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48v Wiring advice


Looking for some advice regarding the DC wiring of this setup

upgrading to 48v system from 24v.

Multiplus II 15KVa.(running ESS)

4 x 280Ah Seplos DIY Packs with EVE 280aH Batteries. (might add more)

40 x 250watt Solar panels. + 2.6kw Ac coupled system on roof (Inherited when bought house)with ET112 energy meter.

4 x 250/85 MPPT.

Couple of Questions.

1. Do I need to fuse between Busbars and Multi.

2. can I use Blue Sea 6006 switches - Only rated at 48v.

Many thanks



Solar Overview.pdf

richie-gorrod asked
pyrorider commented ·

3 Answers

Use of overflow to heat water


I have a novice (perhaps stupid) question regarding use of overflow (not sure whether that is the correct therm) to heat water.

I have a Cerbo GX + 3x Multiplus II 48V/3000 + pylontech batteries. The system is ESS.

I also have a water tank and electric heater (2 kW) in it.

How should I manage the electricity when the battery is full and the overflow is going back to grid, so in that case the electric heater will turn on and store the energy to the water instead of going to grid?

I guess that I can use the relay 1 (or 2) on the Cerbo GX to turn the heater on/off or something like that. Is that correct? Or am I wrong?



jakudo asked
mvas answered ·

2 Answers

BMV 712 positive connection

The manual states to "Connect the M10 eye terminal of the red cable with the fuse to the positive terminal of the battery." This is an 8-10 foot run. Can I connect the cable with fuse to the Lynx Distributor positive?

Positive cable from battery goes through disconnect switch and then connects to distributor. The distributor (positive) sends a cable to inverter, but also connects the solar panels. With the fused cable from the shunt not connected to the battery, I don't get DC readout. So is the connection to the battery terminal required? (or did I solve my own question?)

vick-da-aerbus asked
vick-da-aerbus answered ·

2 Answers

Victron stainless steel inlet sockets: compatible with non-Victron shorepower cords?

Are Victron stainless steel inlet sockets (can't find a specific product page on the Victron website - see here for another source: https://www.kuranda.co.uk/victron-energy/shore-cords-and-connectors/power-inlet-16a-stainless-steel-shp301602000-victron) compatible with non-Victron shorepower cords?

I.e. could I use something like this https://www.distributionzone.com/Products/Cables/Made-up-Cables/5-Metre-Black-HO7RN-F-2-5mm-with-16A-2P-E-Plug-Con?

I have been given conflicting answers so would appreciate some clarification.

Many thanks!

nboatlyf asked
kevgermany edited ·

2 Answers

12v 3 bank charger and BMV 712 iN 36v system wiring help

need a wiring diagram for a 36v system with 3 bank charger and bmv 712 smart. also can i monitor 3 batteries? ive only seen 2 batteries be able to be monitoree

tmacoo4 asked
snoobler commented ·

1 Answer

Wire Guage & Fuse Size - Smart LiFePO4 Battery 25.6V/200AH Smart-a

Trying to determine the Fuse Size and Wire Gauge between a Victron 25.6V/200AH Smart-a Battery and a Lynx Distributor.

Should they match the Fuse and Wire specified by Victron for the connection of the Multiplus 24/300VA? Or should they be both be sized larger to accommodate loads in addition to the Multiplus?

I have searched and found varying/conflicting information online so I wanted to confirm.


vanchitect asked
vanchitect edited ·

1 Answer

Can I remove these? Lynx Distributor - Cable separators


Can I snap these small pieces that separate the cables? The ones circled in red. Just the piece that splits it in half, not the piece between +/-

What is their intended purpose? I need to fit a large cable and don't think it'll fit with this separator.

bodizzy asked
bodizzy commented ·

1 Answer

Battery Isolation Best Practice


I have an ESS system consisting of two Pylontech US5000 battery modules and a Victron Multiplus-II 48/5000/70-50. It's all single phase and based in the UK. Initially I used a pair of basic 150A bus bars but have recently upgraded my wiring in anticipation of adding two 250/60 MPPTs and a 6.8kWp solar array.

Since my US5000 battery modules can in theory discharge at 100A continuous (80A recommended) each, and since I expect to add a third battery at some point, I decided to run separate Pylontech battery cables for each module rather than daisy chaining them.

So I have my batteries feeding into a Lynx Power In module, modified to take fuses, via a 125A mega fuse each. I then have the Multiplus-II feeding from the same Lynx Power In via a 200A mega fuse and a 275A Victron DC isolator. This is on 70mm2 fine strand cable as recommended. My MPPTs will connect to the Power In via 35mm2 fine strand wire and 80A, 70V mega fuses. At this point I will be adding a second Lynx Power In as I need the extra connections.

My question is whether I should have DC isolators on each incoming battery cable or whether it's fine to rely on the Pylontech modules to power down when commanded via the red button and rocker switches, plus removal of the positive amphenol connectors for final isolation? I would prefer not to cut the manufacturer fitted M8 lugs off the Pylontech cables and add M10 ones to work with the DC isolators and I don't feel that being able to isolate the battery modules individually is ideal and might cause problems in itself.

Another option would be to install the second Lynx Power In module and place an isolator between the two Lynx modules. But that would require the 8mm holes in the bus bar to be drilled out to 10mm to accommodate the isolator and even then, the isolator bolts are not long enough to accommodate the spring washer and nut. They are long enough to accommodate the nut alone but then I'd have to use thread lock or locking wire which isn't great. Or maybe use a different isolator. Or I'd have to use little short pigtail cables which adds resistance, complexity and points of failure.

