Electrical gremlins - need help figuring things out.

[George_SD]

On a few recent trips that are only 4-5 hours long, I would get a low voltage alarm. This was happening with minimal electricity use (depth and speed transducer + single display for both).

Today, I needed to look into wiring power for the autopilot and decided to test my power disconnects. I have 3 of them
- negative disconnect
- positive disconnect (engine battery - Group 29 flooded)
- positive disconnect (house battery - Group 29 flooded - brand new)

As I understand:
- negative is supposed to disconnect everything by opening the circuit on DC circuit for both - house and engine.
- positive Engine - should connect or disconnect engine battery from the DC circuit
- positive House - should connect or disconnect house battery from DC circuit.

In essence - i can run on engine, house or both.

Well, here is where the gremlins come in.

I have a volt-meter built into 12v DC panel. I've seen other boats with the same panel show that the tester switch being used to check either of the batteries (my boat's manual is silent on this).

UP - engine battery test
Center - OFF
Down - house battery test

So I've started putting all disconnects to off and looking at what the battery/volt meter shows. Shore power is OFF at the shore and on 110v panel for all these tests. Everything on 12v DC panel is OFF as well.


--- Test 1 ----
Negative - OFF (disconnected)
Engine - OFF
House - OFF

Tester
UP (engine) = no reading
Down (house) = ~4v-4.5v

--- Test 2 ----
Negative - ON (connected)
Engine - OFF
House - OFF

Tester
UP (engine) = no reading
Down (house) =~ 12.6v

--- Test 3 ----
Negative - ON
Engine - ON
House - OFF

Tester
UP (engine) = 12.5
Down (house) = 12.6

--- Test 4 ----
Negative - ON
Engine - OFF
House - ON

Tester
UP (engine) = 12.7
Down (house) = 12.6

List of 12v electrical equipment
- bilge pump
- speed/depth transducers and single display, stereo, vhf
- fridge
- nav/anchor/steaming lights
- cabin lights
- macerator
- freshwater pump
- gas valve


List of 110v/shore power
- AC main switch
- charger
- water heater
- outlets

Questions

1) With all three disconnected - negative and both positives, I think it should be giving me 0, not 4.5v. How is it even possible with everything disconnected to show me voltage and a strange low reading at that?! What could possibly feed it?

2) With negative enabled, but both battery disconnects off - it should be showing 0 for both, right?

3) does this seem to indicate that at least my house disconnect is not really disconnecting?

[George_SD]

Can't find a way to edit the post, so here is more information.

This is a schematic of how batteries are supposed to be wired according to Beneteau. T1 going to the engine battery positive disconnect is labeled as "ENGINE BATTERY TEST", but there is nothing about the switch being bidirectional and it being able to read house battery.




WAGO block layout



12v panel layout



By the way - I was hoping to use the "SPARE" breaker for wiring up the autopilot (since it can be a significant drain, I would rather isolate it so I can flip a switch and remove all associated draw/loads).


I'll be honest - i haven't figured out how the WAGO block works yet and don't understand it to the point where i can work with it. Reading up on this right now.

From left to right:
- Negative (black cables)
- Positive feed (from batteries?)
- Positive individual loads on quick-connect aggregated plugs.

What I don't understand:

1) what are those rectangular and square plugs in the middle of the WAGO strip.

2) My assumption was that each quick-connect block should lead to a single breaker, but I don't think that's the case.

3) I thought perhaps wires on the top and wires on the bottom should correspond as if the WAGO block connects top wire to the bottom wire? Clearly that's not the case as some on top and bottom don't have a pair?

[redwood1957]

Sounds like you have a ground.

[George_SD]

Update on my knowledge.

Originally Posted by George_SD

1) what are those rectangular and square plugs in the middle of the WAGO strip.
-- Looks like they are used to "group" loads and then i assume they all go to a single breaker. Looks like the lead to the breaker/panel is on the left in the schematics and on the bottom on the actual wago strip.


2) My assumption was that each quick-connect block should lead to a single breaker, but I don't think that's the case.
-- ok, this is clearly not the case. I read more and understand this better now.


