question

Hi @kevgermany and @pwfarnell! Thank you for your replies!

I'm sorry, I don't think this is normal behavior. So I stick to my verdict of "fatal error".

But before I go too deep into this, I have to say that I was hasty with my error diagnosis and that I need to correct it.

The strange charging behavior (that the Orion XS seems to spontaneously start new charging cycles) also seems to be independent of the engine shutdown detection. Yesterday I had a voltage on the input side of the Orion XS above the threshold of the engine shutdown detection voltage for a whole day. Despite this, for some unknown reason, it was charged about 6 times yesterday with the absorption voltage (14.4 V). Because there was currently no load connected to the battery (LiFePO4) at the output of the Orion XS, the voltage never dropped below 14.25 V. The float voltage is set to 13.35 V and the storage voltage is set to 13.25 V.

Why does the Orion XS keep spontaneously charging with absorption voltage (14.4 V)?

The Orion XS may not even charge until it reaches the float voltage and later the storage voltage. Do you agree?

Thank you for your ideas for narrowing down the problem!

First, let me show you my circuit.

I monitor the starter battery using a Smart Battery Sense. The historical data from the Smart Battery Sense shows absolutely no drop in voltage for more than 60 seconds, which is why the Orion XS's engine shutdown detection probably did not trigger.

But even if the voltage had been below the engine shutdown detection voltage and later above the start voltage or delayed start voltage, the Orion XS would not have been allowed to charge again because the voltage on the additional battery was still well above the storage voltage and float voltage.

I think it's a good idea to deactivate the engine shutdown detection as a test to see whether the Orion XS still starts unexpected and unwanted new charging cycles from time to time.

Incidentally, the unexpected and unwanted new charging cycles are also not displayed in the history tab of the Victron app (Victron Connect). This obviously only happens in the background. In addition, the time data in the history tab for each of the 5 charging phases is not at all plausible. It all looks like very unfinished software to me.

It would be nice if an official representative from Victron Energy could comment on this.

Thank you very much!

The fact that the solar charger causes small voltage fluctuations on input of Orion XS can hardly be the problem, because the engine shutdown detection only reacts when the voltage is getting below the shutdown voltage for at least 60 seconds. There have definitely not been voltage drops that long and that deep. The Smart Battery Sense produces very accurate historical datas like the BMVs and SmartShunts do.

But even if there were. The Orion XS should not charge even after falling below the shutdown voltage and then exceeding the (delayed) start voltage, as long as the voltage of the leisure battery is above the float voltage (and storage voltage).

The fact that the solar charger is connected to the starter battery has the advantage that the leisure battery can be charged via solar charger and alternator with the help of Orion XS.

In the historical data of the BMV-712 Smart, which is connected to the leisure battery, I was able to detect an unwanted new charging cycle by the Orion XS again today. At this time, according to the historical data of the Smart Battery Sense, which is connected to the starter battery, there was a short, noticeable voltage drop of approx. 0.15 V for exactly one data point and was still well above the shutdown voltage. The resolution of the data at the time of my inspection was 30 seconds. Before and after this noticeable data point, the voltage on the starter battery was at the level of the float voltage. The engine shutdown detection should not have been triggered because neither the voltage was low enough nor the time period of 60 seconds was exceeded. But a new cycle has obviously started again because it was charging up to the absorption voltage again.

Even if I keep repeating myself, a new charging cycle should not have started even if the engine shutdown detection had been triggered because the voltage of the leisure battery was well above the bulk voltage. In cars with an automatic start-stop system or with a solar charge controller on the starter battery, this would inevitably lead to the leisure battery constantly being charged at absorption level, regardless of whether "adaptive absorption" has been selected and a short "maximum absorption time" has been set in the Orion XS settings menu.

And if it were the case that the Orion XS repeatedly starts new charging cycles when the engine shutdown detection is triggered, then there should be a setting where you can actively prevent this behavior. If this option did not exist, the Orion XS would be useless.

As stated previously, and just as an MPPT, or AC-to-DC charger, a new charge cycle is always started when the unit turns back on. That's the way it is.

If the charger (any of the above chargers) is set properly, there is absolutely zero harm to this - it's a non-issue. If your batteries are full, the charger will quickly progress from Bulk to Absorb, and then to Float.

In your case, you have a very unusual choice in the way you've connected your electrical components, and it's causing unusual behavior in the components - this is to be expected. So long as everything is programmed correctly, however, there is nothing to worry about. If you are still concerned, the obvious solution is to redesign your system as would be normal, with alternator to start battery, start battery to Orion XS, Orion XS and solar controller to leisure battery. This will stop the behavior you're seeing.