Battery Switch Location

[Kelly Hanson East]

Some one above posted about starting on one battery and then switching to both to charge. You should avoid this as a rule unless you have wired in the correct type of battery switch and it is well maintained. If the field wire to the alternator breaks, you will have an expensive repair.

Not sure why you wouldnt just start the engine on both batteries?

ALso remember all the advice about 'starting' and 'house' types of batteries can be thrown out with Macs...the engines arent big enough to justify a high cranking amp 'starting battery' (exception for Billy and his twin 140 HPs...

[Frank C]

What he said, except I'm using a single battery for both engine and house.

This is a standard operating procedure called the "odd/even system." You use battery 1 on odd dates, battery 2 on even dates. This does not necessarily imply only one day's usage per battery. If a weekend jaunt begins on an "odd' date, that battery could easily serve needs for the entire weekend.

This system is particularly appropriate for the Mac, where the engine simply never imposes a load deserving of a full sized battery (or full sized weight). This provides both batteries with frequent 'exercise' and approximately equal usage. I'm using identical Gp 29 batteries from Walmart (115 AH @ $70 each). Walmart's batteries are consistently at the top of Consumer Reports ratings.

Should "today's" battery ever become overtaxed, you can always switch to "tomorrow's" battery (waiting in reserve) for an emergency start. Of course, the system also relies upon recharging a given battery before end of its workday, or overnight at the slip.

[Boblee]

It was probably me who said I start the motor with one battery and then switch to both but I didn't explain it fully because the motor runs direct to it's own battery I switch it over to both after starting so that the motor charges both but while starting it won't induce a spike to damage the instruments.
I have an arrestor there to stop these but I think the effect of spikes is cumulative and will eventually cause the arrester to fail ? (our house ones operate like this).
I should do the job properly but it has just grown like topsy and will probably be a job for summer when it's too hot for sailing comfortably.

[c130king]

Our Cruising helmsman had one of the best articles I have seen for boat electrics which could be easily modified to fit any size boat and any type of charging.
Best of all it is set and forget for switching and charging and very simple with some good ideas for all areas of the boat.
If you want Jim I can try and scan for you as there doesn't seem to be the facility to download direct from the magazine.
I do believe this article would help as it is very easy to follow.

Bob,

That would be great.

Thanks,
Jim

[c130king]

Frank,

I assume you have a 1-2-Both-Off switch. Do you use any sort of VSR or ACR or any other component to control the recharging of your batteries? I presume if you have #1 selected then only that battery gets recharged and #2 sits idle (no use and no charge).

Not sure if any sort of protection is necessary. I guess I don't have anything like that on my current setup...but I am not sure what type of battery I have.

However, in my research I have read where some marine batteries (AGM, Gels) are vulnerable to problems from improper charging or overcharging. Is that an issue in your setup?

Thanks,
Jim

[cuisto]

Last year i totaly stipped out the electrical system and started over with better wiring etcetera...in hind sight the trigger for all this was an engine that would not start, lacked power punch needed. turns out there was a problem with the power connections with the starter, but thats another story.

Although it turns out i need'nt have done all this, now that i have i am very pleased with the setup.

Battery 1
small starting battery-used solely for starting, if house battery should fall flat too bad i can run the nav lights and essential systems with the motor running but will not use starting battery

Battery 2
Big deep cycle RV battery, is in favt too big to put in the battery compartment, have to put it in through my galley front (face pannel removed) and slide it back

COMBINER
Next is an automated switch that combines the two so that the charging current will go to both batteries when there is ample charge current
but the batteries are seperated when the current is low. The combiner has 2 little pot switches that allow me to set the combiner voltage IE the batteries combine once there is X amount of current (I set the x) and disconnect if it falls below x..also i can set a Y value as the disconnect due to overcurrent.
In addition to all this there is an added feature where one can and i have add a 3 way (on-off-on) toggle switch which wires into the combiner so that you can if needed FORCE ON or FORCE OFF the combiner.

This system has been for me 100% fool proof. I did lots more while i was at it. I put in a double master on/off switch. ONE switch shuts down house and starting systems without letting the 2 systems connect. It is just like a regular marine on/off but has 4 poles instead of 2.

Now if you want some over kill built a little oak box with a tamper proof door (young niece often joins us) which contains the master on/off the 3 way toggle and a 4 way (off/1/2/both) switch for future development. I plan to add another big house batter for use un longer trips in future and would set up the 2 house units with the switch so that i could move to house to when house 1 was low..this would serve as a reserve once i ran out kind of thing while never touching the starting power.

Now that you have read this, your coffe is gone and so is half your day.
Sorry for the run on post but hope it confuses you even more with too many options to chose from.

[c130king]

Another question...sorry.

