Argofet (Victron) "energize" pin?

[DDW]

I'm about to drop one of these in my boat (the trawler) to solve problems with the Blueseas combiner. The Argofet have a "special current limited energize input that will power the B+ when the engine run/stop switch is closed". This is followed by a wiring diagram that makes little sense at all.

Does anyone know how this pin actually works? And what a "limited current" might be?

I'l ask on the Victron forum, but it is pretty hit and miss over there.

The issue is the way things are wired, the Wakespeed regulator gets it's current for the field from the B+ terminal. Behind the Argofet it will see nothing and won't get powered. I'm guessing the energize input is supposed to be connected to the key power, and would allow back leakage through the fet to supply some power to the B+. But enough? No clue. And their wiring diagram shows something a little stranger than that, perhaps specific to some other alternator.

 

[Howler]

I'm about to drop one of these in my boat (the trawler) to solve problems with the Blueseas combiner. The Argofet have a "special current limited energize input that will power the B+ when the engine run/stop switch is closed". This is followed by a wiring diagram that makes little sense at all.

Does anyone know how this pin actually works? And what a "limited current" might be?

I'l ask on the Victron forum, but it is pretty hit and miss over there.

The issue is the way things are wired, the Wakespeed regulator gets it's current for the field from the B+ terminal. Behind the Argofet it will see nothing and won't get powered. I'm guessing the energize input is supposed to be connected to the key power, and would allow back leakage through the fet to supply some power to the B+. But enough? No clue. And their wiring diagram shows something a little stranger than that, perhaps specific to some other alternator.

Yeah, that diagram puzzled me too, at first. Normally, when an alternator is stopped, the B+ terminal is connected to the battery +, and so "sees" the battery+ voltage. With the ArgoFET in place, the alternator B+ terminal is isolated from battery+ by diodes (or FETs) that pass current in only one direction, and so the B+ terminal sees 0V. Some (non self-energizing) alternators cannot start until the B+ terminal sees voltage.
The "energize" pin, as you suggest, allows a miniscule amount (I have no idea how much) of current to feed through from the "energize" pin to the "Input" lug, which will raise the voltage at the the B+ terminal enough that alternator can start generating That current is only needed for an instant: As soon as the alternator is current, the voltage at the B+ terminal will rise to whatever the lowest battery+ is, plus the small voltage drop across the diodes/FETs.

The diagram isn't that weird. When the key switch is closed, battery+ is connected to the "energize" terminal, which then feeds current to the "input" lug.

 

[Howler]

Yeah, that diagram puzzled me too, at first. Normally, when an alternator is stopped, the B+ terminal is connected to the battery +, and so "sees" the battery+ voltage. With the ArgoFET in place, the alternator B+ terminal is isolated from battery+ by diodes (or FETs) that pass current in only one direction, and so the B+ terminal sees 0V. Some (non self-energizing) alternators cannot start until the B+ terminal sees voltage.
The "energize" pin, as you suggest, allows a miniscule amount (I have no idea how much) of current to feed through from the "energize" pin to the "Input" lug, which will raise the voltage at the the B+ terminal enough that alternator can start generating That current is only needed for an instant: As soon as the alternator is current, the voltage at the B+ terminal will rise to whatever the lowest battery+ is, plus the small voltage drop across the diodes/FETs.

The diagram isn't that weird. When the key switch is closed, battery+ is connected to the "energize" terminal, which then feeds current to the "input" lug.
View attachment 583289

 

[Howler]

There's definitely some weirdness though: https://community.victronenergy.com...200-2-energize-passing-current-to-output.html

 

[DDW]

There are plenty of questions asked about this on the Victron forum, and never a satisfactory answer. An internal circuit diagram of it would answer a lot of questions, or even a proper spec sheet. There are people reporting leakage from output to input, from output to output, from output to energize pin. In some of the threads the moderators ask for more information, then drop out when it is provided. Most of the questions simply go unanswered.

"A small amount of current..." was blowing 20A fuses for one. If I am going to run the Wakespeed regulator from it, it will take about 10 A since it supplies that to the field. If this comes out of the key circuit through the energize pin, there will be blood. What it really should do is turn on a small fet the other direction, which would pinch off at high currents. The Wakespeed will power up, start ramping the current, if that drags the voltage down it will reset again.

