Help Check My Diagram of Proposed Rewire for Chrysler Striper and Johnson 70

[sumocomputers]

I have attached a rewire diagram for my 1980 Chrysler Striper with 1989 Johnson 70, after reading this article:
http://newboatbuilders.com/pages/electricity13.html

Some of the work I have already done out of necessity, but several items are still not done, and I am not opposed to redoing anything that might be incorrect.

Just looking to see if you could take a quick look at the diagram, and see if I am making any major mistakes, or if you have a better suggestions.

Here is a better quality link to the diagram:
https://dl.dropboxusercontent.com/u/2466418/Uploads/Boat_Battery_Diagram.jpg

Thanks,

Chris

 

[dwco5051]

I would run the bilge switch directly off the battery with an inline fuse. The way it is shown when the batteries are off and no one is around the pump would not turn on if the boat started taking on water from rain or a leak.

 

[sumocomputers]

No Title

Good Catch, I never thought about that. Updated photo attached and here:
https://dl.dropboxusercontent.com/u/2466418/Uploads/Boat_Battery_Diagram_2.jpg

I did show an inline fuse between the switch and pump, should it be between the battery and switch or maybe that doesn't matter?

Also I showed another 12V+ coming from the switch panel, but after the switch. The thinking here is if the switch was failing or not activating for some reason, I could manually force the pump on with a switch at the helm.

 

[Grandad]

Hi sumcomputers. I did a criticism of your first schematic as follows:

Install a max 30 A fuse for the #10 near the battery selector switch.

I?m not familiar with the control panel you?ve shown, but it appears to have push-in breakers such that additional device fuses are redundant.

I would keep all devices on separate fuses. Having your nav lights on the same fuse as a faulty fish finder will put your lights out or maybe a faulty horn will cause your bilge pump fuse to blow. It?s also a lot easier to quickly identify the problem device, especially helpful when out on the water.
Move the 10 A inline bilge pump fuse to between the float switch and the battery selector switch.

I would avoid having 2 fuses as shown for the bilge pump. I f the manual switch for the pump must be at the helm (I don?t think that?s necessary), then run a second wire such that the manual switch parallels the float switch. Use only the inline fuse to protect the entire circuit. As it is, with both switches on, you will have two 10 amp fuses in parallel feeding a 4 amp pump motor. I wouldn?t worry about additional voltage drop from adding length to the manual switch circuit, since you?ve shown a #10 AWG wire for the bilge circuit which is already unnecessarily large.

On a personal note, I?ve never fully understood the concept of having a house battery and a start battery, unless you have a large current draw, such as a trolling motor. I can?t imagine being out in the evening and having to switch my accessories including lights off while I start the engine and then switching the battery back over to house. So would one leave the switch in ?both?; voiding the different characteristics of each battery? Why not use 2 identical deep cycle batteries with characteristics adequate to each start the engine and run the accessories? I do this, running on only one battery and regularly switching between batteries to ensure I always have a fresh battery if needed.

- Grandad

 

[wrench 3]

On a personal note, I?ve never fully understood the concept of having a house battery and a start battery, unless you have a large current draw, such as a trolling motor. I can?t imagine being out in the evening and having to switch my accessories including lights off while I start the engine and then switching the battery back over to house. So would one leave the switch in ?both?; voiding the different characteristics of each battery? Why not use 2 identical deep cycle batteries with characteristics adequate to each start the engine and run the accessories? I do this, running on only one battery and regularly switching between batteries to ensure I always have a fresh battery if needed.

- Grandad

I'm running a cruiser and sometimes sit at ancker for a couple of days so a separate starting battery makes sense. We run on both all the time and leave it on both if we're only stopping for lunch or something. If we've been moored for a while but the house batteries still have a reasonably charge left in them, we just switch from 2 to both, start the engine and go. Normally the only time we use only the starting battery is on a cold start at home to make sure it still works OK.
As far as battery types go, the internal design on a cranking battery is set up to deliver a larger amperage over a shorter period of time. Were as a deep cycle will supply amperage over a longer period of time but at a lower rate.

