Advice on adding a third battery

[5150dude]

I want to install a third battery which will be used for the house.
There is room next to the existing batteries, but I might wire an AGM up front.
Do I buy a three-battery switch or parallel the new battery to number two with somthing to keep it from discharging it?
Trying to be a do-it-yourselfer but lack experience.
Thanks,
Dave

 

[Porkchunker]

Send me your e-mail address in a b-mail and I'll send you a file I obtained (either from TheHullTruth.com or BoaterEd.com) that shows all kinds of ways to rig batteries, switches, and combiner/isolators.

Dave

aka

 

[5150dude]

Send me your e-mail address in a b-mail and I'll send you a file I obtained (either from TheHullTruth.com or BoaterEd.com) that shows all kinds of ways to rig batteries, switches, and combiner/isolators.

Dave

aka

Sentja a PM with my email

 

[Hard Core]

I did a third house battery system, and used the Blue Sea kit. It has a 130A isolator/combiner, and another switch. It gives you a quite flexible setup. Assuming you have twins with two switches to control your starting, Parker typically wires one of the switches with the house load. I moved the house feed to the new switch, and wired the engine switch feed to one side of the isolator/combiner (with the house battery on the other side wired through the switch).

So, you can run both engines off of either starting battery (I run both engines in parallel on one battery always leaving one starter fully isolated), and then when they are on they get paralled with the house battery. You can fully isolate both starters with the switch, and by moving the third switch to combine, you can the house plus one or both starters all in parallel for emergency starting.

BTW, Yamaha's support running both engines paralleled together, I haven't checked other engine models. Although only one engine charges at a given time unless you exceed the overall demand of one of the alternators (then both regulators will kick in).

Well, this is hard to describe via text, I have a visio wiring diagram file I can email you if you give me your address.

Barnes

 

[Bryan 2530]

Porkchunker and Hardcore - If both of you could e-mail those documents to me I would greatly appreciate it. I am also planning on adsding a third battery and would love to see the info.
PM's sent.

Thanks

Bryan

 

[TopShot25]

5150, Yamaha makes a charging cable that plugs right into an existing plug under the engine cover to charge an additional battery. The engine already has an isolator built in to this. I have the part number for the optional charging cable for the Yamaha F-150’s if you need it. They run about 35-45 dollars.


Porkchunker and Hardcore I also would like any info you have. I have not found what I think is the best way to wire my house bank either.

Hardcore, what did you hear about Yamaha’s supporting running the batteries in parallel. I understand this will confuse the regulators and mess them up. I would really like to research this if you could point me in the right direction. I have a 450 amp hour house bank and I need to have both engines charge it at the same time and I can’t find the right set up.

 

[Hard Core]

I converted this to .JPG and then downsized it to meet the max res requirements, I'm not sure if it will be legible or not.

The way regulators work is they are trying to source current to maintain a particular voltage, typically in the 13.5-14.0V range for 12VDC systems. Depending upon the regulator design, it can be that the ripple of the regulator is a problem and the alternators fight each other (one source current into the other as the ripples are out of phase). Yamaha engines do not have this problem (I finally spoke to an engineer at the factory). Solution used to be running a phase synch signal between the alternators.

What you will get with two engines in parallel, is that both will source current to your electrical load if and only if the voltage is below the regulator set point on both engines. This will happen naturally if the electrical demands exceed that can be sourced by one engine. Note that the setpoint for both engine regulators is never going to be exactly the same. On my setup, I see the house load migrating quite dynamically across each engine (the voltmeters see what is happening at the engine, not at the house battery). I see voltage droops as a particular engine engages the load, and I see this migrate pretty nicely. I haven't gotten into a condition yet to require more than one alternator (i.e. greater than 35A), but if I do, both alternators will then be in action (at varying levels depending on the resistive differences inherent to each load).

Yes, Yamaha has the house feed, I like the following approach, very flexible, and I can maintain complete isololation with a starting battery in complete full reserve. There are many variations to this solution, this is what I chose, and so far works very well for me.

Hope this helps.

Cheers, HC