Victron's "documentation" doesn't give you a clue. The diagram seems to be drawn with the idea you will connect it to the small bleed diodes in an internally regulated alternator normally fed by the alternator idiot light. It is almost devoid of information.

 

[Howler]

There are plenty of questions asked about this on the Victron forum, and never a satisfactory answer. An internal circuit diagram of it would answer a lot of questions, or even a proper spec sheet. There are people reporting leakage from output to input, from output to output, from output to energize pin. In some of the threads the moderators ask for more information, then drop out when it is provided. Most of the questions simply go unanswered.

"A small amount of current..." was blowing 20A fuses for one. If I am going to run the Wakespeed regulator from it, it will take about 10 A since it supplies that to the field. If this comes out of the key circuit through the energize pin, there will be blood. What it really should do is turn on a small fet the other direction, which would pinch off at high currents. The Wakespeed will power up, start ramping the current, if that drags the voltage down it will reset again.

Victron's "documentation" doesn't give you a clue. The diagram seems to be drawn with the idea you will connect it to the small bleed diodes in an internally regulated alternator normally fed by the alternator idiot light. It is almost devoid of information.

I agree about Victron's info being skimpy, but the diagram is right. It took me several times of looking at the diagram, scratching my head, thinking it was a mistake, walking away, and looking again before I finally twigged to "Energize" being an input terminal that was being fed by the battery+ side of the ignition switch, and not something that was supplying current through the idiot light into D+

"Energize" is an input to the ArgoFET, not an output. In the diagram, when the ignition switch is on, it feeds start battery + to two things: the "Energize" input and through the idiot light to the small bleed diodes ("D+").

 

[Howler]

[...] If I am going to run the Wakespeed regulator from it, it will take about 10 A since it supplies that to the field. If this comes out of the key circuit through the energize pin, there will be blood. What it really should do is turn on a small fet the other direction, which would pinch off at high currents. The Wakespeed will power up, start ramping the current, if that drags the voltage down it will reset again.

With the full disclaimer that I'm spitballing here, I'd look into connecting the Wakespeed's red wire, the one that supplies power to the Wakespeed and is the source of current that the Wakespeed feeds to the alternator field, to the + side of the engine start battery instead of to alternator B+. That way the Wakespeed will always get the current it needs from the start battery, even in the first few milliseconds that the alternator is turning.

 

[DDW]

That doesn't explain why someone on the Victron forum had 20A fuses blowing in the energize line, and Victron suggesting that that just might be possible. How much current does the energize input sink? Where is the power sourced to the b+ terminal in this configuration come from? The energize line? How high will it drive the B+ terminal? enough to turn the FET on and tru to charge the house battery?

It would be SOOOOO easy if Victron had someone other than a first grader write one page of documentation for it. In the Victron world of incomplete documentation, this is the worst effort I have seen.

 

[Howler]

That doesn't explain why someone on the Victron forum had 20A fuses blowing in the energize line, and Victron suggesting that that just might be possible. How much current does the energize input sink? Where is the power sourced to the b+ terminal in this configuration come from? The energize line? How high will it drive the B+ terminal? enough to turn the FET on and tru to charge the house battery?

It would be SOOOOO easy if Victron had someone other than a first grader write one page of documentation for it. In the Victron world of incomplete documentation, this is the worst effort I have seen.

I'm wondering if this is a matter of Victron playing information arbitrage to protect its dealer/installer network, and that maybe they provide real documentation to its distributors and authorized installers but not to the rest of us? Wouldn't be the only company to respond to any technical question with "Ask our authorized reseller from whom you bought the device."

I'm (again spitballing here without knowledge) guessing that there's some kind of internal circuitry connecting "Energize" to "B+" -- maybe just a diode and a resistor -- that allows the device to bring B+ up above zero potential to get the alternator or voltage regulator started. All fine unless, for example, the middle or right battery in the picture is dead or near dead. Then current wants to flow from the + side of the left battery, in through "Energize," through the current-limiting circuitry, to B+, from there back through the ArgoFet, and out into the dead battery. And I'm guessing based on the forum posts about blown fuses and unexpected current flows that the current-limiting circuitry fails in a conductive state, allowing the dead battery or house load to try to suck huge amounts of current through the "energize" port and the ignition wiring. That failure of the current-limiting circuit wouldn't reveal itself until the point that the left battery was at or near full charge and one of the other batteries was closer to dead.

