This site is now in read-only archive mode. Please move all discussion, and create a new account at the new Victron Community site.
Question on the Orion DC-DC Converters.
I am looking at a 24V IN-12V Out Converter for fairly small current output, but one thing that I need to check is one of the devices is a 12V Compressor Fridge. These Fridges have a pretty substaintial inrush current - what kind of peak/overload current can these Converters handle?
I use the Phoenix Inverters for 240V fridges and they are fine at handling big momentary surges. Can the DC-DC Converters do similar?
Hi W. The Orion-Tr's seem to be a fairly common model, so I've picked out this link just as an example: https://www.victronenergy.com/upload/documents/Datasheet-Orion-Tr-DC-DC-converters-isolated-100-250-400W-EN.pdf
There's some specs in there that might help you decide, also the V-sag cutouts and short-circuit A.
The nature of dc loads is that the V may sag if A is limited, but may well 'catch up'. Might depend on your load's protection too (if any).
I grabbed a 48/12-20 (240W) for my dc loads, and totally forgot about a 12V intermittent pressure pump I had, the start load of which was likely quite high. Never experienced any issues.
Thanks for the reply, John.
I've decided to go for the Orion DC/DC rather than the Orion-Tr as the current limit of 20A on the Trs seem a bit low.
This is going in a Live-in Van, with primarily DC loads, which could also increase and so 12V demand could increase. 70A will be more than enough for expansion and I am sure will also cope with the compressor in-rush (which can be surprisingly high. my 34W Fridge has an inrush of nearly 900W!)
And between the 40A and 70A units, I have now decided on the top-power 24/12-70A model now for a couple of reasons.
I think I'm hitting a similar problem, and could use some guidance.
I have an Orion IP67 24/12-20 which did fine (apparently) powering a nominal 5.49A@12V portable fridge for a while, from the 24V house battery.
We upgraded to a new (larger) fridge, rated 11A@12V. I got a couple of "compressor won't start" warnings, and I think I'm seeing some indications of false starts in the current traces from the related SmartShunt--instead of the current going to a nice stable ~2A and there being a regular set of running/idle current plateaus and more or less regular duty cycle, I'm seeing more variation in the duty cycle and what look like some start attempts. I suspect that the overload protection is getting a work-out. The wiring is 10AWG and only about 4 feet from the converter to the 12V outlet, then whatever cord came with the fridge. The drop when running is only about 0.3V per the telemetry from the fridge; 12.4V when idle, 12.1V when running.
The 24/12-20 was, let's be honest, very inexpensive, and small enough to fit the space available. Can two of them be paralleled to the same load, possibly through a Schottky diode-OR? Or I could put a nice big cap, maybe 2mF-10mF, 25V, at the load end, but that has its own perils.
