Strange solar/electrical setup on new boat

[Stanleywester]

Have an interesting electrical setup on a new-to-me vessel which I'm trying to figure out. It doesn't seem "normal" but it is workable. I'm just trying to understand why it might have been done this way and what good reasons there might be for it.

(disregard the propane detector as drawn, it's only connected to one battery)

Always true:
- Solar always charges Engine battery
- House always draws from house battery
- I neglected to draw the alternator output, but I believe it's to the "F" (common) terminal of the battery switch

When battery switch is set to position #1
- Solar charges only engine batt
- Engine starts from house batt
- House draws from house batt

When battery switch is set to position #2
- Solar charges only engine batt
- Engine starts from engine batt
- House draws from house batt

When battery switch is set to position BOTH
- Solar charges both batts
- Engine starts from both batts
- House draws from both batts

When battery switch is set to position OFF
- Solar charges only engine batt
- Engine can't start
- House draws from house batt

Aside from the obvious issues that can be corrected easily (missing fuses etc), I'm mostly curious if this is a typical way of doing battery switching in marine electrical with solar. Seems odd to me, but I'm not well versed in marine electrical.

 

[dlochner]

Well, it's not the way I'd wire things.

Basically he wired the switch to simply select which battery to start the engine or not start it all. There are better ways to skin the cat. Is this on the Cat 22 or a larger boat?

The best place to start your education on all things marine electrical is the Marine How To site. There is an article specifically addressing the 1-2-B switch, well worth the read and study so you can gain insight into how the switch should be wired and used and other ways to manage your batteries. Head there and start studying.

Marine How To - DIY for Boaters - Marine How To

For DIY boaters in an attempt to try and keep the sport as affordable & safe as possible. How To articles for sailboats and powerboats.

www.marinehowto.com

 

[Stanleywester]

Well, it's not the way I'd wire things.

Basically he wired the switch to simply select which battery to start the engine or not start it all. There are better ways to skin the cat. Is this on the Cat 22 or a larger boat?

The best place to start your education on all things marine electrical is the Marine How To site. There is an article specifically addressing the 1-2-B switch, well worth the read and study so you can gain insight into how the switch should be wired and used and other ways to manage your batteries. Head there and start studying.

Bigger boat, Bayfield 32.

I've read it, and I just re-read it. That all makes sense. I'm electrically inclined, and all of the MarineHowTo solutions make sense. He does not show this setup though, doesn't even hint at a situation or reason for putting the house loads on any terminal except common, nor why a charge source (solar) would be on any terminal except common (except in his L3 upgrade note, which is also not my configuration). I'm still curious if there's some genius behind how this was done, or if it was just a PO having lack of electrical knowledge.

 

[Davidasailor26]

I'm still curious if there's some genius behind how this was done, or if it was just a PO having lack of electrical knowledge.

The unusual configuration combined with the lack of proper fusing makes me lean toward the latter.

Why he set it up that way is anyone’s guess. I’m thinking he had problems starting the engine at some point and overcompensated by putting all the solar to that bank.

 

[dlochner]

As the saying goes, "he had a better idea?"

Some very general principles for design:

1. All charging sources, alternator, solar, inverter/charger are best installed to charge the house batteries first.
2. Engine start batteries can be charged from the house bank by an ACR or DC-DC charger. Engine starting requires a lot of energy for very short time, the actual consumption is pretty small on the order of 1 amp hour. It will recharge quickly.
3. It should be easy to isolate each battery bank, a single on/off switch on the DC- of each battery will do the trick.
4. It should be possible to start the engine or run essential nav and com circuits off of either battery. A Blue Sea Dual Circuit Plus switch does this nicely.

As with any principles there can be exceptions, but we don't need to get into the weeds of that right now. Think about your needs and plans and begin to design a system that will meet your needs and plans. And don't forget ABYC standard E-11.

There's another thread here where a guy is redesigning his electric system, there may be helpful information in that thread.

 

[jssailem]

Stan, sometimes it is complicated trying to figure out why a former owner wired the boat the way he did. You indicated the boat is a Bayliner. The original builder's reputation is mixed. Perhaps the former owner wanted to make changes with marginal knowledge (solar was not a Bayliner original equipment).

