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Argo FET

Argofet 200-2 Energize output

Hi, I installed the Argofet and it works fine. The only difference I made was to connect the Ernegize oultlet to the D+ "behind" the control Lamp see the orange line (because it was a lot easier)

As Said before, it works fine, the alternator is charging, the control lamp turns off...

Are there any reasons why that was a bad choice?

Many thanks!



vivacruise asked

0 Answers

Can i use one of the outputs of a Argofet isolator as a connection stud?

My argofet sits between the batteries and the alternator. I want just one one cable connected between the Argofet to the positive battery post of the starter battery. Can i use the output stud on the argofet to connect a cable to the engine starter? I will save some meters of cable and fuse the cable going from the battery


johan-granqvist asked
johan-granqvist commented ·

1 Answer

multiple charge inputs with a single Argo FET Isolator

We have multiple charge sources and two battery banks.

1. Can I attach multiple charge sources (charger, alternator, MPPT) to the same Argo FET Isolator?

2. This relates to how the Argo FET apportions power. The house battery bank size is 1000 Ah and it will frequently be drawn down to 50% of capacity. The start battery bank size is 300 Ah and it will generally be close to fully charged. Will the Argo FET limit overcharging of the start battery bank in this condition?

3. Can the terminal for the third battery bank remain unattached on the Argo FET Isolator?

4. This relates to sizing the Argo FET Isolator. The charger is a Multiplus 12/3000/120. The alternator is rated at 160 amps. Battery bank sizes are 1000 and 300 Ah. Which size Argo FET Isolator do I need for this application?

I wish the manual had more information.

Thank you.

vpbarkley asked
jwfrary answered ·

1 Answer

Charging 2 batteries via Alternator, MPPT and Multiplus

Hello everybody, I have a question about a Victron-setup which is in a boat I bought. There are 2 separate batteries (start/bowthruster and mains net) and 3 chargers: the alternator, a MPPT with solarpanels and a Multiplus (main output to mains, aux-output to starter battery). But..... both batteries are charged by the alternator (via an ArgoFet) and as said via the 2 outputs on the Multiplus but the MPPT is only connected directly to the main-battery (not via the Argofet). What can be the reason for this? I could think of:

- MPPT cannot cope with the large voltagedrops of the start-battery

- Main-accu is empty earlier so needs the full current coming from the solarpanels

- ?

What do you think? I’m thinking of connecting the MPPT also to the Argo-fet (on the same connection together with the alternator) so also the start-battery is always full. We don’t use the charger often so when we don’t use our motor but do use the bowthruster heavily before docking, the start-battery is getting empty and not charges for days and I don’t think that’s good for the battery

please let me know you opinion! Thanks in advance!

pim asked
geko22 answered ·

2 Answers

Argofet and MPPT compatibility question

HI guys,

Can someone with expertise with the Argofet help me, I want to add an Argofet to split charge my VRSLA start battery and my LFP house bank. Easy so far. I want to connect an MPPT controller to the input of the FET and utilize the alternator energize circuit to tell the MPPT that there is voltage. The solar controller needs to see voltage at the battery terminals or it wont start charging.

This is what I had in mind, will it work?


The following is from Victron ArgoFet documentation...

Alternator energize input
Some alternators need DC voltage on the B+ output to start charging.
Obviously, DC will be present when the alternator is directly connected to
a battery. Inserting a Diode or FET splitter will however prevent any
return voltage/current from the batteries to the B+, and the alternator will
not start.
The new Argofet isolators have a special current limited energize input
that will power the B+ when the engine run/stop switch is closed.

Jafa Russell asked
pim answered ·

3 Answers

Charging 2 Lithium banks with MPPT


I'm looking for a way to charge my 2 lithium banks with MPPT and keep them isolated a the same time.

Here is a picture of what I have so far.

The starter has a switchable circuit to keep the Argos energise circuit live and prevent the MPPT shutting down each evening and messing with the history metrics and also give the MPPT a voltage reference when charging as I don't believe it will get one from the Argos input terminal (please confirm if I'm wrong on that). I understand that this will draw around 0.05A to have the Argo and MPPT active, which will be easily replaced by the solar charge going to the starter battery.

