dual battery / sound system

I have read a lot of threads here and on other boards and still cant decide which way to hook up my dual batteries. I was able to get 2 new optima d34m blue tops for next to nothing. I would like to run my amps off of one battery and leave everything else hooked up to the other battery. I really dont want to have to deal with a switch but I can if someone could explain the best way to use it. How has everyone here hooked up their dual batteries and amps? Did anyone use an isolator?

How big is your system? I'm assuming fairly small if you have one additional battery. With dual batteries the extra battery shoudl be for backup only. When you 3, 4, 5+ batteries I'd reccomend something else.

Use a perko only. Hook everything up to one battery. IF your boat doesn't want to start switch to your backup.


Cheap, easy, effective.

#1 batt is main batt, #2 is backup. Run on both untill you stop to listen to the adio for a while, then switch over to 1 only. If you have starting issues switch to #2 and start, or both.

I run 2 deep cycle batteries and we have an isolator hooked up. The secondary battery runs the amps and the first battery is cranking. It was pretty simple to hook up and it will discharge the amp battery and not touch the first battery. When you crank it begins charging the second battery. I got my isolator at an R/V store and its indicated use is R/V or Marine. I have paranoia as well and carry a jump pack in the boat too lol...

I have the exact same battery setup, didn't want to flip any switches or anything, and wanted the peace of mind knowing that my stereo won't drain my starting battery and leave me dead in the water.

And I'm a simple-minded person and don't understand any of the crap discussed in the other battery threads. Based on Psyclone's advice, I went with a Stinger Isolator. It is really easy to install and does exactly what I want it to do... If you want one, let me know as I have an extra. It is similar to the one here:
http://www.hifisoundconnection.com/Shop/Control/Product/fp/vpid/1333954/vpcsid/0/SFV/30046

http://surepower.com/pdf/separatorinterconnect.pdf
Relatively cheap
easy to install
no need to worry about switching anything
gives priority to starting battery
Little/no voltage drop

I have sold probably 5-10 of these to wakeworlders and they have all been really happy. Let me know if you have any questions.

Isolators have a voltage drop so your batteries won't be receiving the full charge from the alternator like they should.

^^& These suggestions are fine,and will work , but I don't like isolators.

#1 some brands have voltage drops
#2 They can potentially combine a dead battery to a good battery and kill both.
#3 when #2 happens , if your boat starts and you continue to jam music you can fry your alternator.


Go with a combiner over an isolator if your lazy about your batteries. A combiner is voltage sensitive.

lol, what brett said.

Should have mentioned my sound system includes an infinity bass link 200w, a 4 channel jbl not sure of watts but will find out when I get home tonight, and a infinty 300w amp. The bass link and 4 channel jbl are in it from the factory and all run off the standard battery. I am taking out the standard battery and putting in the 2 blue tops.

How does a combiner differ from an isolator? Sorry for all the questions but I would like to do it right the first time.

An isolater is basically like a Y valve in plumbing. After it splits it has a diode on each path. The diode with the least resistance is the one that opens and lets electricity travel through it. Once that battery is charged more then the other it will switch over to the other battery.

The combiner/separator is voltage sensitive. Your charging cables are run strait to your starting battery. The combiner/separator is linked between the two batteries on the positive side. If the 1314 receives less then 12.5V it breaks the circuit so you are only charging the starting battery. It also works that if you have the boat off and are playing the stereo the batteries will be in parallel till the batteries reach 12.5V. At this point it will separate the batteries so your stereo is only drawing down the house bank.

I use the Blue Seas ACR system, it doesn't have the issues of a regular iso.

Adam,

A diode-based isolator is automatic, convenient and will work OK, but you'll have a one volt or more loss and voltage on a towboat is too valuable. You want your batteries topped off.

A Perko switch is easiest if you don't mind the manual operation. My favorite.

A combiner automatically isolates and combines at a fixed voltage, although there is not a good reason to wait for a voltage drop in your application.

For an automatic solution I like a simple solenoid/relay (like the PAC or Stinger) that isolates with the ignition off and combines with the engine on. In most respects this is similar to a combiner. Versus the Perko switch, you won't have to redirect your alternator feed, helm buss, etc.

Also, a small maintenance charger is important for use when in storage.

David E.M.

Brett, is there a way to use your combiner/separator in addition to a perko switch?

I have a perko with two batteries and manually switching to #2 battery to listen to music when the engine is off gets old. However I still want the option to disconnect the batteries from the boat electronics to prevent something from draining the batteries when not in use or when I'm working on the boat.

I'm guessing by disconnecting the #2 battery from the perko and connecting it to the #1 battery with the combiner between the pos+ would work? That way if the perko switch is on #1 the combiner would work as normal and switching the perko to off would disconnect both batteries from the boat electronics?

Thanks in advance.
Brian

p.s. If it's possible to use both, please let me know the price of your combiner.

Sounds fine to me Brian. You are just using your Perko as a master disconnect switch which plenty of big rigs, boats and rv's have.

Oh yeah, 58.09 if you have under a 100amp alternator and 109.74 if your alternator is between 100-200 amps.

(Message edited by polarbill on January 21, 2009)

(Message edited by polarbill on January 21, 2009)

"For an automatic solution I like a simple solenoid/relay (like the PAC or Stinger) that isolates with the ignition off and combines with the engine on. In most respects this is similar to a combiner. Versus the Perko switch, you won't have to redirect your alternator feed, helm buss, etc."

Like I mentioned ealier, this method will combine the batteries regardless of voltage....if you kill your stereo battery, it will still combine your batteries...not a good idea.

A combiner will not.

Brain, IMO, that is the best battery setup...using a combiner along with a perko style switch. It gives you complete control.

On a perko switch how does it all work? If i am on battery 1 can I switch it to both or 2 while the boat is running as long as it does not go to off.

