Help wrapping up solar setup.. Few Fuses and Gauge questions.

[Carl Wonderful]

Ammost done here, but cant figure out last few things to keep my setup safe and have peace of mind when I use and leave my boat.

1971 Catalina 22, with a 100 watt solar panel, 100 ah Li time lithium battery, MPPT victron 100/20 controller, 150 amp bus bars, and a (Giandel, pure sine wave) 600 watt inverter. No large draw appliances, just a bunch of lights and fans and inverter for recording music and using laptop and small stuff while I stay over on my little boat.

I drew a diagram to help see what I have so far. I labeled a few spots that I "think" I need a fuse or power switch or larger gauge wire...

-I think I still need a few large fuses (where and what size fuse?)and...
- a power cut off switch wired in.
- Also little unsure about where and when I need a heavier gauge (and what gauge) wire in my setup.
- also if anything looks wrong please help me right it.

Thanks a boat load.

 

[JoeWhite]

Nice fun diagram.
No fuse is needed between the solar panel and the mppt charger. But, you need a fuse from the output of the charger to the battery less than 20 AMPS.
The shunt goes on the negative lug of the battery then the other side of the shunt is connected to all the devices. The monitor is connected across the shunt to measure current in and out of the battery.
And yes you need 2 more fuses on the cables connected to the positive terminal of the battery.
100AH battery will not last long with 600 watt inverter turned on.
Try it when you are ashore.
Size of the cable to the bar, 00
Inverter, 10 AGW.

 

[...3TacksontheWater]

Basically looks good. I would encourage you to get the latest switch panel available:

Electrical Panel Master DC Kit, 7-1/2" x 5-1/4"

Catalina Direct, publishers of the Catalina 22 and Catalina 25 Owner's Handbooks and the largest supplier of parts and Lewmar winches for Catalina Yachts in the country

www.catalinadirect.com

Look up “Jim’s Little Boat“ on Youtube for his electrical upgrade video how to upgrade to this type of pannel. Getting this pannel will take care of your breakers/fuses. Breakers are far more convenient. Fuses blow. Literally. I also upgraded Waffle House’s electrical panel to this kit. I love it. You need to pick up a separate led battery monitor/USB outlets panel to meet your needs. In today‘s world you need both type A and USB C connectivity. I got my monitor/outlet kit off of Amazon. I did select one with a cigarette lighter adapter just in case that ever comes in handy.

Regarding ”your computer” videos, etc. I won’t bring a laptop on WH. The only work related meetings I’ve had on the boat were utilizing an iPad. Between making calls, reviewing emails and presentations, an iPad is lighter stores easier while underway, has downloaded movies and videos to watch in the evenings plus it has a much brighter screen and fantastic battery life compared to most all of my laptops. I may change my mind about this if I start to spend more time on the boat but as it is now, I would rather not bring a much heavier and more fragile laptop along for what is basically supposed to be a break away from the daily routine. lol

Here are a couple of pics of my electrical panel install but the USB outlet panel is having difficulty uploading:

 

[Carl Wonderful]

Nice fun diagram.
No fuse is needed between the solar panel and the mppt charger. But, you need a fuse from the output of the charger to the battery less than 20 AMPS.
The shunt goes on the negative lug of the battery then the other side of the shunt is connected to all the devices. The monitor is connected across the shunt to measure current in and out of the battery.
And yes you need 2 more fuses on the cables connected to the positive terminal of the battery.
100AH battery will not last long with 600 watt inverter turned on.
Try it when you are ashore.
Size of the cable to the bar, 00
Inverter, 10 AGW.

Thanks for the info Joe. I'm trying to understand the specifics of what you've mentioned but I'm still not sure about a few things. Is there any way you could do me a HUGE favor and edit/write a few notes on the diagram I posted.... showing the things you mentioned and where they go? OR maybe depending on what your device is maybe that would be difficult....
If that's the case.

- "But, you need a fuse from the output of the charger to the battery less than 20 AMPS" do you meant I need a fuse on the + and - between the charger and the batter, and those fuses need to be less than 20 amps?
-Shunt- I have it first up from from negative and then little positive from the shunt goes to the + of the battery. So the shunt is correct on my diagram, right?
-so a fuse on each of the 3 wires coming from the positive of the battery? (how big of fuses?)
- I will prob only be pulling 25 to 50 watts from the inverter most of the time, and will only need to do that for a few hours a night when I'm recording music. That 100 ah battery should be able to handle that, right?
-"cable to he bar" ... Does that mean the + and - cables fro mthe battery to the bus bars both need to be 00?

Sorry, I'm just totally stuck on these last few things and got all paranoid from watching videos saying how dangerous it can be if not done correctly with all the fuses and right size wires? Also everyone seems to do things a little different so its hard to know where to take the info from.

I want to be able to leave the boat and let the panel keep charging the battery and not worry about it.

Thanks!!

