ACR Battery Selector Switch - WHY???

A

Almas Only

New member
I don't have an ACR, and after monitoring the threads related to this item, reviewing product literature, and learning how they work, am wondering why I would consider getting one.

I understand that if something comes with the boat, there is the natural inclination to use it. I also understand the desire to make everything automatic. That having been said, what is the battery charging problem on C-Dory 22 type boats that makes this device, and it's many associated problems, worth having?

At the risk of revealing how simplistic I am when it comes to charging batteries while underway, here's what I do. I have two identical wet cell (starting) batteries. One is designated "starting", and is on the 1 position on the manual selector switch. The other is designated "house", and is on the 2 position. In the morning, I put the selector switch on 1, start the motor, power up the electronics, run the windlass, and am underway. I let the 1 battery charge for a while, to replace the draw from starting the motor and windlass. I then turn the selector switch to 2, and let the house recharge for the balance of the day. At night, I leave the selector switch on 2, and run interior lights, wallas and fans as needed, anchor light, and the gps with anchor drag and low battery alarms set. In the morning, I note the battery volts on each setting, and begin all over again.

Sometimes, I forget to switch over to 1 in the morning, and start the motor on the house battery, which has been in use as noted overnight. This isn't the best thing to do to a wet cell battery, but the motor always turns over with a crisp crank, and starts right up.

When the boat is on the trailer, it's connected to the 110 v powered on-board charger 24/7. I've used the batteries in this way for three years. The starting is at 100%, and the house is at about 90%. I'll replace them both before going to the Bahamas, but otherwise, would see if they have another season in them.

Absent massive loading of the house battery, starting out with batteries which are not fully charged, or consistently overlooking a fairly simple switching procedure, I'm wondering what problem would be solved by introducing an ACR into this equation.
 
I, by no means have the knowledge to answer any questions about electrical on a boat but will share what I read in a boating magazine. You are always suppose to switch to the both position while underway for the benefit of the motors charging system. I'm sure I can't find the article to tell you which one it was because, I have an automatic magazine dispenser at my home that dispenses of magazines as soon as they get left where they are not suppose to be. :lol:
 
Alma's Only-

I'm much in the "same boat' with you on battery usage theory, but I do know that these battery isolators, combiners, automatic switches, multiple bank chargers, and battery monitoring systems are intended to allow:

1. Isolation of house and starting batteriess, including starting batteries from each other in twin engine applications.

2. Allow the use of specialized starting, deep cycle marine, combination, and various other types on the same boat.

3. Keep at least one battery in reserve for staring purposes.

4. Isolate voltage sensitive electronics from starting circuits which introduce voltage spikes into the electrical system.

5. Allow selective prioritized charging of batteries by any of the the motors, generator, or shore power.

6. Sell more fancy electronics with very expensive "black boxes" that defy understanding by the mortal souls who pay exorbitant prices for them. :smileo Or at least it seems that way at times!

Nonetheless, the resulting difficult to understand types of electrical and battery charging systems do make for a lot of confusion and consternation.

Basically, I'll have to say that I'm with you on this one!

I simply have two batteries in the back of the boat near the transom, and another two up under the forward dinette seat. Each pair has a "Off/1/both/2" switch, and all four are group 27 deep cycle batteries rated at either 105 or 115 amp--hrs.

I run the boat always with these four batteries in parallel, essentially one big battery!

Because I don't use sensitive electronics on an inland lake (I do have GPS, RADAR, 2 fishfinders, radios, etc., though), the voltage spike issue is never a problem.

Although I do run a engine mounted electric trolling motor on the anti-ventilation plate of the Yamaha 90, I can always sense when it's time to start up the motor or the generator (Honda eu1000) to charge.

The only problem I can see with this set up is that the load on the motor's alternator might be quite high when first re-charging, but no probems so far.

I like not having separate battery types, chargineg needs, complex wiring, multiple switches, and black boxes.

