Two Battery System

[jig head]

As I got my 90 Yamaha 4 stroke and 8 horse kicker serviced, the tech recommended a two battery system for the main motor and kicker with an on and off switch. I like the idea of the switch ,but wonder if the two battery system is going to help performance?

[MattPark]

No, it just gives you another chance to get home if one of your batteries dies. If anything it will decrease performance due to the added weight.

[hot wire]

As I got my 90 Yamaha 4 stroke and 8 horse kicker serviced, the tech recommended a two battery system for the main motor and kicker with an on and off switch. I like the idea of the switch ,but wonder if the two battery system is going to help performance?

Interesting, if his idea was to isolate a battery for electronics, I agree. If it was just to have an aux battery, I don't see a need. If your kicker has a pull start, then you would always have a way to start AND charge the main motor battery. :shrug:

[BIGCSS]

The reason behind a 2 battery system is to have a backup if one of your batteries goes bad while on the water. I have had a couple of batteries in vehicles have a plate seperate and it left the vehicle stranded. A boat takes alot more of a beating than a car, so it is more likely to happen. With 2 batteries the odds are it will never happen to both and you have a way to start the main motor without having to get a jump from another boat. Like I said before between my Dad and I we have had it happen to a couple of batteries and it can be an intermitent thing sometimes also. Just better to be safe than sorry.

[Paul12]

It is a very good idea to have 2 batteries on your boat. I will give you a perfect reason. this weekend while sturgeon fishing by Kelley Point my boat would not start. i switched over to the other battery and it started. After getting home and testing it. I found out that half of the battery was bad. I had just bought the battery 3 months ago. You never know when you might need the extra battery. It is like having a kicker motor when you are on large bodies of water. Never know when you will need it to get home. If you have the room for it, I strongly reccommend the second battery. If you use a Perko switch you can have either battery or both in use so if one does happen to die or lose charge you can charge it while running the motor off of the other battery. If your outboards are newer models, they will be like my Mercury, and they will only charge the batteries while running in gear, not at idle.

[chucks electric]

hello, there are several reasons to have a dual battery set up. first and foremost is safety and reliability. second is your cranking battery should be just that a cranking battery. its not enough to have a good battery but all batteries have to be recharged and maintained. so lets say that you have been out for 4 to 6 hours and restarted your engine 3 to 5 times and ran your electronics the entire time maybe some lights what you have done is consume amp hours that means that you must put the same energy back into the battery that you have taken out. DO NOT be fooled into thinking that the engines alternator has recharged your battery(s) NOT EVEN CLOSE! you have only added a surface charge. if your battery is lets say a group 24 you will have to recharge for about 7 to 10 hours on average to bring that battery back up and do this every time you go out. you have to use an automatic charge relay, the proper battery switch, and a good 3 stage charger that match's your battery(s). if you add a second battery simply as a back up thats great but if you install it to run your house loads that is even better, because it allows you to use the appropriate battery for two different types of loads cranking and deep cycle. you must maintain a float charge of about 13.0 volts as often as possible this is were a good automatic battery charger is worth its money. the worst thing you can do to a battery is not use it, so keeping it top off to say is in effect using it and it will last a good while. if you would like to see a properly wired dual battery system that is wired to abyc standards my shop is in se portland, my cell is 503-381-1193 i can give you a list of parts needed and tell you how to install it if thats what you want to do. hope i have helped you. posting pics is ineffective seeing it in person allows you to put your hands on it and ask questions which i am more than happy to answer.

[hot wire]

I like the idea of the switch ,but wonder if the two battery system is going to help performance?

I think his original question was "performance". At least, that's what I thought...:shrug:

If it was safety or charge rates or.. what would you do?.....well, that's a different question. :angel:


Anyway, there is a huge amount of help available here Jig Head. Good luck with your decision...Happy New Year.

