator.
Isolators are pretty much outdated by now....... (there is an inherent voltage drop in them.... .7 volt I believe)
If you wanted this type of Engine Alternator interface, then an ACR is a much better route to go these days.



**************************************

You made a comment that your bilge pumps, blower fans, and power trim motor etc. are powered by the house battery.
I can understand the Merc Power Trim Pump..... Merc did this routinely by powering this via a direct battery connection.
But something is wrong with the other two connections.
A bigle pump operated manually from the helm, and blower motors operated from the helm, are typically powered via the Hull Harness, of which eventually powers your helm instrument panel.
Either bank should provide power for these, or we have no battery bank "redundancy"...... of which is the entire point of having multiple banks and an MBSS in the first place.

But let's side step for a moment:
I want to explain that there is a rather common misnomer regarding the MBSS, Battery Banks.... (House -vs- Cranking), in relationship to the hull harness power!
All too often we don't consider the MBSS "Common" and engine harness/hull harness interface.
Every OEM electrical item on your boat (that has not been added), receives power beginning from the engine/hull harness interface right at the engine. This is where the MBSS "common" cable connection comes into play!
Nothing is separated out..... other than what Merc did with the Trim Pump. (There are two other items, but let's reserve those for later.)
It can be simple to understand if we do not try to "over-think" things.


First..... try to NOT think of your battery banks as Cranking and House..... (this almost implies that these power two entirely separate systems of the boat) These DO NOT!
Rather think of them as "Cranking Load bank", and "House Load bank" since only the type of bank selected actually changes anything.
The MBSS is nothing more than a device that allows us to "select" which battery bank we want to pull the "load" from.
Think of a kitchen faucet... HOT on one side...COLD on the other......... the spicket is the "common" cable.

The MBSS "common" then delivers the selected 12vdc power to the Engine harness..... from there to the hull harness.

In simple terms, either battery bank will provide "house load power" or "cranking load power" when that battery has been selected. The boat does not really care, nor will it know the difference.... other than that Deep Cycle batteries work best for house loads.

So, what I'm saying is...... we only have a House Bank and/or Cranking Bank when these are selected as such!
But I don't want to confuse anyone regarding a High Amp Cranking battery -vs- a longer duration/lower amp hour 12vdc Deep Cycle bank! Like said...... the engine and hull harness won't know the difference, but since we know which bank is better suited, we simply select the best bank for the task.
Make sense?

This is all predicated on a very basic and simple manual MBSS battery management system..... or as you put it.... "a primitive type of system", but it will serve you well.
If you wished to, you can certainly get much more sophistacated later on by adding an Auto Combiners, etc.
I say.... KIS...... keep it simple.

***********

As for battery cabling (Positive and Negative)..... I prefer to see each battery bank Negative cable make it's own independant connection to the enging block. These banks should not share Negative cables, IMO.
It's called redundancy for a very good reason!

See post #5 in your other thread again. I believe that this schematic will better suit your needs. You can do the ACR if you wish.
Note the rear MBSS terminals and how these are being additionally used.




As for your question regarding cranking better when ALL/BOTH was selected, this could be a result of incorrect cable gauge (size), weak batteries, etc. When you "combine" you create more amp capacity..... thus less voltage reduction from the starter motor while cranking.
You may want to replace the cables with heavier gauge! (both POS and NEG.) You can not get these from an automotive parts store. You may need to visit a Battery/Starter/Alternator shop. They can custom make cables for you in a heavier ga.
Marine tinned wire strand cable is best!

When all is working correctly.... you will crank on bank #1 (#1 is almost always our cranking bank) warm and charge this battery. This is what our cars/trucks do! If un-used.... as in "reserve"... this battery will remained charged. No different than if your car/truck sat for a week or so without being started.

Once underway..... switch to #2 if you wish to at this time.... or leave it on #1 battery.

When Anchored, and when the engine is off, make darn sure that your #1 is being held in "reverse", and that you are operating from #2
Enjoy the radio, lights, TV, what ever.

When ready to leave, switch back to # 1, and fire the engine up.

Again, this is all predicated on a very basic and simple MBSS manual battery management system.

*************************

Yes.... when switched to OFF, all 12vdc power should be cut.
Again, there are two scenarios not yet discussed (un-interruptible float switch power, and radio pre-set memory)


As for your question about charging when ALL/BOTH are selected...... Again, try not to over-think this.
Keep in mind that the MBSS works in either direction. Not only does it direct battery power to the engine/hull harness, it also delivers Engine Alternator Charge back to the bank that is being selected.


