Re: ONAN replacement or not?



I am a big fan of Victron and I am really impressed with the Cerbo GX. Here is a short Victron video which explains the enormous capabilities of the Cerbo GX: 
CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
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On Wed, Dec 2, 2020 at 10:52 AM Karen Smith via <> wrote:

Our electrical monitoring equipment now is a Cerbo GX system from Victron.  Pretty sophisticated, and the amount of data that it keeps track of can keep a data nerd like me entertained endlessly.  

We of course know the usual stuff, battery voltage, power draw, State of Charge.  But also our the AC power usage from either shore power or inverter.  Battery charge and discharge current.  Solar production. Battery temperature. All the status data from our Victron MultiPlus and solar controller are available.  It controls the MultiPlus functions. It is connected to our NMEA 2000 network so it knows where our boat is, and the data it collects is available on our MFD.  When an online connection is available, all data collected is uploaded to Victron’s servers, so is available online even if we are off the boat. You can even control it from “the cloud.” You can request it to send you an email if there is an alarm. It can start the generator automatically based on state of charge, voltage, or current draw, and then shut it down when no longer needed.  All the data and status information is presented in a clear unified context.

We have been really happy with the Victron “eco-system” of products.  They have all performed flawlessly, and it seems every software update bring some cool new feature. I am pretty sure if they had offered a generator, we’d have installed that.  It does play well with our WhisperPower unit, however.  

One of the key parameters for us is to watch the difference between the “high” and “low” halves of the battery bank.  If they drift apart from being identical (half the nominal 24V total) that is an alert to a problem.

One of the keys to keeping a Firefly bank happy is to follow their current user manual very closely.  You have to occasionally do a deep discharge (all the way down to 21 Volts) then charge to full at 0.2 to 0.5C.  For our 464 A-hr bank, that is between 93 to 232 Amps. My understanding is that this is the Firefly equivalent to the equalization charge used for an FLA battery. We have done one of these full cycles since we installed the new system, and we got a little bit more than name plate capacity out of the batteries.

Bill Kinney
SM160, Harmonie
Fort Lauderdale, FL, USA

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