If you seek a way to build a safe, simple system, I would review MaineSail's material and choose a refit that follows his guidelines. If there are additions that you would like, then post what you have done and let us know the changes you want to make. That way, we can help with specific steps that complement your plan.

Here is one design by MaineSail that may work as your base.

Building a DC Electrical Foundation

Every boats DC electrical system needs to start with a solid foundation. The foundation of any electrical system includes the battery system, charging system, switching and all the associated wiring and over-current protection. This was a simple design I did for a boat the owner had already...

forums.sailboatowners.com

 

[Stanleywester]

Thank you all kindly for the thoughtful input. Very much appreciated.

It's a Bayfield (Gozzard), not a bayliner; but even so doubtful anything is original except one of the house fuse panels. I have no gaps in understanding how to turn it into the exact electrical system that I want (I do DC and AC electronic design for a living). I think that number of responses here all lacking of any suggestion that there was some clever design or ABYC standard being adhered to is my answer. That is, it's indeed just a weird design with no secret genius behind it.

 

[dlochner]

ABYC standards are expensive to access, unless, you join ABYC as a Recreational Boater for 5 days free. Once your membership is accepted you will have full access to the ABYC Standards and can read them and save them if you are tech savvy. Much cheaper than buying the $500 manual or $200 membership.

At the boat show I was talking to one of the VPs of ABYC, they are trying to balance the organization's budgetary needs with getting more DIYers to have access to the standards. Their goal is safe and enjoyable boats.

 

[jssailem]

OK.
I found a reference to the Bayfield. Built in Ontario CA. It is reported to be a 30/32, depending on how you want to describe the LOA.

Does the boat have the Yanmar 2 or 3 cylinder auxiliary? With a reported draft of 1.14m (3.75ft), you can sneak into anchorages others will avoid. Is it the Cutter or Ketch rigged boat?

What caused you to decide this is the boat I have been waiting to own?

 

[Indysailor]

Thank you all kindly for the thoughtful input. Very much appreciated.

It's a Bayfield (Gozzard), not a bayliner; but even so doubtful anything is original except one of the house fuse panels. I have no gaps in understanding how to turn it into the exact electrical system that I want (I do DC and AC electronic design for a living). I think that number of responses here all lacking of any suggestion that there was some clever design or ABYC standard being adhered to is my answer. That is, it's indeed just a weird design with no secret genius behind it.

I hope you will follow up with your design diagram. I have some oddities about the house/engine bank solar charging a previous owner installed on my boat and am considering ways to improve it.

 

[Stanleywester]

OK.
I found a reference to the Bayfield. Built in Ontario CA. It is reported to be a 30/32, depending on how you want to describe the LOA.

Does the boat have the Yanmar 2 or 3 cylinder auxiliary? With a reported draft of 1.14m (3.75ft), you can sneak into anchorages others will avoid. Is it the Cutter or Ketch rigged boat?

What caused you to decide this is the boat I have been waiting to own?

Aux is 2cyl yanmar. Cutter rig. Many factors

 

[Scott T-Bird]

I can't tell from the diagram how anything is wired since you don't indicate any + or - posts as far as I can see. That said, it appears that 2 batteries are wired in parallel and it also appears that you have the ubiquitous 1+2+B switch. That all means that you don't have a separate "engine" battery and "house" battery. You simply have one battery bank consisting of 2 combined batteries at 12V. What you don't have (or show) is an auxiliary battery or a dedicated start battery.

I don't know anything about the propane detectors, but you seem to show a positive lead thru the detectors that also connects directly to the house panels. So, that appears to be why you have power at the panels even while the switch is off. You can't start your engine because the starter is connected to the common output post.

This set-up is FUBAR and you should go about correcting it. If you want a dedicated start battery, I would remove the switch that you have and install either a DCP switch or 2 separate on- off switches. The way yours is connected, you just have one battery bank and NOT 2 separate batteries.