Essentially this system solves the problem of multiple battery types, differential charging, etc., by making the battery so big you can't harm it! It also works because it is simple, or as they say....... KISS......or something like that! Works for me!

P.S.: Four new group 27 deep cycle marine batteries @$60 each are a lot cheaper than an elaborate system you don't fully understand or know how to control.

Joe.
 
An ACR is just an automatic battery switch. You don't need it. It's nice to have.
They are not terribly expensive (~$65) nor difficult to add.

My own experience with the 1,2 1+2 setups is that it is relatively easy to forget
to move the switch. I'd rather not have to worry about it, and since I was making
major changes to the wiring* anyhow, it was a good time to add it. And honestly,
I like to play with stuff like this. It's fun. I like flipping the switch on the helm that overtrides the relay from 'auto' to 'off' and hearing the relay click off (the relay was
closed because the battery charger is on and voltage is high). Hopefully, when
I start the boat, the ACR will work properly. I would suggest getting the remote
switch and/or LED so you have some idea if the relay is working correctly.

If you are happy with your manual switch, then I wouldn't go to the trouble of
adding one of these.

Hey, lots of people have very expensive plotters on their boats. I was looking
at the cost of some of this stuff recently. I'll stick with the lower cost units
for now. Heck, before I got the Garmin 188C with the boat, I had a Garmin GPS-12, a
small handheld with no charts or anything.

Mike

*The boat did not have a charger, and there was not enough wire going
forward either. Any time I trimmed the motor, the GPs kicking out a lower
voltage alarm. That should not happen.
 
Interesting thread. As a new boater with no battery switch at all, but two batteries and one stand alone for "just in case" I always wondered about the need for a battery switch or some of the electronics I always read of here. I look forward to learning, as I have learned so much already from this site, of the advantages and disadvantages of switches and such.

Jeff
 
I have a 2003 22 -Cruiser - twin 40s. I have two batteries which are completely isolated from one another. Originally I had a 1, 2, or both switch until I discovered a thread on this site that indicated that the both component could cause harm to the honda charging system. The factory then isolated the batteries and left the orignal wiring (unhooked) to use as jumper cables in the event one battery goes dead. The house is run off the starboard battery.

Any comments are to potential downfall in this systems?

My hunch is I will be replacing the batteries this year. I keep them 24/7 on a charger when not in use and I have to keep a close eye on the water levels.
 
For those who use the 1-both-2 switch there is a simple way to remember to switch from the house battery to the starting battery.

Make a tag or card that says "Switch to start battery" and attach the tag to the key or place the card in front of the tach when switching to the house battery.

This 'memory jogger' can also be used for things like overhead clearance when towing. Or for the drain plug!! LOL
 
For $65 an ACR is a good investment - even if your memory about switching battery banks is perfect. Here's why: the primary advantage of an ACR is it works to maintain optimal charges in BOTH batteries in as short a period of time as possible. This is important because an undercharged battery sulfates and battery life is reduced. When the cranking battery is charged, the ACR switches to charge the house battery and visa versa. There is no delay in maintaining the "perfect" charge in both batteries; the charging system operates at maximum efficiency.

Note as well that switching a selector switch from one or the other single settings (on a partially discharged battery) to "both" will immediately draw down the second battery - another needless discharge. This will happen even if the system is actively charging.

Discharge level and frequency varies so it will affect batteries differently. Adding an ACR is easier than trying to figure this out. Presumably an APC extends battery life. Assuming a marine combo crank/deep cycle costs $65 (an Interstate group 24) and you have 2 ($130) and you save 15% of your battery life with an ACR, you save $19.50 per battery switch out - a payback period of 3.3 years.

Don't underestimate the value of an ACR in automatically isolating the cranking battery during starting and ill effects on electronics. (BTW this has nothing to do with sea or fresh water.) How quickly a $65 ACR might pay off if a $165 VHF or even $3000 all in one system is fried!

Besides, it's cool technology. Guess I better get one.
 
