Charging system

[chasntail]

I am a tractor trailer mechanic, some of our trailers have liftgates on them with a trail charger at the battery bank. my question is the trail charger needs a 12 volt source to charge can i use the alternator power as that source? or should i get the 12 volt source from the starting battery and just have the alternator charge the starting battery. these trail chargers that I am talking about on our liftgates charge two batteries at once. I am looking to have 4 batteries total on the boat and am trying to come up with a way to charge them while the outboard is running any help would be appreciated.

 

[Silvertip]

Re: Charging system

Connecting to the starting battery is the same as connecting to the alternator. All juice for the boat comes from the battery. The alternator replenishes it so it doesn't matter whether you connect to the alternator or the battery -- but at the start battery is a better choice. You didn't say what the power plant is in your boat, but you may be fighting a loosing battle if the alternator doesn't have a higher output than the load you will be drawing. You will not charge four batteries in a 1/2 hour run back to the dock. But then all of this depends on what loads you are running.

 

[chasntail]

Re: Charging system

the motor i have is a 60/40 mercury jet. the chargers have an output rating of 20 amps. I am not sure how they work exactly all i know is that their is a 12 volt power supply that comes from the tractor back to the battery bank on the trailer. its not a big wire 12 guage at best.

 

[pvanv]

Re: Charging system

Hmmm. The "12v in, 12v out" arrangement tells me that these "trail chargers" are actually some sort of regulator and/or isolator. Probably intended to prevent draining the main 12v system of the tractor. Might also be providing a deep-cycle crarging profile for the liftgate batteries.

You can experiment using them, but probably don't need them at all. Just tie in to the regular 12v system (with appropriate switches, etc.) as with any multiple-battery setup.

 

[Silvertip]

Re: Charging system

I can tell you that your Merc outboard does NOT have an alternator that can even remotely keep four batteries fully charged. That engine has either a 16 or 18 amp charging system. You would need to run wide open for hours to top off the batteries. At best it will take care of the start battery and one deep cycle for a troller but even that would be a stretch unless you make extremely long runs to and from your dock or ramp.

 

[chasntail]

Re: Charging system

well thats what i figured about the alternator. thats why i was asking about the trail charger. it takes 12 volt low amp input and its output is 20 amp if needed. I wasnt sure how they worked. oh well guess ill just get a 110v charger installed for when i get back to the dock. my main concern is keeping the starter battery and the auxiliary battery full charged or close to. I spend many hours on the river during the day and night and from playing the radio and running lights i dont want the battery to die.