BTW, 14.5 Charge volts is good, but you should see it taper off.
A good wet cell battery, after sitting for 6-8 hours upon being fully charged, should read 12.4 or 12.6 or so.


I may have missed a few items here.... but bottom line, everything on your boat should be capable of operating from either MBSS selection.... (baring the Merc Trim pump, bilge pump float switch, and any radio preset memory)

I sure hope that this helps, rather than further confuse you.
It's tough to explain some of this via a key board.



.

Ricardo, you are right about overthinking the thing. I may have figured it out at this point.
I joined the two negative terminals using heavy gauge battery wire and now the starter is spinning perfectly with Perko switch set at #2 or house battery. You were also right about the cables. Initially, I ran heavy lug cables from craniking battery but used #10 wire off of house to fuse box because I figured it would not have a significant load draw and that is why the starter was not getting sufficient ground. Ricardo, there is not one thing on my boat electrical system that is OEM. I fabricated the entire thing from scratch. The engine system was taken out of another boat about two years ago. However, I did use Merc. wiring schematics respectively for the engine system when building. Like I said it is a crude or primitive setup but hopefully will work with a little resposible boating on my part. Also, did not want to forget to thank BtDoctor for giving me the idea to directly join main grounds, (negative to negative). I just hope this will work for now. Last question: When selector is set at "all" will both batteries get charged off of the alternator. I have not changed anything on my alternator wiring as of yet and was hoping not to have to. Also, Am I correct to say with selector set at #2 or
house, the house battery will not be linked to the charging system the way the switch is set up? I am a little confused about this one issue. Thanks, Tom

Tom, I contacted ME.com to see if I could do an edit to my previous post. James was nice enough to allow this. I've added a few notations, and it should now read much better, if you care to go back and read through it.
Thank you, James!

Tom, I guess that I wasn't fully aware that the OEM configuration was non-existant. I'd encourage you to bring as much of it back to OEM as possible..... at least in the sense of the main hull harness/engine harness interfacing, so that either battery bank's power (via the "common") can go forward to the helm.
Without..... you have no battery bank redundancy!

GPS, VHF radio, DS, FF, etc, can all be run from a new/fresh dedicated and independantly run circuit forward, that will power a new breaker or fuse panel. In a perfect scenario...., these should never receive power from the OEM hull harness anyway. There is no redundancy should the hull harness go down.
Again.... a direct "common" terminal connection can be a great source for this (don't forget the new NEG as well).
MBSS ON...... and this panel is powered, as well as everything else.
MBSS OFF...... and this panel is safe to leave unattended.
It becomes non-dependant on the OEM hull harness. This is good!


I'm unclear re; your Neg cables. FYI, each bank should have it's own Neg cable to the engine block..... IOW, no neg sharing!

Last question: When selector is set at "all" will both batteries get charged off of the alternator. I have not changed anything on my alternator wiring as of yet and was hoping not to have to.

Click to expand...

Simple answer.... Yes! And you are apparently understanding your MBSS more fully!
Nut shelling this: the alternator's charge is directed to the your engine harness..... of which directs it to the "common" cable, of which directs it to the MBSS "common" terminal, where it is then directed to the battery bank that is currently "selected".
Could be #1, #2 or ALL/BOTH!
However, there is more to this.
Your two battery banks will be of "un-like" batteries! Un-like in terms of battery type (Cranking vs Deep Cycle), size, possibly age, definitely number and depth of cycles, etc.
To charge Un-Like batteries simultaneously, is not the best method, and we should avoid doing this!
For an intitial charge..... there are usually and normally no issues.
But for final charge, best to keep them separated.

This is why our O/B 2-Bank Chargers have two charge leads. The charger is able to "sense" each bank independantly, and adjust charge rate accordingly.
The engine alternator, while ALL/BOTH are selected, cannot do this.
And for that matter, the O/B Charger cannot do this either while ALL/BOTH are selected. This is considered "combining".
We want them to be separated during final charging.

Some will suggest that there are NO issues while ALL/BOTH are selected.
I suggest, do this no more often than need be.... of which should be seldom.

Side stepping again..... if you want to do the above, then the ACR must be added, and the alternator wiring changes. ALL/BOTH would still be avoided during charging, however.
If you manage your banks correctly, it is normally no big deal to leave as is.
Your call!

BTW, with an O/B Charger correctly connected, and when on S/P (if you have S/P), your O/B charger will work while the MBSS is set to OFF!

