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Cyrix Battery Combiner

Can a cyrix-ct work one way for charging.

Can a cyrix-ct work one way (from the alternator to the house battery) and only pass the other way (home battery to start battery) if you pressed the assist.Now when the house battery is charged and topped up, the Cyrix switches to charge the starter battery this is not intended..

stephan-fok asked

0 Answers

Recalibrate Victron battery monitor!?

Interesting one, I have a Cyrix CT, to charge my house batteries of the vehicle batteries. My house batteries were down to 60%. It was freezing outside and had trouble starting so I hit my Cyrix CT start assist button, which connects my house batteries to my vehicle batteries to help start the engine. Worked great, the only problem is now my Victron battery monitor reads 100%, when it's really 60%. I see why this happened, but does anyone know a quick way to recalibrate? I looked into zero calibration, but that doesn't seem like the fix. Thank you

kaplan78 asked
kaplan78 commented ·

2 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
morissen answered ·

1 Answer

Will cyrix ct 120 connect full starter to a consumed service bank and cause damage?

I wonder if I use my service battery to say 11.9, and then start my engine, the cyrix will open to charge both, and I fear a lot of amperes will flow to damage the cables. Does that happen? Has it ever happened.?

morissen asked

0 Answers

Cyrix -ct 120, draining both batteries?

When I leave the boat and the batteries are:

STARTER Batt.=13,0v

HOUSE Batt.=12,5v

after 24h with everything OFF the batteries have both the same voltage (~12.7v).

I thought right away that the Cyrix is connecting both batteries and when I tested with a voltmeter, there is indeed connection from both poles of the Cyrix. Is this a normal behavior?

See video HERE.

My current setup is:


zuzullo asked
morissen answered ·

7 Answers

Cyrix charge generator battery

Hey guys,

I have question regarding charging generator battery from service batteries via cyrix. I would hook cyrix and generator battery (I would connect generator battery on service battery terminal on cyrix) and hook service battery like motor batteries on cyrix. I think this should be ok but I just want to double check with you guys.

Thanks for answering

com5 asked

0 Answers

Cyrix-ct start assist with drained battery


I have a boat with 1 Engine, 1 Starter battery and 1 auxiliary battery.

I would like to use the Cyrix-ct-230 to automatically charge the aux battery once the starter battery has been charged. With the added benefit of having a start assist switch from the aux battery in case the starter battery has been drained.

My question: How would the Cyrix react if I use start assist to combine a full aux battery with a completely drained (or dead) starter battery? Would the Cyrix refuse to connect? I'm concerned that the drained/dead starter battery would drain the aux battery.

kemp-arve asked

0 Answers

Cyrix CT 230A - why is it passing voltage?

I'm trying to figure this out - I have disconnected the Cyrix output from my house batteries. The starter battery wire to Cyrix is connected. I have the ground wire for the Cyrix disconnected.

I am showing start battery voltage on the Cyrix's output. Why? That doesn't seem right?

I am checking voltage at the green circle.


over-and-under-victron asked
over-and-under-victron answered ·

3 Answers

Correct trickle charging method for starter

Hi all - I am very confused about the above topic and was hoping for some input. I have a Citroen Relay 17 reg (which has a smart alternator) which I'm converting to a campervan. I don't use it everyday, and I've been suprised how quickly the starter battery runs down (the immobiliser in particular is apparently a thirsty one). I'm planning out my electrics, but keep reading conflicting info about the best way to keep the starter battery topped up. My starter battery is not a Victron, but the original battery and for economy sake I don't want to change it yet as it's fine.

One method is to not even link the starter battery to the rest of the camper at all, and just use an external trickle charger when needed, however to me this seems like a nuisance. Some people also seem to just disconnect the battery for longer spells and keep the van turned over otherwise, but this is apparently not the best for the battery (not sure how true this is - can only find anecdotal info).

If I design my system to trickle charge the leisure battery then I'm confused between whether I should do this fromthe victron dc-dc charger as I have been told it causes problems when using an MMPT solar charger and a multiplus (which i have already purchased - i have 2 solar panels). Others have said I can just use a cyrix while others a cyrix and a dc-dc charger.

Keeping the starter battery topped up is my priority - having the alternator charge the leisure batteries is just a bonus as I've probably overshot on my leisure battery capacity and my solar panels, and I will be mostly on site where i have shore power, so should never (in theory) need to rely on my alternator to give me a boost. But I want to eliminate the risk of my starter going flat, and reduce the maintenance needed when not inuse.

