Dual Batteries?

[z22owner]

I am putting in a 200 watt amplifier for a new 10" sub in my 1999 Z22. Right now it has the original battery that is well taken care of. (on a charger after use) Should I invest in a dual batt. system? Should I upgrade my alternator? If so, can anyone give me some pointers.

Kevin

[Ed Donnelly]

I have 2 batteries in the Criterion 1 Marine and 1 deep cycle.. When playing tunes I run the deep cycle, then on the way back to the dock I change my battery selector over to charge the deep cycle. This way you don't drain your main battery used for starting and running your engine...Ed

[farmer tx]

Kevin,
On our 22 we have 1 marine bat. for engine only and 2 deep cycle bat.s for the sound system. The sound system is wired through a relay that is energized by the ign. switch. When the boat is underway the charging system charges all 3 bat.s but when rafting up and ign. switch off the sound system draws from the 2 deep cycle battery's. The marine battery is always charged.
Hope this helps.

Later,

[HyperDonzi]

If you go the dual route, Perko makes switches for under 25$.

[MOP]

Another thing you can do is to use a battery isolator along with the combining switch for emergency starts to keep both batteries charging when ever the engine is running. It is a cheap about $40 for peace of mind.

[Fish boy]

Hyper is right, it is not enough just to have 2 batteries without a perko switch that will allow you to use "Batt 1, Batt 2, or All". that way you can switch to a single abttery when just playing the radio and still have the other battery to start and get home should you wear down the first.

[Donzigo]

In thirty years of boating, I've never been without two batteries and a switch. Make perfect sense.

Richard

[oldLenny]

MOP above posted a great dual battery diagram about 6 months ago and wiring schematic...Harbourmaster was the one curious I believe...

Do a search for it...I would NEVER be without 2 batteries and I have always used one when stopped for the music and switched it over if need be to start the boat again. Great peace of mind! :D

Look, here it is...
http://www.donzi.net/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=004872#000004

[Surfer]

The diagram that comes with the Perko switch is all you need, and is an easy mod.

[MOP]

CorrectaMundo

http://www.perko.com/cat_frames.html

Just use seperate grounds!

[HyperDonzi]

One more thing.... Marine batteries will not last as long as car batteries because of the harsher conditions. You will probably looking for a new battery soon, and are you sure you want to buy 2 at the same time?

go to www.overtons.com (http://www.overtons.com) search part number 31620 for the selector switch. 26.99

[Murphy]

Bear with me here... could be a reeeally bad idea...

What about mounting one up in the bow at the tip of the storage compartment. ++ include good weight distribution (already a lot of weight in the stern. -- include that's right over the fuel tank (kaboom). Could this be done safely or is it even worth talking about?

Murph

[MOP]

HYPER
Marine batteries are different from automotive batteries only in the fact with lead acid types they have about twice the distance from the plates to the bottom to allow for wasteage build up. This makes up for the extra bouncing they get. Most people get about three years out of them. I had a big gel in my diesel launch, it was on the boat for five years. It was so strong that it ended up in my 4x4 for another four years than it gave out.

[JimG]

One of my first mods on our new (to us) classic will be dual batteries. As soon as I figure out where to mount them , I'll put in two Maxx29's (IMHO the best bang-for-the-buck marine battery built!), a Perko switch and a Guest 2611 onboard conditioner/charger. That's basically the system I'm running on my other boat, and it's been flawless for almost 200 hours of running time.

Where are you 18 owners mounting the batteries?

JimG

[Cuda]

Hyper, marine batteries also have heavier casings to withstand the banging of a marine enviroment. I would go with 1 deep cycle and 1 marine starting battery if I were running a big stereo system (which I don't) with an isolator. On my 20' Formula, I mounted both batteries on the starboard side to help with the torq list. I've also heard that the deep cycle batteries are made with more, but thinner plates that may bend under the pull of starting.

[harbormaster]

JimG,
I am mounting mine under the back seat.
Alot of folks said to put them in the engine compartment, but I wanted to keep them out of the heat. Also they are easier to get to under the seat.

[MOP]

My experience with gels are they are very tough, 5 years in diesel boat and 4 years in 4x4 which played hard it had no probs with cranking. I have a 16 and am trying to do a safe bow install to help with the bow high running, not happy with the idea of going through the center over the tank. Want to try going through the port side once I figure out how to properly secure wiring without cutting to many access holes. For the guys that don't wish to add an isolator which for those of you that have not played with them is just a split regulator that senses what each battery needs and only supplies power to meet that need. Many of what people call battery combiners just isolate, there are true combiners but 98% of us have absolutely no need for that kind of start power. Another important point it is not good to run on both except for staring help, any battery manufacturer will tell you this. What most people do not understand is that no two batteries are alike even when new. One will seek charge and the other will over charge shortening its life. Good rule of thumb run odd batt on odd date and even batt on even dates. That only applies to guys not running isolators which will keep both up to par all the time.

[JimG]

Interesting topic, for sure! I've been running batteries hooked directly to each other in my boats for years with out an isolator. In fact my four battery system in my cruiser consists of four batteries, each paired, hooked to a perko heavy duty switch. Been flawless for over a year, and I check the specific gravity once a month. Always in the blue.

