The Official Dual Battery Thread

[Kyle's_prostar205]

Thanks for the help with this subject Diesel!

[yzwiley]

This thread is so informative. Thank you to all that contributed, especially Diesel.

These past few weekends I've had some issues with the battery going low while achored and listing to the tunes. I now know what I need to do to fix the issue and will start on it today. You guys rock!!

My solution will be by adding an Optima battery as my auxillary and using the relay as suggested by Diesel.

Thanks again folks.

[cmillertulsax2]

Is the purple wire from the ignition (described on the first page of this thread) that goes to the Borg relay the same as the remote power lead going to the amps?

[shredit21]

Hey diesel, I want to put duals in my 92 ProSport. I was just tryin to understand the diagram you posted in the first posts, and was confused as to where you run the original positive and negative battery cables from the engine to battery. So if my setup right now is stock(one battery, all that good stuff) could you just try and set me straight in my confusion. Thanks alot. -Zach

[Diesel]

Is the purple wire from the ignition (described on the first page of this thread) that goes to the Borg relay the same as the remote power lead going to the amps?

No. The remote turn on from the HU cannot handle the amp draw of the relay.

[Diesel]

Hey diesel, I want to put duals in my 92 ProSport. I was just tryin to understand the diagram you posted in the first posts, and was confused as to where you run the original positive and negative battery cables from the engine to battery. So if my setup right now is stock(one battery, all that good stuff) could you just try and set me straight in my confusion. Thanks alot. -Zach

Leave them the same as factory. No need to change.

[lawdcdpc]

Diesal:

Talked to my MC Service Department at local dealer and they do not know what a relay is? Are you still recommending the Borg Warner R3098? Any idea why MC Service department does not know how to install relay? If MC service can't or won't install the relay, any other suggestions?

Daniel

[Diesel]

Diesal:

Talked to my MC Service Department at local dealer and they do not know what a relay is? Are you still recommending the Borg Warner R3098? Any idea why MC Service department does not know how to install relay? If MC service can't or won't install the relay, any other suggestions?

Daniel

I'd find another service department.

Do they have an internet connection? If so I would send them a link to this thread. Don't let them sell you a perko..........lol.

[unclefud]

What is "head unit"

Diesel,
Found your post while trying to find info on installing dual batteries on my Cobalt. Needless to say, I am not electrically inclined and am not famaliar with you term "head unit" in this article.
Thanks for your reply,
Unclefud

[Chas]

I throw this in for what it's worth - may very well be nothing...

On one or two aircraft I have wrenched on there is a complete second battery system. I saw a similar system on an offshore fishing boat I helped a friend with some years ago. Sounds complex, but it's really not. They added a second battery and a second alternator.

Now before you rule this out, think about it: the second alternator doesn't have to have the high amp capacity of the primary one, it could be an inexpensive unit. I admit that mounting it might be a pain.

The wiring is always controlled by switches in aircraft - they assume the pilot is using a checklist at just about all times, so remembering when to turn things on and off is not a problem, but in a boat, I could imagine wiring the second battery and second alternator together would make it fully automatic: you could run the stereo all day, powering all sound gear from the second battery, and nothing happens until the other battery starts the engine. At that point the second alternator simply begins charging the second battery.

The only difference I see in this and the system proposed at the top of the thread is that the two batteries are truly isolated, so there is no chance of forgetting to turn one off or on, also it doesn't matter if they are matched batteries, or if you have three batteries to run the sound system and one for starting...

Also this would eliminate any potential problem with the high amp flow that is inevitable when the relay closes between two batteries with one battery being dead and the other fully or well charged. At no pont are the two batteries ever interconnected.

I know it has worked for you for years, so I have to imagine that the high flow from the good battery to the low one is not doing any harm, but I could sure see myself running the sound system battery dead, and then turning the key to the 'on' position yet not starting the boat right up. I do this now on my other boat to lower the drive and get one of the two bilge blowers on. I know, that could and should change. But I just can imagine myself emptying the good battery into the bad one.

Free - toss it if you wish.

[TX.X-30 fan]

If you want a bullet proof system this is it!



Alt.' regulator and echo charger for the starter batt/house.

They offer all sizes of systems, you may not need the 150amp I use so calculate the draw and your done.

All I added to this set-up was (2) 2400 amp/hr kinetics agm batteries to run the stereo. I have never had a problem, run the stereo swimming for hrs. Starter batt. is always full.

These are reliable systems used on yachts.

[Ric]

Diesel,
Found your post while trying to find info on installing dual batteries on my Cobalt. Needless to say, I am not electrically inclined and am not famaliar with you term "head unit" in this article.
Thanks for your reply,
Unclefud

welcome fud, some people speak a little bit suggestively around here and I speak for all of us when I apologize for diesel using that type of reference in his posts

[TX.X-30 fan]

Probably got one of those eyeball pm's in the old in-box.


Not that I have a clue what that means.

[VOLFAN]

I have quickly glanced over this thread. Let me know if what I have found is correct.

Only use the same type battery?
I should in NO way use a starter battery and a Deep Cycle battery together?

(Optima highly preferred)(Where can I get one?)
Which two would be better and keep your Acc.'s going the longest and still be able to start the boat? 2x deepcycle or 2x starting?

Ther Perko switch is not that great of an idea the relay is better?

I have just installed an Amp and Sub in my boat and it killed the battery in about 2 minutes. Seems the boat has a low voltage shut off, because when it got below 8 volts it kicked everything off.

[rwoznock]

One of the first things I did when I bought my Maristar last year was put in a stereo with power amps and added another battery with a Perko switch. The problem with mine was the Maristar has the electric pump to raise the motor cover and thats wher I mounted the Perko. For 1000 reasons, sometimes we'd forget to turn the switch to save the extra battery and played the stereo all day without running. There were a few days where be barely had enough juice to start the boat! I found this thread and sought out to buy the relay. I'm in PA and I had trouble finding this part. All 6 of the auto part stores I went to told me they stopped making this device, but one place crossed it to a new number by another manufacturer. Advance auto had 1 of these left which was in Kentucky, so I had them send it up and I installed it yesterday. Thanks to Desiel for his knowledge on this project! IMO the Perko switch does a good job if you remember to keep switching it but this is definately the way to go. Anybody need a Perko switch? LOL!