JaccFrost

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I have seen battery topics but haven't found one that really answers my question.

I am going to add interior lighting beneath the seats, exterior lights to reflect of toons into the water, fish finder on the way. Most likely in future a small sub and amp, nothing crazy m

Of course the factory installed radio, nav / anchor lights.

I only have the battery that came with the boat when I bought it new last year. (Specs on current battery unknown at the moment).

Is or would a second battery be necessary?

I feel like I should, but not positive.

|2014 SLX new last year| only 60 hp Mercury |
 
Personally, I like having at least two batteries just in case.  It's cheap security should you run the battery down or just plain have a battery problem.  On my SW boat I had four.  When I first got my wakeboard boat it only had one battery.  I never did feel completely comfortable until I added a second one.  Never had an issue or anything but it was cheap peace of mind.
 
I completely agree with Havasu. The second battery is great peace of mind, especially when you add accessories and use them for a long time with the motor off. Our strategy is to start off with the battery selector set on Batts 1 & 2. That way they both charge. While motor is off, I switch to Batt 2 to run the accessories. When starting I leave it on # 2. So far it has always started. That way I get max charge on that battery on the way back in. If it were to not fire up, then I have #1 to bail me out. It's cheap insurance. I also love the fact that with the battery selector I can switch to "none" and be sure all electrics are off, and the boat is safe from fire due to a short circuit.
 
To each his own, but I have two batteries and NO switch.  To me, a switch was just an accidental/forgetful/senior moment waiting to happen.

I used Blue Seas automatic charging relay.  Simple to install.  It's an "install and forget it" solution. 

http://www.amazon.com/Blue-Sea-Systems-Automatc-Charging/dp/B000OTIPDQ/ref=sr_1_4?ie=UTF8&qid=1457279833&sr=8-4&keywords=blue+sea+system

The charging relay solution allows you to have a two battery system, with one that starts the motor only.  The other battery runs everything else.  The charging relay combines the two batteries when the motor is running (senses the higher 14V on the system when the alternator is running) so they both charge.  When you shut the motor off, it senses the ~1V drop in system voltage (which means the alternator is no longer injecting current into the system) and it opens/separates the two batteries so you always have a fresh battery to start the motor and everything else runs off the other battery.  You can run the "house" battery completely dead, and you'll still be able to start your boat.

Or, you can do all this manually by installing a "1/2/both/neither" switch, but then remembering when to switch stuff is on you.

I really like the charging relay setup.  Install it and forget it.  And no need to put a hole in your boat for the big orange switch.  Which is another decision to make - Do you put it where you can get to it quickly (think hole in side of seat and big ugly orange switch sticking out) or do you put it in the changing room and have to have people move so you can switch it everytime to get to the sand bar or beach, again when you leave, and again when you get back to the dock.
 
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By the way, the charging relay automates everything Tooner mentioned above.  The charging relay is ~$70.  The manual switch is around ~$40.  $30 to forget about it and never have to make a mistake is money well spent in my situation. 

As far as making sure you turned off everything at the end of the day, if you are worried about that, you could still install a master switch and then either remember to turn that off, or just remember to turn everything off.  :)   Remembering to turn stuff off is the key.  Which switch turns everything off is immaterial to me.

If your fusing is set up properly, having a manual switch offers no increased fire protection.

That said, there are other setups where having switches may offer a little more control of your electrical system, if that's what you want.  The charging relay works for me and gives me peace of mind.
 
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There is one disadvantage to the charging relay setup, and that is you can't manually combine batteries if you wanted/needed to.  Say your starting battery died for some reason (end of life maybe).  The manual switch would let you force the house battery over to the starting circuit so you could "jump start" your motor. 

That would be a rare event, but I have that scenario covered with a spare 2 foot section of #2 gauge copper like the link below.  I would just have someone hold that across the + terminals of the two batteries to jump start the starting battery if it was dead (or bolt it on if I was out alone).  A pair of jumper cables would do the same thing.

http://www.amazon.com/Camco-47480-2-Gauge-Battery-Assembly/dp/B00JGJGLMM/ref=sr_1_7?ie=UTF8&qid=1457281434&sr=8-7&keywords=2+gauge+wire
 
There is one disadvantage to the charging relay setup, and that is you can't manually combine batteries if you wanted/needed to.  Say your starting battery died for some reason (end of life maybe).  The manual switch would let you force the house battery over to the starting circuit so you could "jump start" your motor. 

That would be a rare event, but I have that scenario covered with a spare 2 foot section of #2 gauge copper like the link below.  I would just have someone hold that across the + terminals of the two batteries to jump start the starting battery if it was dead (or bolt it on if I was out alone).  A pair of jumper cables would do the same thing.

http://www.amazon.com/Camco-47480-2-Gauge-Battery-Assembly/dp/B00JGJGLMM/ref=sr_1_7?ie=UTF8&qid=1457281434&sr=8-7&keywords=2+gauge+wire
If I understand this correctly, this part:https://www.bluesea.com/products/7649/Mini_Add-A-Battery_Kit_-_65Awill allow the system to pull from both batteries in an emergency without switching, charges both when engine running, and then separates them when not charging to draw off only one.

------------------------------------------

They make a 65amp and a 120amp. Don't know which I need though.

As for the second battery, does it need to be an identical match to my original battery?
 
Yes, it looks like it just adds the $40 switch so you can combine the batteries if you ever need to.  Or, you can do like I do and have a spare jumper wire on board for emergency use.  It depends if you want the switch, want to drill  more holes in your boat, and do a little more wiring.  You can always add the switch later.