The 2 65A BPs are configured to lithium settings and will disconnect using the BMS charge disconnect going via the BMV relay.

This will not be an approved setup, but will it work as I've gone through serveral designs and this is the only one I haven't spotted any problems with - yet.... :)

If you have a better and supported setup for doing this I would be very interested in the details :)



stocksy asked
pim answered ·

1 Answer

Argo FET in a dual engine installation


In my yacht I have a dual engine installation. Originally the boat builder connected both alternators to the house batteries and put a zener diode as a separator between house batteries and starter batteries. Both sense cables from the alternators are connected to the house batteries. Both engine starts from the single starter battery pack.

I am now looking att installing Argo FET for a better separation solution, but the question arises directly. Should I use one or two Argo FET, is it enough with one Argo FET and connect both alternators to it or should use one Argo FET per engine and alternator.

The goal is to have both engines charging both battery packs.

Any input here would be much appreciated!

jowi asked
jowi edited ·

0 Answers

Argofet 200-2 Energize passing current to output


I am having an issue with some Argofets blowing 10A fuses inline with the energize inputs.

-The energize input is wired to the switched side of the starter battery isolator via 10A blade fuse.

-The alternator B+ is connected to the argofet input.

-Start battery is connected to the argofet output 1

-House battery is connected to the argofet output 2.

When the start battery isolator is on, engine not running, a current drain/load on the house bank, the energize input is supplying current to the house bank, and blowing the 10A fuse. This current path is presumably from the energize input to the input and back to the output with the lower battery voltage.

Is this expected/normal, or may i have a hardware fault?

If this were normal, should everyone be installing a 25A fuse to allow for the 20A maximum mentioned in another thread?



harley asked
mobbzy commented ·

8 Answers

Cyrix or FET diode bridge ?
Hi everybody,

I am in the process of upgrading my boat from a single battery to separate battery banks. I have a few questions about that.

1. what / which technology is best to use and connect to charge both banks with the chargers (shore power, alternator, wind and solar).
2. I have been looking for Cyrix and FET Diode bridges and do not know what is best and how to connect. And if a Diode is a 1 way system how do the chargers know when they are full.
3. What are the best universal settings for AGM batteries if I want to set the BMV712, Smartsolar and shore power charger. Now I notice that my old lead battery is not yet full according to the charger, but the BMV gives 100% and keeps bulking for 30min.

all tips and help welcome :)

greetings Ian



ian-macleod asked
ian-macleod edited ·

0 Answers

Connection Cytrix et Argo 120-ac

Bonjour ,

je suis en train d upgrader mon installation electrique de mon camping car.
J avais actuellement une batterie porteur de 100A et une batterie lithium de 150A, avec un cytrix pour gerer le tout pour une charge alternateur. Le tout relié avec du 25mm².

Jusque la tout marche impec.

J ai ensuite rajouter une batterie 200a lithium et j ai pris un argo 120-2AC, j ai connecte la sortie du cytrix sur l inmput de l argo puis les deux outputs sur chaque batterie.

Probleme j ai plus aucune charge.

Je vois bien au multimetre qu a la sortie du cytrix j ai plus aucune tension, d apres ce que j ai lu sur les forum ca viendrait du faite que le cytrix check aussi la tension en output et pas qu en input comme je l aurai cru. Or les diodes de l argo bloque le signal retour.

Comment puis je contourner ce probleme?

Merci d avance

yuharla asked
Thierry Cortassa (Victron Energy Staff) answered ·

6 Answers

How to connect an argo 120-2AC after an cytrix-CT

hello everybody,

I have actually an cytrix-ct connect with my motor battery and the second battery in my van.
I upgrade the electrical capacity with an second lithium battery, so i have buy an argo 120-ac.

I connect the output of cytric to the input of argo 120-ac and the two output of 120-ac to each battery.

Problem i have no charge ...
I think the cytrix don't know my load because argo don't let the signal up to him.

Anybody have already do that or someone know i can fix it.