[chucks electric]

electrical systems are systemic, it is integrated into every function of the boat from lights to corrosion control. i did answer the question only i interpreted the definition of performance differently than you. recharging a half dead battery with an alternator will destroy it overtime. electronics run erratically under low voltage, this includes late model electronic engines with overheated alternators with leaking diodes because its constantly recharging a half dead battery. i am a technician so i answer a question with the idea of theory and principle rather than simply yes and no answers. sorry for the confusion.

[jig head]

The motors on the Weldcraft are almost new. They are 4 stroke yamahas bought with my boat in 2005. But I did leave a switch on once and ran down the cranking battery. Hence the idea of a switch. Additional question. Is it a good idea to trickle charge the front two trolling batteries and the main cranking battery when not in use? I have the guest charger for the front two. These are Trojan brand batteries and i have heard nothing good about that brand. The front two are hard to get a complete charge into.

[chucks electric]

hello, check the water level if its low top off with distilled water. when you say they are hard to charge how long are you charging them and what is the output of the charger? i have a conductance battery tester this is a much more accurate method of checking batteries capacity and life if you would like i can check them for you. you will need to test each individually if they are hooked together in series or parallel one bad battery can draw down the other and it will seem like they never charge. as far as Trojan batteries go they are a good battery. although there are better ones. using the wrong battery for the particular application can cause it die before its time ie... using a cranking battery for a deep cycle application. the constant deep discharge on a cranking battery will eventually damage the thinner plates. to finally answer your question is yes it is almost imperative to charge and maintain a float voltage while not in use. the two trolling batteries should have at least 20 amps available for them, and another 10 or so for the engine battery. anything smaller than this you may not bring the trolling batteries up in a timely manner. as i said in my earlier posts an alternator will help maintain a battery but not recharge one.

[BARCHASER]

I bought a new NR last year with a Yam 4 strk. I bought it from Perf Marine in Clackamas and had it installed as a dealer option by Perf Marine at their facility south of PDX. I had to buy it in PDX since the NR dealer in Tacoma would not take my old Bayliner in trade.

If you have two batteries installed, be careful of the installation. PDX Perf Marine kind of screwed it up. When they wired the two lines together they just used ordinary bat cables screwed together and then covered with a kind of shrink wrap. Didnt work. Water got in to the join and shorted the whole thing out. NR in Tacoma (actually called Alamar) fixed it. The Tacoma guys said the installation was pretty shoddy. They kept the cables and said they were going to take them to a NR tech meeting to show how not to do it. My experience with NR is it is a heck of a boat and warrenty service is good But, there were two dealer installed options I had which were not well done. The bats and also a bilge pump with an auto switch was not done right either.

[Ethical hunter]

Two batteries has saved me several times, the main problem I have had with two batteries is forgetting and leaving the switch on "BOTH" then having both batteries drain.

EH

[Tinman]

Ethical, I agree that a major problem with a standard one-two-both battery selector switch is the very human tendency to forget and leave the switch on the "both" position. I am certain I would make this mistake sometime.

Therefore, I wired my Dory with two totally independent batteries. A cranking battery and a separate battery for electronics. They are not interconnected in any way. I do have a selector switch that can power the electronics from either battery, but it never allows the two batteries to run in parallel.

The electronics battery is not connected to the motors charging system. I just recharge this battery manually at home. I could probably run all season without a recharge because my electronics load is small.

If the crank battery dies, I can still use the electronics battery as backup. But I have to physically move the electonics battery into place and hook it up.

As a final backup, my GPS and handheld VHF can also run on AA disposable batteries. And I can also rope-start my 88 hp Johnson outboard.

[chucks electric]

hello, you can add an automatic charge relay that will allow both batteries to charge only when there is a charge voltage present and it disconnects when it is not newmar and blue sea both make one i prefer the blue sea because it is adjustable, is current limited and very reliable. you wire this parallel to a regular battery switch.

[Lowranger]

I went the way Chucks Electric suggested and couldn't be happier. Since my motor is isolated my electronics don't "BLINK" when I crank the starter. Here are some pictures as I switched from the off-1-2-both Guest switch. http://www.c-brats.com/modules.php?set_albumName=album206&op=modload&name=gallery&file=index&include=view_album.php