CD25 Dual Outboard Custom Battery Charging System

[Lighthouse Express]

Let me try to demystify my new charging system for you or perhaps confuse you...

My intensions are to improve my CD25 dual outboard battery charging system while keeping it as simple as possible.

I currently have the following hardware: 2 each, 85AH deep cycle starter batteries, one 105AH house battery, a 2-bank 2610A Guest charger, two engine disconnect switches and one 2-ALL-1-OFF Perko switch.

I designed my new charging system with the following thoughts:

I belief simple equals reliable, therefore no automatic charge relays.
I want to keep the amount of switches to a minimum.
I do not want the option to have my two outboard engine charging systems in parallel for any reason.
I want the ability to fully charge all three batteries while under way or on shore power.
I like to have the option to jump-start any of the two starter batteries via the house battery should the need arise.
I like to be able to charge the house battery via port or starboard engine while under way.
The only time I would switch the battery selector to position 1 or 2 would be after the outboard engine(s) start to charge the house battery while under way.

To accomplish all this I choose to replace the 2-bank 2610A Guest charger with a 3-bank 2621A and replace the 2-ALL-1-OFF battery selector switch with a simple 1-OFF-2 selector switch.

Note: The engine disconnect switches allow for easy removal of electrical power from the outboard motors during maintenance. Fuel and sparks do not get along to well unless it is in a compression chamber. Perhaps, as an alternative one could remove the positive cable from the battery posts instead. A bit more work though...

While this design may not be the best solution for your CD25 dual outboard configuration, it might give you some food for thought though…

http://www.c-brats.com/modules.php?set_albumName=Technical-Stuff&id=Battery_Wiring&op=modload&name=gallery&file=index&include=view_photo.php

[hardee]

Hi Heinz,

Looks like a nice simple system. Something I would be interested in if/when I get to add a house battery. Thanks for posting that.\

Considering launching from Sequim for Friday Harbor again?

Harvey
SleepyC

[Lighthouse Express]

Harvey,

With regards to considering launching from Sequim for Friday Harbor again...
We have planned to continue from Friday Harbor, after the event, to go north on our Inside Passage journey returning some time on the beginning of August. Therefore, we have to find a secure place to park our truck and trailer for about three month. I am not sure if Sequim could accommodate us. Perhaps you have a recommendation?

Thanks,

Heinz

[thataway]

Some food for thought: To be a bit of the devil's advocate, since part of the purpose of this forum is sharing information and learning.

A lot depends on how you use your 25. There are switches to turn each time you go out. Using these switches seems like a lot more issues than using a VSR. They are well proven, and reliable. They help to avoid mistakes. You know how your boat runs, but there may come a day when you ask someone to turn that switch for you, when you are busy doing something else. There is the risk that the wrong switch is turned.

Why use deep cycle batteries for engine start?

How do you isolate your electronics when you start the engine? Or are your electronics on the house battery?

When do you decide to charge the house battery and off which engine?

One 105 house may be a little on the small size for a 25, with refer, and cruising demands.
You run some risks of disconnecting an engine and battery while running, and this could damage the regulator.
I would choose a different battery charger, based on the less than sterling reputation of the Guest line.
I don't see any battery monitoring system. Nor do I know exactly how you are going to connect the house systems. But your goal is a charging system.
Best to have the batteries which are being charged from the same engine source, of the same size, type and age. This avoids overcharging one of the batteries (such as the engine start when your house is run down). Unfortunately outboard regulators are not smart regulators.

There are times when you may want "all"--if you loose one engine, or have a low battery starting battery and the other engine not running--or failure of the alternator on the other engine. Although if you have a pair of jumper cables; that would work.

[Sunbeam]

Here is the linked diagram:

[Lighthouse Express]

Thataway,

Thank you very much for your reply… I truly appreciate your feedback.

Perhaps I can address some of your concerns.

Dual purpose batteries are ideal for applications that require starting and deep cycle service. They deliver powerful cranking amperage for easy starting, and low amp draw service for reliable auxiliary power. Dual purpose batteries are a perfect compromise between the unique demands of starting service and deep cycle, low amp draw service.

Since I have a house battery, my electronics will always be on it to provide protection from starting surges and spikes as recommended by the electronics manufacturer. Perhaps it's only my Raymarine system that is finicky...

Regarding what engine I select to charge the house battery, I arbitrarily will alternate between the engines.

Unless one uses Lithium Ion batteries (http://www.lithiumion-batteries.com/lithium-marine-batteries.php) which are very pricy, a deep cycle lead acid house battery much greater than 100AH will add significant weight to your transom area. Perhaps I would be very concerned about water coming into my self bailing ports while having guest on board.

I am not concerned about accidentally disconnecting an engine from the starter battery while running since my engine disconnect switches are mounted out of site. My easy to reach 1-OFF-2 battery switch does not allow for disconnecting a battery from the engine.

I am less concerned about the use of the Guest line charger. Everyone seems to have their favorite brand. The Guest 2610A currently in my boat since 2004 is till working flawlessly...

To keep the drawing simple I did not show the volt meters or any loads.