3) I thought perhaps wires on the top and wires on the bottom should correspond as if the WAGO block connects top wire to the bottom wire? Clearly that's not the case as some on top and bottom don't have a pair?
-- After reading and watching youtube, i see that this was a wrong assumption. There needs to be just one wire that connects it to the positive bus.

[George_SD]

Originally Posted by redwood1957

Sounds like you have a ground.

Can you please elaborate?

[Cadence]

Originally Posted by George_SD

On a few recent trips that are only 4-5 hours long, I would get a low voltage alarm. This was happening with minimal electricity use (depth and speed transducer + single display for both).

Today, I needed to look into wiring power for the autopilot and decided to test my power disconnects. I have 3 of them
- negative disconnect
- positive disconnect (engine battery - Group 29 flooded)
- positive disconnect (house battery - Group 29 flooded - brand new)

As I understand:
- negative is supposed to disconnect everything by opening the circuit on DC circuit for both - house and engine.
- positive Engine - should connect or disconnect engine battery from the DC circuit
- positive House - should connect or disconnect house battery from DC circuit.

In essence - i can run on engine, house or both.

Well, here is where the gremlins come in.

I have a volt-meter built into 12v DC panel. I've seen other boats with the same panel show that the tester switch being used to check either of the batteries (my boat's manual is silent on this).

UP - engine battery test
Center - OFF
Down - house battery test

So I've started putting all disconnects to off and looking at what the battery/volt meter shows. Shore power is OFF at the shore and on 110v panel for all these tests. Everything on 12v DC panel is OFF as well.


--- Test 1 ----
Negative - OFF (disconnected)
Engine - OFF
House - OFF

Tester
UP (engine) = no reading
Down (house) = ~4v-4.5v

--- Test 2 ----
Negative - ON (connected)
Engine - OFF
House - OFF

Tester
UP (engine) = no reading
Down (house) =~ 12.6v

--- Test 3 ----
Negative - ON
Engine - ON
House - OFF

Tester
UP (engine) = 12.5
Down (house) = 12.6

--- Test 4 ----
Negative - ON
Engine - OFF
House - ON

Tester
UP (engine) = 12.7
Down (house) = 12.6

List of 12v electrical equipment
- bilge pump
- speed/depth transducers and single display, stereo, vhf
- fridge
- nav/anchor/steaming lights
- cabin lights
- macerator
- freshwater pump
- gas valve


List of 110v/shore power
- AC main switch
- charger
- water heater
- outlets

Questions

1) With all three disconnected - negative and both positives, I think it should be giving me 0, not 4.5v. How is it even possible with everything disconnected to show me voltage and a strange low reading at that?! What could possibly feed it?

2) With negative enabled, but both battery disconnects off - it should be showing 0 for both, right?

3) does this seem to indicate that at least my house disconnect is not really disconnecting?

Only recent trips, I might question the batteries.

[Stu Jackson]

This may help you:


Beneteau Wiring Diagrams - Maine Sail's corrections - Just in case you have a friend with a Beneteau and want to help him with his wiring Reply #8

https://forums.sailboatowners.com/in.../#post-1456512

[er9]

On my battery selector switch a previous owner connected some items directly to the back of the studs on the switch. Since the battery banks are direct connected to the battery switch posts some items stay energized even with the battery selector switch off.

Im not sure thats helpful to your situation but thought i would yhrow that out there in case.

[Kelkara]

I can't help with your 4.5V reading ... but the rest seems to be functioning as per the wiring diagram, except you have maybe confused the names of the batteries.

The meter switch will be set to read the voltage at the panel with the switch in the up position. And to read the voltage of the T1 wire in the down position. The diagrams shows the T1 wire going to the "engine" battery. Under normal use with the "house" battery on and the "engine" battery off, the up position shows the panel voltage (which will be the active "house" battery), and flipping to down will allow you to check the inactive ("engine") battery voltage.

[Lake-Effect]

Originally Posted by George_SD

On a few recent trips that are only 4-5 hours long, I would get a low voltage alarm. This was happening with minimal electricity use (depth and speed transducer + single display for both)

....

Questions

1) With all three disconnected - negative and both positives, I think it should be giving me 0, not 4.5v. How is it even possible with everything disconnected to show me voltage and a strange low reading at that?! What could possibly feed it?