I'm really starting to tear my hair out on this one - really would appreciate some advice or links! Thanks all

Dylan Tucker asked
kevgermany commented ·

2 Answers

Cyrix CT-120

I have a cyrix ct-120, I think it works perfectly. I specify that I have checked all the connections, that I have done the tests that you recommend.

When I disconnect my starter battery from terminal 87 of the cyrix, I have a voltage of 13.1V. When I reconnect the starter battery, the voltage drops from 13.V to 12.4V.

So I have questions.

Is it normal that the voltage drops immediately after everything I connect terminal 87 while the cyrix has not closed?

Is it normal that when I turn on my engine and the alternator does indeed supply 14.8V, the voltage on terminal 87 remains around 14.6V?

Or quite simply a defective mass in the installation can it cause these voltage measurements which seem abnormal to me? I specify that I have checked that terminal 86 on cyrix was on the general mass of the installation

Best regards

lefeuvre asked

0 Answers

Cyrix continuité des « moins » communs

Bonjour, je suis sur le point d’installer Cyrix, shunt 50/500 et Globallink dans mon bateau en acier. J’ai constaté que la continuité des « moins » communs de mes deux parcs 24 volts n’était pas parfaite : je trouve (de mémoire) une cinquantaine d’ohms. J’ai lu que çà suffisait pour retenir la continuité, lorsque la résistance est très faible ainsi. Toutefois j’ai l’impression que cette continuité doit être excellente pour installer un Cyrix. Je me propose de mettre en place un nouveau câble de grosse section entre les deux « moins » pour parfaire cette continuité. Je n’ai pas suivi visuellement tous les câbles si bien que je connais mal la liaison de ces deux parcs et j’ai une petite appréhension avant de parfaire cette continuité. Est ce utile de procéder ainsi ? Y a-t-il un risque du fait des liaisons existantes mal connues ? Merci. Pepet.

Rousset Michel asked
Rousset Michel answered ·

3 Answers

Solar & Alternator Charging

Hello Community, I recently boat a sailboat and the electrics are shocking to say the least and am rewiring the whole boat from scratch. We are also adding Solar Panels and I would appreciate it if someone could confirm whether the setup I have created is correct?


The expected outcome is that when the outboard is running that it charges both batteries but when the engine is off it prevents the discharge of the starter battery.

Any feedback and comments and advise whether I should use any additional equipment would be greatly appreciated.


seaesther asked
Trevor Bird answered ·

2 Answers

Where to install fuse for Cyrix-ct 120A?

Hi all,

I have a question about where to place fuses when installen a Cyrix-ct 120A? The diagrams show only a fuse installed between the house battery and the Cyrix, shouldn't there also be a fuse between the starter battery and the Cyrix? As present in the wiring diagram of the Blue Sea ACR (in my opinion similar to the Cyrix-ct). Can anyone help me with these questions?

Best regards,

Lucas van de Voorde

lucasvdv asked
Rousset Michel answered ·

2 Answers

cyrix-ct 12/24-120 two battery and solar system

Please, is it problem for cyrix -ct 12/24 120 if it work with two battery and solar system ( boat ) .

Because solar system charging battery all day , and cyrix device stay close for the long time!

Is it problem for the cyrix device , if yes what we must do .

Best regards

imasar6 asked
bazbaz answered ·

3 Answers

PV system (MPPT + LiFepo4) + AGM - how combine for standby operation


I set up tiny pv system with victron MPPT solar charger + victron lifepo4.

System work great day charge - noon discharge but i”m lacking ability to have emergency power (like ups) that will allow me work offline in case power outage (lifepo4) is in constant charge or discharge so i can’t rely on power stored inside when i have couple days of shade - lifepo4 is discharged and i”m working from grid -and this is what i want .

I would like have separated battery just for storage power only to use in case real outage. I make decision - now we have serious condition - i remove all non esential dc load and switch to backup

battery to power my computer.

I bought for that victron agm 110ah.

What will be the best way to combine this AGM as backup so it will be keep fully charged but wont be discharged until I decide?

first part is easy - i just buy isolated dc/dc charger and make it constantly recharge my AGM from that liion battery that is tied to solar but how to connect inverter / dc load?

hardware changing wires to agm seems like bad idea.

i saw boat switch but all of they have mode For combine both batteries - Im afraid how they respond when fully charged agm is connected to fully depleted 100ah lifepo4.

I seen victron have something like diode combiner - does this will be good for my use case?

or buy two isolated dc-dc chargers and hook one of them in way it recharge agm from lithium and second lithium from agm and then just add double throw switch?

in normal mode it will be charging agm - in reverse it charge lithium - that way i left all my load connected to lithium.

any ideas?

opzsgu asked
Mike Dorsett answered ·

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