Adding a Second Battery

[derekpfeiffer]

I was going to add a second battery for peice of mind while on the river. Thought it wouldn't be a bad idea to hav an extra one. I was looking in overtons and found a switch that allows you to use one or the other or both...thought that would be nice so you can use just one while floating and listening to the radio and always have the second to start with, then can switch to both while running to charge them. Any recommendations would be great...such as what cable size should I use to connect them to the switch??

Thanks guys,

 

[tashasdaddy]

Re: Adding a Second Battery

read this. http://forums.iboats.com/showthread.php?t=249593

and this: http://www.acbsphl.org/Tips_and_hints/ABYC_Wiring.htm

be sure you buy a continuous contact battery switch, or you could blow electronics in your charging system

 

[pvanv]

Re: Adding a Second Battery

There's a decent set of diagrams in the FAQ's, but to address your specific concerns:

Yes, a switch is a good idea. It needs to be wired with cabling sized large enough to start the motor. That size depends on the particular motor. Your existing wire should give you a clue. Use marine-grade wire, and follow ABYC standards for crimping and shrink tube at the connectors. The switch is wired only to the Red (positive) battery wires. The Black (negative) is a common "ground".

The "house" battery for trolling, radio, etc., should be a deep cycle type. The "start" battery can be either a start-only type, or a combo. Your existing battery is likely adequate.

If the motor has a charging system, then if the switch is set to "both", it will charge both batteries. Likewise, you can use the "both" setting to start if your main start battery is depleted for some reason.

If you use a shore charger, it would ideally have provision for two batteries. That way, you can charge with the switch in any position, including "off".

Best to not leave the switch in "both" unless using a single point of charge (such as the motor's charging system), or you run the risk of depleting both batteries while running the radio, etc.

All this being said, if what you have now is working OK, and you just want to add some reserve, and you don't draw a lot of power while floating along (no electric trolling motor, etc.), just adding a second battery in parallel (or stepping up a size, say to a group 31 battery) will give you a lot of extra reserve, without even adding a switch.

 

[PondTunes]

Re: Adding a Second Battery

Your factory wiring probably uses 2 AWG wiring to connect the charging/starting system to the battery. If you're going with a 1/2/off/both switch you can take a look at your battery cables to confirm this. I would recommend purchasing the largest deep cycle battery that you can fit/afford. Then using 2 AWG wire for both the positive and negative on the new battery.

Be sure the switch you select specifies that it is a Make-Before-Break style switch, this simply means that when you move the selector switch the new connection is made before the old one is disconnected. Switching a 1/2/both/off switch to the OFF setting or using a switch that is NOT a make-before-break style switch may very well kill your charging system.

That being said to use the 1/2/off/both switch run a cable from the negative on the new battery to the negative on the existing battery. Everything connected to the positive post should be moved to the common post of the new switch you purchase. (Check out a guest or perko 1/2/OFF/Both style switch) This way you can switch between the batteries for sitting at anchor and not have to worry about a dead cranking battery.


Typical operation would be Get on the boat, move selector to battery #1, crank the engine and then move the selector to BOTH (this will charge both batteries while you're underway) Cruise out to wherever you intend on sitting for a while then move the selector to battery #2 (a deep cycle) this will give you plenty of juice to sit and play the radio/run the lights etc.

When you're ready to go flip the switch back to position 1 and crank the engine.

The only pitfall here is forgetting the switch, if you leave it in the BOTH setting you could very likely end up with two dead batteries.

Another option would be to use the Add-A-Battery system from blue sea systems. This system uses a current sensing relay that will automatically charge both batteries when the alternator is producing juice and disconnect the two when the engine is shut down. This eliminates the switch flipping and ensures you always have a fresh battery.

This is probably the simplest way to put a back up battery in place. Using this setup I would recommend purchasing a deep cycle/starting battery and using it as your primary battery. Hook your existing battery up as battery #2 as shown in the diagram. This will use battery #1 for everything starting/sitting etc and maintain a charge on battery #2 while you're underway.. In the event that you run battery #1 down, you can simply move the switch to the emergency combine position and use both batteries to crank your engine. Nothing is connected to position #1 on the switch provided in the add-a-battery kit.

This could be modified a bit further by moving your lights/radio/amplifier to battery #2 and just keeping the starting system hooked up to battery #1 but this gets more complex as you'll have to start changing the boat's electrical system layout.

 

[derekpfeiffer]

Re: Adding a Second Battery

I'll probably be using a setup like figure 1 since I already have the extra battery...and probably don't even need the extra battery but figured since I had it I had just as well install it. Thanks for the help guys..I'll need to look at the cable to see what size they currently are. The motor is a 350mag MPI.

thanks guys

 

[picasso]

Re: Adding a Second Battery

hello sorry to bump such an old thread. i just purchased the add a battery system from blue sea systems and i had a few wiring questions.

- in figure #6 i was wonder what number one pole is used for?
- or the letter "d" stand for?
- where should i hook the main positive cable to?

sorry such a rookie question any help would help thank you

 

[picasso]

Re: Adding a Second Battery

i forgot one more thing. if i were to buy two new batteries do i buy one starting and one deep cycle for number 2 battery? i probably forgot to ask some other questions ill probably remember later. thanks again aloha

 

[pvanv]

Re: Adding a Second Battery

Deep cycle for House use (light draw, long time) loads. The Start battery (large loads, short duration) can be a start-only or combo type.