It seems as if there is an option when using the 1-2-Both-Off Switch.

Some of you seem have everything on the "common" terminal? Everything (Start/Tilt plus DC Control Panel) is powered by whatever the switch is set to. And the alternator will only recharge whatever battery is selected (assuming no combiner).

It seems from reading other threads (going back to 2006) on this topic some must have the leads for the DC Control Panel connected to the #2 terminal thus the "house" (DC Control Panel) is always powered by only the #2 battery...thus there is no option of powering the DC Control Panel with the #1 battery.

Does that sound right?

And with the Yandina Combiner...will it work in either of these two setups? The Yandina installation instructions shows a diagram where the DC Control Panel is connected to the #2 terminal. I assume it will work the other way.

Thanks,
Jim

[tangentair]

I use a off-on-both switch and run the alternator lead to the #1 battery which is a starting (reg auto) battery that came with the boat. I run a deep cycle (wet) cell for the number two battery or house. I could run the "house" to the number 1 terminal or the number 2 terminal basicly it is circuit 1 and circuit 2 and you can call the house and motor by any name or number you like as long as you realize they are 2 seperated circuits that can be combined with the switch in the both setting.

Like I believe Boblee has, I have my motorfeed/alternator return positive wire connected directly to the starter battery (the motor has a fuse at the input) and it is not fused or switched. Even though my switch is a make before break style (also called motor protected), I know that there is no chance of my switching off power or breaking the connection between the motor(alternator) and that battery this way and if I want to charge the house battery I switch to both. Even if the switch is dirty or the contact intermittent, I am still protected. It is easier to replace the switch or recharge the battery than fix the alternator IMO. And when the boat is on the trailer, I do not have to climb inside and switch on the power to tilt or lower the motor.

So even with a off 1/2 both switch, you might consider not switching your motor's supply.

And to answer why I went with off/on/both (in case anyone wonders) my preference is to not do the odd and even so I am not equally using up the life of the batteries so I do not replace them at the same time, so that the electronics are on a seperate "clean" battery service, and I know my starter is fully charged as of the last time I ran the motor for any length of time. This is strictly my preference not an "industry best practice" and I have a very light load on my house circuit at this time. I also have a dual charger that I plug in when the boat is on the trailer in the yard.

[tangentair]

I forgot to add, when any switch is in the both setting and the batteries are connected to the inputs, the outputs of the switch will share the batteries, so your power panel which I guess you will connect to the output will draw power from both. You are thinking to connect the batteries to the 1 and 2 terminals and the power panel and motor to the common correct? I merely suggested that you move the motor/alternator to a single battery which will also still charge the other through the balancer thingee. (had to get technical there).

[c130king]

A couple of days ago I was thinking of going with the 3-switch system with VSR (the BEP switch like Paul S showed).

But, now after reading another 1,462 posts going back to 2004 I think I am going to go with the setup that Frank C and others discuss...not having a dedicated start battery as it is not needed.

I think I will go with the 1-2-Both-Off Switch. Have all start/tilt (and alternator as well since I think they are all the same wire on my engine) and the DC Control Panel on the "common" terminal. Then use the odd/even scheme as Frank describes. On odd days I will set the switch to #1 and everything (start/tilt/DC Control Panel) will be powered by battery #1. Battery #2 will sit idle, unused and be there for back-up if needed. Even days I will use #2. I am used to turning my battery on and off every time I use my boat so this is not a big deal to me.

I don't see a reason why I would ever use the "both" position...assuming I didn't screw up somehow or something malfunctioned. And if I screw up really bad I always carry my jumper battery.

Plus I am thinking I will go with the Yandina Combiner as well. My understanding is that this will ensure that both batteries get a charge no matter what my switch is set at.

Thus I am looking at about $35 for a 1-2-Both-Off Switch (I am not sure of the difference...if any...between a PERKOand a BLUE SEA SYSTEMS). The Yandina is about $55. And two Group 27 Wet Cell Batteries are about $90 each at Defender. Total is about $270. Might be able to find batteries cheaper at WalMart or Sam's or something. Might need a few other little things like wire and connectors but I think I already have all of that on my current set up.

But I also have about 7 months to change my mind again...so who knows.

Thanks,
Jim

On Edit: Got my Tax Stimulus Check today. I guess I will stimulate the Marine Supply industry...

...before my wife & daughter stimulate the clothing accessory industry...

[c130king]

Mac EEE's (Electrical Engineering Experts...phrase stolen from Frank C),

Can anyone explain what "Alternator Field Disconnect" is and why one would need that?

The only difference between these two BLUE SEA SYSTEMS switches, 9001e and 9002e, is that the second one has the AFD. And just a few $ more for the AFD.

Both are make before break.

Appreciate any info.