 

[Stanleywester]

I can't tell from the diagram how anything is wired since you don't indicate any + or - posts as far as I can see. That said, it appears that 2 batteries are wired in parallel and it also appears that you have the ubiquitous 1+2+B switch. That all means that you don't have a separate "engine" battery and "house" battery. You simply have one battery bank consisting of 2 combined batteries at 12V. What you don't have (or show) is an auxiliary battery or a dedicated start battery.

I don't know anything about the propane detectors, but you seem to show a positive lead thru the detectors that also connects directly to the house panels. So, that appears to be why you have power at the panels even while the switch is off. You can't start your engine because the starter is connected to the common output post.

This set-up is FUBAR and you should go about correcting it. If you want a dedicated start battery, I would remove the switch that you have and install either a DCP switch or 2 separate on- off switches. The way yours is connected, you just have one battery bank and NOT 2 separate batteries.

Generally when drawing a wiring diagram, you only draw positive wires, and any device that's grounded you just show it connected to a ground symbol nearby. You can see the grounds in the CCT diagram. Batt grounds are common but batt positives are not common except when switch is set to both. You may need to zoom in but battery lines do show pos/neg symbols. As I noted in OP, the propane was drawn in error, it's only connected to house battery (and grounded). I'm not sure why you think I can't start my engine.. everything is working perfectly. Just a very strange configuration of the switch. The house always has power because it's directly connected to the house battery. As OP, I was simply trying to assess whether there was some brilliance in this configuration which I had overlooked in assuming it was just wonky.

 

[Scott T-Bird]

I'm not following "CCT" - what's that? I don't see battery posts labeled, but there does seem to be an odd connection between the 2 batts that I can't follow what it is. To me, it looks like it is wired in parallel but then I also see a lead from Batt 2 to Post 2 on the switch. That's confusing ... are the 2 batts connected with a positive cable or not? Or is that a negative cable? It doesn't make sense with neg cables leading from the ends of the batteries. I didn't say you can't start your engine. I only said you can't start when switch is off - and that's normal. Why your panels stay powered when the switch is off makes no sense (you say "House draws from house batt" when the switch is off). There is no brilliance in this diagram - only mistakes.

 

[dlochner]

I'm not following "CCT" - what's that? I don't see battery posts labeled, but there does seem to be an odd connection between the 2 batts that I can't follow what it is. To me, it looks like it is wired in parallel but then I also see a lead from Batt 2 to Post 2 on the switch. That's confusing ... are the 2 batts connected with a positive cable or not? Or is that a negative cable? It doesn't make sense with neg cables leading from the ends of the batteries. I didn't say you can't start your engine. I only said you can't start when switch is off - and that's normal. Why your panels stay powered when the switch is off makes no sense (you say "House draws from house batt" when the switch is off). There is no brilliance in this diagram - only mistakes.

Basically, there are 2 types of DC wiring schematics, a single wire and a two wire drawing. The single wire drawing will only show the the DC+ because that is the most important part of the circuit and eliminating the DC- wires makes the schematic easier to understand. Eliminating the DC- also allows the drawing to be better organized with the major components clearly separated and isolated on the paper. In more complex systems this allows for easier understanding of each system component.

Two wire drawings are used with it is time to actually install the system. It is at this point the location of DC- Busbars becomes important. Where and how the DC-s are connected is in large part dictated by the physical structure of the boat. One could also draw single wire DC- schematic which would make the document easier to read.

As for the OP's drawing of the battery connections, one post on each battery is clearly connected to ground (DC-). Since there are only 2 posts on a battery, the other post must be a DC+. This is just standard convention.

 

[Scott T-Bird]

As for the OP's drawing of the battery connections, one post on each battery is clearly connected to ground (DC-). Since there are only 2 posts on a battery, the other post must be a DC+. This is just standard convention.

I don't see any posts labeled. I see 2 leads from the left side of the batteries (one lead from each battery) that appear to be neg because they connect to ground. I see 2 leads (from the top of Batt 2 and right side of Batt 1) that appear to be positive. And I see a lead in the middle connecting the 2 batts. I now suppose that the little marks indicate negative but I didn't notice the 2 little marks previously and it appeared like they would possibly be connected to + posts (which are not shown). I suppose this means that the negative posts are connected. I don't see any posts marked on the batteries. This is very confusing and not standard convention at all. I'm well aware that many batteries have the posts on opposite ends of the battery and some have both posts opposite each other on a short end of the battery. With leads coming off every conceivable position on the batteries, no posts shown, and scratched-out markings, it is just a very sloppy diagram and there is nothing conventional about it.