 

[east coaster]

I recommend you check out Pacific Yacht Systems for the best professional advice on what you are doing. Theny are great, answer questions and have many videos.

 

[rgranger]

Back (30+ years now) when I got the small sailboat restoration bug, I purchased this book

It is very easy to read.

 

[Carl Wonderful]

Back (30+ years now) when I got the small sailboat restoration bug, I purchased this book

View attachment 238107

It is very easy to read.

I do have that book. Its good. I also have a few others, but I guess I'm still just stuck on these last few specifics (of my little system) on fuses basically....

 

[AaronD]

ABYC 11.12.2.2 :'[Fuses shall] have a short circuit current rating that exceeds the system’s available fault current..."

I.e., you need to fuse the positive terminal with a fuse rated with an Ampere Interrupting Capacity (AIC) exceeding your battery's short-circuit current (which is much higher for Lithium batteries than lead-acid, as the internal resistance is much lower). That fuse must be within 7" of the positive terminal (longer if sheathed).

For larger banks that usually means a Class T fuse.

If your battery doesn't specify its fault current (or internal resistance, from which you can compute it), you can fall back to ABYC's table. For a 12v 100 Ah Lithium battery, that would be AIC >=5000; a good MRBF fuse should meet that 5k requirement, and it would mount directly on the terminal, making it easy to meet the 7" limit, so probably easier than Class T in your case.

Naturally, you'll want to go with the cheapest random-letter-sequence Amazon brand for fire safety equipment. yikes

 

[Stu Jackson]

I do have that book. Its good. I also have a few others, but I guess I'm still just stuck on these last few specifics (of my little system) on fuses basically....

https://d2pyqm2yd3fw2i.cloudfront.net/files/resources/reference/20010.pdf

 

[Carl Wonderful]

ABYC 11.12.2.2 :'[Fuses shall] have a short circuit current rating that exceeds the system’s available fault current..."

I.e., you need to fuse the positive terminal with a fuse rated with an Ampere Interrupting Capacity (AIC) exceeding your battery's short-circuit current (which is much higher for Lithium batteries than lead-acid, as the internal resistance is much lower). That fuse must be within 7" of the positive terminal (longer if sheathed).

For larger banks that usually means a Class T fuse.

If your battery doesn't specify its fault current (or internal resistance, from which you can compute it), you can fall back to ABYC's table. For a 12v 100 Ah Lithium battery, that would be AIC >=5000; a good MRBF fuse should meet that 5k requirement, and it would mount directly on the terminal, making it easy to meet the 7" limit, so probably easier than Class T in your case.

Naturally, you'll want to go with the cheapest random-letter-sequence Amazon brand for fire safety equipment. yikes

This is all still pretty foreign to me but...

Is this what I need? Or is this too big for my little system?

Or three is this one, but there's a ton of different amp ratings and volts and options?
Maybe someone can send me a link for what I need so I can stop bothering everyone, lol. I'm trying to understand but at this point all this fuse stuff is over my head and a lot of the terminology is just not making sense to me.

sorry to be such a noob here....

 

[Davidasailor26]

Is this what I need? Or is this too big for my little system?

That BlueSeas MRBF fuse block is the right idea. Note that what you linked is just the fuse block (though the picture shows a fuse in the block). You’ll also need the fuse that goes into the block, probably like one of these - https://www.westmarine.com/eaton-marine-rated-battery-fuses-P022185581.html. There are things that I buy off-brand from Amazon but fuses are not one of them.

Fuses generally have three associated ratings - amperage, voltage, and AIC. AIC needs to be more than the maximum amperage that your bank can provide in a dead short. For a single 100 AH lithium battery the AIC of the BlueSeas MRBF should be adequate. The Voltage rating needs to match or exceed the nominal voltage of your system. Since you’ll have a 12V system, not something exotic like 48V, you should be fine with any conventional fuse. The amperage rating is the tricky part. The amperage rating of the fuse must not exceed the maximum amperage of the wires it is protecting. Generally you’ll have a fuse in a fuse block like the one you linked on the battery terminal to protect the heavy gauge cables going to a distribution bus or circuit panel, and then smaller fuses to protect the smaller wires going to individual charging sources and consumers.

 

[Carl Wonderful]

So you're saying I should use 00 from the battery to the + bus bar. Do I also use 00 from the - bus bar to battery?... And 10 AGW from battery to inverter? Is this correct?

I'm surprised I will need 00 wires from battery to bus bars...I thought with my little system I wouldn't need to go near that large. 00 is some BIG wire! I also was thinking the wires to inverter would be larger than 10 AGW. Just checking that I got this straight.

 

[Davidasailor26]

So you're saying I should use 00 from the battery to the + bus bar. Do I also use 00 from the - bus bar to battery?... And 10 AGW from battery to inverter? Is this correct?