Can i use the the output compensation to connect to the cytrix output thanks that the cytrix can see something?

yuharla asked

0 Answers

EASY SOLAR 12/1600 / Répartiteur de charge/décharge ARGO FET 100-3


Voir photo en PJ. j'ai installé un répartiteur de charge ARGO FET 100-3 (1 entrée 3 sorties). Sur l'entrée sont connectées, le B+ de l'alternateur moteur ET le B+ de l'alternateur d'arbre. Tandis que la sortie 1 est connectée au pôle + de la batterie moteur, et la sortie 2 est connectée au pôle + des 2 batteries de service.

Actuellement le chargeur (Easysolar 12/1600) est connecté sur les 2 bus bar pôle + et pôle - des batteries de service. Tant est si bien que le Easysolar charge uniquement les batteries de service mais pas la batterie moteur !

Mon souhait est que le easy solar charge aussi la batterie moteur.

Question :

Puis-je modifier le câblage en ramenant le + batterie du easy solar non pas sur le bus bar pôle + des batteries de service, mais directement sur l'entrée du répartiteur de charge ? Ainsi il y aurait 3 câbles connectées sur cette unique entrée du répartiteur : alternateur du moteur + alternateur d'arbre + Easysolar.

Aucune incidence pour le répartiteur et l'installation électrique en général avec ce type de câblage ?

Merci d'avance pour vos réponses



olivier-vitu asked
olivier-vitu answered ·

2 Answers

Argo which terminal for Alternator sense?

Hi, I've installed Argo FET split charger to charge my starter and 2 (separate) LFP banks. The Balmar MC614 Regulator states to place the Alternator voltage sense wire onto the largest bank if using a split charger, so in my case that would be the 400ah LFP bank.

Just a little concerned that this will potentially expose my starter to too much current and force it into a high voltage state.

I did think that using the MC614 Batt temp sensor on the starter battery might help. Other option would be to place the sense wire onto the starter battery, but then would that not prevent the LFP banks from charging?

Hope someone with a better understanding of this can help.



stocksy asked
kyleolmstead commented ·

1 Answer

Battery Isolator & Alternator Sense Terminal

I have installed an Argo Fet Battery Isolator. It works well, but when the batteries are full, I am getting a reading of around 15.1 volts at the battery, which I understand to be too high. When I installed the battery isolator, I removed the wire from the sense terminal of the alternator. Should I reconnect that? and if so, to where?

kyleolmstead asked

0 Answers

Sanity check please...

Hi there,

I'm wondering if I can get some feedback about my proposed system. Diagram is below. My concerns are about whether I should be using the Cyrix-ct battery combiner instead of an ArgoFET isolator. Should the MPPT controllers feed to the start battery? as well as the house batteries?

Larger version of pic at DC supply and charging.pdf


marc-kelly asked
marc-kelly edited ·

0 Answers

Argofet 200-2 gegen Wegfahrsperre

Ich zerbreche mir nun seit Monaten den Kopf wie ich es hinkriege, das Ding so automatisch laufen zu lassen, dass ich den Motor anmache und es von selber funktioniert. Habe das 200A Modell, da meine Lichtmaschine 200A liefert und das dicke Stromkabel von der Lichtmaschine an den Eingang verkabelt, sowie Starter und Bordbatterie Plus an die Ausgänge (habe das Modell mit 2 Ausgängen). Masse angeschlossen auch kein Problem.

Energize hatte ich erstmal weggelassen, da dort stand 'optional' .
Mein Problem war, dass sich die elektr. Wegfahrsperre nicht lösen lässt. Ich stecke den Schlüssel rein und er lässt sich nicht drehen, da nichts entriegelt.

Das einzige, was bis jetzt funktionierte war Lichtmaschine B+ und Starterbatterie + am Eingang zusammen anzuschließen und dann an einen Ausgang die Bordbatterie. Ist allerdings nicht ganz optimal, da ich das Bordbatteriekabel immer abschrauben muss, sobald ich den Motor ausschalte, da sonst die Starterbatterie leergesaugt wird wenn ich koche.