 

[Grandad]

Thanks wrench. It seems that the needs of small outboard boats often get designed around the needs of cruisers such as yours. I understand that there's a difference in the basic characteristics of the 2 battery types, but I think the distinction is moot when starting a 70 hp outboard. Sometimes we (including myself) get carried away into overbuilding what could be much simpler. - Grandad

 

[sumocomputers]

Grandad, I will go through your suggestions and rework my diagram.

As to why I have 2 batteries for such a small boat/motor:

1. The boat came with 2, so theres that.

2. My thinking is that if the cranking battery for some reason decide to conk out, the power from the other battery would be enough to at least get the motor started. And yes, I I would probably keep it in BOTH most of the time. When we park the boat, it would be OFF. Also, if for some reason one of the batteries developed a short (and might start blowing fuses), we could isolate to the good one, replace a fuse, and get back to the dock.

But yeah, I know I am probably over engineering this whole thing, but I am trying to think about future upgrades like a trolling motor, radio, etc., thus more battery capacity and thicker wire could make that easier in the future.

Chris

 

[Grandad]

I agree 100% with having a second battery, especially if you're far from home. However, if you're going to use them together and charge them together, you may have some problems. You suggested that one might fail shorted. If your switch is set to "both", the first failed battery will deplete the second good battery very quickly. Also, if the batteries are not identical, your charging circuit will charge to its limited capacity on the lower voltaged battery in an attempt to achieve a balance that may not be achievable. You could add a diode arrangement to the charging circuit, but that will work effectively only when the batteries are not in hard parallel by the switch. - Grandad

 

[Silvertip]

Dual battery switches tend to be the most over-thought, over-designed, improperly implemented and under/mis-utilized feature on a boat. The "house/starting" theory on a small boat with no trolling motor is not a valid theory. On those small boats every accessory including the engine can be connected to the COM terminal on the switch so the power source is redundant. The only exception to the "everything" idea is the bilge pump that would likely be wired directly to one of the batteries. Keep in mind here that I'm not contending a large cruiser would be wired this way since the electrical demands are much different that the smaller runabout style boats. Also keep in mind that an outboard that is properly tuned, the batteries are properly maintained, and an operator that actually knows how to properly start an outboard, can start that engine half the season with no charge whatsoever on the battery. After all, that's the way things used to be before charging systems appeared on electric start motors. I've had a few! So the worry about running down the start battery is really worrying over nothing. With everything on the COM terminal, contrary to popular belief you don't have to be constantly fiddling with the switch and NO -- BOTH is not the preferred setting. Look at the BOTH setting as a simple reason for not carrying jumper cables. That's all BOTH does is provide a jump/charge capability. Use the switch logically -- and it doesn't take a lot of thought to do that. At the start of the day, determine which battery you want to run on for the day and set the switch. If you have an on-board charger that would have had both batteries already topped off so which battery you select is not rocket science. If you don't have an on board charger, you "know" which battery took the most abuse on the previous outing so select it -- YES -- before you even start the engine. That battery will likely start the engine unless you killed it on the last outing which is death to a battery by the way. The full output of the charging system will then go the selected and most discharged battery. On the next outing determine if the battery you used the previous had an opportunity to recover fully. If not, use it again on the next outing. Alternate battery use as others have suggested and both batteries will live longer. And for those with trolling motors, there is no way an outboard will fully charge a deeply discharged troller battery in a few short runs. The switch in this case is really unnecessary except for emergency starting but a set of jumper cables takes care of that issue.

 

[sumocomputers]

No Title

Silvertip - I think the idea of running on one battery or the other makes sense 95% of the time, so I will definitely try that instead of the BOTH position.

Grandad - The reason I have a wire going from the helm switch directly to the bilge pump, is in the event the float switch is failing or not kicking in for some reason, I can bypass it and provide power directly to the pump, no other reason.

If my thinking is correct, I think having fuses in both places makes sense after I moved the inline fuse between the float switch and selector switch.