I'm surprised I will need 00 wires from battery to bus bars...I thought with my little system I wouldn't need to go near that large. 00 is some BIG wire! I also was thinking the wires to inverter would be larger than 10 AGW. Just checking that I got this straight.

Always start by figuring out your loads, then size the wires based on the loads, then size the fuses based on the wires.

You’ll have a 20 amp solar charge controller, 50 amp inverter, and figure 20 amp panel for the lights and fans and etcetera. You’re on a 22 foot boat so figure all your wire runs will be pretty short - maybe 10 foot round trip for the solar and inverter, and 20 foot round trip for the panel.

To figure out the wire gauges based on the above you can use a calculator like at ABYC Wire Size Calculator or a chart like at https://assets.bluesea.com/files/resources/newsletter/images/DC_wire_selection_chartlg.jpg.

From the loads you’ve described above and my interpretation of the charts - The run from your battery to a bus could carry up to 70 amps (inverter plus panel, if no solar is coming in). I’d probably use 2 AWG for that. Fuse that with the MRBF at, like 100 or 125 A. The table says you could get away with AWG 4 or 6, but why push it - this gives some room to grow. The run from the solar controller could safely be 12 AWG, fused at the bus bar at 25 amps. The run from the bus to the inverter could be 6 AWG, fused at 70 amps, and the run to the panel could be more 12 AWG fused at 25 amps. That should keep all of your voltage drops low and keep everything safely wired and fused. Use the same scheme for the ground side, minus the fuses.

 

[Carl Wonderful]

From the loads you’ve described above and my interpretation of the charts - The run from your battery to a bus could carry up to 70 amps (inverter plus panel, if no solar is coming in). I’d probably use 2 AWG for that. Fuse that with the MRBF at, like 100 or 125 A. The table says you could get away with AWG 4 or 6, but why push it - this gives some room to grow.

The run from the solar controller could safely be 12 AWG, fused at the bus bar at 25 amps. The run from the bus to the inverter could be 6 AWG, fused at 70 amps, and the run to the panel could be more 12 AWG fused at 25 amps. That should keep all of your voltage drops low and keep everything safely wired and fused. Use the same scheme for the ground side, minus the fuses.

https://www.amazon.com/HUAREW-Termi...-28-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9idGY&th=1

First off, thanks for the info and everyone helping me get this together and understand this all.

Will this 100 A, MRFB Fuse (and holder) work for me?

You said "The run from the solar controller could safely be 12 AWG, fused at the bus bar at 25 amps"... I thought the solar controller just runs to the main battery lug? Then I would have a separate run from the battery, to the bus bar? OR do I have that also wrong in my diagram from my original post? Man o man, I thought I was close and understanding this stuff.... but now I'm almost more confused as when I started.

I also thought I would run the inverter from the main battery lugs also (like in diagram)...[ I do have a 70 amp fuse for this already,, so that's a start]... But Is this also not a good way to do it? If anyone could link me to a diagram (similar to my particular setup) or something showing a visual of the correct way to hook all this up that would be SO Helpful! I'm a visual person I guess and its hard for me to put everything together.

 

[Davidasailor26]

Will this 100 A, MRFB Fuse (and holder) work for me?

That’s the right idea, but like I said above I’d be more comfortable with a name brand fuse like BlueSeas than whatever a Huarew is. Apply your own risk tolerance for off-brands, but a fuse is a pretty critical element.

Technically you can connect the positive for the solar controller and inverter directly to the battery (like your picture) or to the bus. The limitation is that you can’t have more than 4 connections to a battery lug. Less is better though - often it’ll be hard to connect 3 or more without putting excess tension on the lug. Since you have the bus bar anyway I’d just connect everything to that.

On the negative side, it’s very important that all loads and charging sources be connected to the load side of the shunt, otherwise the shunt won’t be accurate. You have this part wrong in your diagram - you show the inverter and controller bypassing the shunt by running straight to the battery. Those negatives should all go to the negative bus.

 

[Carl Wonderful]

The run from the solar controller could safely be 12 AWG, fused at the bus bar at 25 amps....

The run to the panel could be more 12 AWG fused at 25 amps.

Helped clear up a lot with these last responses. Just had a couple last questions....

"Fused at bus bar". How do I do that? Do I use something like a 25 amp MIDI fuse that connects to the lug on my bus bar that will run out to or from the controller and/or panel?

Lastly, for my Shunt.... Do I just run the little positive wire to any one of the lugs on the positive bus bar? [ I took the recommendation and will be using a bus bar insted of having 3 or 4 things all connecting to the battery terminal.]

 

[Carl Wonderful]

Anyone able to tell me the proper way to "fuse at the "bus" bar"? What type of fuse and where that fuse would go?

 

[Davidasailor26]

Any fuse of the right amperage will be fine there. For the charger and low amperage loads you could probably use an inline blade fuse. It might be hard to find an inline fuse rated for enough current for the inverter, but for that you could probably use a mega fuse or something like it.