Dual Battery Charging

[echo690]

I have a new 2008 2-stroke 50TLR. Can it support charging both the starting battery and a deep cycle battery? Currently it only charges the starting battery. If so what is the best way to accomplish this. The boat is a 16' Xpress boat.

 

[Rasputen]

Re: Dual Battery Charging

there is a way to achieve this.. you can install an isolator and connect your alternator wire to it and then subsequently to the two batteries, it will keep them seperated while charging both, you do lose about 1/2 an amp but should not be noticeable. but you would want to verify if your alternator uses a sensor and what amps it puts out to see if this option will work for you

 

[Silvertip]

Re: Dual Battery Charging

I wouldn't bother. The 50 Yamaha alternator doesn't have very high output. If you are powering a trolling motor with the deep cycle, it would take hours at wide open throttle to fully charge it. Spend the money on an on-board smart charger and plug in at the dock.

 

[Boatist]

Re: Dual Battery Charging

I agree with Silvertip.
Even a group 27 discharged 50 percent is going to take 10 to 12 hours to fully charge. Even if it was a 30 amp Alternator if your running a trolling motor and moving from place to place at the very best it will extend your battery power a few minutes.

Your voltage regulator will limit the alternator voltage to somewhere in the 13.8 to 14.8 volts. At this point it is up to the battery to take a charge. On large 30 amp alternators it would take most of the amps at first but after a few minutes would drop down to 10 amps or less and take many hours to complete the charge.

On small alternators it would take the full current it puts out for a long time and may over heat your charging system. On most 50 HP you are looking at only 8 to 10 amps. If your have long run between spots then it will help a little if it does not overheat your charging system.

 

[echo690]

Re: Dual Battery Charging

Thanks for the advice. That's what I thought since the manual said the output was only 6 amps. I have a good quality pulse charge that I use to charge the deep-cycle.