 

[picasso]

Re: Adding a Second Battery

okay thanks!
- as of right now i have one main positive and negative i guess from the motor
- i also have a main positive cable for all accessories, where do i connect this wire to?
- im sitting here in my boat scatching my head getting impatient but i know ill reget it if i dont do it the right way. cheers!

 

[flargin]

Re: Adding a Second Battery

okay thanks!
- as of right now i have one main positive and negative i guess from the motor
- i also have a main positive cable for all accessories, where do i connect this wire to?
- im sitting here in my boat scatching my head getting impatient but i know ill reget it if i dont do it the right way. cheers!

simple model...
Connect your switch to your batteries (RED/+ lines, starting battery to #1, deep cell to #2) and the two connectors described above to the "common" leg of your switch. The negatives still go (unswitched) to the battery, you will need a jumper to jump from one batteries negative to the other negative (BLACK/- posts)

Remember1.

Is it a "Make before Break" switch. To test turn on lights/stereo's etc, slowly turn the switch from 1 to both to 2. If it EVER stops the lights/stereo you DO NOT have a Make before break (will explain later).

To Run your new setup.
Turn on your switch to #1 (being the starting battery), get it running, slide it to both, this will allow both batteries to be charged.

Get to the beer/fishing/music/ no driving part of the lake, turn off your motor, switch to "2", this will pull everything from your deep cell.

NEVER turn OFF your switch while you are running the motor, unless you like to buy new alternators it will fry a piece in the alternator and you are left with no charging system--- not good.


Ok, what do you do if you do not have a Make Before Break ciricuit.

1. Switch to BOTH, start motor, get to beer/fishing/music location, stop motor. Move switch to #2. see above! If you have this type (doubt it) you will cause the same damage to your alternator by switching between any 2 switch setting.

Hope this helped.

 

[picasso]

Re: Adding a Second Battery

my switch is not the 1, 2, both, and "all" type, its the add a battery switch. It has four posts like the diagram 6 above. the switch has a "on", "both" and "off" position. i think its wired relatively the same idk but. really helpful advice though. the diagram above seems simple enough but i guess with every boat and setup wiring becomes a little different. my current wiring is such as i posted above. \
i went out and bought some positive and negative bus bars so i can jump sone connections. if you know about this setup i would appreciate it aloha and cheers for all of your very helpful advice seriously would be going insane from the million different things the guys at the local west marine is telling me. they are great but are just confusing me

 

[picasso]

Re: Adding a Second Battery

one more thing for my accessory wires do i hook them directly to battery #2 the deep cycle or do i go somewhere on the switch? thanks

 

[skargo]

Re: Adding a Second Battery

one more thing for my accessory wires do i hook them directly to battery #2 the deep cycle or do i go somewhere on the switch? thanks

You go to the "com" terminal on the switch, I did this just yesterday. My switch only has 3 posts, 2 go to each batteries positive terminals, and one goes to the engine. The one that goes to the engine is the one I hooked my accessories to. I added a blue sea fuse block for my GPS/chartplotter and depthfinder, with room for 4 more circuits.
I also added a 20A breaker right at the switch for my fuseblock feed line.

 

[picasso]

Re: Adding a Second Battery

my system is the "add a battery" by blue sea systems. it comes with an acr and a switch. the switch has four posts and the acr has two. i believe starter battery goes to one and deep cycle goes to two. ????? thanks for the replies but my questios above still stang sorry cheers

 

[Blue Crabber]

Re: Adding a Second Battery

Hi Picasso,

Let me see if i can be of some help here. I have not actually installed one of these, but am planning to in the near future and did some research into them and here is what i found.

Here is the link to the instructions for the unit:

http://bluesea.com/files/resources/instructions/990310020.pdf

Also, here a picture from within the instruction book at the above link:

The ACR (Automatic Charging Relay) unit is on the left with terminals marked A B GND SI LED

As you can see in the diagram, the battery switch is on the right and you are looking at the back of it.

The SI terminal on the ACR Relay is not required, just optional. You add a wire from the cranking position on your ignition switch to this terminal and it disconnects your house loads during this time to be sure that no electronics are damaged during enging cranking.

The LED terminal on the ACR Relay is not required either, just optional. You can wire an LED to this terminal and it will light when both batteries are combined. This LED would probably go near the helm for some remote indication.

Hope this helps to answer your question and good luck installing this system. Should provide for some real peace of mind!

 

[picasso]

Re: Adding a Second Battery

thanks blue crabber! funny you should post that, i was reading that exact sheet last night. my mind is gonig crazy with all the different ways to hook up up the same system. im probably going to try my best the concept and wing it. thanks ill wait a little while for may bee some more advice in the mean while im learning every day thanks

 

[mstrubis]

Re: Adding a Second Battery

I recently installed the Blue Sea "add a battery" based on Pondtunes diagram and instructions for maintaining a backup battery. I included as suggested a fuse (I put in a 100 amp) for the wire connecting the + post from primary to position 2 on the switch. It seems to work fine. One thing I noticed is that when the switch is ON and I start the engine initially for the day, it starts my boat then the engine hesitates as if its going to quit and then a surge and the engine races to life. The engine then settles down to a normal rate. When the engine races there seems to be almost a hissing sound. Is this normal or is it a delay from the wiring setup? (My cables are not especially long... most 48")