Adding a second battery

[SteveRay]

Need help/suggestions on adding a second battery to my rig. Cuurent set-up has one battery with and "on -off" switch

 

[Silvertip]

Re: Adding a second battery

You don't indicate what you want the second battery for, or how you intend to use it. I must assume though, that you want it mainly for a back-up starting battery. If that's the case you need a different switch (OFF-BAT1-BOTH-BAT2). Follow the installation instructions. Here's a diagram of what the system would look like. When docked, set the switch to OFF. To start the engine switch to BAT 1 or BAT 2. When the engine is running switch to BOTH. Both batteries will charge. If you leave the switch on BAT 1 or BAT 2 only that battery will charge. If you anchor and have accessories running, switch to BAT 1 or BAT 2 (typically use the battery you DON'T normally use for starting). When you are ready to go, you can try starting the engine on the currently selected battery. If it doesn't start, switch to the other battery, then back to the previously selected battery or BOTH so the discharged battery gets charged again. Typically, BAT 1 is the START battery and BAT 2 is the HOUSE battery. BAT 2 should be a large capacity deep cycle.

 

[SteveRay]

Re: Adding a second battery

Forgot that part.....I want to be able to run the stereo, and some accessories while on the hook and not have to worrk about the battery going dead and have to pull out the "booster pack"....So my "starting" battery would be the starting battery(duh), and I would purcahse another battery however it would be a "deep cycle" and used as the house battery....Here at iboats.com there are some switches for 30-40 bucks and then there are some that seems to be much more expensive, like 120-140....what's the difference and would I be ok with the less expensive one?

 

[Andy in NY]

Re: Adding a second battery

silvertip, wouldnt there need to be an isolator for bot batts to charge at the same time?

 

[drewmitch44]

Re: Adding a second battery

I thought so also Andy. Also i think that the switch needs to me "make before break" type if you are going to switch it at all with the motor running. Im not the smartest person with electrical but that is what i was told when i was doing my wireing. Hey Andy in NY, This is Andy in Delaware. When is the next Andy meeting where we get all the Andy's together. We need a Andy rep. from each state! Andy from PA, Andy from MD, ...............................

 

[Silvertip]

Re: Adding a second battery

No isolator needed. Yes, the switch does need to be "make before break" but I've not seen any recently that aren't. In the BOTH setting the batteries are wired in PARALLEL hence making one big battery out of two smaller ones. The real issue here (and it is apparent in this series of posts) is that people want this switching capability but they don't have a clue what the switch is for or how to use it. In very simple terms, the switch provides you with the ability to 1) turn off the entire electrical system (as in the OFF position). 2) Run all accessories and start the engine from BAT 1 (as in BAT 1 setting). 3) Run all accessories and start the engine off BAT 2 (as in BAT 2 setting). Or 4) Run all accessories and start the engine from BOTH batteries (as in BOTH setting). You don't need to change the wiring of your accessories as long as the electrical system is fed from the COM (common) terminal. You therefore can run everything from BAT 1, BAT 2 or BOTH so you have total flexibility. As I said, if you want to be sure you have a good start battery after being anchored and listening to a high powered stereo system, switch to BAT 2 and run the equipment from the deep cycle. When you get ready to leave, BAT 1 will still be fresh as a daisy. Switch to BAT 1, start the engine and go. Switch to BOTH to charge both batteries. If you happen to run down BAT 2 pretty far, switch to BAT 2 when underway so it gets topped of quickly -- and a 10 minute run back to the dock won't do that so make sure you use a charger to make sure the deep cycle is fully recharged as soon as possible. If you happen to be cruising and notice that the Voltmeter is showing less than 13V (as in the alternator took a dump) you are now running on battery power alone so you could switch to BAT 1 (or BAT 2) until it got low enough that the engine began missing, and then switch to the other battery to get the rest of the way home. Lot's of options with the switch. You just need to understand how to use it. And adding an isolator (essentially a big diode) which allows current to flow in only one direction to each battery would mean you would not be able to draw anything from either battery. Or if you turned the diode around you could not charge either battery. Believe me guys, an isolator is not needed.

