Battery setup help newbie

[RustyDave]

Hi guys. First post. Need some help. I bought a 08 Larson 23LXI last year. I love it but I really have no idea about the battery setup. There's 2 12 volts wired in parallel I assume and connected to a hub that is controlled by an on off toggle switch by the throttle. I'm told the switch is to allow the second battery to charge and to use it when I'm running but I'd like more details than that. The dealer wired it differently this year but I'd really just like to know more about the way its done. I've attached the latest picture with the device the switch operates circled in green. I've also attached last year's wiring. Any help would be appreciated and please feel free to dumb it down for me. Thanks in advance.



Last years wiring:

 

[RustyDave]

I'd also like to know in the current wiring is the primary battery on the right and if the toggle switch is strictly a charging switch or it's to run the second battery. The dealer mentioned to put the switch on once it's running. They don't deal with Larson so I'm not convinced with these answers.

 

[gm280]

First of all, what are you actually wanting to do with two batteries? With out being there and taking readings and verifying the setup, it looks like the starter solenoid is being used to parallel the two batteries when turn on. I am assuming that switch you talked about, switches the solenoid on to accomplish that. But what are you wanting? Are you merely wanting the second battery as a back up? If so, I'd install a battery switch. Then you can select one battery or the other battery separately or even both is you want. And there is also an OFF setting as well. But you have to you tell everyone what you are wanting to do with the two batteries...

 

[dingbat]

I'd also like to know in the current wiring is the primary battery on the right and if the toggle switch is strictly a charging switch or it's to run the second battery. The dealer mentioned to put the switch on once it's running. They don't deal with Larson so I'm not convinced with these answers.

Interesting setup..... A slave relay (starter relay) being used to connect the batteries in parallel for charging purposes.

An inexpensive setup with a number of possible failure modes, primarily related to manual operation and the lack of fail-safe preventatives.

Surprised given the availability of relatively inexpensive automated alternatives.

 

[RustyDave]

First of all, what are you actually wanting to do with two batteries? With out being there and taking readings and verifying the setup, it looks like the starter solenoid is being used to parallel the two batteries when turn on. I am assuming that switch you talked about, switches the solenoid on to accomplish that. But what are you wanting? Are you merely wanting the second battery as a back up? If so, I'd install a battery switch. Then you can select one battery or the other battery separately or even both is you want. And there is also an OFF setting as well. But you have to you tell everyone what you are wanting to do with the two batteries...

Well that’s just it. I’m new at this. Ideally I’d like the 2 batteries. One for starting and as a back up. We like to float around and listen to tunes so I guess the other would be for that with the motor off. If it gets low I’d at least have the other battery to start. The boat sits in a marina so not sure how charging looks. I guess primarily run on both while the engine is running to charge both.

I like your idea. Lots of wires running to these 2 batteries. Is this a project I could take on with limited knowledge or better to get a qualified tech to do it. I did figure out my travel trailer electrical issues last year so I don’t mind a challenge.

 

[76SeaRay]

I don't see where any power is being drawn off the battery on the right unless it is connected to the first. It looks like it is intended as a backup battery. If you are not running but using the accessories on the boat (relay off), then you could drain your primary starting battery. If so, turn the relay on and connect the backup battery to the main starting batttery to start your engine. Leave the relay on during engine run to charge the backup battery but turn it off when at the dock or drifting and using accessories????

 

[RustyDave]

I don't see where any power is being drawn off the battery on the right unless it is connected to the first. It looks like it is intended as a backup battery. If you are not running but using the accessories on the boat (relay off), then you could drain your primary starting battery. If so, turn the relay on and connect the backup battery to the main starting batttery to start your engine. Leave the relay on during engine run to charge the backup battery but turn it off when at the dock or drifting and using accessories????

Sorry are you referring the top or bottom photo? I’m confused.

 

[gm280]

That all sound great IF the second battery is the battery used to close the solenoid (relay). If the solenoid is wired for the main battery to close it, and the main battery is too low to crank the engine, then that could mean the solenoid may not close either. Just some food for thought....

I typical battery switch is usually manually operated. A much better setup for just such an issue of a dead battery...

 

[dingbat]

That all sound great IF the second battery is the battery used to close the solenoid (relay). If the solenoid is wired for the main battery to close it, and the main battery is too low to crank the engine, then that could mean the solenoid may not close either. Just some food for thought....

I typical battery switch is usually manually operated. A much better setup for just such an issue of a dead battery...

The solenoid is wired between the two batteries. It is simply a remote "combine" switch.

One would assume the solenoid is powered thru the accessory (common) output of the select switch making it "hot" to the battery in use.

To answer the OP original question, looks like all they did was swap the hot cables around, making Battery 1 now Battery 2 at the switch

 

[KD4UPL]

There are significant differences in your pictures. Where does the apparently new large blue wire go in the top picture?
Your switch and solenoid combine the batteries so they both charge when running. Fine.
Do you have a stereo with amplifier(s)? If you want to run the stereo from one battery with the engine off while leaving the other battery in reserve to start the boat then your wiring is not right because nothing is hooked to the left battery with the solenoid off.
If you just want the left battery held in reserve to start the boat if the right one dies then the set up will work except that the solenoid switch isn't powered from the left battery so you won't be able to combine them if the right one dies.
I would get rid of the switch an solenoid and get an automatic charge relay. Connect your engine starter and the basic boat electrics to one battery. Connect your stereo, VHF, and whatever aftermarket electrics to the other battery. Let the ACR combine them when the engine is running and let them be separate when it's not.

 

[iggyw1]

Rusty Dave,

The simplest answer is to get a battery control switch (about $30 new) connected on those batteries. You can run battery #1, OR you can run battery #2, OR you can run battery #1 & #2 at the same time. With the motor running, you will charge whatever battery you have it switched to. If you use battery #1 and run it out of juice, switch the battery switch to battery #2, start your motor and switch it back to battery #1 to re-charge it, or put it on "both" to charge them at the same time, but it would charge one battery at a time quicker. . I have this set up on my boat & I have no problems with dead batteries. This was also mentioned in post #3 above.

 

[RustyDave]

Rusty Dave,

The simplest answer is to get a battery control switch (about $30 new) connected on those batteries. You can run battery #1, OR you can run battery #2, OR you can run battery #1 & #2 at the same time. With the motor running, you will charge whatever battery you have it switched to. If you use battery #1 and run it out of juice, switch the battery switch to battery #2, start your motor and switch it back to battery #1 to re-charge it, or put it on "both" to charge them at the same time, but it would charge one battery at a time quicker. . I have this set up on my boat & I have no problems with dead batteries. This was also mentioned in post #3 above.

Thanks! That’s the plan. Already booked into get it done at the beginning of a June. I’d tackle it myself but don’t want to mess it up.