Three batteries, two motors, two switches

triumphrick

Lieutenant Commander
Joined
Jun 26, 2008
Messages
1,737
OK, I want to add a house battery to our boat. Have two Interstate Marine starting batteries, two motors and two Perko off/1/2/all switches. What would be the best way to add the third battery. I have an idea, but my search did not show this configuration...thanks, Rick
 

Big Keepers

Petty Officer 1st Class
Joined
May 13, 2007
Messages
293
Re: Three batteries, two motors, two switches

Not so sure I would go with an isolator. They suck up charging amps due to the diodes inside that make them work. But you may not have a choice if your system is going to be complex. Also you need at least one battery switch if not two of them, but not necessarily one, two, both switches. A bit more info on how your existing batteries are hooked up would help. Also what kind of motors do you have? Twin outboards? Twin inboards? Newer EFI outboards or older CDI two strokes? Are the starting batteries hooked up together somehow for emergency starting or are they completely independent of each other? Does one battery start both motors and the other is a back up? You said you have two switches that are 1,2,both switches.

I am a big fan of Blue Sea's add a battery kit that uses an automatic charging relay instead of an isolator. But I have one outboard and two batteries only. Its been a while since I had to figure out how to hook up three batteries with two engines.

To begin with I'd say you want an on/off switch by itself to shut off the house battery so that any electronics you left on won't drain it. Also you'll want to install an inline fuse as close to that battery as possible to protect all that wire and your electronics. Probably a 30 amp fuse will do, it depends on how much current your house battery will be supplying. Then you need to hook that battery up to your alternator/charging system somehow to charge it. An easy way to do that is the add a battery kit. Use one of your motors to charge the house battery and its dedicated starting battery. The other motor will only have to charge its own battery.

If both of your starting batteries are hooked up together via a separate on/off switch, you can link them in an emergency to get your motors started. If the picture in my head is right you may need as many as four switches in this set up, all on/off switches will do. Again it depends on how your existing batteries are hooked up and how they are getting charged right now. You might only need one on/off switch and a one, two, both switch if you prefer those.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,537
Re: Three batteries, two motors, two switches

One two port switch has its common to your starter with terminal #1 going to one start battery and terminal #2 going to the common of the second two port switch. The termonal #1 of this second switch will go to the other start battery and terminal #2 will go to your house battery. Then hook an ACR between start battery 1 and start battery 2 and an ACR between start battery 2 and the house battery. Like the original poster said, have an on/off switch between the house battery and the loads that are on it.

Second option is to not allow the house battery to ever start your engine. In this case you don't need the second two port switch. You just hook uo the 2 start batteries to the switch but still have 2 ACRs as described above and the on/off switch for the house battery.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,537
Re: Three batteries, two motors, two switches

Toss the switches, get a 3 bank isolator.
Toss switches? How do you expect to connect the batteries to the engine? Isolators are old school and don't let your batteries get fully charged. Better to use an ACR.
 

Ridemywideglide

Petty Officer 2nd Class
Joined
Jan 13, 2009
Messages
166
Re: Three batteries, two motors, two switches

Toss switches? How do you expect to connect the batteries to the engine? Isolators are old school and don't let your batteries get fully charged. Better to use an ACR.

I would connect them with cables, but that's me..

You should read the link I provided above.
 

Big Keepers

Petty Officer 1st Class
Joined
May 13, 2007
Messages
293
Re: Three batteries, two motors, two switches

First off if you don't use switches in your set up then you're asking for trouble. Wires linked from battery directly to engine? You'll still bleed off amps and slow drain the battery.

That hellfire set up sounds hokey pokey to me. Bottom line is that any isolator out there relies on diodes to work. If a diode fails you don't know about it until your batteries fail you. They claim that the voltage loss is less than half an amp or whatever when the battery approaches full charge, but what about when the battery is taxed and in need of a decent charging current? My guess is you are losing almost a volt like all other isolators. The Blue Sea ACR's are also a lot smaller than any isolator out there. The one on my boat is less than 3" by 3" and you can find them thinner than that. The best part is that you have zero, none, nada in the loss of voltage department.