I agree 100% with you that actually providing information would make Victron's products a lot more attractive; it appears that their choice not to do so is deliberate and strategic rather than ignorant.

 

[DDW]

Or lazy.

The scenario you propose is exactly what I was worried about. If my house battery is very low, and I power the energize pin from the key circuit and start battery, what exactly happens? At one point in a Victron answer, they say that there could be 20A flowing in the circuit, but not for long enough to blow a 6A fuse. That only adds to the mystery of what is inside that box. Just hooking it up and having it work in normal circumstances isn't enough for me.

 

[Howler]

Or lazy.

The scenario you propose is exactly what I was worried about. If my house battery is very low, and I power the energize pin from the key circuit and start battery, what exactly happens? At one point in a Victron answer, they say that there could be 20A flowing in the circuit, but not for long enough to blow a 6A fuse. That only adds to the mystery of what is inside that box. Just hooking it up and having it work in normal circumstances isn't enough for me.

Well, if I were king of the world, I'd arrange the innards of the box such that there would be no charging (i.e., no current flowing from B+ to any of the batteries) whenever there was any current flowing from "Energize" to "B+", which ought to take care of any of the problem scenarios. And then I'd publish a full spec. And maybe even a circuit diagram. I'm no EE, but the whole works really doesn't seem like a particularly complex bit of circuitry, with the devil being in the details of circuit protection, safe failure modes, etc.

[edit: On reflection, this won't really work, because whenever any of the other batteries are at a lower SOC than the start battery, there will be current wanting to flow from "Energize" to "B+", and you don't want to shut off charging under that condition. ]

 

[Howler]

Thinking about this a little bit more... Whenever the voltage on the start battery is higher than the voltage of any of the other batteries, and the ignition switch is closed, current is going to want to flow from the start battery, through the energize pin, through the ArgoFET's internal "energize" circuitry to the ArgoFET's B+ pin, from there back through the ArgoFET's internal isolator circuitry, and into the lower voltage battery. (in other words, the start battery is going to try to charge the lower voltage battery through the "energize" circuit.

All that's needed to prevent this from being a problem is that the internal "energize" circuit permit current only in the forward direction (i.e. from the "energize" pin to B+, and that it be a true current limiting circuit (i.e. not a fuse or circuit breaker, but something that actually limits current down to some small amount.) A diode and a resistor would probably do.

If people are seeing 20 amps flowing through the "energize" circuit, it means that the current limiter just isn't working, either because it has failed closed, or because it wasn't designed correctly in the first place.

 

[DDW]

I don't know what is in the Energize circuit and apparently Victron wants to keep it a mystery. I am going to attempt to reverse engineer it. It is possible it is even just a straight wire through to the input post - that would accomplish the goal and be current limited by the 6A recommended fuse and normal operating circumstances.

 

[AnIdiot]

I have an Argofet installed on my campervan. It charges the twin engine and single house batteries.
I was confused about where the connection should go until I realised that it didn't really matter: it just needs to be hooked up to a 12V source, so that the Argofet can start up the alternator. Once the alternator's going, it's redundant.
It's current limited and IIUC won't see reverse flow, in the diagrammed setup, because with the alternator running the energiser and input/B+ connections will be at the same voltage.
I don't see how it would be blowing a 20A fuse... that seems like a faulty unit or misguided wiring...?

 

[Howler]

It's current limited and IIUC won't see reverse flow, in the diagrammed setup, because with the alternator running the energiser and input/B+ connections will be at the same voltage.

Not necessarily. Consider the case of a start battery at 13.8v and a deeply discharged house battery at 11.2v. With the alternator running, the voltage on the B+ connection is going to be the voltage of the lowest voltage battery, plus the voltage drop across the ArgoFET (very small). So let's say once the alternator is pumping out current in bulk phase, the voltage across the house battery is 11.8v or so... You've still got 2 volts of difference between the "energize" terminal, which is connected to the positive side of the start battery and the B+ terminal.

