New motor, batteries, and charger - help!

[Brian D]

As the subject line says, I am getting a new motor, new batteries, and a new charger for my Lancer 27. So where do I need the help? Read on.

My old motor was a '95 Yamaha T9.9 that gave up the ghost. I am sure it would be a simple fix but confidence is low. So I am purchasing a '12 Yamaha T9.9 to replace it. Same fit, form, function, except... this motor is electric start. The previous was manual start. Ok, that is the first part.

I am also getting a new battery charger. Guest 16102 12 amp 2 bank charger. i think that is all I need for shore charging. My electrical budget is not that big on the water. So I went with a smaller charger to replace the burnt out Xantech 20amp 2 bank charger. Ok, that is the second part.

I am also putting in new wet batteries, 2 group 27. this is what I had before and worked well. So basically nothing changed there. My previous batteries fried when the charger fried. Which fried first I have no ideal. But I am sure it was something I did or didn't do.

Here is where I need the help. If I still had the manual start motor this would be a no brainer. But because I am now putting in an electric start motor, I need to know how to wire the motor into the batteries or battery switch. The last motor had one wire connected to a battery isolator and it was connected to the two battery's POS posts. Will I do the same thing or connect the hot wire to start the motor to a single battery or to the battery switch?

I am not sure of the wiring for this. I will be home again in December. The new motor will already be installed and tested. Any advise on how to wire the new motor to the batteries would be appreciated. Maybe all I need is to connect it to one battery and call that the starter battery.

Thanks in advance.

I have added a diagram to what I think is correct, but not 100% sure.

 

[Paul F]

Your wiring diagram should work well. If you wish to charge both batteries while motoring, you have three options. First, without additional cost you could wire the alternator to your switch. What we did simply, on another boat was to use the #1 battery on odd days and the #2 on even days. This kept both of them charged all summer long. Second, after starting the motor you can switch to "Both" batteries and charge them both at the same time. Third, replace the isolator with a combiner attaching both batteries together and forget it. When one battery reaches 13.5 volts the other battery will be connected and be charged as well. All of these options will work for you.

 

[Ed Schenck]

Personally I too like your diagram as is. It gives you the flexibility of either battery to start. Your electrical needs must be very light. I would combine those two batteries as the house on one switch position and a third small battery for starting. But I like sailing at night and having enough power for reading, anchoring, and a small fridge load.

 

[JoeWhite]

The diagram looks OK. I am concerned by the comment by Paul to "after starting the motor you can switch to "Both" batteries and charge them both at the same time". I am told not to change the switch setting when the engine is running as this will cause a sever damage to the alternator. On my system I have a third battery that is for starting only in case the house bank is too depleted.

 

[Brian D]

So Paul, are you saying to remove the alternator from the isolator and connect it to the the common post on the switch? If so, I never thought of that. But I have the isolator, I might as well use it.

I have a smaller third battery that is in the boat right now. It is the only battery with a small charger and is being used only on the bilge pump. I don't know the CCA on this battery. It could be enough for the starter allowing me to move the two Grp27 batteries to the house bank. But like I said before, my electrical budget is small (VHF, GPS, Autopilot).

I was also thinking of adding a 60watt solar panel and controller. That would tie in with the rest of the charging wiring.

I am curious about the alternator to the common post on the switch. Could you elaborate on that, please. Thanks.

 

[Sumner]

When our two 12 volt batteries on our Mac are no longer good, I'm switching to two 6 volt batteries instead. I think we will get more bang for the buck and everything will work better.

Right now we always have our two 12 volt batteries combined anyway and they charge and use better that way. They are the same kind, but one is about 6 months newer than the other and they don't perfectly match up voltage wise.

Our 9.8 HP Tohatsu has elect. start and always starts in a couple seconds and has manual start backup, so I see no need for a start and house battery combo like what we have on the Endeavour.

I also have the output from the outboard...

http://purplesagetradingpost.com/sumner/macgregor2/inside-30.html

...always connected to one battery to avoid any potential problems with the diodes in the alternator circuit. We can't accidentally mess up this way throwing switches. That battery is also combined with the other with....

... a manual switch, bottom left arrow, that is always "on".

If for some reason I needed to take the battery out of the circuit that is always hooked to the outboard....

... I could just leave the combine switch "on" and pull the fuse on the #1 battery and now the outboard would only be connected to the #2 battery.

We don't do it, but do have the option of running the house load off of either battery.

Still I think all of this is best replaced by two 6 volt batteries and will do that down the road. It simplifies charging from either the outboard or an external 110 v. charger and also maximizes the charging,

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

Mac-Venture Links

 

[Joe]

...I am told not to change the switch setting when the engine is running as this will cause a sever damage to the alternator. On my system I have a third battery that is for starting only in case the house bank is too depleted.

You can switch batteries while the engine is running as long as you don't switch through "off".

