Main Fuse on Battery

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fallguy1000
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Re: Main Fuse on Battery

Post by fallguy1000 »

jonnymac wrote: Mon Dec 20, 2021 4:42 am once again, jumper cables don’t need protection because you are standing there when they are in use. be careful with that analogy.

remote what? and what does ACR stand for?
fallguy1000 wrote: Sun Dec 19, 2021 9:00 pm
jonnymac wrote: Sun Dec 19, 2021 8:53 pm There two different situations the wire going from the battery to the starter can have problems. one is during starting when starting current is running through it. a properly sized wire is going to be fine because either the starter will die or the battery will run out if juice before you really need to worry about the wire.

the second is when its just sitting there with battery voltage applied with the full potential of the battery available for damage through that thick cable. this is the situation you would want a fuse or breaker. when you aren’t on the boat or paying attention and there is a problem. a fuse or breaker keeps your boat from burning down. a battery disconnect switch might be a better option here as you get all the protection, and better reliability.
I have four remotes on the Skoota and one ACR. ACR instructions say, do not fuse! Basically, it'd be like fusing jumper cables.

The other thing about the remotes is you can hide them a bit AND lock them out so they cannot be remotely triggered. So a wpuld be thief tries to flip the remote switch and it fails. Then he decides to seek the remote if he is smart enough to even anticipate it is being used as a lockout device, and that takes considerable time to hunt or trace starter wires. My starter remotes are behind locked doors, so first they have to break open the doors.
Remote battery switches.- disconnects. I can disconnect all 3 of my start banks and I can disconnect all charging sources.

ACR is automatic charge relay; a device which allows separate banks to support each other, like jumper cables with a switch..
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fallguy1000
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Re: Main Fuse on Battery

Post by fallguy1000 »

I took a quick look at the wiring diagram and there is one major issue I don't like.

If you leave any of the console stuff on; then your not going to start. And this is a no-no for seagoing vessels.

How do we eliminate that? Put all loads behind a switch, or relays that only work when the engine key is forward.

On the Skoota, I am using the switch method.

But this should be the first thing you do is protect your starter battery from all those loads or especially one load being left on. A few of my devices turn on when power is on, or stay in last state.

Get rid of the 200 amp fuse.

Install the switch so it must be on to power the bus and fuse block both sides of the boat. So the switch connects to the battery switch unfused. Two cables come off the load side of the switch.

Run one cable to a 4 post power bus and rate it for 90amps with a mrbf on the bus and 4 gaige wire. Run the other cable off to the starter unfused with a heavy enough cable like 2/0 to 2 gauge to your power post for the starter cables.

Then from the power bus run another wire back to the transom fuse block with a 30 amp mrbf fuse and 8 gauge wire. And same for the front fuse block.

Clear as mud?

You really want the starter load isolated from the other stuff.

Now, the one caution here is this...you have a lot of load coming from your start battery. And this can leave you stranded. How? Well, you flip the battery switch and have a couple pump switches on and they start pulling loads before you start, or you turn off the engine, but leave the tunas running. All a very bad approach. There is a much better way, but it requires a second battery. Basically, you have a 'house' battery and a start battery. And you only allow the house battery ti be charged by the starter engine key forward. This costs more, but is much safer. The charging is controlled by an acr. Another benefit to this method is the house battery can support a failed start battery at sea. None of the loads are managed off the start batteries.
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fallguy1000
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Re: Main Fuse on Battery

Post by fallguy1000 »

Here is an acr better explained. They show an AC charger on the house bank and don't show the loads, but you'll get the basic concept. The outboard does charge the house bank with engine on signaling.

By the way, my ACR is not used this way. Mine is setup more like a jumper cable. If I see low power on one start battery, I can combine them. But this drawingnis conventional acr and done to protect the starting battery for vessels where it might be dangerous to discharge, like drifting out to sea..or getting caught in real rough seas or cold weathers.

https://www.bluesea.com/resources/578/S ... 20A_SI_ACR
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OrangeQuest
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Re: Main Fuse on Battery

Post by OrangeQuest »

Here is a lot of especially useful information on electrical systems for boat and marine applications.
https://www.bluesea.com/support/article ... ing_Relays
They have a lot of info on selecting wire, fuses and other things that get you to spend money but protect you boat and a trouble-free electrical system for your boat.
"that it isn't just an ordinary sort of boat. Sometimes it's a Boat, and sometimes it's more of an Accident. It all depends." "Depends on what?" "On whether I'm on the top of it or underneath it."
A. A. Milne

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Re: Main Fuse on Battery

Post by TomTom »

fallguy1000 wrote: Mon Dec 20, 2021 7:59 am I took a quick look at the wiring diagram and there is one major issue I don't like.

If you leave any of the console stuff on; then your not going to start. And this is a no-no for seagoing vessels
I don’t understand this - do you mean when I am on the boat if I try and start and I don’t switch off the GPS, VHF, Tuna tubes etc, they will draw so much current that there isn’t enough for the engine?

Or do you mean that if I forget to switch off the “Battery Cut Off Switch” for a few days whilst I am away they will drain the battery?

fallguy1000
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Re: Main Fuse on Battery

Post by fallguy1000 »

The way you drew it; anything can be left on and draw the batteries down.

So, say you are drift fishing and leave on the fishfinder and the tuna tanks and a livewell circ pump and nav lights, etc. You can draw the single battery down too low to crank.

I am not worried about the on dock issues.

I will mention, my Raymarine Dragonfly turns itself on when I turn the battery switch from off to on.
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fallguy1000
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Re: Main Fuse on Battery

Post by fallguy1000 »

You can add this device as well to make sure it never happens which is less cost.

All your non-engine loads go theough this. So you mrbf the 90amp fuse to this and then this goes to your power bus. Then if suddenly your tuba tubes and fishfinder shut off; you know you need to start the engine.

https://www.victronenergy.com/battery_p ... ry-protect
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Re: Main Fuse on Battery

Post by TomTom »

fallguy1000 wrote: Mon Dec 20, 2021 3:00 pm The way you drew it; anything can be left on and draw the batteries down.

So, say you are drift fishing and leave on the fishfinder and the tuna tanks and a livewell circ pump and nav lights, etc. You can draw the single battery down too low to crank.

I am not worried about the on dock issues.

I will mention, my Raymarine Dragonfly turns itself on when I turn the battery switch from off to on.
Ok - I understand now. Thanks for your help and the Victron energy looks interesting.

I always carry a Booster Pack/ Jumper pack with me on the boat - but it would be a useful addition for sure.

Other than the risk of flattening the one battery do you see anything else inherently dangerous/ bad with my diagram?

fallguy1000
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Re: Main Fuse on Battery

Post by fallguy1000 »

Well, like I said. No to the 200 amp fuse.

And the non-starter loads need to be coming from same place. It would be odd to run the transom loads from the power post at the transom and difficult to fuse nicely, so I'd run a power bus at the console and keep some 30 amp mrbf on hand. And a fuse block at each place. Then if your tubes suck a bait and throw a fuse; you can quickly find the fuse block and fix the clog and be back on in a jiffy. Then the only loads on the heavy wire are for starting.
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fallguy1000
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Re: Main Fuse on Battery

Post by fallguy1000 »

You can make a common bus at the transom. Then all your negatives will come back via the heavy wire. But run a solo 8/10 wire from the power bus to the fuse block at the transom.


I can draw it later if u need more help or you can redraw and I will edit.

Wiring diagrams can be 2 dimensional.
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