Falco":3i9htnlf said:
Don't underestimate the value of an ACR in automatically isolating the cranking battery during starting and ill effects on electronics. (BTW this has nothing to do with sea or fresh water.) How quickly a $65 ACR might pay off if a $165 VHF or even $3000 all in one system is fried!

Besides, it's cool technology. Guess I better get one.
Click to expand...

Now you did it ! I guess I better get in line. Hey Marc, you reading this thread?
 
C-Sick,
I have the same setup just a year older. I also have two batteries each wired to each motor and independent. Since the "House" battery is a function of which one I have selected I see no advantage to an ACR in our case. A technique I use on my boat when cruising and especially when doing a lot of fishing(trolling on one engine for extended periods), is keep the battery switch on position 1 for odd days and position 2 on even days. Even this might be hard to keep track of if not for my digital watch. I have gotten four full seasons out of two group 24 batteries using this method. Works for me.
 
Many people seem to have onboard chargers and I am considering one. I also like to keep things simple.

How do you power the charger? - Plug charger directly into an extension cord. Or is it wired into a shore power system that gets plugged in?

I don't like the thought of carrying one of the large 30amp yellow dock cords. But I also don't want to have an electrical hazard by not having a grounded, reverse polarity indicating, circuit breakered, full up system.

Is there a simple/safe compromise?

Steve
 
I certainly cannot argue with the points Alma's Only makes. If best practices are followed then the system is best without any fancy stuff.

I guess the most accurate way for me to answer would be to say I like having the ACR for the same reason I like the feature on my truck that shuts off the headlights 30 seconds after I forget to. The only purpose my fully functional Off-1-2-Both switch serves is to disconnect the motor from the battery when leaving it sit for a while in the water or on the trailer.

I do recall that Les does not like using the things. I think his thoughts are more for maintaining optimum battery condition. But with Costco just down the street, I replace the batts at 2 years and get a few bucks back on the three year warranty.
 
Steve, When your boat, family and marina's safety are involved, don't compromise!

Alma's Only, The Blue Sea's ACRs are a valuable tool on boats with twin engines. Dreamer has 2 Optima AGM engine start batteries. Once they are fully charged, the ACRs conect them to two Lifeline 275 amp-hour house batteries. Actually, each engine, start battery and house battery are in a separate charging system. While at anchor or at a marina, the selector switch is turned to ALL. This gives a 550 amp hour house bank to use or charge if shore power is available. The next morning, Batt 1 or 2 is selected to be the house/electronics battery of the day.(Batt 1 on odd numbered days, Batt 2 on even days)

The charging output on the Honda 150s is not what one would hope for but it does the job. The wiring includes manual paralleling of the batteries for emergency starting. (see photo album) All the Blue Sea equipment is top notch in my book and I don't worry about it failing underway. This may seem somewhat complicated but it about as simple as I could get on a twin engined boat with moderate to heavy electrical demands.
 
As Noted by Jeff, C Pelican (which we used to own) has two batteries always connected in parallel, plus an "extra" battery which is isolated--and not hooked up. We never had the need for a switch or an ARC.

For the simple and low battery draw on the 22, I would think that an ARC is overkill. We moniter battery voltage. With the 22, we just checked it with a hand held digital volt meter. With The 255, we have two ARC's, lots of electronics, an inverter, refigeration'/freezer, and 5 batteries--a much different situation. We could do the same with a good battery switch (Make before break). The ARC does isolate the electronics during start, low voltage and spikes which might occur during this time.

We do have a simple volt meter (Ok I got a really good deal on a Link 1000 so we now track amps)--and I check battery voltages as we are running. If an ARC was not working--or I didn't switch over the batteries I would pick that up within 15 minutes of leaving the dock/anchorage. I moniter battery voltages during running every 30 minutes or so--plus at anchor every 6 hours give or take.

Bob Austin
 
Because I was redoing wiring anyway, and because I was going to a three battery, two engine setup I put in two VSRs (ACRs by another maker). There are also three switches incorporated into the circuits plus I kept one of the original on off all switches.