And my helm switch panel does not have any circuit breakers, I was just using a generic graphic for that.

I have attached an updated diagram along with most of your other suggestions, please tell me if you think I am still incorrect on the bilge pump thing.

https://dl.dropboxusercontent.com/u/2466418/Uploads/Boat_Battery_Diagram_3.jpg

Thanks,

Chris (the over-engineering guy)

 

[bruceb58]

Use this type of switch instead:
https://www.bluesea.com/products/551...Battery_Switch

That way you can turn off the house battery to it's loads. With the switch you have, you can't do that.
You can still combine if you absolutely have to.

I have this type switch on my pontoon boat.

 

[sumocomputers]

Use this type of switch instead:
https://www.bluesea.com/products/5510e/e-Series_Dual_Circuit_Battery_Switch

That way you can turn off the house battery to it's loads.

Damn, already bought the 1-2-BOTH-OFF switch. Seems like my switch would work like the one you linked to, no?

I am thinking I should be able to switch the house loads off with my battery switch when we are done with the boat, which is somewhat redundant anyway since I also have toggles at the helm for every load.

Maybe I am missing something...

 

[Grandad]

Duplicate post.

 

[Grandad]

That's looking better. You'll want to place the fuses before the switches when you get that far. In regard to the bilge pump control, I understand your concern for having a manual overide to start the pump if the float sticks in "OFF". I like to also have manual control to turn the pump off if the float sticks "ON". To do this you'll need a 3 position ON, AUTO, OFF switch. That's what I have installed.
http://www.iboats.com/Bilge-Pump-Sw...203957--session_id.162612321--view_id.1186625
Also, I don't like having 2 fuses potentially feeding one device. To keep the bilge pump circuit sensibly short, I've installed the control switch near the stern, rather than at the helm. Each to his own. - Grandad

 

[bruceb58]

Seems like my switch would work like the one you linked to, no?

Nope. You would need a separate switch going to the loads from your house battery. Actually, you have no separated loads on your house battery. All your loads are on the common of the switch. As you have it drawn, there really is no house battery. You have 2 batteries that you select to operate everything at one time.

Nothing really wrong with that. It's how my Wellcraft is set up. For my pontoon boat, I wanted a true house battery which seems like what you intended.

 

[sumocomputers]

All great suggestions & comments, thanks guys.

Grandad

-My fuses are in fact before the switch, my diagram was just wrong.

-I will look at wiring a separate 3 position switch close to the bilge pump, and only have a single fuse for it. Great suggestion for forcing it both ON and OFF, didn't think of that.

BruceB58

-The truth is, I really only need a single battery for my setup, and the second one simply came with the boat, and so is just intended to be used as a backup. I will probably just alternate running off of a single battery every few trips. I do have a longer term plan for a trolling motor, so once I have that, the 2 batteries will make more sense.

-I understand what you are saying now about being able to turn off all the loads. I think for now, I can just use the helm switches as well as the battery switch I have, since I believe both the 12V+ battery terminals (1 & 2) are not connected to the Common terminal in the OFF position. This would be the position I would use when storing the boat.

 

[bruceb58]

-The truth is, I really only need a single battery for my setup, and the second one simply came with the boat, and so is just intended to be used as a backup. I will probably just alternate running off of a single battery every few trips. I do have a longer term plan for a trolling motor, so once I have that, the 2 batteries will make more sense.

Like I said, I have my Wellcraft wired this way so it's totally fine to do it that way. If at a later date, you want it with the other type switch, just move the feed going to the fuse panel to the other position on the switch.

Think about adding an ACR and you won't have to worry about switching between the batteries all the time. With my Wellcraft I just run on one all the time but the ACR keeps both charged.

 

[sumocomputers]

Good tip on the ACR, did not realize such a thing existed. I might look at adding something like it, when I also spend the money on the CDI voltage regulator. I own this boat with 2 other guys, so I gotta be careful how I spend our money.

https://www.bluesea.com/products/7610/SI-ACR_Automatic_Charging_Relay_-_12_24V_DC_120A