2) With negative enabled, but both battery disconnects off - it should be showing 0 for both, right?

3) does this seem to indicate that at least my house disconnect is not really disconnecting?

There's two things to be addressed:

1. Why do the batteries poop out after 4 or 5 hours
2. The switch/meter stuff

With respect, #1 is the priority, and the answer there will be one or more of:

• batteries aren't charging properly or fully
• one or more batteries are failing
• (less likely) some wiring issue between the batteries and the panel
• (much less likely) battery alarm not set properly

Without digging into #2, you can use a handheld meter to measure the battery voltages right at their posts. You need to confirm that they are charging long enough at usual charging voltages ( > 13.5v). If charging seems ok... when you get the alarm, check the battery voltages... if they're below 11.5v, they're not holding a charge. Next step is to get the offending batteries checked.


#2 - those are almost impossible to sort out remotely. (and it's Sunday and I'm lazy ) Seek out a friend with electrical experience to look over your shoulder and guide you as you examine, test and take measurements.

[calmissile]

I looked at your original question/complaint about getting periodic low voltage alarms and the conversation evolved into the 'strange' 4.5 volt reading and the construction of the breakers and modular plugs.

I have never used WAGO connectors or breakers but looking at their catalog I am impressed with their products. I have 3 or 4 lathes and mills that are European made and they all use the modular type of electrical connectors into the various controller boxes and make for very easy troubleshooting as well as easy modification of the wiring. It is unfortunate the USA has not adopted some of the same modular and DIN standards.

Let me first address the 4.5 volt reading since it is a non-issue. The condition you are getting this reading is with the ground disconnected via the switch. High impedance voltmeters will provide erratic readings when one lead or the other is left floating (not connected). This is what you are experiencing and is not a valid testing configuration. You will notice that when your ground switch is closed the readings are correct for both battery banks. Forget the 4.5V reading, it is a non-issue.

Your original question is why are you getting the intermittent low voltage alarms? Since I do not see a detailed schematic of the alarm mechanism I am unable to analyze the issue in any detail, but here is some fundamental data you might find helpful..

If the system has no bad connections, both battery bank switches are closed, and the engine is running, the alarm would be due to the alternator not putting out enough current to raise the voltage above the set alarm voltage.

For a given RPM of the engine, the loads on the battery exceed the alternator capability at that RPM. For example at idle RPM, the output of the alternator may well not provide enough current to keep the voltage above the alarm set level.

If the low voltage alarm is occurring while the engines are at normal RPM's, then you either have excessive loads on the bus, or you have a failure somewhere in the charging system or in the wiring connections. It could be something as simple as the alternator belt slipping when under load, or a bad connection somewhere in the charging path.

The way I would personally troubleshoot the problem is to add all all the normal loads you would have when underway and run the engine(s) from idle up to normal RPM while watching the voltmeter. Exercise the autopilot and any other intermittent loads that might be experienced (refrigerator, pumps, etc.)

You should be able to determine in this worse case scenario, if the alternator is capable of keeping up with the demand of the loads. Since the alarms are intermittent, it may indicate that one particular load may be the cause of the issue.

Another rather simple explanation is that the battery has become high resistance internally, or the battery connections are not making good contact. If the battery terminals have already been cleaned and the low voltage alarm persists, then the easiest next step would be to temporarily swap out the battery and see if the alarm disappears. There are battery capacity testers that put a load on the battery to determine their capacity but my experience with them is not very good unless the battery has so much resistance it becomes obvious it is the problem. Best way I have found is by substitution. Hope this helps.

My boat uses Blue Sea panels and breakers and I am not happy with this company products for a number of reasons. When you buy a panel the breakers current ratings are pre-defined and I am unable to purchase new breaker/switches of the same type that came in the panel. Mine use a nice looking rocker switch (unlike the toggle switch breakers) and they have been discontinued and no longer available. Having the currently available toggle switch/breakers stick out of the panel would be a rather ugly unprofessional looking installation.

I am impressed with the WAGO catalog of products as well as the DIN mounting options. I may at a later date remove all my Blue Sea breakers and switches and convert to a modular system such as you have on your boat. My experience with the modular wiring and connectors on my industrial machinery has already led me to conclude that it is far superior to the kluge I find in most USA products.