My alternator puts out 65A max, I think.  I'm sure most of the time it is putting out less.  So, you might get by with the 65A, but if its a few bucks more, the bigger one is safer.  Look up the specs on your alternator.

I used to use our latest "failed" battery from our cars as my house battery (but not as the starting battery).  While they won't start a car at 0 degrees, they'll run the stereo (stock) just fine for hours at 80 degrees.  Actually, I've never had a "dead" car battery run totally dead on the boat due to the warm weather and the stereo not drawing much current.  I had bad luck with Interstate batteries in our cars the last 5-6 years, so every couple years I'd rotate out the old house battery and replace it with whatever car battery recently failed.

That said, since my boat was on it's 5th year last season (with the original starter battery that came with the boat), I bought a new starting battery last season, and moved my old starting battery over to the "house" position.  Its like playing musical batteries, but I squeeze out every ounce that way.  Actually, doing this rotation is no extra trouble since I take the batteries out of the boat and bring them inside each winter anyway.  Usually when a car battery fails, its in the winter, so I just go downstairs, grab the old house battery and trade that in as the core exchange, buy a new one for the car, then use the recently failed car battery for the house power next boating season.

If you install a second battery, make sure you use a box that's big enough so you can use just about any sized battery.  Then you are not limited by physical battery size.  Ask me how I know that one.  Make sure you use a box though.  A friend of mine had a battery with an internal fault and it got so hot one day when he was out boating that it burned his finger when he touched it after the boat wouldn't start.  I'm sure it was dangerously close to exploding.  Use a box with a lid, and use a strap. 
 
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For me I need the ability to totally isolate voltage to just the batteries, rather than relying on switches at the helm to be sure that everything is really turned off. Remember that one side of the switch always stays hot. I'm an "Antique car guy" and a long time ago learned that the only sure way to prevent wires from melting, and fires starting is to totally isolate the battery or batteries when done for the day. The automatic relay sounds great, and I may some day add it to our boat, but in my case, WITH a manual isolation switch. All I lose with that method are the presets on our radio, but since I usually use the USB or iPod as a music source, it's not an issue.

When we first got the boat I was appalled that there was still power at the trim up-down switch. We found that out the hard way when accidentally touching the switch on the throttle while covering the Benni with the mooring cover. Our boat stays in the water year around, and I just feel better leaving her "dead in the water". The manual switch is also lockable, adding an extra measure of security.
 
Not sure what was done on mine, but I never lost the presets, I just lost the clock. And that was actually kind of nice because at the end of the day it worked as a timer for me and I could double check the hour meter. So I knew how long I was on the boat and how many hours were spent under power. I used my phone for land time.
 
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Here is what I have done on 3 boats now. The Yandina combiner ensures both batts are charged. The switch ensures a day listening to music doesn't leave us stranded. I set switch to 1 and forget it. I turn it to off for trailering and between trips. Never had an issue.



http://yandina.com/c100InfoR3.htm

Lots of options. All will work.

Brian

 

 

 
 
I appreciate everyone's input. This is a great community here with so many willing to help. Thanks fellow Benni boaters.
 
No problem.  There are lots of ways to do the same thing, and I think the major alternatives are pretty much covered here so people can decide what is best for them.

I have to mention though that part of the circuit in the diagram Brian posted is missing.  The "DC Panel" (which runs the stereo, horn, lights, etc) needs to have a path to the ground on the house battery.  Since the DC Panel and the house battery are both tied to "post 2" on the switch, no matter what position the switch is in, you will always have power to your house loads (stereo, horn, lights, etc).  The switch will not disconnect the house loads (or prevent a fire), if that's what you intend.  But, if I had a switch, I'd want it wired that way so I wouldn't lose my stereo presets or clock setting.  I'm not concerned about fire since the circuits are all fused and breakered again at the dashboard.

The switch in that diagram only does two things the way it is wired in the diagram:

1) It disconnects the motor.  Not sure why you'd want to do that.  If it's fused, there's no "fire hazard" (that's the sole purpose of a fuse).  Maybe this would disable the tilt/trim if you felt the need to do so.

2) It should allow you to combine the start and house batteries (only if the switch has a "combine" position, some do not).  This would be convenient if your starter battery ever dies so that you can "jump" it with house battery.  Again, a spare jumper cable or section of wire does the same thing.

What am I missing?
 
We used a Yandina too and wired ours similar to Brian's diagram, except we moved the motor power lead directly to battery 1 and the DC panel power to the selector switch common. This dedicates battery 1 to the motor and allows us to select which battery the other accessories use. Typically it is always set to 2, but we can disable the panel and accessories easily then with the switch. Position 1 is used solely for 'jump-starting mode' if ever would be necessary. Just another option for these combiners which are really cool, simple devices.

FYI - the Yandina also has 2 other modes available that allow you to override it without disconnecting any dedicated power wiring. The additional modes are 'forced on' - batteries combined even at the lower voltage and 'always off' - even in a charging state.
 
I use a battery tender.
 
What type of trickel battery charger to use for winter storage?
I've read that "trickle chargers" are not advisable for leaving attached to your battery all winter long. I've got a "smart" charger (forgot the brand) that I use that seems to do a great job. With my last boat, my battery lasted over seven years, to which I attribute (right or wrong) to the smart charger.
 
In the winter months/off season.........Every 30 days I put my charger on the boat battery and give it a good charge until it automatically shuts off. I have always done this with good results. I also do this with my tractor battery..........
 
I went with two battery’s for the peace of mind. If I’m at ancor with the radio on watching the grands splashing around I don’t have to worry about draining the battery to the point of not being able to crank the boat.
 
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