Dual motor start batteries

P

pcg

Member
So for a dual motor setup - like two Honda 60s, how many start batteries are used? Can a single battery be used to start both engines, one at a time? And both motors then charge the single battery?
 
I don’t think it is good to have two alternator charging the same battery, they don’t play well together and tend to fail early/more often on this kind of setup.
 
I would rig the setup for one engine to charge the start battery and one the house battery if dual 60's. If you have more than one house, then the second off the motor charging the start battery with a automatic charging relay.
 
We have twin Honda 60’s & before them, back to 2003, Honda 40’s. Same simple set up, which was done originally by the then factory & then used for both sets. Each motor has its own start battery & for the house, either starting battery #1, #2 or combined can be used, which is chosen by using a Perko 1, 2, combined or off switch.

With the Honda 40,s when doing a lot of rpm changes with the batteries combined it twice caused a charge coil on one motor to burn out. I was told when switching to the Honda 60’s the burning out of the charge coil problem when batteries were combined had been corrected. Not wanting to find out again in a remote location if that was true, I now only combine the batteries to the house, when running the windless or if batteries on the low side to start the Wallas. The Honda 40 only had 10 amps of output, so when doing mostly displacement speed on one motor, the Honda 2000 generator was a big help. I still carry the Honda generator on a long cruise, but now it’s very seldom used with the Honda 60’s putting out 22 amps apiece.

The two batteries are AGM size 24.

Probably better ways as Bob suggest to do it, but I'm satisfied with the present set up.

Jay
 
Hunkydory said:
We have twin Honda 60’s & before them, back to 2003, Honda 40’s. Same simple set up, which was done originally by the then factory & then used for both sets. Each motor has its own start battery & for the house, either starting battery #1, #2 or combined can be used, which is chosen by using a Perko 1, 2, combined or off switch.


That was my set up with twin 40 Yamis. Worked just fine. I thought that was the normal set up.

Martin.
Click to expand...
 
Jay and Marti's set up is the same as mine for twin Yami 40's. BUT, I am running 2 Group 29, FLA RV Deep Cycle batteries. I run on both most of the time, but each engine charges its own battery and they start off the both switch.

That was the original setup buy the original owner. I was his 43rd and last boat. I think he knew what he was doing.

Harvey
SleepyC :moon

9_Sept_Seq_2019_Cal.thumb.jpg
 
pcg":4r8hk0s4 said:
So for a dual motor setup - like two Honda 60s, how many start batteries are used? Can a single battery be used to start both engines, one at a time? And both motors then charge the single battery?
Click to expand...

Some people will say it's ok if the outboards are identical. I do not agree - I say a battery for each engine and completely isolated from each other.
 
I’d do a group 31 AGM marine combo deep cycle starting for the house battery and a 24 marine starter for the other. If you want to have an onboard charger go agm for both. That way if the house gets drawn down it can still start and will also last a long time vs a flooded lead acid deep cycle. That’s what I have.
 
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