Switched vs Unswitched Distribution on My Boat

[@robertduncan4612]

Jeff, I have been rewatching Pacific Yacht Systems' videos from several years back and find them so worthwhile. I hope that I have a more thorough understanding about boat electronics but it amazing how much I had forgotten over time. I took a lot of energy and commitment to produce these videos. I want to thank you for all of your efforts.

[@DaveAdams308]

Thanks again for the great info. Always watch and appreciate your efforts. 😊

[@ATL_Service]

Great video, and really well explained! Thanks Jeff

[@brucefay5126]

Nice video, good graphics and explanation. I really liked the quieter/calmer intro music.

[@PacificYachtSystems]

Thanks for the feedback, Bruce

[@theislandpackrat]

That was great, Love seeing a diagram!

[@PacificYachtSystems]

Glad you liked it!

[@robertschulke1596]

You are seriously up at 05:00 posting videos?! That’s dedication.

[@PacificYachtSystems]

Good one.

[@RuffieLego]

Cool video! Very interesting!!

[@PacificYachtSystems]

Thanks for watching!

[@billb48843]

Good Morning Jeff - kind of a self improvement question - I remember a blurb on a channel / reading / ? about ABYC cabling ends / lugs. Tin plated cable and lug (corrosion - OK), no depth hole in the wire end (water ingress and again for corrosion - OK), ??CLEAR heat shrink?? with adhesive for visually checking corrosion on the lugs / cable. Yet I see everyone using red / black to match the wire. I've looking and searched various standards (Personally I think that's a great practice). Then we get into bolts, washers, and lock washers. Back in my apprenticeship / journeyman (early to mid 70's) all of our heavy power connections (4/0 up into the 1000mcm range) many of the buss bolting was using silica-bronze lugs, bolts, nuts and "belleville" (cupped, disc spring) washers instead of split ring with the though being that rather than a "Point source load" at the split, the axial load disk spring gave a higher, more uniform loading over a greater area. Perhaps a whole topic about cable lugs, bolt ups etc - lol.

[@PacificYachtSystems]

Thanks for the comment, Bill. Will keep this in mind for future videos.

[@Biker1bob]

Been watching your videos. I dont see it shown here. I know from your other videos you like the Starter motor to not also be the alternator connection. So If I have a run from the battery to the Alternator unswitched - do I also run the starter motor unswitched? The fuse on the Alternator should be sized for the wire/output of the alternator. A Starter motor can pull 150amps.. so do I fuse that? Some have told me the starter motor is an unfused line.

[@neilb2793]

Thanks Jeff, I really like the diagram and helps me understand better. Begs the question where would an inverter /charger go?

[@wojciechoniszczuk4882]

To unswitched dist. Why? Anserw is result of addition: nverter can be allways connected to battery but charger cannot. Inverter&charger is a sum of two components i mean... 😃

[@MrBarstow]

You would put an inverter/charger going to the unswitched side, but with a disconnect in between for servicing the ac system.

[@MrBarstow]

kzbin.info/www/bejne/nYXMfZmNmK5jhM0 29:39 I think is the diagram

[@PacificYachtSystems]

Hi Neil, Inverter/chargers should always be fused at the source of un-switched distribution with a service disconnect installed near the inverter for service and emergency disconnect. Thanks for your comment

[@joesvec2268]

Jeff thanks! So I have 4 - 100 AH lithium batteries in parallel, plus a battery charger, and a MPPT solar controller they can all be hooked up to the busbar with no worries about a switch between any of these? Also when connecting each battery to the busbar can I share a terminal with these? Finally, does it matter what position on the busbar I connect each battery? In other words if I wasn't using a busbar I would need to hook the batteries together diagonally to insure balancing. Any concerns here with using a busbar? Thank you so much!

[@tomclause9555]

Thanks Jeff! That helped me as well.

[@PacificYachtSystems]

Thanks for the feedback, Tom

[@OneStepToEscape]

Thank you for the video. 1) In case i have a charger and inverter as one device (Victron Multiplus) how should i connect it ? Switched or Unswitched. 2) Mppt (solar controller) marked on the picture as unswitched device... In this case how it will be disconnected ? Definitely we need a possibility to disconnect it when leaving our boat alone for a long time. Everything probably should be disconnected from an electricity (battery) if you want to leave it for a long time... How it should be organized ?

[@PacificYachtSystems]

An inverter/charger should be connected to a dedicated switch connected to the unswitched side of the DC distribution. Disconnect the solar controller by removing the fuse in the circuit.

[@redwood1957]

Questions on the switches. #1 The switch before the inverter looks like a blue seas house or battery switch 12 v dc. #2 in most cases, don't you put a switch on the solar input that goes to the solar controller? Now if your solar panels are fused at the solar panel what is a switch that meets abyc to interrupt the solar in? some are using battery switches some are using solar switches that are used in residential cases. thanks Mike

[@anthony445]

i believe you want a PV isolator switch or a DC disconnect 2 pole.. whatever you get you need to switch both positive and negative leads from solar panel to charge controller.

[@mickekciht9188]

If I have a starter battery, where does it go in your diagram?

[@ninoadp100]

Great display an explanation

[@PacificYachtSystems]

Glad you like it.

