dual battery setup

Anyone have a link to setup dual batteries? I have 92 with the battery in the cooler floor. I want to add another battery, possibly wire it up towards the front of the boat. have the Alt charge both batteries, etc. I seem to have problems with batteries every year and I think its the wakeboarding running below 3k rpm, (not charging enough) (2) amps, head unit, sat radio, etc. Just seems to kill me. So for my own personal peace, I think wiring up a dual battery config will help me a lot.

Any thoughts?

Thanks everyone!

tommer12, Your battery and alt. is like a water pump and a water tank.If you take more out of the tank than the pump can supply the tank will run dry,does not matter how big the tank is.
Get a bigger pump"alternator" you have a 65 or smaller now.Get rid of the boom boom boom or go with a higher amp rating 100 amps and above.
Bigger pump not a larger tank......................boat dr

100A alternator is the way to go instead of the dual batteries. Your stereo is drwing to much current for the alternator to handle, doesn't make a difference if the alternator is turning 1000 rpm or 5000 rpm is still will but out the rated amperage at idle if it doesn't then the diode trio or rectifier is bad or you lost a winding in the stator.

Tommer, Listen to the guys here on this site and not the ones over on planet nautique or the2001.com. Let all of them put multiple batteries in their boats only to find out that if you don't replace the juice, it gets used up!!

Tommer, I bought a 100 Amp 12SI GM alternator through e-bay and bought a kit to convert it over for marine usage. Here's the link for the kit: http://www.amarket.com/imscrkit.htm   

This kit will fit the 10SI (most popular) or the 12SI (heavy duty). Both of these alternators use the same mounting bolt spacing and are considered to be universal fit. Brian

Nutty, We never "slam" anyone on this site. All of our comments are just suggestions. I however was wondering if you are driving a ski boat or a sound studio on the lake? Do you have any room left in the boat for the driver,observer and skiing gear?

Nutty, Wow, you do take on challenges. Keeping up with the kids sound systems isn't easy. I like your creativity with the crank mount RWP to make room for the extra alternator.

We too have the kids on our lakes running around with daddy's $$ boat. I would love to have $ to spend on a new boat (so would my kids) but that isn't the case. The kids are happy with the 77 and it's old enough to be a "cool" classic with their friends.

I too get disturbed when I can hear the music blasting from the other side of a 1000 acre lake. Makes me think of devious methods of disabling their sound systems!!

I'm glad you have come up with a sound system that you can enjoy while you're sking.
Happy skiing and keep it up. I haven't been on skis in 20 years.

quinner wrote: 8122pbrainard wrote: I haven't been on skis in 20 years. Pete, We are going to have to get you out there on Green next month. I love skiing and couldn't imagine not doing so, it is great fun skiing with some of the young guns like Hollywood and co. just to show an old man can still keep up!

Chris, I'll be up north the week of the 4th so I guess I'll have to do some practicing! I doubt that I could even do a hot dog off the dock anymore. I still have my old slalom but I'm sure that it's now to short for my weight!! I'll give you a progress report in a couple of weeks. I know there are alot of older people still skiing and I really should have kept up with it. The wife still goes for a run each day if the weather is nice. Don't forget though that I do have 12 years on you too!

Hey Quinner, there is a thread on this site where someone posted a very nice dual battery setup (wiring diagram and pictures). He used a heavy duty solenoid which was activated by the ignition switch to isolate the two batteries. When the engine is running the alternator charges both batteries. When the ignition is off, the cranking battery is now out of the circuit of the sound system and its capacity is reserved for cranking.

Ouch Peter....that stings. You just have to know WHO to listen to on those other sites (or any discussion site for that matter, including this one)...and then you still should do your own research on the subject before taking someones word as gospel. I've been bit by not doing due dilligence in more than one instance, and thats listening to trusted sources. Everyone can be wrong from time to time.

With that said, I agree that the alternators used the early PCMs cannot keep up with modern stereo systems. I recommend the 55A mando as a minimum...and the 100A for those going to multilple amps. I will warn anyone to take a good look at how their boat is wired before slapping on a 100A alternator.....particularly on the early boats. On our boat (88 SN), the main dash circuit is not protected from the alternator and hooking up a larger amp alternator w/o upgrading the wiring is a serious hazard.

As for a installing a second battery, I think that every boat should have one. There are many different ways to go about it including "perko" switches, isolators and/or combiners. I have been very pleased with the Yandina combiner so far. You can read more about it at www.yandina.com.

8122pbrainard wrote: Tommer, Listen to the guys here on this site and not the ones over on planet nautique or the2001.com.

Thats quite a blanket statment, Pete. I'll agree that the info you get here is generally better than elsewhere- but there are knowledgable people on all the CC sites. I post on all 3, as do several others.

Bremson and I put together this diagram for a dual battery set up. The perko switch is normally in the position that only connects the starting battery to the charging circuit, but can be switched to allow the boat to be started with the 2nd battery. The combiner opens the circuit between the 2 batteries when either is receiving a charge- otherwise they are isolated.



It gets a little trickier when you upgrade the alternator, which is usually necessary on the older boats running a decent sized sound system. The main engine breaker needs to be upsized to handle the new alt output (as well as the wiring between the alternator and battery). The 10awg wire running to the dash also needs to be upsized or fused/breakered- it can handle the stock alt output but thats about it.

TRBenj wrote: 8122pbrainard wrote: Tommer, Listen to the guys here on this site and not the ones over on planet nautique or the2001.com. Thats quite a blanket statment, Pete. I'll agree that the info you get here is generally better than elsewhere- but there are knowledgable people on all the CC sites. I post on all 3, as do several others.

Tim, You are absolutely correct. I could have said it in a nicer way. I too visit the other site and do occasionally post.