Setting up a system that I’m hoping will take either split phase or single phase grid input into two inverters connected to a single battery bank. It appears that the Split Phase 180 (L2 floating) option allows for some level of phase shift between L1 & L2. However, after searching and searching, I cannot find details on the limitations of the amount of phase shift the system will accept in official Victron documentation, which is frustrating. Can someone point me to detailed documentation on split phase systems? I have found a lot of information on 3 phase and parallel configurations, but detailed documentation on split phase systems is poor. Can L2 float ±180°? If so, it should work. However, I found some archived (and old) threads on the old community site that indicates there may be a much tighter limit on the L2 phase shift (I saw mention without reference to ±60°) at which point the L2 inverter will refuse to accept grid input.
If there are no good documents which give real detail of split phase systems, as I suspect, could someone tell me what the limits of phase shift are for a Dual phase 180 (L2 floating) system? Is a Dual phase 180 (L2 floating) system set up in VE.Bus System Configurator the equivalent option to a Split Phase 180 (Autodetect) system as set up in VE.Bus Quick Configure? Why the different terminology?
Split-phase means single phase 240V “split” into two 120V phases with a neutral. The split phases are 180° out-of-phase with respect to each other. In a three phase system any two phases are 120° out-of-phase from each other.
The L2 floating and L2 floating with return is useful for building a 120/240V split phase system that can also charge or synchronize to two phases of a three phase system. If you don’t include the “with return” option, then when the inverters sync to the two phases with 120° phase rotation, they won’t return to 180° phase rotation when disconnected.
The “floating” doesn’t mean it will accept a range of phase rotations. It’s 180° or 120°.
If the different phase rotations don’t yet make sense to you, then I would suggest you first download Victron Energy’s PDF book titled “Wiring Unlimited” and then search on YouTube for videos that compare single phase to three phase power delivery. I think that will help clear it up for you.
I’m familiar with wiring unlimited. Nice text, but does not address this subject whatsoever.
I’m also familiar with single, split, and 3 phase electricity.
You say “floating” doesn’t mean it will accept a range of phase rotations. It’s 180° or 120°. You may be right, I’m obviously not sure, but I cannot find this in any victron documentation. Can you provide a source for this statement?
The graphic they use in VE.Bus Quick Configure sure implies it is more than just 2 phase arrangements that it will accept, but perhaps I’m reading too much into that–just trying to find the document where it is spelled out.
I teach two-day Victron training classes for engineers, electricians, and installers who purchase from us. I have commissioned countless single, split, and three phase systems. Victron does not provide detailed documentation for all of this so I can’t point you to any specific documentation. I can only assume the reason for this is that your average Victron user does NOT understand all the ins and outs of complex electrical systems, and certainly not phase rotation, and should probably not be doing this on their own. If I were a multi-national corporation selling sophisticated and deadly power electronics, I would prefer to encourage customers to seek professional help for multi-inverter systems as a means to limit liability rather than document everything.
You get to choose whether or not you want to believe me. Or, you can rig up a test stand with phase converters that allow you to modify the phase rotation and then you can test how it works. Also consider that maybe you’re hung up on solving a problem that doesn’t exist.
You are likely to encounter fluctuating voltages and frequencies, especially in mobile environments. but fluctuating phase shifts is not likely. Perhaps someone smarter than me can chime in here.
Good luck with your project and learning along the way. (there’s no sarcasm in that sentiment)
The problem I’m hung up on solving is understanding how the unit operates, and yes that problem does exist on this end. If L2 were allowed to change from 180° out of phase to 0° (in phase) with L1 when connecting to different grid sources, it would enable me to set up the system I’m designing in a very flexible manner, which is why I’m trying to understand the full details of this option. I also enjoy reading technical manuals and understanding deep details of equipment like this. If it operates as you state, I think something like “120/180 Split Phase Auto Adjust” would be a far better way to describe it in the set up software than “L2 floating”, and a few simple sentences in the manual seems like a good idea (understatement).
Your answer that Victron “does not provide detailed documentation for all this…” is unfortunately the same answer I was coming up with. Your assertion that limiting liability can be achieved by poorly documenting the operation of ‘deadly power electronics’ you sell to the open public is frankly ridiculous. I have been really impressed with the Victron equipment I’ve bought & installed from the standpoint of performance, flexibility, system integration, and especially value. With that said, I find the documentation a horrible, disjointed cobbled together mess. I have found online forums such as this one to be an OK source of info but really painful at times as well.
If you have purchased Victron equipment already, then per Victron’s own policy the distributor from whom you purchased your equipment is REQUIRED to provide technical assistance and warranty support. If they don’t, then an email to salesUSACanada@victronenergy.com should quickly resolve that. That said, I have two tips for you:
Use VE.Bus System Configurator instead of Quick Configure
Uncheck the box “switch as group” for the AC input you are concerned with.
#2 will allow you to charge batteries if only one of the phases matches the configuration you set for the inverter group. If the AC input equals the configuration you have set for the inverter output, and you wired things up properly, then all inverters in the group will sync and charge. This is a common configuration item for split-phase systems installed in mobile environments that will plug into different shore power configurations.
P.S. We design systems around a variety of OEM products. Victron’s documentation is better than most. The documentation is written for the professional, not the hobbyist. And I don’t just mean the Victron professional, but a professional in the power systems space. Having written plenty of technical documentation myself, writing for the n00b is an order of magnitude more work for little gain. Victron provides Wiring Unlimited and FREE courses on the Victron Professional website - and they allow end-users to join VP. Again, that’s better than most companies out there. One way you could contribute to the body of knowledge is to write said step-by-step documentation for every scenario. Once you do, you’ll realize how much time, energy, and money went into learning everything necessary to write such documentation, and you would also realize that’s a valuable skill and maybe think twice about giving it all away
In this case, it’s not ‘how’ the documentation is written regarding the details of L2 floating, and what the feature’s limits are, it’s that it isn’t written about at all, at least not as far as you or I can figure out.
Regarding unchecking ‘switch as group’ so that at least one MP would work when the AC input “doesn’t equal the configuration you have set”, I understood that before. What I didn’t understand (because it isn’t documented anywhere), is what does and does not ‘equal’ the configuration. The description “L2 floating” and graphic showing L2’s phase moving over a large rang relative to L1 gave me some hope it might accept any phase relationship between L1 and L2.
At this point I think my best bet is to suck it up and add an autotransformer between the MP and the single phase grid input to convert said single phase grid input to split phase. The other grid input and generator are both split phase. I did not want to go to this trouble, complexity, or expense if I didn’t have to, but at this point it seems like the simplest solution due to MP limitations. I know I’m not the only one who would appreciate a firmware update to increase the flexibility of these systems such that there would be an option where they would automatically recognize and accept either split or single phase inputs. Lots of users have asked for this on the archived community site, but apparently not enough to warrant the development of such a feature.
I have the same problem, grid here is Y, 127/220V. Loads are 220V connected to L1 and L2 without N.
Want to use a Multiplus 48/3000/230.
After reading the docs available, it seems the solution in my case would be keeping the ground relay always open.
This way I could connect the MP input to L1 and L2 without N and the AC out would feed the loads with L1 and L2.
Maybe I’m missing something here, but I guess it should work.
