Tohatsu MD50B2 and battery isolator

[swilk]

I would like to use a battery isolator to charge both boat batteries off of my motor. I do not have a service manual and finding wiring schematics online is proving difficult.

I am assuming this is the regulator... Can I just take the regulator side of the red wire connection to the isolator? I could then bring bank 1 of the isolator back and connect to the motor side of that connection?

 

[alldodge]

Howdy

I'm not an outboard guy, but an outboard does not output much in the way of current. You could install an isolator but it would take a long time for it to charge up both batteries. The outboard as I know it, is just good enough to charge up it's own start battery. I think you would be wasting your time

 

[swilk]

I have a ProMariner dual charger installed as well....was just looking for a way to charge both while actually out on the water. Its proving to be a touch more difficult than I first thought....

The boat is a 1860 Polar Kraft I'm setting up for ducks and fishing. Biggest draw on the aux battery will be 10,000 lumins of led lights I'll use when going hunting in the mornings. Lights will only be used when the motor is running.....

The other draw will be a trolling motor when fishing....obviously only used when the motor isn't running.

Isolator isn't a perfect solution but coupled with the ProMariner I want to give it a shot.

 

[alldodge]

What about just adding another battery?

 

[swilk]

Limited space. Two 6g fuel tanks, two batteries/boxes and the ProMariner charger eat up the space.

Getting the motor to charge both batteries is easy....keeping those batteries separate while gaining the ability to motor charge both is a little more complicated.

 

[sam am I]

keeping those batteries separate while gaining the ability to motor charge both is a little more complicated.

Nah..............

http://promariner.com/products/prolsocharge-series/

I have ran one of these (three batt's) for maybe two yrs now, not an issue yet. Works quite well and doesn't need to parallel the batteries to charge a battery.....i.e., once started, it senses when the start battery is full (1 minute or 20 minutes) then switches it out (if V alt < V Batt, see below) of the charge circuit and routes all the current available to the low/exhausted aux battery.

Some other iso systems will/can only parallel the exhausted/low aux battery with the now full start battery, wasting energy sometimes by back charging one battery into the other if the alt supply voltage drops below the start battery voltage. This drop in alt voltage occurs when say a 10A (20A, 30A, 40A, 50A....100A) system (Your Shindengen reg/rec looks like a 10A unit) is trying to charge a battery that is drawing higher then 10 Amps.

This/these types of iso prevents this by switching into anti back charging mode and are optimized for that if and when a battery requires more charge current that a alt can provide. Even my 40A wimpy merc system, sometimes it isolates two of my three batteries when the third battery is pretty low due to it being used to make coffee with a 750 Watt inverter.

Once the aux battery is up to snuff, the system will then parallel both the start and aux batteries, keeping them both topped off. It'll jump back into the anti back charging mode though anytime you pull down one of the batteries too low.

If the motor is running and with your 10,000 lumen light, you should draw about roughly 11 Amps, with both batteries topped off, it will iso the aux battery pretty quick once your switch it on.

Of course when the motor is off, all batteries are auto-magically isolated by default

It works for me and how I use my systems, seems your need might be similar ......GL

 

[swilk]

I have an isolator from ProMariner.... Not that exact one but same idea. Problem is my outboard has a single cable that goes to the battery for both starting and charging. If I simply connect that cable to the isolator it doesn't allow current to flow backwards to start the motor. I need to separate the charging circuit from the start circuit and send just that to the isolator.

 

[sam am I]

I need to separate the charging circuit from the start circuit and send just that to the isolator.

You have to separate the red wire out/off the battery + under the hood, yes.

Run that (the red wire) to the alt in of the iso, then run the "batt1" of the iso to the start batt and "batt2" of the iso to your aux batt.

Follow their crappy schematic (an idiot made that I think). Snap more pic's of your motor's wiring etc and post if ya need more help

 

[swilk]

Just leave the other side of that red wire disconnected under the hood? I guess going from the ISO to the battery actually makes that connection without the need to take it all the way back to the connection under the hood.....?

 

[sam am I]

Yes, break it at that fuse in your pic above and add you own fuse in the reg/rec path to the ISO's "alt in" term.

Then "Batt1" of the ISO goes to where you disconnected the red wire (the start Batt's post if you like).

And "Batt2" of the ISO goes to the aux batt.

Fuse (20A's should work for you, think I used 100A) both charge paths at the battery posts that are going to the ISO's "Batt1" and "Batt2" terms..........We want you safe!!

 

[tommarvin]

I don't have a clue about an iso switch,it should be a good search and study.

We have a battery switch, your choices are Batt 1, or Batt 2 or both, will this work for you?