As I suggested earlier....., crank/warm engine on # 1..... this battery will be brought back up shortly. Watch your volt meter..... you will see the reading decrease as the battery returns to a good SOC (state of charge). Your mental gauge will be by how easy/hard the engine is to fire up. Hard starting.... lots of cranking, it will take longer.

.

Ricardo, you are the best! I have read your posts over and over and I think what you said about the O/B charger is what I will eventually do! I like the idea of it being able to detect and charge each bank with correct voltage.(not undercharging or overcharging) And I understand at this point I have un-like batteries charging with no way of controlling or for a better word "correctly maintaining" both respectively other than physically selecting at this point. My biggest mistake at this point was that I ran lighter gauge ground wires(#10) directly off of house battery (one to engine block and one to fuse panel grounding block) which I think was causing the lack of adequate amperage for starter load. However, I did build conduit under floor to bilge area when I rebuilt boat so with a little sweat, I think I will be able to correct the grounding condition which was only occuring when attempting to start with MBSS set at #2 or house. I was leary about hooking the two main grounds together on each battery but was unable to get starter spinning fast enough as I said with selector set at #2. I originally wired it this way with the intent on not needing alot of amperage drain and was planning on powering auxilliary equipment and electronics. I will have to use one of the original 10 gauge as a fish to hopefully pull the heavy battery ground wire and bolt to block. I think this will work.

My biggest mistake at this point was that I ran lighter gauge ground wires(#10) directly off of house battery (one to engine block and one to fuse panel grounding block) which I think was causing the lack of adequate amperage for starter load.

Click to expand...

I'm surprised that load did not fry that #10 wire!

use one of the original 10 gauge as a fish to hopefully pull the heavy battery ground wire and bolt to block.

Click to expand...

Tom, I'll read all of your post later tonight...... but are your battery banks NOT in the engine bay?

Ricardo, no my batteries are located forward between two front seats under floor, under common hatch, seperated by center stringer,on individual mounts.* There is conduit on both port and starboard sides under floor that leads to engine compartment. One for each bank.* The distance from #1 bank to starter lug is approximately 10 feet. The distance from #2 bank is about the same.* The only reason that the #10 gauge wire did not fry was because I immediately recognized that something was not right and stopped!* You could hear the starter loading down with the selector only at #2 setting.* Again, I agree that the common ground is not the answer either.* I admit at this point, that I made a critical error with respect to main ground on #2 or house battery. Simply*did not understand that the ground for this particular battery was not adequate with respect to*the way the switch is wired. (unfamiliar)* Oh, by the way, the reason I installed the batteries in that specific location was specifically to try and add some weight to the forward bow section and keep stern from being weighed down and cluttered.*(very limited space)* Also was trying to keep them in a safe or protected area on boat.* Also, I have*installed dual bilge blowers to try and pull out any vapors or gases that could possibly build up under floor and in battery area.* Adding the heavy gauge ground wire*to #2 or house*is definitely the answer*for me at this point.* Just another setback at the moment!* And again, I agree that the common ground that I just*installed between both ground banks*should be removed, because I believe that I am stealing ground from #1 which makes them sort of*joined at this point. Taking away any independence of the two systems.* I will try and install new battery ground wire tomorrow!* talk to you soon, Tom
*

Tom, moving weight forward is always a good idea, however, moving batteries forward to achieve this is not advisible, IMO. These batteries best serve us when they are in the engine bay where hull bounce is less, and cable length is less, etc.

There are many other items that can be jockey'd around to distribute weight forward........ I just don't think that wet cell batteries belong outside of our engine bays.
These also emit gasses!

Yes, each bank should have it's own heavy ga. Negative cable running to the engine block.
Each bank's Positive cable (to the MBSS #1 and #2) and the Positive "common" cable to starter motor, should be of equal heavy ga. also.

For a given load, the Amps that are conducted through the Positive cables, are equal to the Amps that travel through the Negative cables. This is a rule that applies to any 12vdc circuit..... (i.e., the combined length of both pos and neg must be calculated as the total circuit length).

Make sense?

.

