Electrical Systems - Starting or House?

[friz]

Rewiring the project. I am deciding what systems to hook up to the starting battery and which to the house bank. I recall seeing a thread about that last year but haven't found it. Obviously the starter/ignition run off the starting battery. Beyond that, which of your systems are powered from where? Does the ABYC give any guidance on this?
Nav lights
Cabin lighting
VHF Radio
Sonar
Bilge pumps
Engine blower
Water pumps
Gages on the helm
Outdrive Tilt/Trim
Trim tabs
12v reefer
Anything else?

[john61ct]

Anything needed for navigation, safety etc on Propulsion circuit, but if high-amp deep-cycle loads need better than "just starter" batteries.

House gets all "non-essential" aka Auxiliary loads.

Personally I like making the "starter" a deep cycle "reserve" bank, same chemistry and charge voltage as House bank.

And be able to join either House or Propulsion load circuits as needed to either bank, or join them for jump starting in a pinch.

[Scot McPherson]

I am with John on this one. Both of my banks are the same AGM deep cycle batteries. I generally leave the bank switch to BOTH because it keeps both batteries at higher voltage, both when cranking and when house is drawing power. Neither bank dips very low and that's better for the battery's logentivity. If and when I got concerned that I need to preserve juice on my start bank, such as night time sailing with the house circuits being heavily used, and my starter battery needed to be isolated from the rest of my DC system, then I flip the switch to 2 when the engine isn't running and start the engine from 1. But so long as I have a source of power into the system (solar, battery charger, engine running) I keep the switch on BOTH.

[Stu Jackson]

Originally Posted by friz

Rewiring the project. I am deciding what systems to hook up to the starting battery and which to the house bank. I recall seeing a thread about that last year but haven't found it.

1. Obviously the starter/ignition run off the starting battery. Beyond that, which of your systems are powered from where?

2.Does the ABYC give any guidance on this?

Nav lights
Cabin lighting
VHF Radio
Sonar
Bilge pumps
Engine blower
Water pumps
Gages on the helm
Outdrive Tilt/Trim
Trim tabs
12v reefer
Anything else?

1. Start on start or reserve bank

2. Everything else is house

OEM 1-2-B Switch Wiring History Alternator/Batteries & "The Basic" 1-2-B Switch BEST Wiring Diagrams

Basic Battery Wiring Diagrams This is a very good basic primer for boat system wiring: Basic Battery Wiring Diagrams

This is another very good basic primer for boat system wiring: The 1-2-B Switch by Maine Sail (brings together a lot of what this subject is all about)
http://forums.catalina.sailboatowner...d.php?t=137615

This is a newer primer for boat system wiring design with a thorough digram: Building a Good Foundation (October 2016)
http://forums.sailboatowners.com/ind.../#post-1332240

The Short Version of the 1-2-B Switch Stuff: Electrical Systems 101 This is a link to the Electrical Systems 101 Topic, reply #2

What are ACRs, Combiners & Echo Chargers? (by Maine Sail) [scroll to the top]
http://forums.catalina.sailboatowner...d.php?p=742417 and Battery isolator / voltage regulator / batteries

[Stu Jackson]

I disagree with john and scot

Here's why:

Largest House Bank 101 (by Nigel Calder)

Calder battery sizing & stereo-battery connection

[Scot McPherson]

Stu, I was just going to compliment you on a nice set of links....now I am not :-P


hehe

[Scot McPherson]

Stu,
So I read your reasoning on the other site, but to be quite honest...your reasoning is why I keep the banks joined during normal use. Both batteries are discharged much less.


Keep in mind, my batteries' discharges are barely touched. I run everything LED and conserve power by cutting the power to stuff even when it's not being used (complex circuits can leak power even when not in use). Even when sailing overnight with all nav equipment running, and house lights on etc, my voltage hasn't ever dipped below 12.5V, and I think maybe once I saw it go as low as 12.37 volts.


Nigel's quote:
2. All other things being equal, any increase in the overall capacity of a battery bank will produce a disproportionate increase in its life expectancy (through reducing the depth of discharge at each cycle).


So you see, I draw less from each battery by sipping off both.

[john61ct]

I would at least put an LVD on the starter/Reserve if they were usually joined to House.

I'm way too forgetful about manual switching, kids stay up late cranking tunes, playing on screens, movies on the 48", maybe leave a fridge open, stuff happens. . .

[serah]

Everything but the engine starter off the house bank. Everything.

