question

mapi69it avatar image
mapi69it asked

Cyrix or Argo FET

What are the main differences between the cheap scheme 1 and the more expensive scheme 2?

I have no shore power but i will add PV in the near future.

Thank you,
Marcoscheme-cyrixargdiode-copia.png

Cyrix Battery CombinerArgo FET Diode
2 |3000

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2 Answers
Mike Dorsett avatar image
Mike Dorsett answered ·

In terms of end user, not too much.

The difference is that the Argo fet feeds back voltage information to the alternator, and is capable of compensating for volt drop between the alternator and the argofet, resulting in slightly improved performance at the end of the boost / bulk charge.

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mapi69it avatar image mapi69it commented ·

Thank you for your answer!

About Cyrix, Victron says "The main feature is that there is virtually no voltage loss so that the output voltage of alternators or battery chargers does not need to be increased."

I would like the starter battery to be recharged by the alternator and the service battery by the solar panel. My aim would be to keep the two circuits isolated, and connect them together only in case of a real emergency via a paralleling switch.

Would you be so nice to help me to archieve this goal?

Thank you!

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jetlag avatar image
jetlag answered ·

I used a Cyrix-ct 120A relais in a similar installation.

The relais was located between the starter battery and the service battery. The solar charger was connected to the service battery. BUT - the Cyrix relais is a bi-directional relais, that mean, it measures the voltage of both batteries (in case the relais is open) and closes the contact when the voltage is rising on the one or other battery. So you can charge the service battery via alternator, but also can charge the starter battery via solar (when service battery is full).

But with that feature both batteries are not really isolated from each other because you can't deactivate this automatism.

With the switch you can force the relais to connect both batteries what I sometimes used in winter when the starter battery was a little weak to start the diesel engine.

If you still want to isolate the batteries, you need a standard relais without any "Intelligence". With a switch you can then only manually connect or disconnect them.

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