Hi, on our boat we use two Orion 24/24V 17A (non-isolated) parallel to charge our 400Ah/24V LiPo battery. Initially, after starting the engine, both Orions work for about one minute, then one Orion goes from bulk into absorption mode. We have optimised the cable length and diameter, but without success. Any idea for a good solution?
Show us screenshots of the 2 Orions when this happens plus your absorption and float settings for better diagnosis, otherwise we are guessing.
A charge current of 34A into 400Ah should be in absorption right to 95+% SOC and battery voltage should be 13.8V or so.
The normal cause of early absorption is high resistance in the output wiring due to loose connections, corroded connections or fuses, frayed wire, cheap resettable breakers like the ones shown below. Get your multimeter out and when charging, check the voltage at the Orion output and the battery, then track down the high resistance. It can be in the positive or negative cables, including the common negative between batteries.
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Screenshot with both in Orion in bulk mode
Screenshot with one Orion in absorption mode after 1 minute
I don´t use cheap breakers, the installation is new and not corroded
Cables are very short with recommended dimensions
I can´t find any voltage drop
If you have t chargers into a battery bank, then one of them will always go into absorption first while the other stays in bulk. If the battery bank can accept more then 34A then both will be in bulk, as the current drops below 34A one will tend to go into absorption first providing 16A and the other 17A, this will continue until it gets to a total required of 16A at which point both will go into absorption or one may even drop into float. This is because there will be a small difference in the voltages seen at the two chargers, the higher one will go into absorption first, see in your data one is at 28.20V and one at 28.19V.
You still have an issue because with 34A into your batteries you should be in bulk for a long period of time. You DO have a voltage drop issue, both of your chargers are showing 28.24V but your battery protect is showing 27.0V and the one battery you have shown is at 13.43V, so if I assume you have 2 12V batteries in series then if the other is 13.43V then they are at 26.86V, which is close to the Battery Protect value. Somewhere you have 1.2 to 1.3V being lost which is affecting your Orions by making them see a higher voltage than the batteries are really at.
The other observation is on the input voltages to the Orions, one has a higher input voltage, 28.4V compared to 27.0V, if these are from the same alternator / starter battery then one of the cables has a 1.4V drop.
You really do need to check all your cables with a multimeter and confirm the measurements at the battery terminals and the Orion terminals on both input and output. The Orions are working as expected with the voltages they are seeing.
Thank you for your help. I have checked all connections and found a blown 30A Midi-fuse between one orion and the batterie, which I not recognized before. Maybe it was blown since the first installation. Now both Orions stay in bulk mode. The output-current is not much higher than with one Orion, but the battery is nearly full. I will check this next days, when we are out on sea.
If your versions support it you should setup a VE-smart network. One Orion will act as a master and the second will follow whatever the master is doing as a slave. The BMS or Smartshunt should be included in the network as remote voltage/current/temperature sense. Only then charge currents are divided properly and voltage drops over cabling is elliminated. I did this with MPPT’s and Chargers, not sure your orions will support.
@VerreyckenGerd are you sure that the older Orions do work in synchronised charging tjey did not used to but may have finally been included. The newer Orion XS does as do MPPTs.
Good point, no i am absolutely not sure. Put some "if"s in the anwser.
one mor question to my configuartion. I have a 12V alternator for the starter battery and an additional 24V alternator for 3 different 24V-battery banks, 2 AGM and 1 LiPO.
I would like to know, if I could charge my 2 Orions for the LiPO batteries directly from the 24V alternators or do I have to use one of my 24V-AGM batteries as buffer??
You must use a buffer battery, when people have used them direct from the alternator they report large voltage cycles as the voltage / current control on the Orion fights with the voltage control on the alternator. Some people manage it but it is rather by luck, mostly it does not work.
All depends on a few factors. An alternator makes AC, this AC is rectified with semiconductors. The halfwave rectified peaks are sometimes buffered with a capacitor before they go into the voltage/current regulator. So it depends on your vehicle. The power rating of your alternator and the capacity of the capacitor play a role here. You could try it without first. Using a heavy weight AGM only as buffer is far from ideal.
But it is not to smooth / buffer the ripple voltage, it is to decouple the dynamics of the two sets of voltage controllers and there are lots of people who have tried without and got voltage cycling, this is ehy Victron always show the engine battery between the alternator and the Orion. Withput the battery, the intermediate voltage swings rapidly as current changes.
It is aldo about load dump, of the altrrnator os only dupplying the Orion and the BMS shuts the Orion down the alternator voltage may spike for a short while, the lead acid battery absorbs this. You can add on protection devices, the alternator may have good enough diodes to stop this. Again, people without buffer batteries have damaged alternators.