2nd Battery

[The Bottom Line]

Ok guys here it goes. I've been trying to read up on it but cant find the answers I'm looking for.
I own a 1989 V20 with one battery located under the removable bait bucket located next to the engine. I have all of my electronics hooked up to it and plan on adding a few lights to my boat this year. I want to add a second battery and was just wondering where everyone has placed it. There is no room for a 2nd one where my battery is now. I was thinking about putting a second one in the cabin and connecting all of my electronic to that battery.
I have a 2nd deep cycle battery in my garage.
Would I be able to use that?
And do I need to put some kind of recharging system or alternator somewhere?
Any help is greatly appreciated!
Thank you in advance.
- Jim

[Destroyer]

Yes, your deep cycle battery will do just fine. If you place it in your cuddy just make sure that the primary wires coming to it from your alternator are of the proper size to overcome the resistance of the extra length. You should already have some kind of recharging system on your engine, so second things first... What kind of engine do you have? That will dictate what kind of alternator, where to place it, and if it can be replaced. As to the do you need another one question, that depends on how much you'll use the batteries. So, if you are only going to use the second battery for some small electrical stuff, then you might not need to replace your present alternator with a bigger one. It all depends on the drain that your equipment will put on your present system. The easiest way to determine that is to add up the electrical requirements of all the different items you plan to power. That will tell you how much electricity you'll need, and conversely, how big an alternator you'll need to power all of it at the same time. Some items, like trolling motors, need large amounts of electricity. Other items like radios and fishfinders need comparitively small amounts of power. Your job will be to determine your maximum power consumption, and then size your system accordingly.

[step up here]

If you go to the second page of this forum look at the second thread
V21 DUAL BATTERY SET UP you well see three pages of info about your question.

[The Bottom Line]

Thanks I will take a look at the other page.

Destroyer,
First off, thank you for the great response! I have a VHF, stereo, a few lights and bilges. I want to add some more lights but I am sure they are not too much drin. My engine is a yamaha 130 hp.
Also, i saw your out of NJ. Where do you go out of?

[keepitgreen05]

on my step lift i have 2 batteries in the back center in between the bait buckets there is a little door and the 2 batteries and the bildge fit in there just fine and it is a short run of wire to the battery switch i dont know if the boat was made like that or someone put it in as i am 28 and the boat is 25 i dont know but they fit there just fine tomorrow i can put a picture up if you would like

[Destroyer]

Originally Posted by The Bottom Line

Thanks I will take a look at the other page.

Destroyer,
First off, thank you for the great response! I have a VHF, stereo, a few lights and bilges. I want to add some more lights but I am sure they are not too much drin. My engine is a yamaha 130 hp.
Also, i saw your out of NJ. Where do you go out of?

I usually either launch @ Laural Hill ramp in Secacus and run downriver to the Staten Island/Sandy Hook area or I launch in Leanardo State Marina and run out to Sandy Hook that way. (Once in a great while I'll launch out of Atlantic Highlands). Either way I usually fish that area... either off the NY or the NJ shores. I used to live in Toms River, so I know the Barnagat Bay area pretty well, but it's been a while since I trailered that far down. (It's 90+ miles each way).

[The Bottom Line]

If you could throw up a picture that would be great I'm curious to see how it is set up so I can get some ideas.
Thanks

[keepitgreen05]

sorry for the wires i am actually charging the right now

[reelapeelin]

Originally Posted by keepitgreen05

sorry for the wires i am actually charging the right now

Thats what I did w/my '84, but turned the two batts long-ways front-to-back and all the way to the sides...that left clear access to the bilge pumps and bilge areas in general...

[tartuffe]

Dual Battery Wiring


This article describes several techniques for interconnecting outboard motors and dual batteries. There are two distinct applications: single engine installations and dual engine installations.Single Engine/Dual Battery

The use of a single engine and dual batteries is one of the most common installations found in outboard powered boats. Interconnection is straightforward. The diagram below shows the typical wiring.

Dual Battery/Single Engine Typical Schematic
NOTE: The battery positive leads are shown in red. The negative leads are shown in green for clarity; code suggests the use of yellow wire. Wiring gauge is determined by current demands and length of the run. Typically 2-AWG is used to connect to the batteries; 10-AWG is used to connect to the distribution panel. The single switch is an OFF-1-BOTH-2 switch.
JWH.

The use of a switch and wiring like this is recommend with dual battery installations. A brief explanation of the operation of the switch in this circuit follows.
In the OFF position, the two batteries are disconnected from all loads. The OFF position is used when the boat is being stored or otherwise not in use. It prevents any drain from the batteries. This can be useful if a circuit has been accidently left on, say a cabin lighting circuit or similar drain. Such a load can completely discharge a battery in a day or two, leading to an unanticipated dead battery situation when you return to your boat. On some switches a key lock is provided, allowing the switch to locked in the off position. The provides another level of security in preventing the boat from being used when left in storage or unattended.
In the 1 position, all loads and charging currents are connected to the No. 1 battery (the PORT battery in the illustration). Starting current for the engine starter motor is supplied by the PORT battery. When the engine is running, surplus current developed by its charging circuit will flowing into the PORT battery. Current to lighting and other loads will flow from the PORT battery. The STDB battery is completely isolated and has no load current, nor does it receive any charging current.
In the 2 position, all loads and charging currents are connected to the No. 2 battery (the STBD battery in the illustration). Now it supplies current required by starting and running, and it receives all the charging current from the engine. The PORT battery is totally isolated.
In the BOTH position, the two batteries are connected in parallel. This has a number of implications. Unless the batteries have exactly the same state of charge, the combined voltage to the two batteries in parallel will sag to a voltage somewhat lower than the highest battery's terminal voltage. Current from the higher voltage battery will flow into the lower voltage battery and begin charging it. As long as the state of charge in one battery is higher than the other, the lower battery is more of a load than a source of power. Eventually, the batteries will reach an equilibrium, and they will both have the same terminal voltage. At that point they will both tend to supply current to loads that are attached to them, and they will both receive charging current furnished by the engine.
It would seem like operating in the BOTH position would be beneficial, but that is not always the case. Even thought the batteries will eventually rise or fall to the same terminal voltage when connected together, they will not necessarily become exactly the same. A battery (or any source of electrical engery) can be though of as having an internal resistance. The lower this internal resistance the greater the current it can supply. The internal resistance will also affect how the battery absorbs charging current. Even though they are connected in parallel, it is possible that they will supply unequal currents to the loads, and it is also possible that they will accept unequal currents from an the engine charging source.
If the batteries are significantly different in their age, their type of construction, and their state of charge, this unequal distribution of current can be more significant. To describe the situation in the simplest of terms, when two batteries are connected in parallel, they will probably tend to behave more like the weakest battery of the two than the strongest.
Paralleling the batteries can come in handy in some situations. For example, both batteries may be discharged to a point where neither alone can provide enough current to crank the starter motor, but combined in parallel they can turn the engine over.
If one battery is fully charged and the other is totally discharged, connecting them in parallel (by using the BOTH position) can cause very high currents to flow between the batteries. Extreme heat can be generated by the sudden charging of the discharged battery. Use caution in this situation. It is better to recondition a discharged battery by slowly re-charging it with an AC-operated battery charger.
The arrangement of the contacts of the typical OFF-1-2-BOTH permits the operation of the switch in the range of 1-2-BOTH without ever disconnecting the batteries from the load or the outboard charging circuit. This is important, as it is possible to cause damage to the charging circuit if the battery is disconnected while the engine is running. By choosing the path of rotation of the switch, it is possible to change from 1 to 2 without moving through the OFF position.