Houseboat Electrical Rebuild

[tafische]

I purchased an old houseboat recently and want to redo the electrical to make it more modern. The boat will be docked in a slip with 120v 30 amp. Would you please give me any suggestions or errors in my proposed setup?

On the 12 Volt side -
- A dedicated battery on the outboard motor. The alternator on the outboard will charge the start battery and then once charged the isolator will send extra current to the house batteries to charge
- A dual output marine charger to charge both the motor battery and house battery
- Solar panels/charger that will go directly to the house batteries to add capacity while on the water

On the 120v side
- An input of either shore power or generator depending on the situation
- An inverter transfer switch with 30amp AC passthrough to keep the 120v side live all the time

I will also be wiring the battery charger to work only on when shore/generator is present so it doesn't loop when on the inverter.

 

[alldodge]

12V side
Unless your outboard is a newer modern ones, the motor will not be able to produce much current to charge both Bats. The isolator is a bad choice because it charges both Bats at same time, if you really want to go this route use a ACR auto charge relay

Never heard of a 12V to dual 12V charger, and again see see my first post

120V side
Shore power to AC/DC panel to AC side transfer switch
AC side breaker to 120V outlets and a 2-bank 120V Bat charger
Cable from Gen to Gen side transfer switch

 

[tafische]

12V side
Unless your outboard is a newer modern ones, the motor will not be able to produce much current to charge both Bats. The isolator is a bad choice because it charges both Bats at same time, if you really want to go this route use a ACR auto charge relay

Never heard of a 12V to dual 12V charger, and again see see my first post

120V side
Shore power to AC/DC panel to AC side transfer switch
AC side breaker to 120V outlets and a 2-bank 120V Bat charger
Cable from Gen to Gen side transfer switch

Thanks for the input!

It is an older 2 stroke but figure any extra charge should go to the house. I was looking at an isolator that only sends power to the house once the start batteries are charged. I see there are different types such as an ACR so I will research those further.

On the charger, it is a ProMariner charger with two distinct 12 volt charge outputs. As far as I understand it, this is made for this very purpose.

 

[cyclops222]

If you use dock 120 vac power ? All wiring will be to modern National Electrical Code standards.

 

[alldodge]

I was looking at an isolator that only sends power to the house once the start batteries are charged. I see there are different types such as an ACR so I will research those further.

That's not how a isolator works. An isolator is just high current diodes. Each standard diode has a 0.7V voltage drop across it. It does not distinguish between a good or bad battery, nor one that is full charged over half charged.

The ACR does do such things and has no voltage drop

 

[tafische]

That's not how a isolator works. An isolator is just high current diodes. Each standard diode has a 0.7V voltage drop across it. It does not distinguish between a good or bad battery, nor one that is full charged over half charged.

The ACR does do such things and has no voltage drop

What device do you recommend here? That is the purpose of the post. Trying to figure out exactly what devices to use.

 

[alldodge]

With a 2 stroke OB don't use anything, just not worth it

 

[cyclops222]

You have every electrical gadget drawn up to eventually be connected.
Get everything to work on paper first. Before buying anything.

 

[ESGWheel]

This sounds like a fun project and glad you are seeking guidance as these systems and the interconnection therein is not a simple matter. In addition to grounding requirements (AC, DC and AC to DC) there are also “isolation” requirements to preclude “Electric Shock Drowning”.

Suggest reading up on ACRs (here is a link that has a lot of good info) although as AD suggests the weak output of a 2-stoke motor may not be worth it. But at least this link will let you better understand how they work (vs an isolator).

Also please see this link on ESD. The preferred device these days from what I have read is to use an Isolation Transformer (IT) vs the older method of a Galvanic Isolator (GI). Both work but with a GI there is an issue of not knowing it is working unless periodically tested. Please read up on these devices to choose.

Other items to consider: polarization on the A/C side; your intended load on the AC side off the Inverter; wiring sizing and type, etc. Here is an excellent site with a lot of how-to info: link. I would also recommend getting Nigel’s book “Boatowners Mechanical and Electrical Manual”. It’s quite good.

For the solar aspect that adds in an element of control complexity. There are sites out there aplenty about adding solar. As a suggestion I would plan for that contingency but not try to tackle it until you have the AC and DC sides all set up and working as you want. Then, after a year or so, go for the solar > you may find that easier / better to add more batteries.

Please understand I am not trying to deter or alter your course. This is a great project and will be fun and satisfying. But as soon as you said “120V 30Amp shore power” in what sounds like a from an almost scratch start I wanted you to be aware it is not like wiring up your house.

Lots of good folks here that will help including myself but for me, I will need a lot more info to be able to. PM me if interested.

 

[tafische]

Absolutely great advice and thank you! That is what I was looking for. I plan to take it slow and work out a system that is both safe and works for me. Obviously I don’t have every detailed planned out in my crude drawing but just trying to get a start. Thanks guys!

 

[ESGWheel]

Absolutely great advice and thank you! That is what I was looking for. I plan to take it slow and work out a system that is both safe and works for me.

Sounds like off to a good start!

Here is what I am willing to do: I will commit to seeing your project thru to completion with an initial focus on getting the design done. I like to draw things and while I do not have the best methods, I get thru it. If you prefer to do it, that is fine as well. An example of my work due to helping another like yourself is attached for a sense of my diagrams. While I am not an ABYC certified electrician I know my way around circuits and have been studying at some length the ABYC requirements and other elements of shore power boat wiring. This does not mean I am an expert. There are many experts here that will help us along and at the end of it I will urge that an ABYC certified electrician review the design prior to installation. May cost you a few hundred but well worth it.

But I do have a few qualifiers / requirements of my own.

• I ask you to also see this to the end as well. It’s frustrating and not beneficial for anyone when someone posts an issue, gets lots of help and then disappears. Did it work? What was the resolution? Silence. If some force majeure or other reasons require you to postpone or drop the project a ‘conclusion’ post to that effect needs to be done so folks are not ‘hanging on’.
• While we will necessarily do a lot of communicating offline (via PM, etc.) to sort thru things, posting updates, challenges, solutions, and the like are necessary so that others may benefit as well from your project. Sharing is the core of this forum and I strongly believe in that.
• I tend to be verbose. This is due to in part my not knowing the knowledge and skills of others, so I tend to try to explain thoroughly, sometimes even to the extent of pointing out the obvious. It’s also just my nature. No offence is meant, and none should be taken.
• You will get homework assignments. These are intended to draw out your requirements or just help educate. The first two are below.
• Lastly, and this is non-negotiable, this needs to be fun. While it may be frustrating at times for both of us, if we are not having fun, we are doing something wrong and need to reset.

If you agree, here are first the 2 assignments:

1. Post the data of your boat and engine, so year, make model, etc. If you got a picture of it, please post that as well.
2. Private Message (PM) me with your vision of how you are going to use this Houseboat. Examples: Enjoying it tied up at the pier with the occasional 2 to 6 hr outing - or - Mostly underway but with no overnights unless at the dock with Shore Power - or - Just what? Please include those AC loads (TV, Microwave, etc.) you expect to be using while underway. From there we’ll do some of that back and forth offline and get it settled and then post the final result. This document will become the “need to design to” requirements.

Let’s go!