I like bruce's second option. That house battery doesn't need to be hooked up to your starting batteries. Bring a jump pack instead.
 

Ridemywideglide

Petty Officer 2nd Class
Joined
Jan 13, 2009
Messages
166
Re: Three batteries, two motors, two switches

First off if you don't use switches in your set up then you're asking for trouble. Wires linked from battery directly to engine? You'll still bleed off amps and slow drain the battery.

If leaving your battery hooked up, drains it, then you need to figure out where your problem is.

That hellfire set up sounds hokey pokey to me. Bottom line is that any isolator out there relies on diodes to work. If a diode fails you don't know about it until your batteries fail you. They claim that the voltage loss is less than half an amp or whatever when the battery approaches full charge, but what about when the battery is taxed and in need of a decent charging current? My guess is you are losing almost a volt like all other isolators. The Blue Sea ACR's are also a lot smaller than any isolator out there. The one on my boat is less than 3" by 3" and you can find them thinner than that. The best part is that you have zero, none, nada in the loss of voltage department.

First, "hokey pokey", that's strange because they are designed to do EXACTLY what the OP is looking for. I think if you actually R E A D the link you may see that.
Second, your full of crap about your Sea Blue having no voltage loss. R E A D thier website.

ML Series Heavy Duty; <40mA Charge state, <10mA Sensing state.
L series w/coil; 12 Volts DC/0.13 Amperes DC, 24 Volts DC/0.07 Amperes DC
SI Series; 15mA

And here's thier version of a "hokey pokey" auto-charge/combiner unit.

CL-Series BatteryLink;

Automatically combines battery banks during the charging cycle and isolates under discharge
Limits current flow allowing smaller wire size
Adjustable high voltage disconnect
Adjustable low voltage disconnect and combine voltages
Activates from any charging source?alternators, battery chargers, or solar panels
Senses charge voltages on up to two battery banks
Ignition protected?safe for installation aboard gasoline powered boats
Noise free circuitry will not interfere with other devices
Low current draw when closed: <0.2A

.2??? The hellroaring product does the same thing, and is rated .012...

Sure sounds hokey pokey to me...


on edit;

Here's hellroarings stated voltage drop fot the 75300a model;
Voltage drop at 5 amps to the auxiliary battery system
< 0.05, <0.02, or < 0.01 Volts
(depends on configuration used)

Not anywhere near half a volt...
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,537
Re: Three batteries, two motors, two switches

hey Ridemy,

The site you are linking is for an ACR...not a diode isolator.

And...the Blue Seas does not have a voltage loss...possibly a small amount due to internal resistance of the power FETs but not due to a diode drop.

here is a quote from the website you posted:

http://www.hellroaring.com/marine.php

"We recommend that you do not use plain diode isolators. We recommend an automatic combiner as the better solution. But, since mechanical relays/solenoids have their own problems such as sticking contacts, arcing and contact wear, we recommend our solid state automatic battery isolator/combiner as the best solution."



Bruce
Electrical Engineer
BSEE MSEE
 

Ridemywideglide

Petty Officer 2nd Class
Joined
Jan 13, 2009
Messages
166
Re: Three batteries, two motors, two switches

Chill out please - QC
 
Last edited by a moderator:

Ridemywideglide

Petty Officer 2nd Class
Joined
Jan 13, 2009
Messages
166
Re: Three batteries, two motors, two switches

hey Ridemy,

The site you are linking is for an ACR...not a diode isolator.

And...the Blue Seas does not have a voltage loss...possibly a small amount due to internal resistance of the power FETs but not due to a diode drop.

here is a quote from the website you posted:

http://www.hellroaring.com/marine.php

"We recommend that you do not use plain diode isolators. We recommend an automatic combiner as the better solution. But, since mechanical relays/solenoids have their own problems such as sticking contacts, arcing and contact wear, we recommend our solid state automatic battery isolator/combiner as the best solution."