[smac999]

first never shut off the neg switch. it's a weird european thing that is highly frowned on in north america. especially because people start adding things direct to battery and start creating bad ground loops when it's shut off. I normally remove the ground switch wiring on these boats. it will cause all kinds of weird stuff to happen. the bilge pump and battery charger still need to be on the battery side so they both still work when all the swtiches are off. so a working neg switch still does not kill everything.

2nd the jumper between the 2 pos switches is a terrible design and likely causing your weirdness. as most people don't understand what it does. as either battery is powering your panel and boat. I would remove it. and instead put an ACR there. they basically come up with the cheapest and simplest way to charge the house from the engine battery. and failed horribly. it works sort of like a 1-2-all switch exempt nobody knows it was put in all when both are on.

it puts both batteries in perminatly parallel if both switches on are. (which if you are on the boat it is common to have both on) this means when you are sailing you are draining both batteries and then you'll be stranded with a dead motor battery. you actully have to shut off the engine battery swtich every time you stop using the motor, and then turn it back on when you need it.

you've have a much easier time troubleshooting voltage problems to the boat if you removed that jumper. even if you decide you want it back on later.

ideally the volt gauge should be wired before the swtiches and should always show voltage if the battery switches are on or off. it looks like the engine one is wired that way. but not the house. so really it's a engine battery voltage / panel voltage gauge. but panelvoltage could be from either battery depending how the switches are on.

the jumpers between terminals are jumpers. IE that neg block is all one connection because they are all joined together.

forget the silly analog panel gauge and get yourself a victron 712. which will also give you battery capacity and amps of the house.

[calmissile]

Originally Posted by smac999

first never shut off the neg switch. it's a weird european thing that is highly frowned on in north america. especially because people start adding things direct to battery and start creating bad ground loops when it's shut off. I normally remove the ground switch wiring on these boats. it will cause all kinds of weird stuff to happen. the bilge pump and battery charger still need to be on the battery side so they both still work when all the swtiches are off. so a working neg switch still does not kill everything.

2nd the jumper between the 2 pos switches is a terrible design and likely causing your weirdness. as most people don't understand what it does. as either battery is powering your panel and boat. I would remove it. and instead put an ACR there. they basically come up with the cheapest and simplest way to charge the house from the engine battery. and failed horribly. it works sort of like a 1-2-all switch exempt nobody knows it was put in all when both are on.

it puts both batteries in perminatly parallel if both switches on are. (which if you are on the boat it is common to have both on) this means when you are sailing you are draining both batteries and then you'll be stranded with a dead motor battery. you actully have to shut off the engine battery swtich every time you stop using the motor, and then turn it back on when you need it.

you've have a much easier time troubleshooting voltage problems to the boat if you removed that jumper. even if you decide you want it back on later.

ideally the volt gauge should be wired before the swtiches and should always show voltage if the battery switches are on or off. it looks like the engine one is wired that way. but not the house. so really it's a engine battery voltage / panel voltage gauge. but panelvoltage could be from either battery depending how the switches are on.

the jumpers between terminals are jumpers. IE that neg block is all one connection because they are all joined together.

forget the silly analog panel gauge and get yourself a victron 712. which will also give you battery capacity and amps of the house.

Agree with all your comments. Sound engineering.
I am not familiar with the ACR component you mention but agree with the functionality of it. I will look into incorporating one on my boat. As you mentioned, leaving the switches in 'both' is a recipe for accidentally running down your starting battery.

[Oceanride007]

Think you need to get your volt meter out and measure again, I have a aissue with Hull voltage close to Negative potential, but the leakage is quite small, its not important right now. Heres a dwg of where/how I tested and my results.


Test 1.
Resistance Neg Bus to Hull = .7 K ohm, Pos Bus to Hull = 7.7 K ohm.


Test 2. Voltage Neg Bus to Hull = .023V, Pos Bus to hull = 13.35V.


PS My boat is metal.

[Oceanride007]

Its quite OK to have a resistance path to hull, but not great to have paths on both Pos & Neg, you may very well have that.