Victron Orion 12 | 24 75% output power

[BillyGoat]

Hey all. I have a truck camper setup with 2 100ah lithium batteries in series for a 24v system. I ran 4awg cable from the 2022 Tundra starter battery to an Anderson connection in the bed of the truck (about 12ft) and then another 3 feet of 4awg to a fuse block where I switched to 6awg for 2 feet into the Orion 12 | 24. This is an isolated Orion with a round trip of about 35ft of 4awg.

I never get over 12 amps (normally 10amps while driving) from this system. I originally thought it was the known overheating issue so I installed a computer fan behind the Orion and this hasn't helped. While completely cold I get about 11.5 amps and then it drops to 10.

Troubleshooting steps I have tried:
check voltage along the system

- 14.2 at the starter battery

- 14.15 on the other side of the fuse at the battery
- 13.6 at the Anderson connector
- Orion saying 13.45 at the end (about a 5% drop)

I have lowered my engine cut-off to 12.8 and also completely disabled the engine detection cutoff completely with no change to the input voltage.

The system is drawing 0.4 amps while everything is off so I have factored that into the input numbers from the Orion.


I drained the battery to 4% and tested with my 120v charger and the battery takes 60amps from that so the bms is willing to accept the charge.

I'm out of ideas for why this isn't working to full capacity besides the cable run/voltage drop. But I understand that it should still be putting out full power even with the drop if the engine detection is off. Any help would be greatly appreciated!

 

[BillyGoat]

temp probe is not accurate. unit is about 45 degrees f

 

[BillyGoat]

 

[HRTKD]

Are any of the cables or connectors getting hot or feeling hotter than the rest of the system? If so, that could be your problem. The 13.6 volt reading at the Anderson Connector is where I would start.

 

[chrisski]

I have had a bit of problems with the Anderson cables and also expect that the problem is there. I've seen corroded connectors, recessed pins causing bad connections, wiring into the connector frayed.

===========

My Victron SCC derates itself when in direct sunlight about the same amount you mentioned. I see you installed it in the bed of the truck, so it is removed from the hot engine compartment. Is this exposed to direct sunlight?

The heat that causes derating is anytime it is exposed to sunlight on a warm day. The outside ambient temp could be 115 F, and as long as it shaded, the SCC pushes out 100%.

 

[rickst29]

It is my understanding that that the operating voltage within the engine compartment will be allowed to "settle" to a voltage around 13.5 - 13.6 volts, with ECM regulating the alternator to maintain only that Voltage after it "thinks" the battery has been adequately re-filled from running the starter.

With tight cable connections into that battery, the under-hood "starter battery" battery terminals should show that lower voltage value after the engine has been running lfor longer than about one minute. I suspect that your 13.6V Anderson measurement does reflect the actual state of the battery terminals as well, if taken at a later time.

Your weirdness is the the input voltage at the ORION converter in your last image, in which it is NOT pulling any current but "feeling" only 12.24V input voltage. That's too low, unless the Tundra is both turned off and it's battery is very low - or if it is under heavy acceleration.

There is another pair of settings, "Inuput Voltage Lock-Out"' and "Input Voltage Recovery", which could be too low in your situation. But I would have the same recommendation as HRTKD - start the Adnderson connectors and other terminals, because your wiring has maybe allowed too much voltage drop in cricumstances of higher current.

 

[SpeedFusion]

On the Orion DC-DC ignore the 15A output in your case and look at the watt output. (360w) The Orion is only rated for that much when cold, when it heats up it derates the output. Victron says the derate is 1.5% output for every 1C above 40C. I normally see ~10% less max watt output than advertised on all my victron equipment. My three 12/12-30 (360w) even with fans peak sustained output is around 330w.

So in your setup with a 28.4v absorb and 11.5a output when cold, its giving you ~325w or 280w when its hot.