Bruce
Electrical Engineer
BSEE MSEE

Since you completely changed your post.....

They call it an isolator.... If you know something they don't, maybe you should call them up and tell them they don't know what the hell they invented.

I guess actually they call it a Battery Isolator/Combiner... Wouldn't want to start another war over symantics....
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,537
Re: Three batteries, two motors, two switches

Your first post stated to use a 3 bank isolator. Since there aren't any 3 bank isolators that aren't dioded based I was going off your first statement. What do you use and why?
 

Ridemywideglide

Petty Officer 2nd Class
Joined
Jan 13, 2009
Messages
166
Re: Three batteries, two motors, two switches

Your first post stated to use a 3 bank isolator. Since there aren't any 3 bank isolators that aren't dioded based I was going off your first statement. What do you use and why?

Edit - QC

It charges 3 batteries, and isolates them from each other when not charging...

I use 1 battery, AND no switch, in my boat.. I'm really livin on the edge... :eek:
 
Last edited by a moderator:

Ridemywideglide

Petty Officer 2nd Class
Joined
Jan 13, 2009
Messages
166
Re: Three batteries, two motors, two switches

Here's a link, maybe you can click it, and read about all the stuff that your telling me they don't have...

http://www.hellroaring.com/bic75300.php

This also has all the specs...

So, like I said in my first post.

TOSS THE SWITCH AND GET A 3 BANK ISOLATOR...

Of course, on another page on that site (you'll have to click a couple times) they do recommend (and have nice little pictures) of installs with different switch configurations.
 

Big Keepers

Petty Officer 1st Class
Joined
May 13, 2007
Messages
293
Re: Three batteries, two motors, two switches

You have a 1971 boat with a 1979 motor. You may be able to get away with no switch. It is still stupid, especially if you have any kind of accessory attached to that battery.

But hey who am I to speak? My instructors must have been teaching me the wrong ways to fix boats.
 

triumphrick

Lieutenant Commander
Joined
Jun 26, 2008
Messages
1,737
Re: Three batteries, two motors, two switches

THANKS TO ALL THAT POSTED.......:redface:

Jeeez..where is Silvertip when you need him...:p

I sure appreciated his diagrams and wiring expertise...

I do have a configuration that will work. As noted, I have two perfectly fine Perko switches mounted to the cover of a transom hatch and don't care to toss them. I have decided to utilize one of those switches with one isolator and let one motor charge both batteries.
 

crackpot

Recruit
Joined
Jul 17, 2009
Messages
1
Re: Three batteries, two motors, two switches

OK Duderons,

Attached is a schematic diagram of my 2300wa DC Circuit after rewiring from the factory. It seems that the 115's only have one alternator wire feed rather than the two offered with the 150's or higher. Evedently Polar's ideology was that you will have enough juice in the house battery after leaving port for your entire trip and figured that departing with a fully charged battery would be sufficient, It seems rediculous but it's true.
Polar even went the extra mile by cheaping out and did not install an isolator. By placing the battery switch in the both position you will charge both batteries but by the same tolken you will also drain both batteries if you are drifting or anchored with the engines not running and use too much power to run your all electrical stuff guess what???. "What a bunch of Cheepo's"
I installed an extra house battery and split the dc load. Then I installed 2 Charge on the Run Chargers. Since the extra voltage also upset the CO detector I had to install a series 1/4w 1n4001 on the hot lead of the CO detector. It Seems to be working OK
Crackpot
Fight Fire with Fire :mad:
 

Attachments

  • 2300WA.jpg
    2300WA.jpg
    31 KB · Views: 0

Big Keepers

Petty Officer 1st Class
Joined
May 13, 2007
Messages
293
Re: Three batteries, two motors, two switches

