Installing dual batteries switch on twin OB F115 Yamahas

[Striper Blues]

I have to admit I'm confused about the best way to install a dual battery switch on my twin F115 setup. I've read a number of articles on how to and they seem to conflict with each other. I guess I'll start with simple stuff first.....

Can I use one Guest dual battery switch if I have 2 motors each with alternators? I know that each motor has a dedicated battery, but I would love to be able to switch to a dual selection if one runs down (left a light on) to start both motors.

Can I do this with one switch? If so does any one know where I can get a wiring diagram and parts list?

thanks.

 

[Silvertip]

Re: Installing dual batteries switch on twin OB F115 Yamahas

You could connect the positive battery cable from both engines to the COM terminal on a single switch. That would enable you to start either engine from either or both batteries and either or both batteries would be charged from either or both engines depending on whether both were running or just one was running. Check back in a bit, I'll post a diagram for you.

 

[Silvertip]

Re: Installing dual batteries switch on twin OB F115 Yamahas

Here ya go. You MUST connect the negative terminals of both batteries together for this to work. Red lines are POSITIVE battery cables. Black lines are NEGATIVE battery cables. You can start either engine on battery #1, Battery #2 or both. You can charge one battery or both. With both engines off you can run accessories from either or both batteries. The recommended way to use a switch is to use only one battery when anchored/docked. That leaves the other battery as the fully charged start battery. Switch to it when starting.

 

[Striper Blues]

Re: Installing dual batteries switch on twin OB F115 Yamahas

Silvertip,

Awesome, exactly what I needed. Thanks for your help!

 

[rodbolt]

Re: Installing dual batteries switch on twin OB F115 Yamahas

bad bad bad
not a good way at all.
use the 05 marine tech guide to get the correct wiring diagram for your engines,
the above diagram can lead to funny things.
you will need at least one on/off switch and on on1,on2 and both type switches.
otherwise the batery sensing circuitry in either engine cn do odd things.
the objective is to isolate both batteries from both engines.
the F115 motors also have battery isolators built into the regulators.
its all explained in the 04 and 05 marine tech manuals.

 

[Silvertip]

Re: Installing dual batteries switch on twin OB F115 Yamahas

While I don't have access to the manuals you reference, briefly, what are the "odd things" you mention? It would seem that if the only issue is voltage sensing, Yamaha needs to do some work in the electrical department. On board charger outputs are routinely paralleled and seem to survive nicely. Here we have two charging sources charging one or two batteries. The regulator in each engine should be able tell when it needs to "output" and how much. I'm not disagreeing with you -- just want to know what the issue is.

 

[Propnuts]

Re: Installing dual batteries switch on twin OB F115 Yamahas

The F115's do not have isolated auxilary battery leads. F150hp and above hp and Z150 and above hp.

 

[rodbolt]

Re: Installing dual batteries switch on twin OB F115 Yamahas

ok
propnuts knows best.
I am out.

 

[Propnuts]

Re: Installing dual batteries switch on twin OB F115 Yamahas

Come on Rodbolt......where's the love man

 

[Silvertip]

Re: Installing dual batteries switch on twin OB F115 Yamahas

I'm fully aware that some engines have the isolator. However, even if it does, the auxiliary battery output is not needed in this scheme. Isolators are used when two batteries are separated (such as a starting and trolling motor or house battery). In this application, the poster wants to simply run each battery individually on a per-engine basis or parallel them. That does not pose a sensing problem. Paralleling the primaries from both engines would in my view not pose a problem. I still would like someone intimately famliar with the electrical system to explain why it may be a problem. Every time one automobile is used to jump start another you are doing the same thing and there is no consequence. Those two vehicles can be left connected running or not with no consequence. I've been wrong before and will admit it (unlike the vast majority of our poiticians).

 

[Striper Blues]

Re: Installing dual batteries switch on twin OB F115 Yamahas

Sorry I have been traveling, but I appreciate all the feedback, although I have to admit I'm a little confused as to whether to pull the trigger.