I like it for all of the reasons Joe said, and for what Mike said comparing it to the chime for lights left on (by the way this becomes more important with each passing year).

Also sort of covered by Joe's point number 5 - but, my deep cycle house battery is charged by both engines when both are running so it is recharged faster. Also without throwing any switches etc. my house is kept charged when I troll with either engine alone for extended periods.

My onboard 110v charger is three banks and is separate from the vsrs and switches.

Joe wrote and I find all are true:

1. Isolation of house and starting batteriess, including starting batteries from each other in twin engine applications.

2. Allow the use of specialized starting, deep cycle marine, combination, and various other types on the same boat.

3. Keep at least one battery in reserve for staring purposes.

4. Isolate voltage sensitive electronics from starting circuits which introduce voltage spikes into the electrical system.

5. Allow selective prioritized charging of batteries by any of the the motors, generator, or shore power.

6. Sell more fancy electronics with very expensive "black boxes" that defy understanding by the mortal souls who pay exorbitant prices for them.

Previous boat with single engine (and much larger alternator) always ran with two batteries and single on off all selector switch. Never had a problem.

Regards,

Mark
 
Mark, I originally planned to charge a single house battery with both engines through ACRs. The problem, as it was explained to me by a marine electrician, is that each charging source senses the elevated voltage caused by the other, thinks the battery is topped off and drops to float. He said he has found no way to charge a house battery from two sources. It would be nice to combine the alternator outputs for a higher charging rate. Have you tried this system and tested charging rates?
 
An ACR will not help with the problem of two simultaneous charging sources.

A 7600 can be used with two sources that are not generally expected to be in use
at the same time. You could, with the appropriate jumper put your alternator
on one bank and the charger on a second bank. When voltage is high on
post A, the relay will combine. Additionally, if you run a sensor wire
from the 7600 to bank B, the relay will combine if the voltage goes up on
that side. So, you could connect your alternator to post A and your
charger to B.

If both charging sources were active at the same time, then the one of the
charging sources will probably drop to float.

I have a two bank charger wired as such. When the charger is on, it is good
to disconnect the ACR using its manual override switch to prevent the charger
from charging through one bank.

I plan to make a relay cutout that will cause the ACR to open when the charger
is on. This falls under the department of "unnecessarily complex yet cool".

I think there are devices that uses diodes that will combine charge sources effectively,
but there is a votage drop across the diodes. So, you need to sense the battery
voltage at the battery. This can be done with some alternators, but I don't know
how to do that with an outboard. It wouldn't be easy.

Mike
 
I have read this thread 2 times but I still have a question or 2 that maybe you all can help me with. I have a new CD 22 and I am in process of adding a "house" battery. I found with 4 foot cables I can put one down where the bilge pump is and reach the other battery and switch.

I have the shore power and battery charger package on the boat. I have purchased a blue sea 1+2+both switch but havent installed it yet.

Question 1 is if the engine is running, can I safely switch from battery 1 to 2?
Will the alternater automatically adjust to the different charge draw?

Question 2, If I have the battery switch on both at dock with the battery charger on, will it charge both ok? The batterys are NOT the same. One is a starting battery and the other is deep cycle.

Thanks for any advice.....
 
Bill,

Everybody has their own ideas but I am personally uncomfortable with putting a battery down on the sole of the boat. Mainly because I want my power supply (for the bilge pumps, etc.) up higher where a single big wave into the cockpit won't swamp and short it out. I also don't want it where it can be kicked, have things dropped on it, etc. I have a 22' cruiser and Les put my house battery plus the battery control switch in the starboard lazarette and the two engine batteries in the port lazarette. They are a little in the way when I am trying to get to fuel filters, etc. but otherwise they are neatly tucked away. I just took a hose to the cockpit as part of my spring commissioning routine and I'd be really leery of doing that if my battery was exposed back there by the bilge. YMMV.
 
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