Ricardo, thanks for posting back. I fished the new heavy duty ground wire for #2 battery with a light gauge wire that I had left in the conduit for that purpose and it was a little tough but was able to get to the block and bolted everything back up. Switched to #2 and tried turning over and everything went well. I agree with you about positioning batteries towards the rear but just don't have the room back there to do so. The engine box takes up alot of room and did not want to put them on either side of stern because it would take up the little bit of room that is left for standing close to stern with respect to fishing. The boat is not that big and it was a challenge trying to lay the thing out. That length of cables does not do much for the batteries I guess and also agree about bouncing but I guess I will have to be the responsible type of boater and go easy unless it were a blue bird day and you know how that goes. lol I also understand how the gasses from batteries (especially batteries that are getting overcharged) can be nothing less than explosive. I installed two bilge blowers for that reason. (Not saying it is any guarantee but I think it will help. I guess I will have to open hatches for five or ten minutes everytime before I try and fire up boat. I am most concerned about the overcharge issue and was going to eventually go with an O/B charging system. I guess it will have to do for now with a little management on my part. Thanks again for all you help, talk to you soon, Tom

1973 Browning Marine said:

I am most concerned about the overcharge issue and was going to eventually go with an O/B charging system. I guess it will have to do for now with a little management on my part. Thanks again for all you help, talk to you soon, Tom

Click to expand...

Tom....... two things here:
One...... for some silly reason I've been thinking that this was a small cruiser boat..... ya know.... engine bay, small cabin.... etc!
Two...... I've also been thinking that you were simply re-doing an existing two-bank system.
I may have misunderstood you.


As for the above comment..... What "overcharge issue"? Engine Alternator Charging???
If so, this should not be an issue. Your boat's alternator (in terms of sensing battery and charge rate) is no different from your car/truck.
After a 200 mile road trip..... is your car battery still OK? :rolleyes:

A good working engine alternator will determine the charge rate, and will cut back when necessary. Doesn't matter which bank you have selected. The alternator won't know the difference if the battery banks are healthy.

Do note that alternators typically cut back charge rate rather quickly. This requires more time to replace the Amp Hours used. They will do the job.... just takes longer.
A good 20 or 30 amp O/B 3 Stage Smart Charger, will do a much better job once back where shore power is available.


Sounds like you've wrapped this one up.
On to the next, eh?
(you do know that it never stops, right? )
.

Oh boy, you can say that again! lol I still have alot of work to do on the boat such as transom mount transducer, flush mount stainless rod holders (3), exaust water shutter, vhf radio and antenna, maybe a fairly cheap stereo if I hit the lottery, and a punch list about a mile long! lol. However, things are looking up and I will take one step at a time or as you say "Process Of Elimination" or (POE). Was hoping to plan a trip to Raystown Lake in PA sometime this season with my kids, that is why I am most probably driving you guys nuts!lol I heard good things about Raystown. It was created by the Army Corpe of Engineers around 1903, I believe after the Johnstown flood. It's like 28 miles of navigable water with 118 miles of shore line surrounded by rolling hills and trails. It averages somewhere around 60 feet and is around 200 feet at the deepest point of lake. They have striper,brown trout, large and smallmouth bass,and landlocked salmon just to name a few. It's a really clean body of water when you consider that I am used to looking at the Schuylkill river and Delaware river. No comparison, and you even get to eat the fish you catch!lol Not too many places like that left. I have been trying to finish the boat with the hopes of doing this in the near future. Boy, I even surprised myself with what I have learned, accomplished, and overcome, with the knowledge and guidance from you guys on this site! Most people quit half way into something that I tried to tackle but unfortunately, I am a hard headed Irishman and refused to give up. So, thanks again everyone for the continued support. all the best, Tom

Just for a comparison if you will about wire guage size and this should make sense to you from what I read on your "voltage" drop issue due to wire guage size.

For many years I have been running 2 cranking batteries in my boat, All connections got to battey 1, including battery 2. Battery 2 only has a red and black "battery cable" Guage wire connecting it to battery 1. My alt basically charges both at the same time all the time. Again, both are cranking batteries.

Ok now for the story, I had been running a 120 watt (60 watt per channel) 2 channel amp for my stereo set up for years and I used 10 guage wire to power the amp and it was hooked up to battery 1. Worked fine for 12 plus years.

Last year I purchased some new and more powerful equpiment, I LIKE MY MUSIC LOUD!!
Anyway I had a 150 watt per channel new amp connected the same way as my old 60 watt per channel, newer more efficiant and bigger speakers........well after a couple of uses not only did I blow my speakers I also took the amp out ( started to over heat under partial power and shut down).

Lesson learned: 1 guage welding cable from battery number 2 to my new 175per channel amp and new speakers.....now all is good as I can supply the amp with the propper current (~40amps +/- ) to power it so it will not over heat. The 10 guage could not supply enough current and the amp and speakers did not like it at all.........

