Hi, attaching a schematic I’ve drawn up with the various components, wire cross-section and fuses for what I plan to build. I’m new to this but have some experience with AC as well as a basic understanding of DC systems, I’ve read Wiring Unlimited multiple times and used the victron toolkit to hopefully spec the right fuses and wires but it’d be great to have a second opinion or two to see if I’ve omitted anything obvious.
The solar panels, eventually, I plan to upgrade, these are just some we’ve inherited - hence the rather oversized MPPT controller for just 6 panels.
The generator I know is small, it’s one we already have - if we end up needing it a lot and it’s too underpowered I’ll get a bigger, 7KVA diesel genny. The second part of this system will be a microhydro set up, this is just the first stage to get us going and I hope to expand it as we understand our needs. With solar in summer and hydro in winter the generator will, hopefully, become redundant so I’m reluctant to spend thousands on one.
As I expand the system we’ll also add more US5000 batteries, I hope these will do for now. I don’t want to daisy chain them so I’ve done one cable per battery using Megafuses in the Lynx Distributor as protection - the idea being the switches on the batteries themselves will isolate if I need to do maintainence. Be interested if people would recommend an dedicated isolator and/or a fuse closer to the battery on each positive wire?
Location is Wales, UK, many thanks for any advice.
Never switch the negative pole (minus) in your system.
ONLY switch the positive.
If you are really completely ‘OFFGrid’, then consider using a pure inverter (Phoenix) and realise the whole generator and hydrogenerator thing via a 230V to 48V high-performance charger. Then you won’t have any problems with the AC In of the multi.
Saves money and trouble
It is no problem to connect or disconnect the PV 2 pole … i.e. plus and minus at the same time … There is no danger here.
It is always a challenge to get a generator running on the AC In of the multi. Certain standards must be met so that the multi recognises the generator and does not disconnect it again. I don’t want to say that it won’t work. There are enough installations where a generator is accepted and works perfectly. If you now want to integrate other generators / hydro etc. into the system, it becomes more complicated.
However, there are already some posts in the forum on the subject of ‘Generator on AC In’ … Inverter or AVR …
The power supplies from Huawai or Eltek work with a very wide input spectrum and are very insensitive to fluctuations at the input … such as a hydrogenerator
Thanks, I’ll do some reading and see if anyone’s used this generator with the MP-II, I have a feeling not as it’s too small. Nothing is final on this so I’ll research the Phoenix
Other things to consider is the generator breaker should be a 2pole C40 breaker.
Apparently I shouldn’t earth the Lynx distro and it should be a floating system?
“The second part of this system will be a microhydro set up”
It will be much more interesting to connect this system … do you already have voltages or other performance data?
The advantage of the ‘AC In’ is the direct power supply from the generator through the Multi, the ‘Power Assist’ and the charging of the batteries by the Multi’s charger …
One idea would be to integrate the generator via AC In and integrate the hydro via the DC side
It’s just an idea at first … so the drawing would only be a plan.
Depending on the performance, you can also use an even larger multi …
In addition, there is of course the graphic component on the display: this is of course much more ‘lively’ and detailed with the Multi.
Re: the hydro: We’ve bought a property with an existing turbine, it’s ancient (100 years old) and the alternator/generator is long gone but the pelton wheel and penstock is in serviceable condition. I’ve yet to do flow calculations but we have about 35m of head over 200m on a 4" pipe. My plan is to use the turbine to turn a 3phase induction motor backwards wired in with capacitors to a bridge rectifier to get DC. It’ll be similar to running a wind turbine on the controller side, I’m not sure how well victron MPPTs adapt to this but i know Solis or the Midnite Classics can.
It’s a task for the future though, for now this solar setup should get us up and running!
I’m sure it will be a cool project with the turbine.
If the voltages are suitable, an Mppt is certainly a very good choice, because the ‘water power’ works much more evenly than a wind turbine under changing wind conditions. If the operating point can then be found, the power yield will be good.
Why are you only using 250W modules? Can you get them cheaply or is there no other way to install them due to their size?
They’re what we’ve inherited with the property so i might as well use them- I’m installing them on the roof of a barn.
Again, once we’re up and running I’m going to get a much bigger array up on the hill behind the house - it’s a much bigger project involving trenching and framing a structure for the panels etc. I’ll use the overspecced 250/100 SmartSolar with them and either retire the 250W array or get them a smaller MPPT.
I’ve had a few changes suggested via a Facebook post so I’ll redraw my schematic. Is it best practice to keep it all contained in the same thread here?
Changes are I’ve gone for 3 srings of 2 in series of my panels, changed the combiner and downgraded the MPPT to a 150/70
Upsized the crossection of MPPT cables to 35mm2
Genny Breaker to C curve 40A
Downsized AC ables to 10mm2
Removed Earth to Lynx Distro to eliminate a ground loop(!)
Removed isolator on Neutral DC to MP-II
I know this question has been done to death but some advice I’ve been recommended is to use a 125A MEGA and smaller 50mm2 cables for the Multplus instead of the T-Class 200A and 70mm2 which is what the manual recommends. Any input on that appreciated?
The multi-cable size is to reduce ripple. If you use 50mm you can check ripple. If it’s high increasing the cable size will help. The T-Class is for the battery. You can get 80V ceramic ANL fuses that work well with these installs. If you want to use a mega you can they are also in 80V.
You can screw the isolator switch directly to the Lynx distributor. There are videos on how to do that. Makes it very neat the disconnect is always a point of failure they are not designed very well and hard to get a good torque setting.
Your 32A isolator is too small now. That will struggle to break the 30A coming from the solar array. It should be 1.5 times the current. You have gone from 10A to 30A. Need a 30x1.5 45A or larger to be able to disconnect and extinguish the ARC.