Thanks,
Jim

[c130king]

I did not do enough digging on the bluesea.com website before I posted my question. I found this...

Alternator Field Disconnect
An alternator field disconnect is used to protect the diodes in an alternator when the battery switch is inadvertently turned to the "OFF" position. Essentially it turns off the alternator output. Below is a description of the operation of an alternator and how the AFD works.

An alternator is basically an AC generator powered by the engine. It consists of electromagnets mounted on a rotor spinning inside windings of wire, called a stator. A relatively small field current is supplied to the rotor, powering the electromagnets to create a magnetic field. When the rotor is spinning and a field current is supplied to the rotor the alternator generates AC current.

There are typically three separate windings of wire in the stator positioned so the AC current generated for each winding is out of phase with the others. This allows a smoother, more continuous output.

To change AC current into DC current, diodes are used as a rectifier. A diode will only allow current to flow in one direction, essentially a one way valve, allowing AC current to become DC current. The regulator is the device which supplies the field current and controls the power output of the alternator. An external regulator is mounted close to the alternator in the engine compartment. An internal regulator is contained within the alternator housing.

There are typically four connections on the alternator, an output terminal to the battery, the ground terminal, the field connection, and a separate connection to the stator.

If a battery switch is turned off while the alternator is producing current, the voltage will increase due to the sudden elimination of the load. This will burn the diodes out in the rectifier quickly. To prevent this, a battery switch with an alternator field disconnect (AFD) can be used. The AFD is a secondary, isolated, single pole switch within the battery switch, through which the alternator field current source wire from the voltage regulator is wired.

The AFD is constructed in such a way that the AFD switch does not close until slightly after the main switch contacts have closed and it opens slightly before the main switch contacts open. This insures that there will always be a path for the alternator's output current when the alternator is producing power. The field disconnect will only work on alternators with an external regulator. The diagram below illustrates the connections. Blue Sea Systems battery switches 9002 and 9004 have an AFD.

Makes sense based on what I have read from some of the posts about turning the battery switch to "off" while the motor is running.

I think it may be difficult to find the appropriate wire coming off my alternator and feed it to the switch.

Does anyone have this type of protection on their switch?

I am thinking of foregoing this option.

Thanks,
Jim

[pokerrick1]

when it's too hot for sailing comfortably.

Too hot for sailing?? - - - no comprende??

Rick

[tangentair]

I did not do enough digging on the bluesea.com website before I posted my question. I found this........

Makes sense based on what I have read from some of the posts about turning the battery switch to "off" while the motor is running. That is why I recommended connecting the alternator return/motor feed wires directly to a battery. This is the power to start the engine, then when it is running the return to charge the batteries
I think it may be difficult to find the appropriate wire coming off my alternator and feed it to the switch. I do not think Mercs even let you do that.

Does anyone have this type of protection on their switch? Everyone that buys a modern switch that is make before break has some sort of the protection. But there is no protection if you turn the switch to off, the protection is that there is no momentary break as you switch between 1/2/and both or on/both

I am thinking of foregoing this option. Probably a good idea but be sure the main switch is a make before break switch and you at least add a label warning not to turn off the switch while the engine is running.

Thanks,
Jim

Are you still thinking that you have multiple circuits coming from your battery to the motor? There should only be a red and black set of power leads. There will be instrimentation circuits like tach and temp and the start/run key switch. There will be tilt switches with wiring to them. The alternator circuits are not provided on my engine. But to the batteries you should only have a 12v red/black circuit. When these two wires get to the battery(s), then there is the switch and charging load protection circuits that maybe between the actual batteries and those red and black wires. It is how you choose to connect your batteries to these 2 engine power leads that is a matter of preference.

[RickJ]

Tang is correct. You can only do clever things like AFD with an inboard engine where the alternator circuitry is directly accessible (much like a car). An OB is a "black box", you just have one big pair of wires that suck current from the battery to start it, and pump current back to charge it. There's an alternator in there generating the charge current, but it's not practical to start tweaking with it.

I don't know if OB's typically have built-in protection for the alternator in the case of disconnection from the battery while running, I guess it should be possible to find out from the maker, but could be a difficult question to get an answer to. As tang said, if you're going to switch under power, ensure you have make-before-break, and never switch "off".

My battery arrangement is starter + house (I know it's not considered necessary, but it came that way), so the motor is permanently wired to the starter battery. A VSR cross-charges the house battery. I quite like this arrangement as it means I know I have starter power even if I run the house flat. Conversely I can switch any circuit to run off the starter battery if required (e.g. if the house goes flat I can run the essential nav. gear from the starter). If I just had one battery I'd want to carry a jump-start pack, so I think of this as the same thing but permanently wired in!

Cheers, Rick