Blank Canvas 12v installation...any advice welcome

[deckie]

Howdy all...hope its a good year for you so far.

As an experienced boaty confronted with a new blank canvas i'm determined to learn about the dark side this time around. Always used pro's for all but the very basic wiring in the past. Near end of a full refit suiting needs and about to repower.
Faced with a few options but the background is that there will be two new batteries placed forward in a 15foot glass cuddy...about to be repowered with a heavier 4stk and also a bait tank down back...so it was either fuel or battery weight going fwd to maintain hull performance and the decision to move about 45kg of total battery weight was made. Like many others this hull has always performed better with a little extra weight fwd so i dont envisage problems there at all. Can always change back if disappointed.

Obviously things like voltage drop and increased vibration have been factored in but its time to install and thought i'd ask for some assistance to avoid likely pitfalls.
This rig is being refitted as a bay scooter with night fishing in mind. Mainly inshore Sydney.
Wanted a solid dual system and happy to pay overs for the right batteries and the extra large cabling...if it works well it opens up so many options and space as well as being able to use far more available 12v power.

Included a pic summarising some distances, accessories, what i already have in the shed and what i am thinking of getting. Fusebox has a common neg and pos bus on it. No idea about earths and the like. I've always liked/had 20A Carlingswtich's and going with them again. Going to get the heavy cables cut to correct lengths and any lugs done properly. Solder and crimping terminals using resin heatshrink and using HD s/s/rubber cable mounts for long runs..already prepped and waiting.

54937

Already have: Bluesea x12 Fusebox with common neg and pos bus, Bluesea 4 pos Batt Switch, 10x 20A Carlingswitch, 2x Cig skt, 1x 50A Anderson plug, 1x15A 2 pin T skt, 2x s/s batt clamps.
Planning to get: Bluesea Auto Charge Relay OR BEP Voltage Sensitive Relay, Ctek 7or10A charger, Nasa BM1 Battery Monitor.
Likely Accessories House Battery: Anch Light(0.2A), Stereo(4A), 27meg(1A), Bilge Pump(3A Intermittent), Bait Pump(2A/hr avge use), Deckwash(6A Int), Single HID Spotlight(7A), Assorted LED's cabin/deckfllood/gunwhale (max2.5A)
Likely Accessories for Start Battery: LED Navs, Horn, Sounder/GPS


1. Particularly interested in correct cable sizes u would go with for lowest practical voltage drop for a new donk plus assisting with charging. Including cable run to distribution panel area. I understand its BIG cable and thats fine and planned for. Have looked up cable gauge calculators but all sorts of different gauges and hoping for some assitance/conformation that is plenty but not total overkill.
2. Where YOU would properly mount/place a battery isolator switch(s) and auto charge relays or voltage senstive relays would be a massive help. Read somewhere that a VSR might be a pain clicking in and out too often if placed a fair way from a house agm, but not enough knowledge to know. Perhaps they arnt required at all.
3. Proper size and placement of any major inline fuses for the cabling/motor.
4. How to properly wire (what needed) for accessories to run off both start and house batteries. Some things i figure are best kept seperate such as sounders on a different circuit to pumps. But knowledge is just trial and error mistakes from the past and amateurish at best.


Plenty/Easy access behind dash and happy to mount any essential stuff inside/outside bunks or anywhere u like...as long as placement is good for this type of setup.


Basically its a blank canvas and a slightly unusual/different setup. Need to get on with it tho so ANY advice is greatly appreciated and hopefully i can reciprocate with experience in other areas. Really want to learn something on this project but avoid simple/obvious traps for young players (or in my case old players lol)

Thanx for any help and your time.
Steve.

[Chimo]

Steve

Off the top of my head and IMHO I'd run the GPS and sounder off the house to keep away from engine spikes. I had an Auto Battery Coupler fitted that connects and disconects the house and starting batteries depending on voltage and also when the motor is started.

No doubt the elec specialists on here will have other comments.

It does seem a short boat to hang a heavy 4s on tho, hopefully the performance wont be as bad as a friend of mines short boat with heavy 4s which seemed to work hard to climb up onto the plane and had to go quickly to stay there or it fell back into the hole again.

You may need to consider trim tabs not so much for side to side levelling. although thats their main use, but also to lengthen the hull even when the tabs are fully up. We are talking Lencos or Bennets or others with a plate.

Also you may consider fitting a foil on the motor to also aid bum lift so it will plane slower with the extra weight in the bum as well as the rest of the hull.

At the end of the day; if you may need some of the above; would a longer hull be worth considering (in a perfect world with $s available?)

Good luck with it all.