[@rbourgon]

Bonjour Jeff. In the diagram, I don't see a fuse between the unswitched bus bar and the switch or one between the switch and the switched bus bar. I'd be tempted to put one close to the unswitched bus bar to protect the cables/switch going to the switched bus bar. Does that makes sense? If not, please explain. Thanks for sharing...always super helpful. Merci 😉

[@MrBarstow]

My guess would be since all the powers going into the unswitched bar are fused then it's unnecessary. For instance if your running on the battery and the wire past the switch gets shorted, then the fuse on the battery would blow. The main thing to look for would be transitions to smaller wires that cannot handle the load of the larger wires and fuses. Just my thoughts

[@MrBarstow]

I've been thinking about this all day and the only hangup I have is, let's say all the wires are rated for 100 amps with 80 amp fuses and charger inputs to the bus at a max of 80 a piece. Could the wire dead short just enough to pull 60 amps evenly through the chargers, but for a total of 120 amps, frying the second wire but not frying the first two wires or tripping the breakers. This is purely hypothetical because I think the likelihood is practically zero, but it's an interesting though experiment. Unless it would cause a voltage drop increasing the output of the chargers till they pop the fuses.

[@PacificYachtSystems]

Good eye Richard, all cables need to be fused at the source of power, in this case the battery terminal. Depending on the length of your run an additional fuse could be added between the un-switched and switched distribution for protection of the cable. Thanks for the comment

[@MrBarstow]

@@PacificYachtSystems awesome response, thank you for clarifying.

[@Boat_FishingDoduJeju]

Thanks.

[@PacificYachtSystems]

Glad you like it!

[@unwin42]

You mentioned it being different for an inverter+charger (like a Victron Multiplus). Would that get connected to the unstitched distribution side with its service disconnect switch?

[@koffibanan3099]

kzbin.info/www/bejne/hKe2Yp-MZdGbgKc

[@MrBarstow]

Yes. kzbin.info/www/bejne/nYXMfZmNmK5jhM0 The diagram is at 29:39.

[@PacificYachtSystems]

Hi Joshua, that’s right. Inverter/chargers should always be fused at the source of un-switched distribution with a service disconnect installed near the inverter for service and emergency disconnect. Thanks for your comment

[@philippedubois4462]

Hi, great videos! Preparing myself to redo the electrical system on my sailboat, I was wondering how many wires can be put on a single screw in à terminal Block connected to the distribution panel and how would you connect 2/3 instruments on the same screw . Thanks

[@PacificYachtSystems]

Max of 4 connections per terminal.

[@Captain-Paul]

Why do items on the unswitched distribution side not draw power from the battery charger (when it is charging) & ‘steal’ it from charging the batteries?

[@PacificYachtSystems]

Hi Paul, yes the loads on any battery, including the switched or non-switched distribution are effectively powered by a charger when the battery charger is running.

[@bobhamilton298]

I have a Blue Sea 5511E Dual Circuit Plus switch with SI-ACR and their diagram shows the positive return from the engine (alternator or starter) connects to the top switch terminal. So there is a switch between the battery and the engine. Does this go against what you said in this video?

[@PacificYachtSystems]

Thanks for your comment Bob, service switches are required between a battery and engine for safety and care should be taken that they are left in the on position when running if alternator output is not separated.

[@constanzo84]

Great stuff! May I ask what software you use for making these diagrams?

[@PacificYachtSystems]

Microsoft visio.

[@seanrhone5306]

Diagrams make a HUGE difference, at least to people like me.

[@PacificYachtSystems]

We totally agree, visuals always help conceptualize the full picture

[@uvahooful]

In your diagram you show all unswitched connections to the HOUSE battery… is that accurate?

[@MrBarstow]

That is accurate. Your start battery is on its own circuit and charges with the motor.

[@PacificYachtSystems]

Yep.

[@besearchingforwisdom6267]

I'll keep a switch added to the "unswitched" circuits and leave it on and have it designated for emergency disconnect only.

[@alexsails80]

That was my thought also. When work needs to be done to the always On/"un switched side" it would be nice to just flip a switch to Off instead of having to disconnect wires and battery cables. Jeff, Any thoughts on this?

[@besearchingforwisdom6267]

@@alexsails80 He showed it in a video a couple years ago and I thought it made sense. kzbin.info/www/bejne/nYXMfZmNmK5jhM0

[@PacificYachtSystems]

Thanks for the comment, we find best practice is to not have a switch, this avoids potential mishaps incase critical loads are left disconnected

[@javierbetancourt9388]

💯

[@PacificYachtSystems]

Thanks Javier.

[@kikiwak]

Hi Jeff. Great video! I have a question about fusing, in particular my Victron MultiPlus inverter/charger. The manufacturer recommends a 400A Class-T fuse for the inverter/charger. My inverter charger is connected to a service disconnect, then the un-switched distribution, and finally on to the house battery bank. My question is, in your various diagrams you show two fuses in this scenario. One at the battery, and one at the un-switched distribution point. Where should my Class-T fuse be? Battery or un-switched dist? And what type and size of fuse should I use for the second location? Example: kzbin.info/www/bejne/h6aXaYuJhsxmpc0

[@PacificYachtSystems]

Your inverter/charger class T fuse should be connected at the positive unswitched distribution. Make sure the fuse between the battery and unswitched dc distribution can handle all the simultaneous loads (e.g. inverter + windlass + DC panel).

[@alcibiadesmarcialneto922]

I think unswitched loads must be shown separated from the switched ones. The provided diagram doesn't show them.

[@PacificYachtSystems]

Sorry for the confusion, in the attached schematic, the unswitched (always on) circuits are on the left and the switched loads are on the right.

[@alcibiadesmarcialneto922]

@@PacificYachtSystems yes, this is very clear to me, but on the left it looks like there are only power sources, there is a “fuse block” that can be or not to supply the unswitched loads.