Rodbolt, You've never steered me wrong so I too am interested in understanding what your saying. I will see if my CD version of the rigging guide gives me the details. But if not where can I find a wiring diagram?

Also I was reading the 12V Bible for Boat wiring if I remember the title correctly and he talks about putting an isolator in the loop. If I recall he calls for the use of a particular type diode? I will reread.

Thanks again to all for feedback, I very much want to put in a capability to run batteries separately or in parallel, but do not want to do anything to void my warranty or of course cause damage.

Striper

 

[Ray Neudecker]

Re: Installing dual batteries switch on twin OB F115 Yamahas

rodbolt is so seldom even partly wrong that I am reluctant to disagree with him. I still don't understand why Silvertips diagram would not work either.
When you get through your annual celebration and get back home, please review this again and see if you can make this a little clearer for us all.

 

[Silvertip]

Re: Installing dual batteries switch on twin OB F115 Yamahas

I agree that if the dual battery isolator is used AND there is a trolling or house battery(s) in addition to the two start batteries that we are then dealing with a different and more complicated switching system. But I see no problem with a single battery at each engine being paralleled. Just call me curious!

 

[Striper Blues]

Re: Installing dual batteries switch on twin OB F115 Yamahas

Guys,
I looked this up in the 2004 and 2006 (I don't have the 2005) rigging guides. Basically they say the same thing about the Battery isolator. "quote"

"The purpose of the Yamaha Battery Isolator System is to prevent draining the engine cranking battery by electrical accessories. The Battery Isolator Charging System allows for the simultaneoous charing of the engine cranking battery and an accessory battery. ONce the eingine is started, the battery with the lowest charge potential will receive the majority of the charging systme output. When the batteries are brought up to the same charge potential, both batteries receive equal charge output.

Optional battery isolator leads are available for the following engines:
F220/LF200, VX150/DX150, F225/LF225, SX150/SX200, Vz225/VZ250/VZ300, Z150/LZ150, Z250/LZ250, Z200/LZ200, Vx200/VX225/VX300, VZ150/VZ175/VZ200, F150/LF150, Z300/LZ300.

I don't see any reference to F115, but is that just for the leads kit? Or can I assume it means there is no isolator on the F115 which would make Silvertips diagram applicable?

 

[Silvertip]

Re: Installing dual batteries switch on twin OB F115 Yamahas

It really doesn't matter if the isolator is present or not. You don't have to use the "accessory" leg in the posters situation. If the isolator is present and each engine is feeding two batteries that's a very different application and requires different switching.

 

[Striper Blues]

Re: Installing dual batteries switch on twin OB F115 Yamahas

Silver,
I'll have to ask you to bear with me, but if I follow the original diagram and I select both on the one switch, do I have 2 engines trying to charge both batteries simultaneously? Or is that not what you mean ?

thanks again,
Pat

 

[rodbolt]

Re: Installing dual batteries switch on twin OB F115 Yamahas

the F115 does not have the factory Isolator as far as I can tell tonight, however the regulator used is a battery sensing type and with both regulators trying to charge each other it may lead to overheating and burning one out or creating voltage spikes the ECU does not like.
last one wired like the above picuture was a maycraft from a semi-local dealer.
complaint was occasionally one of the F225 motors would start stumbling, especially after the trim or trim tabs or spreader lights were switched on. 3 hours of investigating finally lead me to the cause, improperly wired battery switch. told the customer what it would take to correct it, customer said Yamaha 6 year warrenty, I said its not yamaha.
the rigging/selling dealer called and gave me personally a load of BS about wiring them that way for 20 years. I politly told him he had done it wrong for 20 years but I was impressed with his consistency and total lack of reading the tech bullitens.
anyway next thing we know my field service rep was there.
he spent 8 hours making the same diagnoses and billed the rigging/selling dealer for the tech time to resolve a non-yamaha but rigging induced failure. wire it as you wish but its in the 05 marine rigging and marine tech guides, read it or not.
thats all I got to say about that.