Nach 3 lästigen Monaten wollte ich das nun ändern. Also alles wieder wie im Schaltplan angegeben angeschlossen. D+ an Energize und einen Schalter welcher an Energize und Starterbatterie angeschlossen ist. Dann ist D+ eigentlich unnötig(?) Nun leuchtet die blaue LED, sobald ich den Schalter anschalte. Die Wegfahrsperre entriegelt und sobald die Zündung auf den 2. Klick ist (also bis vor Motorstart) Fängt es an zu flackern. Die blaue LED spielt Disco und geht an und aus und das im Sekundentakt, das Kombiinstrument auch, also alle Warnleuchten etc. Der Motor lässt sich nicht starten. Ich habe in dem Zuge auch versucht Den Energize Schalter mit Bord- anstatt Starterbatterie zu verbinden, allerdings ohne Erfolg.

Habe Kabelquerschnitte von 75mm² für die Stromverbindungen und 2.5mm² für die Masse und Energize. Die Starterbatterie hatte 12.8 und die Bordbatterie 12.87 Volt.

Ich hoffe, dass Sie mir irgendwie weiterhelfen können! Sonst wird es in der Ecke landen und ich muss ein 25 Euro Trennrelais aus China einbauen, was ich unbedingt vermeiden wollte.

Habe einen 2006 Vito W639/4

Mit freundlichen Grüßen,
Julian Münzer

Julian Münzer asked
Julian Münzer edited ·

1 Answer

Argo fet or Cyril-ct?


I’d like to use your products in my 30 feet sailing boat in order to charge the starter battery ( 1x 70 Ah battery ) and the services batteries ( 2 x 115 Ah flooded batteries put in parallel).

Is it better to use your Argo FET 100-2 battery isolator or your Cyrix-ct 12/24-120?


skuner asked
francesco commented ·

2 Answers

Why is there voltage on input on a Argo Fet when alternator isn't connected?

Voltage on input point with no alternator connected

kobus asked
Alan Piggot commented ·

3 Answers

Does my proposed use of Victron 3-200 Argofet Isolator make sense?

I am planning to install the Victron Argofet 3-200 Isolator in my forbie to provide charge for my Starter and two Auxiliary batteries. Each of the batteries is of a different type, the starter is your typical wet cell albeit an ultra performance Century, the Aux1 battery also under the hood is an AGM and the battery in the rear is going to be a LiFePO4.

I of course want to make sure the Starter battery takes priority and isn't drained by all the devices powerd by the other two Aux batteries and I believe this is exactly what an isolator does.

Next, I want the Aux 2 battery in the cargo to get the best charge (highest voltage and current) which i assume the CTEK Dual 250S and Smartpass will hopefully take care of ie make up for any voltage drop resulting from length of cable from the front under bonnet to the rear cargo as well as getting up to 120Amps into the Aux 2 battery (dependant on input which is unlikely to be anywhere near that dependant on charge of other batteries and alternator output so probably overkill but i wanted to make sure these weren't the limiting factor).

The Aux 1 battery under the bonnext just provides additional power for the UHF radio etc and has a momentary switch plumbed in to join it with the starter in case the starter does actually die.

I also plan to attach the Victron phoenix 12/1200 inverter to the LiFePO4 battery for 240v,

Anyway my question is... Is the use of the Victron Argofet Isolator in this configuration sensible? I thought it looked ok but I have read that it may not be ideal due to there being three different battery types and capacities which may result in the starter not getting a full charge or even eventually going flat when using the Victron isolator in this way.

For clarity in demonstrating my setup I have excluded from the diagram, all fuses and circuit breakers which have been used extensively at both ends.


the-tango asked
the-tango edited ·

1 Answer

2 alternators to 3 battery banks with 1 argofet

Hi there,

i am looking to switch from a competitor to all victron but i cant work out how to integrate the Argofet with my two alternators and 3 battery banks.

is it possible to connect 2 alternators in parallel to the single input of the argofet (obviously if the combined ampage is less than the Argofet rating) and have them split between the three bank?

the only info i found on twin engine installations was to use 2 argofets which i assume means i need to run another separate set of charge leads from the 2nd argofet to the batteries which sounds messy

nfluester asked

0 Answers

Connecting battery 1 and 2 to make jumpstarting possible on Argofet
  1. Beste,

    Wij hebben een Argo fet gemonteerd met twee accu’s. Startaccu en huishoud accu.