 

[DDW]

OK I reverse engineered it. The Energize input appears to be just a diode connected to the Input post. I did not test if there was some kind of current limit, but it appears not, and the forward resistance is very small measured at 2A. People are reporting blowing 20A fuses in this circuit in that scenario. So it is much worse than that scenario:

Suppose you connect the Energize through the keyswitch as is suggested by the documentation. You have run your house battery way down to 8V. You turn the key switch on and the 12.5V start battery is effectively shorted to 8.5V (8V plus the 0.5 forward diode drop). I tested all that. The only limit to current would be any fuse in the keyswitch wiring and the wiring itself. Once the alternator is up and charging things look good again, if nothing was started on fire in the interim.

 

[Howler]

OK I reverse engineered it. The Energize input appears to be just a diode connected to the Input post. I did not test if there was some kind of current limit, but it appears not, and the forward resistance is very small measured at 2A. People are reporting blowing 20A fuses in this circuit in that scenario. So it is much worse than that scenario:

It's very hard to tell, poking around with a multimeter, whether or not there's any real current limiting circuitry, unless you actually drive the unit into the regime where it starts limiting current. Below that, there should be very low forward resistance; as many current limiting circuits are going to look like nothing's there until they start limiting.

But since Victron won't tell us how much current the "current limited" energize pin is supposed to be allowed to sink, I wouldn't be surprised to hear that there's nothing but a diode there.

I'm thinking that for this application, you want a real current limiter, and not just something that opens the circuit if too much current is drawn, otherwise if you had a dead or nearly dead house battery, it would be hard to raise the voltage on B+ high enough for long enough to get the alternator going.

 

[DDW]

Aware of all that, being an EE by training and career. Determining otherwise means possibly testing to destruction, I'd be happy to do that if you want to send me one . The fact that many posters have gotten it to blow 20A fuses suggests that there may not be much of a current limit. Victron's response on their forum suggests they may not have a current limit.

Nevertheless, even if there is a current limit at say 10A, using it the way they suggest seems like a pretty bad idea.

 

[AnIdiot]

I take it you've seen this post:

Johannes Boonstra (Victron Energy Staff) answered · Sep 11 2020 at 5:50 PM
Hello Harley,
The energize circuitry is quite simple. Its an electronic fuse (10A) in serial connection with a diode forwarded to the input. This fuse can supply more then 10A temperately but when the fuse heats up the current is limited.
The way it needs to be used is dat the energize gets its power from the starter battery (so when the starter battery is switch OFF there cannot be power on the energize input!!!) through the ignition switch. So as soon the engine is started the energize circuit bring the starter battery voltage to the B+ input. Current on the energize whilst the starter battery is switched of means there is an installation fault made! Beside this the neutral is also internally fused with a 2A fuse to protect internal components. PS as a general note; an Argofet should not be paralleld on the same battery and power by different alternators. Due to the fact the alternators arent symmetrical it can occur that the splitter gets overheated from switching its input on/off.
+-------------‐-----------------------

Which, along with the installation manual, says it's current limited.

They state a 2.5 sq mm wire should be used (which can carry 29A or so, depending on environment) and which aligns with the " more than 10A temporarily" above.

I can see that there are people on the thread complaining that they are seeing blown fuses but I'm not seeing any detail on their installations.

I'm also not sure why they have chosen 20A fusing... it's a sensible enough choice for protecting a 2.5 cable that's expected to carry a 10A load but perhaps overly conservative for this scenario, given that Victron don't advise including a fuse at all (presumably because their limiting is expected to keep the wiring within it's capacity).

What's the fault you're seeing?

 

[Howler]

I take it you've seen this post:

Johannes Boonstra (Victron Energy Staff) answered · Sep 11 2020 at 5:50 PM
[...]
The energize circuitry is quite simple. Its an electronic fuse (10A) in serial connection with a diode forwarded to the input. This fuse can supply more then 10A temperately but when the fuse heats up the current is limited. [...]

I'll defer to the actual EEs on this thread, but I believe one would normally describe this as "the circuit is interrupted" and not "the current is limited."

The way it needs to be used is dat the energize gets its power from the starter battery (so when the starter battery is switch OFF there cannot be power on the energize input!!!) through the ignition switch. So as soon the engine is started the energize circuit bring the starter battery voltage to the B+ input.

This actually has nothing to do with whether the engine is started or not, it has to do with whether the ignition switch is in the "on" position or not, irrespective of whether or not the engine is running.

This is, I believe, the kind of sloppy technical information from the manufacturer that people are complaining about.