We purchased a new boat in October 2021 and immediately put it into charter service. Therefore, we were on the boat a limited number of times each year. We have decided to sell the boat. In the process of addressing pre-listing survey items, the electrician has decided the cables between the Quattro and batteries are undersized. The cables clearly do not meet the 2x120 mm2 spec in the Quattro manual. There is also the issue of ISO 13297 conformity. In that standard, the only cable sizes specified for 10,000W at 12v (833A) would be 2x120 mm2 or larger. The Quattro is the 12/5000/220 version.
The manual says the inverter max power is 10,000W, which I assume is the nominal power (results from online searches are confusing on this point). Continuous power rating is 3,000 to 4000W depending on temperature. The warranty manager at the selling dealer says the battery cables to the Quattro/inverter are 2x50 mm2 and are adequate for 3,500W max, close to the inverter continuous rating. I suspect for two reasons the boat as originally delivered has inadequate cabling: 1) the cables do not meet the Quattrro specs and 2) the warranty manager says the cables are aequate for something smaller than our Quattro’s max power.
I have searched the Quattro manual and find the inverter will shut down on overload when the “nominal power of the inverter is exceeded.” I take it 10,000W is the nominal power. I find nothing on setting a lower overload shutdown limit. Is it possible to set a lower overload shutdown limit on the inverter to make the existing cable conforming, adequate and safe?
No 5kVa is nominal, 10kVa is max peak for a few seconds.
Almost any diameter cable can do that for a shrot duration
What you would want to size for it the max continuous rating over the distance it is run for (return length) without (or less then 3%) voltage drop under those amps drawn.
5000VA on 12v is 420 ish amps. Math all good in your question)
If the system has a 4m return path to the bus bar using the victron toolkit even 120mm², so you definitely want 2 runs of something big.
And the manual is what matters in the end as that is what the manufacturer has set as the min requirement for a stable system.
But… In a boat space is an issue. Sometimes this colours decisions.
So we will run the ‘accepted’ set up and you will see some pretty evil volt drop, the inverter will shut down on under voltage most likely on larger loads. So 4000watts at 25°C its max continuous rating. The temperature also matters as it derates when hotter.
I gather, at the 4kW max continuous rating, the 3.5kW cables are inadequate. It doesn’t matter whether nominal is 10kW or 4kW, both exceed the allowable rating for the factory installed cables.
Your reference to node red is the first this newbie has ever heard of it. My understanding is node red is accessible through a firmware upgrade on the Cerbo GX. The boat was delivered without a Cerbo. The first time I accessed the Quattro in VE Configure, all settings were at the factory defaults. I suspect the overload shudown limit on the Quattro was also unchanged. For example, the charger current limit was at 165A, but the Quattro manual says it should not exceed 10-20% of the battery Ah capacity. For our 560Ah batts, that would mean 112A max. We went through two sets of AGMs before I caught that oversight. I’m thinking, if the manufacturer didn’t bother to change the charging limit to match the factory-installed batteries, it certainly didn’t install a Cerbo with upgraded firmware to change the inverter nominal power to match the factory-installed wiring . . . . and then remove the Cerbo before delivering the boat.
What I would be interested in is the voltage drop between the bank and the inverter to evaluate if the cables are undersized. (Which i think that they are) And then of course how often and long you run that load for? Do they also get warm - warmth is bad as well.
I guess the oversight in basic programming does not inspire much confidence. I won’t comment much on 2.
