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aegir avatar image
aegir asked

Cerbo possibilites

Having just ordered the Cerbo and working on replacing my lead batteries with lithium I want to exploit the Cerbo's features as much as possible.

So the setup in my boat is as follows

no-name 75A alternator

Argo Fet 3-200 1. lithium bank 200-400ah. 2. starter battery lead-acid. 3. bow anchor windlass battery lead-acid

victron 75-15 mppt with one 100watts panel

victron 1200/50 inverter/charger (latest model)

712 battery monitor

And once it arrives the cerbo


Now i intend to connect the 712 and MPPT with VE.direct and the inverter/charger with VE.bus

First question: Is the VE.bus rj45 cable a standard ethernet cable or is there a special pinout listed somewhere?


Second question: With everything connected to the cerbo can i configure the inverter/charger to charge lithium batteries?


Third question: with all this tied together can the inverter/charger use the battery temp sensor from the 712 instead of its own battery temp sensor?


fourth question: Can a battery temp sensor connected to the cerbo be fitted to the negative or plus pole on the alternator to monitor the alternator chassis temp and can i set a certain temp to trigger one of the relay ports? (starting a cooling fan)

cerbo gx
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1 Answer
machined avatar image
machined answered ·

Yes the inverter charger will charge your lithium batteries but only from shore power or a generator.

You can't pump power straight in from the alternator so you need to figure out some sort of DC to DC charger (Orion Smart 12/12/30) going from your starter battery if you plan to charge those lithium batteries off the alternator.

Get an automotive charger or blue smart ip65 to charge the anchor battery.

The inverter charger will get the 712 battery temp from the Cerbo but again the inverter charger only charges from Shore or generator power.

100 watts of solar is almost like having no solar at all. I would try and get more if you can. The biggest Victron DC to DC charger is only going to send 360 watts max to the batteries so you'll be running the engine forever to get yourself charged up.

As for the fan, the cerbo can take a temp reading from your battery and can send you an alarm but I'm not sure it will trigger your relay based on the alarm. I could be wrong on that one but I was trying to do a similar thing with the water level meter and couldn't figure it out without additional programming.


Good luck.

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aegir avatar image aegir commented ·

Thanks! the dc-dc charging is not an option as its only 30amps and the lead battery it takes the DC from barely can take in 30amps from the alternator, one if the reasons i want lithium is the huge charge they can handle. as im on a sailboat im not using my engine that much, but have lots of power drawn when the sails are up because of autopilot, fridge and so on, and also lots of time spent on anchor without shore power. So preferably i want all those 75amps the alternator is supposed to deliver into the lithium when i run the engine in/out from the anchorage or if i need to fire up the engine only to charge the batteries.

Regarding the anchor battery it only gets charged by the alternator through the argo fet, but when you mention it i really should have a trickle charger on it.



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