Dodge has been rolling Cummins diesels out the door with twin batteries without isolation for years, too. My first set went six years, just plain old lead/acid batteries.

JimG :)

[Surfer]

Lacking storage in the 18, I glassed in the compartment under the seat for cooler ect., and mounted plates (glassed marine ply) from stringer to chine, just aft of the firewall. Battery placement in the new ones is in the engine compartment, I figured that was good enough for me, dosen't get that hot in there.

[MOP]

One thing I heard over and over in factory tech schools and from battery reps was not to run on both use one or the other, it will extend the life. True in duel enging boats you have something to switch over to, but most of our gang run single engine setups and need to always consider having a backup or as I like to put it redundency.

[JimG]

M.O.P., I'm with ya! :)

Mine will be switched, so I can run out on one and back on the other.

I'm talking about the "weak cell" issue. I've heard it all my life, but I've never had it happen. I've run this system for years!. How can Dodge couple batteries, and have no apparent issues? My truck batteries are red/red and black/black. Just standard HD Diehards.

[MOP]

We have three yard trucks with diesels that have dual batts, we get 2-3 years out of them. We get much better life out of our gas vehicles single batt setups. My junk with one batt my old 97 Park Ave got a new one after 5 years, my 4x4 was sold with the 9 year old gel and my 98 Dakota has the original. I had hands on battery monitoring of about 300 boats, guys that used them right or had single batt setups got decent life out of them. I did a ton of custom electronics rigging for our new boat division and if the customer went for the extra bucks I would run an isolated battery and isolated wiring away from all else strictly for the goodies and used Guest isolators on the installs. Many of them I up graded the alternators to higher amp units to handle all the stuff. I am very fanatical about wiring, I have seen to many bad things happen including fires at our docks. Over sized wire and proper fuses are always better, secure the crap out of it and seal all connections and ends. I to this day have guys come back to me for special jobs, I can and have done butt connector jobs in the bilge in the water that unless damaged are still in use today 16 years after I quit wrenching, I do it my way as my customers lives may depend on it. Want to cut corners don't talk to me. If your wiring is crappy I get out the bushel basket and just start cutting. Another place I learned a lot about batts was in the service, I was an aircraft tin knocker my shop was next to the battery shop. I learned about rebuilding batts and how important many things are for lead acid batts. I could do another couple of pages on chargers, wiring, solenoid circuits, fusing, proper isolating of electronics etc. But my fingers get tired.

[JimG]

M.O.P, I stand humbly corrected... You've seen a whole lot more battery systems than I have. :)

JimG

[CDMA]

I have been always wanting to add a second battery in my 18....but after this winter and seeing how much effect removing weight from the transom affected the boat I will stick with the single any day....just keep a jump in the truck....

She planes faster, less propensity to porpise, and just all around feels like she rides better....send your boats on a diet boys....

Chris

[Air 22]

I'm w/ CDMA...My 22 came w/ one Batt but just incase I keep cables in tote bag. No radio to worry about so no need for a second Batt. Make sure you buy a batt that has the correct CCA cold cranking amps. Not enough will surely be a problem especially for big blocks! Not sure but but the USCG requires boat manufactures not to install batts in the engine compartment, heat, fire etc possibilities. CDMA is this the case w/ Donzi? My 22 has it under the rear seat. Eng problems such as a fire the batt can be disconnected easily etc!

[MOP]

I sell mostly larger boats and most have there batteries in the engine rooms, the smaller stern drives still come with the battery under the under the fish box in the transom or in front of the engine. The small boats are several new lines in my yard. I do not think the CG has any reg on the placement except a well ventilated area.

[harbormaster]

Heat also will decrease the life of your battery.
That is Why I prefer to keep them under the seat.

[riverrat]

you don't need a radio in a classic! if I did I would have a hard time cutting into that dash

[MOP]

Most classics i have seen have the radio down in the panel under the dash by your right leg.

[Air 22]

The Coast Guard does have a requirement on Batt placement...Check them out! wink

[MOP]

Ok this took about an hour I hope it answers all battery placement questions. This is cut and pasted from the Federal Registry so go argue with them!

Sec. 111.15-5 Battery installation.

(a) Large batteries. Each large battery installation must be in a room that is only for batteries or a box on deck. Installed electrical
equipment must meet the hazardous location requirements in subpart.
111.105 of this part.

(b) Moderate batteries. Each moderate battery installation must be in a battery room, in a box on deck, or in a box or locker in another space such as an engineroom, storeroom, or similar space, except if a
moderate battery installation is in a ventilated compartment such as the engineroom and is protected from falling objects, a box or locker is not required. A moderate battery installation must not be in a sleeping space. An engine cranking battery for one or more engines must be as close as possible to the engine or engines.

(c) Small batteries. Small size battery Installations must not be located in poorly-ventilated spaces, such as closets, or in living
spaces, such as staterooms.
(d) Battery trays. Each battery tray must be chocked with wood strips or their equivalent to prevent movement, and each tray must have non-absorbent insulating supports on the bottom and similar spacer blocks at the sides, or equivalent provisions for air circulation space all around each tray. Each battery tray must provide adequate
accessibility for installation, maintenance, and removal of the batteries.