Install an automatic charge relay to charge your start bank first (really, it shouldnt often get that low... Unless you have starter issues) and then kick in the house bank once adequate charging for the start is done. Both banks are deep cycle, house bank is much much larger.

We keep a battery switch to combine the batteries if there has been some sort of short/failure. Two years with this new boat and we have never once had to do this. Fingers crossed.

As human proof of a system as we could have come up with.

[Roy M]

I have two banks, House and Engine. Anything that is affected by heavy voltage drop, for example, electronics, is on the more massive house bank. I don't like starting the engine only to see the nav electronics reboot. And, on the same note, some of my circuits I prefer to use only when the engine is running, for example, the watermaker, the high pressure, high volume seawater washdown pump, the high draw DC outlets that feed the electric fishing reel socket, and the windlass. So, I made my circuit breaker panel use white handle circuit breakers for circuits fed by the house bank, and red handle for the engine start bank sourced circuits. It's simple and intuitive.

[Andy on Destiny]

It would seem do you want security in separate banks, so it is almost impossible to find your engine battery bank dead, or do you want longevity of the house bank which is for sure the largest possible bank capacity?
Personally I chose simple lead acid for the engine, as small a bank as was required and a big as possible 2v gel house bank, located in 2 banks over the keel. We can emergency start the engine off the house bank by a master switch ( Remember that you must also be able to disconnect the engine bank at the same time or you will suck the juice out of your good battery)
We also have an always on circuit protected by a manual master switch and fuse, plus a switched circuit that runs off a remote master switch. This way when we leave the boat we just hit the remote switch and kill all non essential circuits in one hit, shut 2 seacocks, hit the inverter and we are good to go.

[Pizzazz]

It does not make sense to me to have house and starting batteries and leave the switch to both most of the time. Typically, the house and starter banks are of different size and/or age, so they discharge at different rates for the combined voltage. Thus, after a few hours they will be at different states of discharge and you get current flowing from the bigger bank to the lower bank which is wasteful. It is much better to keep it simple, all loads from the house battery and the starter you can connect directly to the starting battery (as mentioned before this avoids the electronics reset at start time).

The more interesting question is where you connect the alternator output. If connected to both at the switch, you have to always remember to switch to both after starting the engine on battery 1. Typically it does not happen. This is a good case to use a combiner. Alternatively, you can connect it to the house bank but then you need to monitor the starting battery and charge it every now and then (less work but could leave you stranded). In my case, I have a solar panel that typically charges the starting battery. It is good as an alternator backup and it always keeps the starting battery charged. Last point, for the solar panel, typically you can use a simple double throw switch since the max current is low (around 5 amps for 100 watts).

[sailcrazy]

While I can appreciate the back-up logic of having both banks be a similar type battery, we opted to select batteries designed for the loads they will typically see. We use Trogen T-105s for the house bank (6 batts, 675 amphrs, designed for multiple deep cycles) and a conventional mx-free start battery( designed for big load, short duration starting duties). All are lead-acid, similar chemistry and parameters, and we always replace all at the same time so they are all the same age. The start battery is recharged via the genset alternator and/or a Balmor Duo-charge from the house bank. The house bank is recharged via the batt charger, the solar controller, the windgen controller, and the main eng alternator. I did build in a paralleling sw, so I can connect the 2 banks, but have never had to use it. And since the start battery is isolated, and recharged by the house bank (1-way only), I never need to worry about it being dragged down by a house load. So far, 14 years after I installed the system, it has worked flawlessly.

[barnakiel]

In our boat, only the starter is wired to the starter battery.

b.

[Scot McPherson]

pizzazz, my starter is wired directly to the starter battery leads with nothing but a fuse between them.


The alternator and all charging sources are connected to the bank switch (except my battery charger which connects directly to each individual bank)


The bank switch stays in the both position UNLESS I am sailing at night time and the engine is not running. That's the only time the switch is set to 2. It's the only time that the starter battery needs to be isolated from the house, it's the only time the engine may need to get started when the house battery may be partial depleted. Otherwise, the batteries remain tip top charged.


If on the hook, it's just like sailing. Once the sun goes down, isolate the starter. However, I still have yet to see my batteries dip below 12.37 volts after several days of overcast weather, but one day of sun shine always brings it back up.


I am not however running a frig or A/C or heat or air compressor or anything like that off of the batteries. I only run LED lights and electronics (a chrome book, iphone and nav/communications equipment.