And remember an extra battery is another load on your alternator. Make sure you have an alternator that will handle running all of your boats electrical needs. And make sure you are using the proper size wire to hook up the 2nd battery.

i believe you can switch from 1 to 2, but i know for 100% sure you are not supposed to switch past "off" as it could damage your alternator.

when using a manual switch with in conjuction with a combiner it simply gives you the option to switch to "both" in an emergency situation as well as turning it to "off" for storage without disconnecting everything.

My alternator is 25 amps at idle and 70 amp max at 2000 rpms. Should this be enough for my system?

batter separator is the way to go, hook it up and forget it.....


Sure Power is the best IMO....

Are the sure power separators marine certified? I dont want any fires on my boat.

You do not want to switch a perko to off while the boat is running. You will blow the diodes in the alternator.

(Are the sure power separators marine certified? I dont want any fires on my boat.)

yes they are...

adam, hook up with brent, he can give you a good price on them..

Brent: days are getting longer

Ken, who is Brent?

J/K

hey brent which one's are you selling now? the 1314's or the 1315's? pretty sure I have a 1314 which is not uni-directional. i need to go look at the wiring and give you a shout.

I usually sell the 1314 so that it gives priority to the starting battery.

ahhh, that's right. k thanks, i forgot that.

Since I'm doing some serious upgrading to the system in my boat over the next couple weeks I've been doing some digging. I'm gonna be running a lil over 4,000 watts. For right now I have a starting battery, one Optima red top and (for now) two VMAX http://www.vmaxchargetank.com/audio.html 2500 series batteries. They are 130 amp hours and for the way I play my system, they should last me a couple hours or so. Nice thing about these batteries, no worries about smoking the stock altenator. They show VERY little load while charging. I too will be using a PAC isolator so I don't have to worry about flipping any switches.

I've done some testing and with my tower set up, 2 Pro485's and 2 MB-8's all pushed with Digital Design amps and just off the stock type starting battery and the red top, I can get an honest 4 hours of play time at damn near full tilt. The VMAX's are gonna be just for the two subs, around 2800 watts. I'll probably be lucky to get 2 hours with those DD subs thumping, but only time will tell after I get it all installed. If all else fails, I add another two to the bank.

BRETT
lol.... i was talking to brent when i was typing, sorry dude, hows buz up there?

Not too bad. You guys staying busy down on Argyle.

yeah, short handed makes it really busy, im ready for a vegas weekend....

I was thinking about going to vegas for opening weekend of the NCAA tourney and my buddies bachelor party but I think I have decided not to go. I can't handle vegas for more than 48 hours or so.

yeah, about 3 days of partying is about all we can do.

" Nice thing about these batteries, no worries about smoking the stock altenator. They show VERY little load while charging. I too will be using a PAC isolator so I don't have to worry about flipping any switches. "

I'm curious to know what technology these battery's have that "trick" the alternator into not sending a full charge to the battery. The majority of stock alternators are NOT battery chargers. If you use them that way they will burn up eventually.

Batteries are failry simple, I don't get how it coudl turn away a charge coming from the alternator. If you run your batteries down, and start back up and continue to play yrou stereo loud, run other accesories you will smoke your alt.

I'd rethink the PAC isolator.....you should go with a combiner and a perko style switch.

Guess I should have made my post a lil clearer.

I understand about the burning up the alt. I don't use the alt as a battery charger while trying to keep the system cranked. If I'm out that long with the stereo full tilt and drain those batteries, then the stereo is either off or just on enough for us to hear while we're cruising around the lake for an evening ride or just heading back in. I can still run lights etc and have the system on, just not full tilt even if they are quite discharged.

Why do you not like the isolator? I've used several before and had no problems at all with them.

This IMO is the best way to run a dual battery setup. See mikeski's link to a drawing.

http://www.wakeworld.com/MB/Discus/messages/65921/Boat_Battery_Diagram-262940.pdf

If you choose nto to use the perko go with a combiner over the isolator...think of a combiner as a smart isolator.

Let's say you parked the boat and ran the stereo off the second battery. Some time later you go to start the boat, starting battery is nearly full, the stereo battery is way down.

The combiner looks at both batteries, one is at 12.4 volts, the other is at 11.5 volts. Neither are high enough to cause the combiner to connect.

When you hit the starter, battery 1 drops to 10.5 volts, battery 2 stays at 11.4 volts. Combiner keeps them separate.

The engine starts, alternator starts pumping out minimal amps because the RPM is low. Voltage on battery 1 climbs to 13.0 volts. This is still below the threshold for the combiner, batteries are kept isolated, what little amps the alternator is providing goes into battery 1, making sure it gets charged up.

You idle out of the 5 MPH zone, and hit it. RPMS climb up, the alternator starts cranking out maximum amps, battery 1 voltage climbes to 13.5 volts. Now the combiner connects the two batteries.

You're going fast so you crank up the tunes to hear the music over the wind noise. Maybe it is getting dark and you turn on the tower lights. Maybe it is cold and you are running the heater. You left the blower on so it is drawing current, and you are trying to empty the ballast tanks so the pumps are running. Bottom line, the alternator can't keep up, and voltage drops below 13.0 volts. The combiner senses this and isolates the two batteries, making sure the starting battery is kept full.

Exactly...

battery diagram 2.0:

Upload Scotts Wiring Schematic.pdf (72.0 k)

I'm sorry to make you guys keep saying the same thing over and over again, but if I wire my two batteries in parallel and add a combiner on the positive line, am I good to go for the summer?

This is how I have mine wired never have to worry about it. The best of both worlds it’s a Perko and a Automatic Combining Relay. I have a green let wired to the led terminal of the ACR so I can keep tabs on it. http://bluesea.com/products/7650