The One, Two, All switches were never really intended to be used the way most people use them i.e. charging both batteries at once. People need to remember that these devices were used for decades, long before people started to load their boats up with am/fm cd players, flood lights, expensive gps/sonar combos, lots of courtesy lights, etc. They did not have a lot of amps being drawn off their batteries. Most boaters ran their boat on battery #1 for a while, then switched over to #2 for a while. The Both selection was for emergencies only. Then people started to always run on both because it made sense to them that both batteries would be charged at the same time. That is half true, both batteries are partially charged at the same time. By leaving the switch in both the weaker battery draws off the stronger battery while the engine attempts to charge them. The end result is always a weakening of both batteries in the long term. Plus if one battery decides to short out and you have the switch on both, the shorted battery will drain the good one real fast and you now have two dead, useless batteries.

Isolators came along and were great but the major drawback is you can lose as much as 1? volts to the diodes in the isolator that allows it to perform its function. If you're battery needs 13 volts to charge and it only gets 11? then you have to run the motor a lot longer to fully charge the batteries. When a diode fails both batteries are immediately linked and you have the same problem as leaving the switch on "both."

The marine industry wanted devices for boats that were essentially idiot proof to some extent because, let's face it, the majority of Americans are idiots, especially the ones who buy expensive boats to supplement their egos. The stories I've heard about idiot boat owners could fill a thread all its own. Like the guy who didn't realize he had to put the safety lanyard on to start the motor. He thought it only worked to keep the boat in gear and to keep him from flying overboard. Yeah that lil red coily thing will hold your 250 pound butt in the boat when you hit that sandbar or rock.

Every device will have positives and negatives. You need to weigh the positives against the negatives and see what product will work best for your application. It also helps to have some common sense which unfortunately is not too common these days.
 

triumphrick

Lieutenant Commander
Joined
Jun 26, 2008
Messages
1,737
Re: Three batteries, two motors, two switches

The One, Two, All switches were never really intended to be used the way most people use them i.e. charging both batteries at once. People need to remember that these devices were used for decades, long before people started to load their boats up with am/fm cd players, flood lights, expensive gps/sonar combos, lots of courtesy lights, etc. They did not have a lot of amps being drawn off their batteries. Most boaters ran their boat on battery #1 for a while, then switched over to #2 for a while. The Both selection was for emergencies only. Then people started to always run on both because it made sense to them that both batteries would be charged at the same time. That is half true, both batteries are partially charged at the same time. By leaving the switch in both the weaker battery draws off the stronger battery while the engine attempts to charge them. The end result is always a weakening of both batteries in the long term. Plus if one battery decides to short out and you have the switch on both, the shorted battery will drain the good one real fast and you now have two dead, useless batteries.

Isolators came along and were great but the major drawback is you can lose as much as 1? volts to the diodes in the isolator that allows it to perform its function. If you're battery needs 13 volts to charge and it only gets 11? then you have to run the motor a lot longer to fully charge the batteries. When a diode fails both batteries are immediately linked and you have the same problem as leaving the switch on "both."

The marine industry wanted devices for boats that were essentially idiot proof to some extent because, let's face it, the majority of Americans are idiots, especially the ones who buy expensive boats to supplement their egos. The stories I've heard about idiot boat owners could fill a thread all its own. Like the guy who didn't realize he had to put the safety lanyard on to start the motor. He thought it only worked to keep the boat in gear and to keep him from flying overboard. Yeah that lil red coily thing will hold your 250 pound butt in the boat when you hit that sandbar or rock.

Every device will have positives and negatives. You need to weigh the positives against the negatives and see what product will work best for your application. It also helps to have some common sense which unfortunately is not too common these days.

Ahhhhhh Sooooooo......spoken like a true New Yorker....:rolleyes:

Thanks, crackpot...your diagram is spot on and just what I was hoping would get posted. Welcome to the forum!
 
Top