Dual battery with 6 amp charging kicker

[TheBigGuy]

In recently bought a new to me boat and am doing some wiring upgrades. It came with a 2006 115HP merc 4 stroke and a 9.9 4 stroke manual start kicker. I swapped in a 1991 Honda 15hp electric start long shaft that has always worked flawlessly for me. It charges at 6 amps which I know is a little lower power than preferred, but better than no charging and no electric start. The boat is wired for only one charging source, with a 1-2-all-off switch. Main motor is started from battery 1 - starting battery, Battery 2 is deep cycle - house battery with electronics-downriggers connected to it.

Below is a diagram of the current wiring configuration:

How do you suggest wiring in the power cables for the charge/start feed to the kicker. I am not really interested in getting into any more complicated setups. I don't want to add an auto charge relay (ACR) or a solenoid/isolator circuit. I just want to keep things simple. I was simply planning on adding the cables to the second battery. The motors may run for brief periods together while one or the other is warming up. I don't think this is a big issue if only for brief periods.

How would you suggest wiring up this configuration with two charge circuits from the motors with a single battery selector switch.

Thanks in advance for any suggestions.

 

[Charlie]

Six AMPS out of the kicker, to the battery(s) is not very problematic. The chances of ever putting the battery(s) in a overcharge with six AMPS, very slim to almost nil, before you have any radios or other electronics running! The only problem you MIGHT have is the main alternator running the same time as the kicker, if they are not isolated could possibly get a feedback through the battery and possibly blow your kicker’s charger? That is a COULD – not at all meaning it will, as for that to happen the battery would have to be completely charged, not accepting any charge from the main? That MIGHT be problematic, it could happen. I do know people that have had to replace kicker chargers?

For one of the correct answers, it is best to keep them separate: two alternators, two separate batteries, two battery switches. That gives you the capability to keep the two alternators separated. The other correct answer… it is best to hook two alternators to one battery by the use of a Dual Alternator Controller, something like this one: http://www.amplepower.com/products/dac/index.html

Either of the above will prevent the two alternator feedback problem! Now those are the correct answers, want to know what I would do… hook the kicker up to number (2) deep cycle battery and forget about it, replacing something THAT MIGHT go wrong is less time consuming and cheaper than either of the above!

 

[Island Fish Lifter]

Connect it to the "common" pole on your switch, you wont have any problems.

I would verify the kicker charging system is actually working.

I also believe Honda kickers dont use a regulator so keep an eye on your electrolyte level from time to time.

Fill the dam tub!

 

[TheBigGuy]

Thank you both for your answers much appreciated.

 

[Charlie]

I am surprised no one has asked this question before.

This is not about using one engine charging two batteries, or two engines charging two batteries; it is about two engines charging one battery. That is NOT the ideal situation there!

With the kicker, the only time you will ever have an issue is when running both engines at the same time using the same battery – as that creates a link to both of the 'engine' charging systems. If you wire a kicker directly to the common, that link will continuously expose the kicker charging system to the main engine charge – I am not sure I would do that? IMHO If done momentarily (e.g. starting the main) is one thing, but it is not good to run both engines for any length of time (e.g. number (2) battery is low, so let me charge it, while still trolling on the kicker). To do the later you really should be shutting off the kicker.

If the kicker is wired directly to number (2) you only expose the kicker charge to main engine charge, if the selector switch is on number (2), limiting the exposure. The goal is… keep those charging systems separate while running both, especially for long periods of time!

“The problem with having two charging sources is that care must be taken to not connect the two chargers together in a way that damages one or both of them. Experience suggests that if two engines' chargers are wired in simple parallel and charge a common battery or bank of batteries, it is not unusual for one of the chargers to suffer a burned out stator coil. The cause of this is most easily explained if a fundamental rule of charging circuits is understood: the charger should never be operating without a load (a battery) connected.”

“In circuits with parallel connection of two engine charging circuits, it is likely that the voltage produced by them will not be precisely equal. If one unit has an output approximately one volt greater than the other, the effect of this will be to electrically disconnect the load from the lower voltage output engine. This may result in damage to the stator coil of the engine producing the lower voltage output.”
http://continuouswave.com/whaler/reference/dualBattery.html

I don't think this is IMHO?

 

[Island Fish Lifter]

charlie, I hear what youre saying, but your thinking waay too much into it. Systems like this have been connected like this for years. It wont be a problem. The main engine will stop charging when it reaches a certain voltage, and the kicker will probably keep charging past that voltage.. period.

Fill the dam tub!

 

[Island Fish Lifter]

woow, look at that. You really did give him the right answer.. what was I thinking[:0]

Fill the dam tub!

 

[Charlie]

Yes I did!

Nice delete!

 

[TheBigGuy]

Yes Charlie is probably right. That is the way I was leaning anyway. I considered connecting to the common terminal, but wasn't sure that was a good way to go. I had read about the possibility of burning out the stator on the kicker. I think it's not a big issue if they only run together briefly at the same time, at least that was several responses I had read.

I think I can minimize that possibility by trying to make sure I start the main motor always with the switch in the 1 position. When I start the kicker with the main running I will again use the switch in the 1 position. I will try to only use the switch in the 2 position when I need a top off charge from the larger amperage on the main motor when running back at the end of the day. I think this shouldn't risk frying a stator as long as I don't run the kicker and the main together on the 2 or all settin for any length of time.

I am also going to add a large disconnect/off switch to the second batteries positive terminal for the boats electronics. That way I can shut off everything when on shore and not have to worry about the house battery draining down from a short or having forgotten to shut a piece of equipment off.

Thanks for your opinions, you can never have too many answers to your questions, much appreciated.

 

[Charlie]

If you are wired as above and always start your main using #1 and your kicker is wired direct to #2, I really don't see the need and wouldn't add any other switches (KISS)? When you turn the battery switch off everything that needs to be will be off. The only thing that will have current will be the kicker?

 

[Hoochiebob]

Came across the same issue with my new kicker. I wired in a heavy duty three position key switch that is similar to a car ignition (off,start/run,accessory).Wired the charging system through the accessory switch so that it will be isolated with the turn of the key.
Quick and simple.

Then again being an electrician helps a lot too.

Hooch

 

[Charlie]

Hooch,
I understand your principle, but with that switch discribed? Now you can see how easy it is to confuse me?

How are you doing that (with that switch) without running one or both of those engines and having the charging system(s) not remain constantly connected to a battery?

You might want to take another look at that and make sure the engine(s), while running remain connected, without going through any kind of ‘off’ position… That would not be a good thing! It has to do with things like creating spikes, blowing computer chips, stators, rectifies, regulators and/or all the above.

This is just one site that warns of that… there are many; including, Owner's manuals.
http://continuouswave.com/whaler/reference/dualBattery.html