Cheers
Chimo

[deckie]

Tx Chimo...she's a good hull with a new bum fitted for repowering. 2stk 60 suzi (great old motor) came off and believe it weighed about 85-90kg wringing wet. New 60 4stk going on weighing about 108kg. With battery weight coming off the back and added fwd it seemed to be the answer. She was never back heavy before and very nippy out of the hole so trying to maintain that. Alternative is an extra 10hp from a 70 2 stk yammie which weighs about the same and would be more punchy...but i've decided to sail into the new world and dont need the speed. Net result should be a very similar ride if not even less heavy at the back.
Need a lightweight <5m rig and she's perfect for me right now...only one way to find out about the ride...give her a whirllllllllllllllll.

Sounds a smart idea keeping the sounder away from engine spikes. been on rigs where the bait pumps etc would interfere and just assumed best to keep seperate but i reckon you're right..cheers..will do.

[Chris Ryan]

I got a dual sense VSR recently for my rig; allows the charging across both batteries automatically once a 13.7v charge has been reached without needing to change using selectors.

You can get automatic selector/VSR's now too which will switch power sources based on load/voltage so you don't need to have a selector switch and a VSR.

[deckie]

tx chris. Dont know enough to decide between one of these
54940(Bluesea auto charge relay) and a BEP VSR. Never had either but told they do a good job. Probably do the same thing. Seems like what i need too. Figured extra big cables will help the charging thru to the AGM house battery.

With a longer than normal cable run i'm unsure where to place it as well...i'm guessing closer to the house agm battery.

Any idea on the piccy supplied where you would mount the batt switch and/or vsr for this type of setup ?

[Chris Ryan]

All my gear is mounted at the rear mate (need to offset the 130kgs sitting in the front when underway :) )

I got my dual sense VSR from AME products and just followed the instructions. There are some good mechanic/electrical guys here that can answer better than me.

Cheers,
Chris

[Chris Ryan]

actually deckie, just reading the doco online for that device, it would be mounted near the batteries as it needs to connect to both batteries so to protect and sense the autocharge across both.

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

[deckie]

tx for that Chris...yeah i guess in this setup it can/should be well fwd between the two batteries. My only concern with these ACR and VSR thingies is whether it'd be clicking in and out too much ..considering these 60HP only have a charging capacity lucky to scrape 15A at cruise speed. Only one way to find out i suppose 8-). Anyway the VSR is an option and more important things to get right if i'm gonna do this.
Not sure where any main cable fuses should be either or how many...figure one inline fuse v close to each battery but thats a guess too.

Some strange stuff i still cant figure out about boats and 12volts. Doesnt make much sense to me. Best and most fun car i;ve ever had was a ALFA GTV6 with a 2.5l V6 motor, a dirty great big starter motor and THE BATTERY IN THE BOOT miles away from the business end. Nothing enormous about the battery either. In 20 yrs she always cranked first time even in winter and u felt she could crank two cars. But here's the wierd thing...the cables didnt look near as big as what these "cable calculators" are telling me for a simple boat with a similar length cable run but to what must be a MUCH smaller starting current need.

Its a different setup to the "norm" of course but there's absolutely nothing unusual about these sort of cable runs...think about caravans/4wd's/trailers etc...hell even top end race cars that cop a pounding usually have the battery in the boot and surely a bloody great V8 needs a bit more juice to start it than a 60HP outboard.

I've looked up manuals online for a yammie 60 4tk and new honda bf60 but neither tell u a damn thing about the actual starting current requirements. I figure thats what i truly need to know to gauge the size of cables...rather than charging. Figure i can charge the house battery easily enough from home each time and isnt a massive current draw even at night.

I factored in 60 Amps (a total guess of starting load requirements for a 60hp that might be way off) over a 4m one way cable run to the battery and i get an answer of about 42sqmm battery cable if i only want 1.5% voltage drop.....which is apparently 1 AWG or 1 B&S or something like >12mm outside diam. Thats half inch cable for godsake. :o ...to simply fire up a smallish outboard rather than a V8 supercar :-/. Then i go looking for some on the net and noone seems to stock tinned cable more than 32sqmm (2AWG) so i figure i must be doing something wrong if noone even stocks the stuff that size. Surely i'm not the only one happy to take away the weight of a small person sitting on the transom.

Imagine having your mother in law straddling the outboard back there over the transom as u take off...u'd give her the boot wouldnt u ? Especially when you get better fuel economy, better performance, more space and far better holeshot. It's a 50kg slab or so and new battery/12v technology absolutely begging to be used as designed...not much point denying the newer technology if it means big advantages.

At 130kg tho you're a full 45kgs heavier than me so i guess i should be factoring in mates weights also lol ;D. Sick of thinking about it and just want to get on with this stuff so i might just go and buy something thick in black and red or just give up and truck her down to a sparky.