 

[Silvertip]

Re: Installing dual batteries switch on twin OB F115 Yamahas

Life is a learning experience so lets go one more round here. I find it rather ironic that the Chevy Duramax diesel is available with two totally separate 100+ ampere alternators feeding a single electrical system. Granted I have no idea how they are regulated but I suspect they are conventionally regulated and apparently do not interfere with each other or the vehicle ECM. Call me persistent but I still see no reason why a regulator with reverse current protection would have a problem being paralleled with another identical unit. Regulators need to block reverse current from a fully charged battery with the engine off so they should be able to withstand the back feed from the other engine. Both charging systems will sense battery voltage and each "should" charge accordingly and therefore each will output roughly half what it normally would in a single system. In fact, one regulator should not even know the other is there. I guess I'm beating this issue to death so I'll just let this one go. Wish I had a twin engine setup -- I'd actually try it. 'Bye and thanks for listening. Striper -- quess you need to do some more checking. In the mean time -- keep the batteries dedicated to each engine. However you end up doing this, let us know.

 

[rodbolt]

Re: Installing dual batteries switch on twin OB F115 Yamahas

I wasnt aware the duramax used a water cooled solid state regulator with altenator rotor speeds in excess of 5000 RPM. however I dont work on cars/trucks anymore. I am a yamaha outboard master tech with 6 years in the USN's advanced electronics field and over 30 years of outboard service experience.
most higher amperage automotive style altenators use stator current type regulation, most all yamaha regulators use the shunt type regulation, meaning any excess current is shunted to ground or basically the diodes short the excess to ground. this creates tremendous heat hence the water cooled regulators.
the above referenced wiring diagram has both engines electrical systems tied together regardless of switch position.
an electrical failure on one engine will most likly take out the other instantly.
as one engine overvolts it can try to use the other engine's regulator to shunt the excess instead of its own causing a daisy chain failure that wont be covered under warrenty as its not wired as per reccomended wiring from yamaha for 2 motors and two batteries.
seems stiper blues may need to continue reading his 04 and 06 rigging guides as the wirieng diagrams for the various combinations of engines and batteries and associated switching is in the guides. for a reason actually.
back when I worked on the jonston county TX EMT stuff we delt with 100 amp twin leeche neville alt,twin battery set up stuff all the time. but the system was vastly different than any outboard yamaha setup.
in the navy I worked with everything from 400mV twisted pair to 440VAC 60Hz to 110VAC 400Hz stuff on a daily basis.
again it was wired vastly different than the 26Kv DC stuff the klystron required.,
if ya really wanna have fun chase a 1uSEC 400mV pulse through 75ft of cabling through 5 water tight compartments.
but wire it as you wish, if it does funny things its up to yamaha to warrenty any damages and it may work fine for life, however it may not.
why not just use 2, 3 position switches?
that way you could use either or both for emergency cranking/running and normal running both engines electrical systems will be isolated.
batt 1 positive to both switch batt 1 terminal,batt 2 to both batt 2 terminal and each engine to its respective switch com terminal. the negatives of all batteries must be tied together with a wire not smaller than the largest negative cable in the system.
also instead of running the hull cables to the batt terminals I run them to the switch comm terminal except the auto bilge which I run to the batt 1 and/or batt 2 terminal on the switch. helps keep acids from eating the ring terminals.
also keeps me from shutting off the auto bilge switch/pump.
after having all your batt cables crimped with a good compound crimper using tinned lugs of the correct wire and ring size drill a small hole in the lug at the area the cable bottoms into, heat said area with a small propane torch and add a bit of rosin core solder suitable for electronics.
wont prevent cable corrosion but it will slow it down some.

I usually place all hull wireing on one battery and the auto bilge on the other battery terminal at the switch, that way the odds of killing the auto bilge battery are lessened in the event I forget to secure the switch's at the end of the day.

 

[Silvertip]

Re: Installing dual batteries switch on twin OB F115 Yamahas

I am enlightened and am aware of and respect your experience. I sure hope my comments weren't interpreted as something other than what an inquiring mind would wonder about.