Brando
Well-Known Member
I think you'll certainly want isolated starting batteries for each motor. Starting batteries as I understand it are not designed to be discharged heavily like a regular deep cycle. Your house bank could be 2 6v in series or 2 12v in parallel. I added the blue seas add a battery and am very happy with that setup. Keeps the start isolated and ensures both banks are charged by combining when needed.
BearCove
Crew Member
I run twin 150 Yammis also and have a 4 battery setup, I have a battery isolated as a starting battery for each engine and the other two are for my electronics and other things I run on my boat. Two are starting batteries the other two are deep cycles
I have never had a problem with this set up besides the batteries getting old and having to be replaced.
Cheers
I have never had a problem with this set up besides the batteries getting old and having to be replaced.
Cheers
Here is an article by Yamaha on this subject - it is a good start:
http://yamahaoutboards.com/yamaha-a...-tips/understanding-marine-electrical-systems
What the article does not mention is that the outboard's charging system is designed to charge starting battery's but not deep cycle battery's. The deep cycle battery's will be overcharged which shortens their life. You can use this configuration & just replace the deep cycle when it fails. You could also not normally charge the deep cycles while underway unless they go dead (switch them to the crater with a manual switch), then charge them at shore using a battery charger made for deep cycles.
More complex systems from a company named Balmar are available but you are looking at least $1000 for the Balmar solution, but is is totally plug & play with no switches involved. If you are just running down riggers & fish finder probably no need for the expensive system. I have one but I have lot's of electrical powered extended trip type luxery's.
http://yamahaoutboards.com/yamaha-a...-tips/understanding-marine-electrical-systems
What the article does not mention is that the outboard's charging system is designed to charge starting battery's but not deep cycle battery's. The deep cycle battery's will be overcharged which shortens their life. You can use this configuration & just replace the deep cycle when it fails. You could also not normally charge the deep cycles while underway unless they go dead (switch them to the crater with a manual switch), then charge them at shore using a battery charger made for deep cycles.
More complex systems from a company named Balmar are available but you are looking at least $1000 for the Balmar solution, but is is totally plug & play with no switches involved. If you are just running down riggers & fish finder probably no need for the expensive system. I have one but I have lot's of electrical powered extended trip type luxery's.
Dark
Member
Exactly, I got rid of my 6 volt golf cart batteries because I thought they were over charging compared to my RV. My RV/ smart charger would go all summer without adding water to the batteries, in the boat the 6 volts needed water every 3 weeks.
I now run 3 deep cycle AGM marine batteries hopefully these are more compatibly with the outboards charging system.
I run one starting and two house batteries with a main switch and Blue Sea Auto Charging Relay.
My main and my kicker charge all three batteries automatically
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sly_karma
Crew Member
I'm intrigued by the battery configuration for twin engines in the OP. Why the need for two starting batteries and two house? With the Add A Battery system I have, both the kicker and main both start from the same battery. Why would it be any different for twins? And the house loads should remain unchanged despite the choice to have two 115 hp rather than say one 225 hp. Weight is a concern though. A pair of 115s will bring a weight penalty over a single 225, plus a little more again because of the double rigging. Adding two more batteries and wiring will make it even worse.
There are issues when charging the same battery bank with 2 engines.
Here is Balmar's solution:
http://www.balmar.net/?page_id=15277
FYI the Balmar site contains other info on "battery issues".
The OP may be resolving this issue by using his configuration.
Here is Balmar's solution:
http://www.balmar.net/?page_id=15277
FYI the Balmar site contains other info on "battery issues".
The OP may be resolving this issue by using his configuration.
Wild Bill
Well-Known Member
I was going to suggest that, redundancy is the only thing I can think of.
The issue Balmar discusses regarding 2 alternators charging one battery bank I have never had any issue with and I have installed 2 alternators on one engine many times. It's over $1000 worth of gear and would require modifications to the alternators if they have built in voltage regulators.
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Wild Bill
Well-Known Member
The units with One engine, one battery and two alternators were trouble free for years. Couldn't get higher output alternators in same size frame those days and also stuck with single belt drive.
I don't know how they normally wire up dual outboards however diagrams I looked at wired the engine positive leads to a common battery bank. Can't see any way of using Balmar stuff on flywheel stator outboards, but I could be wrong. Newer outboards with belt driven alternators might be possible however with computers you have to be really careful as the computer will know you did something and put the unit into limp mode.
The only other way to stop the voltage regulator high limit switching would be to run a completely independent battery for one of the outboards and controls but I don't think its that much of an issue.
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