 

[Paul F]

Brian, I am warming to this topic as I have messed with the electric set up for a long time. Yes you can charge the batteries as by just hooking them together at the switch. An isolator or combiner does it smarter by allowing the first battery to get up to charge before balancing the charge over the second battery set. A combiner is preferred over an isolator because it it more efficient with the limited amps involved and it does not heat up as an isolator does.

As was said earlier you have the best engine option for a failed battery in that you can start your engine manually. Here is the new set up I have rigged up this summer on the boat.

All the batteries are charged with one alternator and one shore power charger by the use of a combiner. I actually hook the combiner up to the terminals in the large 1-Both-2 switch. Attaching the wires to the 1 feed for the starter battery and the 2 feed for the house bank. This equally charges all of the batteries at the same time. There are many more expensive charging systems out there but this has worked for me for many years.

O.K. when getting the boat ready to go sailing this is what is done. The large 1-Both-2 switch is set to "2" (House Bank). The small second On-Off switch has a red key that I keep by the back of the boat near the engine water valve so that I remember to turn the water valve on. I turn this small switch on to start the engine. You can see that once these two switches are set there is no need to touch them until the sail is over.

A few weeks ago, I was coming back in from a sail and the engine would not start. The 5 and a half year old starting battery had failed. To start the engine I simply turned the 1-Both-2 switch to Both and started the engine with the house bank's batteries.

I hope I haven't made mud out of battery wiring and switching with this example and plan. It works very well and is tested,

 

[Joe]

My setup uses TWO 1-both-2 switches. House and Motor. Lots of options.

 

[Brian D]

Make and model of the combiner please. Sounds better than the isolator. Since I am virtually replacing everything battery related, might as well look into that also. Thanks.

 

[Brian D]

OK, I added a new image based on what everyone was talking about. Note that the switch and the isolator are gone, with a combiner and my energy load, I feel that I really do not need it. A solar controller has been added but it is only in the planning stages.

Thanks for everyone's advise, feel a little more comfortable now. But this all hinges on when I get home and see if it indeed works.

 

[Maine Sail]

OK, I added a new image based on what everyone was talking about. Note that the switch and the isolator are gone, with a combiner and my energy load, I feel that I really do not need it. A solar controller has been added but it is only in the planning stages.

Thanks for everyone's advise, feel a little more comfortable now. But this all hinges on when I get home and see if it indeed works.

Brian,

For safety reasons you should technically have a battery switch to kill bank power if needed. If that were my system, and I could technically start the motor by hand by pulling the cord, both batteries would get combined into one big bank. Then no need for the ACR and only a single ON/OFF. You bank would also last longer because you are cycling it less deeply and you would have more cranking amps, not that you need it with that motor...

This is how I would do it..

One large bank hard wired in parallel
One ON/OFF switch
All charge sources led direct to the bank
Proper fusing as close to the battery as possible for everything connected to it

 

[Brian D]

Thanks, Maine, I will take that into consideration. Right now, since I am bored and there are no bombs being dropped, I am just going through different configurations.

Sorry, ACR (rectifier)? For the life of me I am not getting that to spell out. LOL Must be getting old.

 

[Stu Jackson]

"Real World" Wiring Diagrams

Brian,

While you're in the "thinking" mode, you might want to consider improving your wiring diagram. How? you ask. By considering the actual way you would wire it on the boat by dealing with actual connections and wires and "landing spots." For instance, your diagram has wires tapping into other wires along their runs.

Over on Sailnet recently, Maine Sail and I wandered into a post where the contributor posted his wiring diagram. Regardless of what you choose to do, it might serve you well to think about the wires themselves.

Like this:

 

[Stu Jackson]

Sorry, ACR (rectifier)? For the life of me I am not getting that to spell out. LOL Must be getting old.

Try www.bluesea.com. The ACR is a relay between two battery banks, like using the B position on a 1-2-B switch.

Just type in ACR in their search engine box.

 

[Maine Sail]

Thanks, Maine, I will take that into consideration. Right now, since I am bored and there are no bombs being dropped, I am just going through different configurations.

Sorry, ACR (rectifier)? For the life of me I am not getting that to spell out. LOL Must be getting old.

ACR is Blue Seas branded terminology for a voltage sensitive relay (VSR) or "Automatic Combining Relay".

They automatically combine banks when a charge voltage is present and automatically disconnect them when not charging.. With a pull start motor you can be the "reserve bank" so no need for an ACR..

 

[Brian D]

Oh, so then an ACR is just another name for a combiner. I have worked with splitter/combiners in my satellite jobs many times. A rose by any other name...

Stu, my drawings are in color showing different circuit path by color. Black will never connect with red or blue or green. So my drawings are fine. Granted, I normally do not add grounds as they are understood. If the drawing was in all black, as the one you added, then all those little "jump overs" are required. Also, connections are normally "dots" and no orthogonal cross-overs. No improvement needed, but I appreciate your comment. And I do appreciate the drawing, that gives me more ideas to work around in my head. :dance: