Redundant charging from kicker?

[nphilbro]

Since my fishing pursuits take us into salt water currents I want to be sure I have as much mission critical redundancy as reasonable. I already have redundant propulsion, fuel source, fuel line, communications (w/cell phone), interior/exterior light source. Both engines use the same fuel mix.

My main is a Johnson 140hp with Evinrude 15hp kicker with charging. I have one battery that's 850ca and will be installing another sometime this week.

The batteries will power nothing unusual but over 8+ hours I'm concerned that when using the main for only about 15-45 minutes at launch and maybe sporadically a few times in the day there will be too much drain to fire it back up or it will toast the battery(s). During the day I run the radio (nothing fancy), bilge, blower, dual downriggers, tilt/trim (only with main), GPS, fish finder, washdown pump, VHF.

I have two questions:

1. Can I, and if so, how should I connect the charging into the system from the kicker since I'm not sure if it would discharge somehow into the electronics of the main engine?

2. What type of battery should I use for the secondary with this type of use, I'm guessing a straight up deep cycle or should they be the same?

I have a Guest box that allows me to switch from Off/1/Both/2 settings.

The kicker has a pull start so I'll at least be able fire that up if everything goes dead. I'm also aware that there's not much charge coming off a small motor at fast idle, but it's got to be better than nothing and I like the thought if it needed to it could be run fast enough to add enough battery to start the main.

A follow-up to this might also be concerning what, if any, consequences would there be if the were boat running briefly - as in, main was hard starting that day for some reason and wanted to be sure it was firing before killing the kicker (just covering my bases).

Call me paranoid, but these currents can throw a boat into rocks a lot faster than the coast guard can respond. Even on calm water the tides will move you in a hurry.

Thanks!
NP

 

[Georgesalmon]

Re: Redundant charging from kicker?

I have the same situation. I solved it for peace of mind by using a large dual purpose battery on my kicker. I run everything off my kicker battery and leave the main eng battery just for the main engine. Thus when the kicker is running it keeps all my electronics and downriggers working with it's little 6amp charging circuit. I figured if the worst happened and I ran the battery down on the kicker I could always pull start it. Not so with the big engine.

http://continuouswave.com/whaler/reference/dualBattery.html

Here are some ideas.

I used the "new" diagram. I did add a Batt ON/OFF switch to the neg line so I could shut everything off. I am anal.

 

[nphilbro]

Re: Redundant charging from kicker?

Thank you! Excellent link, George.

I especially like how it outlines the logic and operations. It also verifies my assumption of potential damage to the charging systems without isolation.

It looks like I'll use the "new" system with a simple shutoff bridge switch between the positive terminals and the dual purpose switch since everything is still addressed but it keeps safe operation really simple- which is important when I have to delegate this responsibility.

Like you said, isolating all the operational electronics to a dual purpose battery connected to the kicker that's constantly charging makes perfect sense.

A quick question for you, George (and anyone else who could weigh in): I was thinking of installing an isolator switch at each of the positive leads vs. a single ground disconnect because I'm extremely concerned that transient voltage will build up in the engine components. Have you had any issues with this? I was surprised to see information and instructions for most battery terminal isolators, even though they say "universal" explicitly refer to disconnecting the ground. Also, even those sized for the positive terminals don't seem to be rated for the full cranking amp requirements so indicate they are for batteries used for a different purpose.

This was my initial thought. I'm thinking it's off the mark now?

 

[Georgesalmon]

Re: Redundant charging from kicker?

Honestly I don't know how any transient current could appear if there is no path for it. I installed a battery sized ON/OFF switch with ALL negative leads on one side and the two Battery negatives on the other. Had to use a Neg buss bar as the bolt on the switch was not long enough for all the neg leads. Your idea sounds like it would work but I would make sure the isolator switches would carry enough current. I also used #4 wire for the Pos leads to the Batt 1/2/both/off switch so I could parallel the batts for starting in an emergency. #10 would have handled everything in normal operation. I also plan on never having one engine running when I do this (if I remember). I even made a sign. I am really concerned about blowing a stator or something else expensive on an engine. I know some people do this all the time but it worries me. I also looked at all kinds of other isolator and electronic devices to accomplish what I wanted and nothing seemed just right for me.

edit: I didn't add the shut off to the pos engine leads because I never wanted to have a situation where I could shut off the pos engine lead even by accident. I guess i could have the same problem shutting off my neg switch but I can not forsee a situation where I might do that except in the garage.

I see a lot of kickers out there and wonder why some marine electronic firm hasn't made something for us. There is a lot of stuff for inboard engines where you can get to the charging wiring but nothing for outboards.

 

[Georgesalmon]

Re: Redundant charging from kicker?

nphilbro




Better pictures. One shows the batt switch and the shut off switch panel. One shows the promariner battery charger which somehow recognizes each seperate batt even with the neg's combined. One shows my downrigger breaker panel. Two Big Jons and two scotty's. I have the onboard charger because since I always use the kicker battery to run the house electrics, I worry that it might be run down when I come back if I have used the downriggers a lot. I could select the main battery for house when running but then I have to shut the electronics off and on again when I start the kicker. The only thing I have that draws much juice is the sportpilot autohelm when running. The rest of the house draw is really very small even with the nav lights on so I just leave the kicker batt selected all the time. I I don't run the ocean but Lake Michigan can get very scary too.

Gotta tell you. I spent many hours last winter searching people, phone calls and the net for this solution and it works great for me.

Good luck.
George

 

[Jlawsen]

Re: Redundant charging from kicker?

Two things to know... 1. Never disconnect a running engine with a charging system from it's primary load source (battery). 2. If charging system a and charging system b both have voltage sensing regulators then then one or both may stop allowing charging current to flow if they sense an over voltage state.

Setup your kicker with a kill switch and a timer relay so that the kicker is stopped when the relay switches. I have my North River setup so that it uses the two spare lugs on the key switch for this. When I turn the key switch to on it kills the kicker and then 5 seconds later the relay switches. I put a LED above the key switch that shows when the relay opens and it's safe to start the main. It might sound intricate but it's really pretty simple.

 

[Georgesalmon]

Re: Redundant charging from kicker?

I agree never run an engine thats not connected to a battery. I think I understand what your talking about with the relay. However I at least really need to run both engines at the same time for a few min. I need to keep the boat under power in large seas. I can not sit DIW while waiting for the kicker 4-stroke, or main engine 2-stroke to warm up enough to put in gear and give me steerage. With the above I can run both engines as long as the Batt switch is not in the "both" Position and never have the charging circuits connected together.

 

[nphilbro]

Re: Redundant charging from kicker?

Great information.

I appreciate you sharing your research. It will be easy enough to adapt to my setup now. Seriously, it's amazing how little information on this type of setup there is!

I can't see running both engines very often or for very long but that's not to say it's not necessary if suddenly caught in a strong tidal current when round a point. Few things have scared me more than being rudderless in a riptide since many riptides occur with some degree of randomness and just 50ft from rocky shores where a shelf shoots up from 400ft- so there isn't much tolerance between good and bad luck. These are also the spots that hold the best fish and are quiet most of the time so they are best spots to run downriggers. Redundant systems are more about safety than convenience in the Puget Sound.

To make sure I understand procedure:
In the instance of firing the main while kicker is still running I would need to switch the battery control from Battery 2 (kicker) to "BOTH" and that would allow me to start the main and power out to a clean position. I would then shut one engine down, then point the switch to the corresponding battery of the still running engine.

 

[nphilbro]

Re: Redundant charging from kicker?

I could select the main battery for house when running but then I have to shut the electronics off and on again when I start the kicker.

I'm not quite sure I follow this. Doesn't the current remain continuous to the house draw as you switch from 1 to Both to 2? I was under the impression that the best procedure only required shutting the motors down in the correct order.

 

[snowfish1]

Re: Redundant charging from kicker?

One thing you can do if you have any worries about losing battery, is get yourself one of those portable jumpstarters. Their farily cheap, and the one I have has 3-110v outlets on it so you can charge a cell phone if you need to if your phone roams alot and eats up battery. Great item to have onboard.

 

[Georgesalmon]

Re: Redundant charging from kicker?

I wasn't very clear. What I meant was that when I switch the "house" batt switch from batt1 to batt2 (through "OFF")There is a slight disconnect that cuts the power to my gps, depth sounder and auto helm for a and they shut themselves down. I have to restart. At least my humminbird says in the lit to use the shutdown button and not to cut the power. I don't go through "both" because I'm training myself to never do that unless all else fails.

When I run both engines at the same time they are completely electrically isolated as long as I DO NOT PUT THE BATT SWITCH IN BOTH. Sorry about the caps. Both engines will run together just fine, no problems. DO NOT DO THAT WITH THE SWITCH IN THE BOTH POSITION. Sorry about the caps. Only use the "both" position in an emergency and only with one engine running.

The battery switch only designates which battery (and engine) is powering the house loads.