And why would somebody draw 2 separate leads to ground (one from each battery) and also show negative posts connected? What could possibly be making sense here?

 

[Scott T-Bird]

Also, the original post appears to say that when the switch is turned to OFF, House <panel> draws <power> <directly> from house batt

Why would that be? The diagram appears to show a positive linkage from the battery to the panel thru the propane detector. I don't know how these things work, and OP says the diagram for the propane detector is incorrect anyway. So how is anybody supposed to make any sense over this?

My observation is that the installation appears to be FUBAR, the diagram is FUBAR and there is no confidence that the diagram even represents the installation. It's all FUBAR. Time to start from scratch ...

 

[dlochner]

This is very confusing and not standard convention at all.

Attached is an excerpt from a much larger and more complex electrical schematic drawn by a professional marine electrical engineer. Notice the absence of negative wires from the batteries. Single wire drawings are acceptable. On this particular schematic there are negative wires shown where their connections are critical to the system. The OPs drawing is more of sketch and really shouldn't be held to standards maintained by professionals.

Others on this thread are not experiencing the difficulty you seem to be having understanding the drawing. I"m sorry that you are having that difficulty, however, your criticism is a bit over done and antagonistic.

 

[BAD ORCA]

Also, OP i believe that the 50Amp breaker is on the wrong side of the charge controller. From my understanding it should be between the solar panels and the charge controller, not between the charge controller and the batteries. I believe the reasoning is that if you disconnect the loads after the controller, the panels are still producing current and this current if turned off after the controller has nowhere to go and can damage the charge controllers.

And, it should be a dual pole disconnect like one of these...

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www.amazon.com

My best guess is that maybe this boat was once on a mooring and the PO wanted to make sure the engine batteries were always charged and topped up full for starting and to keep the bilge pump powered? If my boat was on a mooring I might consider having a small 50 watt panel connected to start battery full time and a larger array to my house. Maybe just a simple solution implemented by PO to prioritize the starting bank? If so, certainly not the best approach but not everyone has lots of electrical knowledge or is up to speed on new devices/best practice.

 

[dlochner]

Also, OP i believe that the 50Amp breaker is on the wrong side of the charge controller. From my understanding it should be between the solar panels and the charge controller, not between the charge controller and the batteries. I believe the reasoning is that if you disconnect the loads after the controller, the panels are still producing current and this current if turned off after the controller has nowhere to go and can damage the charge controllers.

And, it should be a dual pole disconnect like one of these...

Loading…

www.amazon.com

This is not a settled question in the world of marine solar systems. The reasoning you present, the panels produce power even with the controller disconnected is sound, especially in high voltage high current systems. In smaller systems with perhaps one panel it may not be necessary. If one is installed, it need only protect the positive side, a double breaker does not add any additional protection. I did not install any circuit protection between the panels and controller.

There is considerably less controversy about circuit protection between the DC+ bus bar or battery and the controller. ABYC is quite clear that all circuits connected to an unregulated power source have circuit protection sized to protect the smallest wire downstream from the circuit protection device (fuse or circuit breakers). A battery is an unregulated power source because in a direct short between DC- and DC+ the full capacity of the battery can pass through the short, which can be hundreds of amps. Alternators, solar panels, and battery chargers are regulated power sources. The amount of current they can provide in a direct short is limited by the capacity of the device. A 100 watt solar panel can not produce more than 100 watts which is about 4-5 amps @ 20-25v. Cabling can be used that can handle that load even in a direct short.

Perhaps the strongest reason to including a switch of some sort on the DC+ from the panel is for servicing the controller. Some controllers, like Victrons, have a specified order of connection, i.e., the controller must be powered up and connected to the battery (or DC+ bus) before receiving current from the panels. There a ways to accomplish this with blankets over the panel, disconnecting one of the panel leads, or waiting until nightfall. I"ve done all three. A switch would be more convenient.