I agree with you that it would be best to have the batteries, which are being charged, to be of the same size, type and age. However, that is not practical as the house battery is typical of somewhat larger capacity.

I do not have a need for the “ALL” position or jumper cables since my 1-OFF-2 switch with a high amp rating allows me to put the house battery in parallel with any of the two starter batteries for charging or emergency start assist.

Thanks again,
Heinz

[Lighthouse Express]

Sunbeam,

Thanks for making the schematic visible...

I did try that but was only able to get the link???

Heinz

[Sunbeam]

[Lighthouse Express]

Sunbeam,

I will copy your directions on how to display an image into my Documents directory on the hard drive since I may not remember the procedure in three month... ('')

Heinz

[Lighthouse Express]

Sunbeam,

Didn't you have a voltmeter in your dashboard already when you got your CD22?
Your BMV-600S looks very nice though. I assume it is a lot more accurate than the analog ones...

[Sunbeam]

[Lighthouse Express]

Sunbeam,

I do like your way of thinking...
I also like information. A $149.00 does not seem to be to bad for something accurate.
I have to take a closer look at it online and see if I can monitor multiple batteries and what shunts I need to look for current readings.
Christmas is coming up... perhaps...

Heinz

[Sunbeam]

[Will-C]

I'm not a big fan of Guest battery chargers. I replaced mine when it failed with a three bank Charles 20 amp charger. It has switch settings for lead acid, Gel, or AGM batteries. They are built in the USA and seem to be pretty well built. Mine was about $285 dollars from WWW.defender.com. So far so good.
D.D.

[thataway]

From Lighthouse Express:

Dual purpose batteries are ideal for applications that require starting and deep cycle service. They deliver powerful cranking amperage for easy starting, and low amp draw service for reliable auxiliary power. Dual purpose batteries are a perfect compromise between the unique demands of starting service and deep cycle, low amp draw service.

But you are not using these batteries as house batteries, or even dual purpose, only as starting batteries. You would be better served by a battery designed for only starting purposes.

Since I have a house battery, my electronics will always be on it to provide protection from starting surges and spikes as recommended by the electronics manufacturer. Perhaps it's only my Raymarine system that is finicky...

Good idea to protect electronics from the surges and decreased voltage during engine start. All of the electrics do better if they avoid these surges, and that is why I prefer the VSR--where you cannot leave the house and engine start connected by accident (not switching off the house battery, if an engine stalls, if you stop to land a fish, or just drifting watching whales etc.


Unless one uses Lithium Ion batteries (http://www.lithiumion-batteries.com/lithium-marine-batteries.php) which are very pricy, a deep cycle lead acid house battery much greater than 100AH will add significant weight to your transom area. Perhaps I would be very concerned about water coming into my self bailing ports while having guest on board.

The average C Dory 25 would not be worried about water intrusion--but I can see your point, since you have over 700 lbs of outboards sitting on the stern, and I 222 lbs less in the C Dory 25 I owned. I never had a problem with water in the cockpit, even with a full ice chest, freezer, and gear box in the cockpit--well over 300 lbs extra, and extra people. We also carried an extra house battery aft. Our experience suggests that a single 105 amp hour battery is not adequate for cruising in a well equipt 25. But each of us has our comfort level. If you really are planing to run form San Francisco to the PNW outside, then you would have a loaded boat.

I am less concerned about the use of the Guest line charger. Everyone seems to have their favorite brand. The Guest 2610A currently in my boat since 2004 is till working flawlessly...

You have had much better luck with the Guest chargers than I, and many others had. I have had 5 fail in the last 15 years. The point is if you are "upgrading" You might consider going with a brand with better known reliablity.

To keep the drawing simple I did not show the volt meters or any loads.

OK--what digital battery monitoring system do you have?
How are you going to connect the house loads? All on the 105 amp house battery? Or is one or both of the engine start battery going to share some of the work--such as trim tabs, windlass (where you want the engine running when using the windlass), Bilge pumps? Macerator pumps?


I agree with you that it would be best to have the batteries, which are being charged, to be of the same size, type and age. However, that is not practical as the house battery is typical of somewhat larger capacity.

Again, not difficult when up grading the system is a good time to make all of the batteries equal (especially in these small boats)--size age, type and capacity. Minimal difference in cost, and although you don't appear to be going to use either of the engine batteries, you may find that there are gong to be times that you will need more capacity for the house loads. For example you may not want to stress the house battery, by pulling up the anchor with the windlass, when it is already discharged significantly after a night on the hook.

I do not have a need for the “ALL” position or jumper cables since my 1-OFF-2 switch with a high amp rating allows me to put the house battery in parallel with any of the two starter batteries for charging or emergency start assist.

You may have missed the point, and it might be rare, when you may want to charge both engine start batteries, and the house battery, from one engine. By leaving the "All" in that battery switch, it would allow this.

The 1/2/all/0ff is usually used with two batteries, and then going to the house load where you can select the house/engine start from one of the two batteries. rather than in the way your are using it--noting wrong with your way. C Dory has had some very "innovative" ways of hooking up twin engine boats, my major experience was with the Tom Cat 255. [/quote]