Must be some sort of clicky in club these sparkies have lol ;D. They try to make it far too complicated with 5 diffrent ways of describing what is essentially just a piece of metal inside a piece of plastic. AWG/B&S/sqmm/mm/guage etc...pffft. This isnt exactly a very long cable run...hell if i punched in the starter motor requirements for the average family sedan it'd probably say i need high tension wires from Sydney Electricity.

I simply figure the engine starting requirements are the most important and bottom line...and i arnt powering caravans full of fridges and inverters. ::)

Good whinge ??? lol ;D U can tell wiring isnt my thing. ;D

[Chris Ryan]

LOL - very good deckie. Great chuckle for the morning.

I had issues in getting cables too - longest I could find was about 1500mm long in the right diametre in the stores. A mate of mine is the GM of a 12v specialist distributor and they do/can make custom length cable for you; I think you are in Sydney from memory so the details for the Sydney office is:

AME Products Sydney
42 Kurrajong Avenue
Mt Druitt, NSW 2770
Call: 1300 883 263
Phone: 02 9832 3200
Fax: 02 9832 3399
Email:sydney@ameproducts.com.au (sydney@ameproducts.com.au)

See if they can help you.

[PADDLES]

hey deckie, 16sq.mm is good for the 60A.

as for voltage drop however. at 1.16ohm/km your 5m (always use a fudge factor) run is 10m (2c = double the length) / 1000m times 1.16 which gives 0.0116ohms. now good old V=IR gives you 60amps times 0.0116ohms = 0.696V as your voltage drop or 5.8%. 25sq.mm is 3%. 35sq.mm is 2.6%. this is only for your starting circuit though. your charging circuit will not have anywhere near that current and can be much smaller.

i'm only an amateur with 12V boat electrics (i design industrial electrics), but i've found that a battery world store (i have nothing to do with these guys so it's not a shameless plug for them) has just about everything you will need including the cable and lugs.

[deckie]

yeah thats about what i get paddles...its really only about 3.5m (one way) from donk to crank battery but i was building in serious overkill as well ...to get it down to only about 1.5% voltage drop.....coz it cant hurt and will prevent any issues and assist charging from a smallish alternator.

The 60Amps though is a total guess ;D...an allowance for starting a 60hp coz even the motor manuals dont want to tell you what is good...they'll give u minimum battery requirements and thats about it.

Thats how i arrived at the 42sqmm cable (B&S,1AWG,"13mm" cable)...just seems rather huge for what is really not much more than popping a battery into the centre console of a tinnie....plus not being easy to get tinned cable that size made me think its way more than needed. Only a few bucks extra for the heavier cable and weight is only 1-2 kg more per 15-20 feet of cable ...so no reason not to run it coz the advantages are HUGE. Txverymuch for the help confirming those sizes.
Tx Chris...might give em a call. My local (Syd Nthn Beaches) guys have plenty of UNtinned cable up to 50+sqmm but not tinned which i was told to seek out...i'll do some more accurate measurements so there's little slack or chance of kinks.

Also unsure if i need to run that sort of grunt all the way back up to the bus on the fusebox under the dash...says its rated for that sort of cable so no harm running it all the way i suppose.

[Chris Ryan]

Just to clear up a potential perceived conflict - I don't have anything to gain from the AME details; just trying to help out.

[PADDLES]

g'day deckie, if you mean the supply to your fusebox for your auxiliaries (like sounders, gps, nav lights and the like) you won't need anywhere near that size cable. most loads on your boat will be quite small and also will have quite a low diversity factor (this means that they are very rarely all on at the same time) so a 6sq.mm feed will be bucketloads of current capacity and still be easy to handle/install.

[Fed]

Hi Deckie, I think you're confusing the 1.5% drop with an actual drop of 1.5V which would be closer to reality.
It would not be unusual to measure the voltage at the starter motor while it's turning over and get a reading of 11 Volts which is well over 10% drop.

[deckie]

tx paddles yeah i figure somewhere around that 4mm/10AWG/10B&S/6sqmm/thinstuff lol size ..(any other type of damn measurement they can think up ??) will be fine for the fusebox to switches/accessories stuff (maybe a bit more for a spotty and deckwash)... but i'm thinking the cable from the battery switch/battery up to the common bus connections on the fusebox. Same deal ?? The fusebox has whats called a "common negative bus" at the top and a "positive distribution bus" at the bottom..with space for 12 fuses...is that thin stuff what u would run from the actual battery switch and/or batteries up to these bus connections on the fusebox too ? I was thinking a fair whack heavier but fair enough.