    Nu zou ik graag accu 1 en 2 willen koppellen doormiddel een schakelaar. (Dit om overstarten vanuit huishoudaccu mogelijk te maken in geval van een lege startaccu)

    Dan is de vraag. Mogen de twee uitgangen van de argofet gekoppeld worden om zo eenvoudig stroom te kunnen gebruiken vanuit de huishoud accu? Op deze manier loopt er geen stroom via de argofet. Kan de argofet beschadigd raken wanneer beide uitgangen met elkaar gekoppeld zijn? Of hebben jullie een andere oplossing?

Groet Guus

guusje asked
guusje answered ·

1 Answer

FET isolator with battery charger

I just installed an FET isolator and it seems to be working fine. Is it ok if when my boat is parked at the house I connect up a standard 12V battery charger to the isolator and charge both batteries at the same time just like the alternator would if the engine was running?

casey-pries asked

0 Answers

Argo FET 4.4V voltage on input terminal with no alternator running

I have acquired a yacht wired with three 12V batteries on outputs. With the engine shutdown and no alternator running I have 4.4 Volts on the Input terminal and alternator circuit - I am not wiring the "energise" terminal. Is this usual or indicative of defective isolation as I am experiencing battery capacity leakage on one battery bank when not using the system for several weeks.

pmdent asked
vga commented ·

2 Answers


I'm going to replace an old 160A isolation diode to an ARGOFET 200A Isolator. I have a well-functioning VolvoPenta std. 115A Mitsubishi alternator in my boat. What I'm a uncertain about is whether it is necessary to connect ENERGIZE to D + on the alternator?

olaf asked

0 Answers

Argo FET 200-2, reverse current flow?

In my boat I am struggling with a hidden current thief. Got my hand on an inductive ampmeter and measures above 3 amp reverse flow on the generator input cable (when the engine isnt running). How is this possible? Isnt the Argo FET supposed to prevent backflow?


mmosberg asked
mmosberg answered ·

3 Answers

Alternator not charging with ARGOFET


I adopted my engine with an Argofet 200-2, so that I can charge 2 different battery packs. Unfortunately I can't install the Argofet as proposed in the specification, as the ignition switch and the resistor is integrated in my engine control unit.

As proposed in the Victron datasheet:


My System looks like this:


I know that my alternator needs dc voltage at B+, therefore I used the energize Input. Unfortunately this energize input doesn't work in my system and the alternator is not charging and producing voltage. Why has the resistor / lamp to be between Engergize Input and D+?

While testing I accidentaly interrupted the ground cabling from the Argofet. Funnily without ground, everything works fine, but I doubt that's the ideal solution.

Does anyone know how the ArgoFET looks like / works in detail and what could be the reason for the malfunction.

Thanks a lot


waibel asked
jwfrary commented ·

0 Answers

Argofet 200-3, current distribution

I'm wondering how the Argofet distributes the current to each bank. I have three banks on the boat each regular lead / acid. I have been checking the charge current from the alternator and it looks like when the alternator is providing 40 amps it all flows to the (large) house bank (output #1) and to the start bank (#2). The #3 bank, used for the bow thruster only gets 2 to 3 amps. This is resulting that the #3 bank is always low. The cable between #3 and the Argofet is a beefy 2/0AWG but much longer then the other 2.

henklor asked
Daniël Boekel (Victron Energy Staff) answered ·

1 Answer

Argo FET 200 capacity

Hi, In my boat I am adding a Delco 28Si alternator which supposedly is capable of giving up to 250A. I could reduce its output to around 180A-200A, but it might when starting and for a couple of minutes nevertheless yield up to 250A. Is the Argo FET 200-3 capable of handling this current? I.e. is it OK to exceed its rated specification of 200 A for either longer or shorter periods?

There will be three battery banks connected: 600 Ah LiFePO4 House bank and 200 Ah +105 Ah AGM banks for thruster and starter, respectively.

Thank you.


eirik asked
eirik edited ·

0 Answers

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