 

[Silvertip]

Re: Adding a second battery

No isolator needed. In the BOTH setting the batteries are wired in PARALLEL hence making one big battery out of two smaller ones. You don't need to change any of the wiring to your accessories as long as the electrical system is fed from the COM (common) terminal. You therefore can run everything from BAT 1, BAT 2 or BOTH so you have total flexibility. As I said, if you want to be sure you have a good start battery after being anchored and listening to a high powered stereo system, switch to BAT 2 and run the equipment from the deep cycle. When you get ready to leave, BAT 1 will still be fresh as a daisy. Switch to BAT 1, start the engine and go. Switch to BOTH to charge both batteries. If you happen to run down BAT 2 pretty far, switch to BAT 2 when underway so it gets topped of quickly -- and a 10 minute run back to the dock won't do that so make sure you use a charger to make sure the deep cycle is fully recharged as soon as possible.

 

[SteveRay]

Re: Adding a second battery

Silvertip, Are the more expensive (like 4x) batt switches the ones that have an isolator in them?
As you said, I won't need one but just curious.

 

[Don S]

Re: Adding a second battery

None of the battery switchs have isolators in them, however there is a better way to go than the isolators.
This system works great, you don't have to change battery switch positions, you can't use your stereo or lights or electronics to kill your starting battery by forgetting to move the switch.
I've installed these for several customers, and myself and we all like it.

"http://bluesea.com/category/2/productline/overview/329

 

[PondTunes]

Re: Adding a second battery

This question gets asked a lot and there are several ways of solving the problem.. If you are going to be sitting listening to the radio, running the lights and livewell etc. I would recommend the blue sea systems add-a-battery setup as well.

I say the add-a-battery setup would work better for your situation for a couple reasons.
1) Once set-up the system is automatic when underway the charging relay will automatically charge the batteries as needed and prevent drain from the starting battery at anchor.

2) Once wired up you won't have any extra steps to remember since you aren't switching switches.. Your batteries will charge and there isn't anything new to do every time you go out. You also don't have to re-educate the family on how to properly set the switches.

3) You still get the combine feature of the Off-1-2-both switch if you need it.

Here is a link to a previous post that is similar to your question.

http://forums.iboats.com/showthread.php?t=220892

 

[SteveRay]

Re: Adding a second battery

I should clarify that I do not have anything more than the stock stereo system and no aftermarket amps and the such.
As for eductaing the fam...it is just the admiral and I and she does not come anywhere near that stuff....although she has been learning

 

[rob711]

Re: Adding a second battery

i've been considering adding a second battery..i understand the 1,2 all concept...the add a battery system seem the simpilest as there seems to be no switching really..it would appear to be on, off or both...heres my question....does it know what battery is hooked up where..ie starter vs house..is it really as worry proof as it would seem..could i go out and drift for hours with all my electronics on...worse case is i'd kill my house battery..but when its time to head in and i go to start the engine it will use the still fresh starting batt....why then would u choose to combine batts..sorry for the most likley already answered question

 

[PondTunes]

Re: Adding a second battery

i've been considering adding a second battery..i understand the 1,2 all concept...the add a battery system seem the simpilest as there seems to be no switching really..it would appear to be on, off or both...heres my question....does it know what battery is hooked up where..ie starter vs house..is it really as worry proof as it would seem..could i go out and drift for hours with all my electronics on...worse case is i'd kill my house battery..but when its time to head in and i go to start the engine it will use the still fresh starting batt....why then would u choose to combine batts..sorry for the most likley already answered question

Yes it knows when your house circuit is being drained and responds accordingly. Under normal use the charging relay (black box) will detect when the house circuits are in use and there is no charge present from the alternator. When this happens the charging relay breaks the connection between the two batteries.

It also acts like a disconnect switch for BOTH circuits. There are four studs on the back of the switch. The bottom two studs are connected to the batteries while the top connect to the charging/house circuits. Switching to OFF will sever the connection between battery #1 and the engine & battery #2 and the house circuits.

Once the engine is cranked the connection is closed & normal charging resumes. The cranking isolation seperates the batteries when the starter is engaged preventing spikes in the power from reaching your house circuits.

The combine switch is there in case something happens to your cranking battery, perhaps it died or busted or maybe the bilge monster ate it. The combine switch is there for emergency and bypasses the automatic relay to give you access to the spare battery for cranking.