Fed...unsure what you mean. My understanding is that 11V is a flat battery. It's less than 3.5m from crank battery to a 60HP along very very thick cable. Why would the battery be flat or 10% voltage drop ? A 60 Amp load over a 22 foot (up and back) 42sqmm/ 1AWG cable works out at only about 1.3% voltage drop. I'm perfectly ok with that.

Are u saying the starter motor on a 60hp 4stk will need a heap more than a 60A allowance ? I guessed the 60A...if anyone has a better idea more or less i'd be grateful.

[PADDLES]

yeah deckie, 4sq.mm is good for 30 odd amps and 6 is good for 40 odd amps. the loads you will be putting on that thing will be mostly in the order of less than an amp for lighting and tenths of an amp for electronics so you can get away with pretty small cable from your fusebox to any devices. 6sq.mm should be fine from your battery to the fusebox.

fed's sort of right deckie, but the voltage dip when a huge load (starter motor) hits the battery is usually more from the battery than the cable.

[Fed]

If you're happy using 42sqmm cable then go for it, all I meant was that a smaller cable like 25sqmm would be fine.
1.5% voltage drop is a tiny amount (< 0.2V) and sure less is better but there's no need to strive for that low.

[oldboot]

First issue is to ensure that the batteries ( regardless of type) are properly ventilated..... being under the seats or whatever in the cuddy does present an issue.......if the cuddy cab remains open at all time the issue is less.

Some call for all battery enclosures to vent "to open air", other prescribe on deck fitting.
If you run some sort of sealed or VLRA type batter the issues are less.. but ventilation is still necessary.

Make sure you mount the batteries upright....as has been discussed before...the advertising may say operate any position..but somewhere there will be a recomendation for upright mounting.

#2B&S should be fine.....as you said before lots of production cars and almost all competition vehicles have the battery mounted in the rear.....these cars have higer compression ratios and bigger motors than most outboards.......outboards draw pissy cranking current in comparison.
Hell I can crank and start my 60Hp with a piece of string ( ok rope).

#2B&S is easily available... whitworths have it tinned for arround $10 a meter...I think bias are now stocking it too.
The lugs whitworths stock are better......quite a few of us have crimpers (look out crimp / solder argument to follow)...any premade cable you buy will be crimped.

As for the VSR... I decided not to fit a VSR to my boat.... because of the infrequent running, short runtime and low ( realy pissy) charge capacity of the outboard.

Most of the charging will be done from the mains.

I currently run an A/B/both switch....... but i will be fitting a more comprehensive manual switching system soon

Those bluesea fuse blocks are nice..mmmm

As far as worrying about voltage drom in a #2 B&S (35mm2) cable... the terminal voltage of the battery will probaly drop more under cranking.

Don't forget a main fuse/ breaker for your house load.

And make sure you battery cable are well protected from chafing or damage... they will all be unfused.

OH don't forget the lanolin spray.....on every joint and screw.. before that joint is made or tightened.

cheers

cheers

[deckie]

If you're happy using 42sqmm cable then go for it, all I meant was that a smaller cable like 25sqmm would be fine.
1.5% voltage drop is a tiny amount (< 0.2V) and sure less is better but there's no need to strive for that low.
Yeah sorry mate i can see what u were getting at now...i'm not too cluey about this stuff. Much appreciated thanx...maybe i was going a bit overboard on that cable too.

Oldboot u are a legend mate. Great to do a project where u learn something but that helping hand is crucial. You and the others are welcome aboard anyday guys. This is the rig i KNOW i will use the most the next 10yrs or so ...a lightweight glass (not that i dislike tinnies ;D) that is setup for nights as well. Needs to be manouvred around the driveway and easy at the ramp in a breeze by myself....this thing is just the perfect size to make it FUN rather than a chore. Want to be able to just head off anytime even by myself.

Its reassuring to get confirmation of cable sizes with the help from Chris, Paddles, Chimo and Fed. 42aqmm did sound a bit HUUUGEEE ;D.

The inline fuses i'm not sure about at all. On the included updated picture i placed it on the +ve near the house battery...is this even close to correct or where would be better guys ? is there a size fuse that would suit ?....any other big fuses ? Are there supposed to be any earths or earth posts?

What i might do is do the installation WITHOUT a VSR/ACR at this point and look at it later. These alternators arnt that big as u say and added to the longer cable runs it might just be a pain. I dont have qualms manually switching and will simply home charge the big house AGM and let it run down to minimum 30%. I'm guessing it may never get past 50% each trip anyway.

Here's the updated picture summarizing it with cable sizes etc. Hoping its not tooo far off sensible but if there's anything i've got wrong or could be better plz just yell out.
TX
Steve

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