Now I also know that the correct way to do this would be to get a new battery, battery 3 and it should be a high amp hour deep cycle and connect it to a battery switch solely for charging it after use. May be doing this in the future.

Anyway heavy battery cable is always needed no matter what the purpose and it then can be connected to a BUS or common location ( power distrubution pannel) where you can connect other things such as cabin lighting etc etc. Also the longer the distance the heavier the guage needs to be.....

just my thoughts...

kghost, I totally agree with you! It was a huge mistake not running heavy cable from the beginning on my house battery, not to mention a pain in the arse to fish it through the conduit that I had previously installed along stringers and under floor. Thank God a buddy happened to come by my shop on Sunday and helped me to get it pulled through. Would have been a bear to try and do it myself! Anyway, all is well and starter spins nicely at the moment on house battery which was not the case in my previous posts. Switch is working as should be. I will remember that tip. It is expensive enough to do it once the wrong way let alone doing it right the second!lol
all the best, Tom

Was just wondering how you charge the house battery?

read you post but was getting lost.......... lotsa words.

Assume you select "1 & 2" or "all", so then batteries arnt isolated during charging (alternator running), which is fine..... but you gotta remember to switch back after running the engine , i would always forget, and flatten both batteries

anyway alternate method is to use an auto charge relay(ACR), but this beast uses a different type battery selector switch. (not your perko)

http://bluesea.com/category/2/productline/overview/387

setup both batteries with common ground (big) back to engine block, one batt for house, other for cranking.
Install above relay between battery positives, when the ACR relay senses alternator running (above 14 volts) on engine battery, it auto connects the batteries together, and hey presto, both batteries get charged whilst engine is running, and both batteries isolate the moment you shut down the engine

Thats how I do it now, and havnt looked back.
Installed in customers boats aswell, idiot proof.

PS, I never put a bilge pump after any sort isolator switch, direct from battery only. this is a must on moored vessels.
One other thing, selector switch for bilge pump, 2 positions only, Auto and On. never have an "off " position.

tuna_man said:

1. Was just wondering how you charge the house battery? read you post but was getting lost.......... lotsa words.
2. Assume you select "1 & 2" or "all", so then batteries arnt isolated during charging (alternator running), which is fine..... but you gotta remember to switch back after running the engine , i would always forget, and flatten both batteries
3. anyway alternate method is to use an auto charge relay(ACR), but this beast uses a different type battery selector switch. (not your perko)
4. Install above relay between battery positives, when the ACR relay senses alternator running (above 14 volts) on engine battery, it auto connects the batteries together, and hey presto, both batteries get charged whilst engine is running, and both batteries isolate the moment you shut down the engine
5. PS, I never put a bilge pump after any sort isolator switch, direct from battery only. this is a must on moored vessels.
6. One other thing, selector switch for bilge pump, 2 positions only, Auto and On. never have an "off " position.

Click to expand...

1. He will switch the MBSS to #2 position for engine alternator charging of the House Bank.... (which is typically #2) Yes..... lots of words used to help explain.
2. Agree. For those who may forget, then yes..... a different configuration and the ACR is what you'll want.
3. Agree, Perko's MBSS are of lessor quality in my book. Bluesea is much higher quality.
4. I'll always suggest a connection to the # 1 and # 2 rear MBSS terminals, and avoid direct battery connections. These two are schematically identical as if a direct # 1 and # 2 battery connection........ but eliminates small terminal corrosion and the dreaded battery "Rat's Nest".
5. Agree with first and third parts..... disagree with second part. There is no need for any direct battery connections OTHER THAN CABLES ONLY! Again, the rear #2 terminal of the MBSS (house bank) is perfect to power the float switch (fused of course).
6. Only manual pump operation should be sourced from the helm (On/Off switch). The bilge pump Float Switch (or Auto, as you refer to) should NEVER receive power via any type of switch that would have the potential to cut power...... At least not for a moored boat. (see #5 again).

I hope that makes good sense.

err Rick were on the same plain here, i refer to "direct" in the schematic sense, not the physical............
I observe the discussion so far is purely schematic/functionality based....(except the original posters ref to under floor conduits etc, which does tend to defer from the actual issue.) Mark.

Ah... Gotcha, Mark! Thanks for clarifying!

(It's just that I cringe when I see or hear of Accessory "Direct Batt" connections, and/or a float sw being powered from the helm.)