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Author Topic:   Charging 36-volt Battery Bank From 12-Volt Charger Source
standard 17 posted 05-30-2007 12:28 PM ET (US)   Profile for standard 17   Send Email to standard 17  
I have a two battery set up with a [P]erko four-position battery switch in my 1987 Outrage 20, which works fine. I'd like to add a 36-volt trolling motor. How can I set this up so that when I add my third battery, I can take advantage of my Yamaha F150's alternator to charge all three batteries when running and not draw down them so much that I can't crank my main engine after running the electric motor for extended periods?


Bella con23 posted 05-30-2007 01:52 PM ET (US)     Profile for Bella con23  Send Email to Bella con23     
First of all I think your asking a bit much from the alternator of your Yamy 150 if you intend on drawing the three batteries down with a trolling motor.

With that said I would remove the current four position house switch and install a three battery switch arragement so when you are running the outboard you can select "All" on the selector switch and charge the triple bank.

If my memory serves me, Bluewaterpirite had some pictures of some nice installations on this site.
Also read in the CW reference section pertaining to dual battery installations This section give great advice on the proper installation and care of multiple batteries with a single and dual charging source.

jimh posted 05-30-2007 07:51 PM ET (US)     Profile for jimh  Send Email to jimh     
If the batteries are wired in series, as they must be to provide 36-volts to the trolling motor, they cannot be directly charged from the outboard motor. The motor only supplies about 14-volts of charging current, and it cannot charge a bank of batteries connected in series to form a 36-volt system.

There is no simple wiring solution to this problem. Nothing will accomplish what you want without very elaborate wiring and switching.

Your best solution lies in finding a device which will convert the 12-volt charging output from the outboard motor into a 36-volt output that can be used to charge the series-connected bank of three batteries. I have no idea if such a device exists, however, I believe it may. If there are such things as 36-volt trolling motor, there may be such things as a 12-volt to 36-volt convertor to charge them.

I recommend you look for a specialty product in a battery charger. Ask around websites which are more oriented to fishing and electrical trolling motors. A 36-volt trolling motor does not sound like a run of the mill trolling motor to me.

Bella con23 posted 05-30-2007 09:24 PM ET (US)     Profile for Bella con23  Send Email to Bella con23     
I apologize for the mis-informative answer on the trolling motor wiring question. I got to stop reading Continuous Wave during working hours.

Jim brought up the (now obvious to me) point of getting 36 volts from a 12 volt system and somehow charging the batteries once the outboard is started.

I looked on line and found what appears to be one answer, at what price I don't know. One of it's most important features are that it will not allow the battery charge run down to the point that it can't handle starting the outboard.

standard 17 posted 05-30-2007 11:11 PM ET (US)     Profile for standard 17  Send Email to standard 17     

That is exactly what I need! Thanks for link. Jim, the motor in question is a Motorguide 109 pound thrust which requires 36 volt power.

Thanks ya'll

jimh posted 05-30-2007 11:32 PM ET (US)     Profile for jimh  Send Email to jimh     
Bella--That is exactly the gizmo I was speculating about. Just the ticket. Good find.
standard 17 posted 05-30-2007 11:38 PM ET (US)     Profile for standard 17  Send Email to standard 17     
Unfortunately, it is not yet in production, they are still testing it. They have a 24 volt model available.


jmorgan40 posted 05-31-2007 07:03 AM ET (US)     Profile for jmorgan40  Send Email to jmorgan40     
I have a 1988 Outrage with 4 batteries. a cranking, Aux, and 2 trolling batteries in a 24 volt bank for my Lenco Troll-n-Tabs. I installed a system called the Stealth Charging System. Since I have the 24 volt trolling bank and the 12 volt Aux, the system is setup to charge all three as a 36 volt bank but they still operate independently. The Stealth system would probably work for your setup as well. All batteries are always fully charged between runs to fishing spots or on the ride back to the ramp. It works great. In fact alot of tournament fisherman are running the system since they are so hard on their trolling batteries. Below is a link to a past discussion about the setup. I have also emailed you a wiring schematic the owner made especially for my setup. Better yet, maybe Jim cam weigh in and post it. It is a PDF file. I know Jim was skeptical of the system when I first discussed it, but I have been running it now for over 2 years with no issues. It is flawless and all 4 of my batteries are always charged to their max. Good Luck, let me know how you make out or if you have any aditional questions. Joe.

jimh posted 05-31-2007 09:03 AM ET (US)     Profile for jimh  Send Email to jimh     
Here is a link to the Stealth Charger website. It looks like it will also accomplish the function you are seeking:

Joe--Thanks for the first-hand account of the Stealth Charger. If all those professional fishermen are using it, it must be a good set up for them.

where2 posted 06-02-2007 10:18 AM ET (US)     Profile for where2  Send Email to where2     
I have mentioned the Stealth Charger before on this website when folks have inquired about trolling battery charging. Our 25' Boston Whaler Frontier at work has one mounted to charge the 24v battery setup we use for the hydrographic depth sounder equipment. It has been working fine for more than 2 years now... It works exactly as advertised. The model we have had an option of running it in 24V charging mode, or 36v charging mode. The wiring diagrams were straight forward. We never have to swap the series wiring of the 24v batteries to parallel wiring even to charge them at the office.

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