For my new off-grid project I want to have about 15kW inverter. So, I consider one MultiPlus 15000 or two MultiPlus 8000 or three Multiplus 5000.
Having one unit is easy and straightforward. I did that before. Having more then one unit adds a benefit of redundancy. I like it. I guess that parallel connection should not be too difficult.
The most important consideration for me becomes noise. I have MultiPlus 10000 at home and it can be pretty loud, especially you feel it when you are in the middle of nowhere with no noise pollution.
The 8000 needs an external transfer switch in parallel. You donāt get automatic redundancy as soon as one unit drops off you lose all output and will need to re-program. 3x 5000 would probably be the best due to price and availability. Or go for the 1x 15000. Not sure if 3 units doing 4000w will be as loud as 1 doing 12000w. It would be interesting to find out.
The bigger the less noise under small load, parallel units is an option but can be tricky to get running smooth, can cause a lot of issues and you need to be exact on cabling
I donāt think that re-connect/re-program would take too much time. A little bit of manual work is better than weeks without power if a single unit dies and replacement is nowhere close. At home I use Multi 10000, and I have old Multi 5000 as a back-up on the wall next to the main unit. If anything happens to the main unit, I will reconnect wires from one unit to another one and Iām ready to go.
I cannot tell for sure (and that is why I ask here), but I had a feeling that my old Multi 5000 was not that noisy as new MultiPlus II 10000.
Multi 10000 can be absolutely silent when it does no cooling, but at some level of load it starts the fan and it becomes bad. It is not too bad, but Iād like it to be quieter. And that level of load does not look too high.
Depending on how your DB is set up you can always split the DB and run multiple systems.
For example one smaller systm that does lights and essentials (like fridges)
One for the heavy lifting like pumps hot water etc.
The redundancy is already there as lights will remain on if the heavy lifter overloads and shuts down. The newer firmware on the GXs will be able to control two inverter systems.
Multi RS is a quiet option as well.
We have the Inverter RS. So as offgrid as it getsā¦
They can three phase and parrallel.
If you familiarise yourself with the process and have the mk3 cable ready and laptop, maybe a few ethernet cables handy can be easily done. If you design the system for easy isolation of the AC and DC for removal it should ok. Make sure you update on what you did.
Sorry, I did not understand that. Do you mean parallel connection of multiple Multiās? Iām sure it is doable.
I am not too focused on āeasy isolationā. I just like an idea to have several devices and an option to use only one of them if another one suddenly died. It doesnāt need it to be an automatic process. It just need to be doable. Hopefully Victron products would not start dying on regular basis. My experience with Victron devices so far was extremely positive.
If you parallel 3 5000ās it would be rare for one to fail. I am in Australia and I can buy 4 5000ās for the price of a 15000 so parallel is competitive. If you want to parallel 3 to make 15kva you can. If one does fail the whole system goes down and needs to be reconfigured. You can do that but the DC and AC are also in parallel and without isolation for each inverter it will be difficult to take one out for repairs and use 2. For example, you will need DC isolation from the battery and AC isolation for the input and output of each multi. Otherwise, there will be live DC and AC wires all over the place. Have a look at wiring 3 multis in parallel and see how it will work for you.
Thank you! Another excellent product I was not aware about. It goes in category āinvertorsā, while I used to look at āinvertor/chargerā. Bad on me
Multi RS does not support parallel, but Inverter RS supports parallel. And AC coupling too! And āautomatic redundancyā! Three Inverter RS together are lighter than on MultiPlus II! So much to love.
My last and most important question: Victron says āquietā - how quiet is āquietā? Especially for two (three?) working in parallel?
I was thinking to disconnect some DC and AC wires and then reconfigure the system. Quick and easy. However, it looks that there is a more superior product available for me - Inverter RS Smart Solar.
I am not sure about that I donāt have any experience with them. Most people are drawn to Victron products because of their low-frequency toroidal transformers. I guess they might be cheaper to make and lighter to install.
All valid points. Probably, we have to trust Victron that these devices are equally good as āclassicalā ones with their own advantages (smaller weight) and limitations (somewhat lower surge capacity). @Dave (above) uses two units in parallel in the off-grid set-up, and he is happy with their performance.
To be honest I have nothing to compare with, the fans donāt seem to come on that much (at below 1kw unless a hot day) and when they do i donāt think itās too bad (but other might disagree), all i can say is they have been rock solid and not missed a beat.
For me the facility of keeping electric supply (if one should fail or adding/replacing one) is very important as we have a small holding and might have some heat on for an animal and i cannot have that fail. If i need more power i can just add another RS
They come with 5 years warranty as standard but can be extended to 10 years if needed.
Iām off grid and have two Multiplus 5000ās in parallel.
Re Noise: their fans go on at the same time. Iām not convinced the combined decibels are less than what youād hear from one 10 kVA.
Pluses: I havenāt yet experienced one failing and the other kicking in. It would be nice. I thought that I would need to reconfigure the āslaveā if the 'āmasterā unit fails? Which means the other doesnāt just kick in.
Cons:
I have an issue with the temperature sensor and both units are about to go away for repair/diagnostics, which means I will not be left with a āworking spareā. My installer is lending me a 10 kVA unit until it/they come back.
My concern is you arenāt supposed to parallel units that are not manufactured at the āsame timeā ie. the serial numbers are supposed to be close or even sequential.
If one has failed, this implies to me that I will not be able to parallel the repaired one with the old one. Iām regretting my decision to parallel two 5 kVAās. I have no idea how Victron is going to make this whole again.