So, my question again is, is it ok to run the standard 2m Pylontech cables in a ventilated conduit from the batteries to the Lynx Power In and simply have the inverter with a 275A DC isolator and each MPPT will have a solar PV DC isolator. Then when I want to power down the whole system I would isolate everything in sequence before commanding the primary battery to shut the whole battery array down before toggling off the rocker switches and finally removing the positive leads for guaranteed isolation. Before that last step I would observe the Cerbo GX and MPPTs were powered off to ensure no load was present. This would be a much more elegant solution with fewer DC connections but I want a sanity check on the safety and compliance aspects please.

Many thanks.

Craig Chamberlain asked
Craig Chamberlain commented ·

1 Answer

Cable Size Difference for 12V/3KVA

I was looking at the recommended cable size in the manuals for the MultiPlus 12/3000, the Phoenix Inverter 12/3000 and the Phoenix Inverter Smart 12/3000 (230VAC versions). All of them have 3KVA inverters but the recommended cable sizes are different.

Multiplus manual recommends 2 x 50mm2

Phoenix Inverter recommends 1 x 90mm2

Phoenix Inverter Smart recommends 2 x 95mm2 (with a note saying one cable must be able to carry full fuse rated current without overheating)

All 3 recommend a 400A fuse

Is the recommendation for the Phoenix Smart a bit over kill or is there a good reason for the much larger cable requirement? The 95mm2 cable doesn't fit into the cut outs in the Phoenix Inverter Smart body, the small plastic cut out liners need to be removed in order to fit 95mm2 cable into the inverter. The 95mm2 cable not fitting the cut outs and being double the recommendation for the other two devices seems strange. Can anyone let me know why the Phoenix Inverter Smart requires the extra cable size?

spudgun asked
waldemar answered ·

3 Answers

Cerbo GX to BMV-712 Options

I've got a new Dynamax motorhome. They installed a BMV-712 in the center of the layout but the rest of the electronics are easily available.

I loved my Cerbo in my previous RV so I am doing it again...but I dont think its going to be possible to get a ve.Direct cable from the BMV to the Cerbo GX..or anywhere for that matter, it was installed before the walls were in and the com cable now runs under the shower and out of the floor quite a ways away from the nearest physical access. I can get to the back of the BMV, but only a few inches from there. Plus I think the wires are zip tied in, so I dont think I can just pull the com cable as a guide to fish 2 new wires through.

Any other options to get BMV data to a Cerbo than going from the BMV with a cord?

I'd love to Bluetooth, but I think the answer to that is still No.

Motorhome is fully RV-C, but don't think that'll hook up to a BMV. (for battery..I'll be diving into that later to get more data to the Cerbo)

I could go to the shunt quite easily from the Cerbo...but how?

Seems very redundant, but maybe a SmartShunt inline with the BMV shunt? Or is there a way to send 2 outputs from a single shunt to a 2nd BMV installed in my electronics bay?

Open to ideas...

ghostrider asked
klim8skeptic answered ·

1 Answer

Lynx Distributor Usages Clarifications

Hi All, my first time with Victron products and Solar Energy. Questions about Lynx Distributor. Considering that has 4 slots fused.

1) May I connect the whole system in One Lynx Distributor Unit?.
Slot 1: Multiplus-II 48/3000 (Fused)
Slot 2: SmartSolar MPPT 250/100 (Fused)
Slot 3: Lithium 48V Pylontech US3000 (Fused) (3 parallel modules connected with cable kit 120A/2000mm lenght)
Slot 4: Venus GX (Unfused as brings its own in-line Fuse)

2) Fuses sizing should be MEGA 125A for all 3 Slots? (i.e. Littlefuse MEGA 125A/58V for 48V)

3) Is there a minimum lenght for Cables of Slot 1 and Slot 2, I have available AWG2 35mm2 nominal cable (33,6mm2 actual section). For Slot 3 cable kit size came Pre-Fabricated.

Please if you see any safety issue advice, this is an Off-Grid system. 3000W Panels Array (4series x 2 strings). (SmarSolar is oversized for future expansion duplicating whole system)

Thank you,


sanchuka asked
ponzoa commented ·

2 Answers

Where to purchase a V-Sense Cable?

I have done a pretty thorough internet search and have not been able to find a vendor that sells the V-Sense cable which, for some reason, Victron does not include with new multiplus purchases (T-Sense IS included, surprisingly). Any ideas? Is it possible to "roll your own"?


Stephen Otto asked
kcsbk answered ·

2 Answers

Earthing and power feed on this system...?


My plan is to have a solar system with pylon Li batteries supplying 6 lower powered circuits in the house - lights and some socket ring circuits - with the grid charging batteries when needed. The grid will also permanently supply my higher-powered circuits such as the shower and electric cooker (the solar system will not be involved here).


I have 3x 3.5kW pylon batteries, Multiplus II 5kw, 9 x 455W panels in 3 paralleled strings of 3 panels, 250/100 smart soar MPPT , lynx distributer and cerbo gx.

I have attached my wiring diagWiring plus poss consumer unit layout 2.pdfram for the solar system (p1) and for the consumer unit (p2). I need to get an electrician to check and wire this but just have a few questions for you guys if you can help…


1.Is the grounding/earthing safe and correct?

2.With this set up is there any way in which I might be putting power back into the grid or is it just one way? If I am not putting anything into the grid do I still need to fill out the G98/99 applications?

3.How long could my cable runs be consumer unit to the inverter charger? I am still unsure as to whether to have the solar gear in the garage or a different room in the house or even in the loft…

Apologies if some of these questions are very basic!

taddy asked
daza edited ·

4 Answers

Which Victron components should be connected directly to the battery?

Hello! I have a 12V system in my RV with two 12V LiFePO4 batteries wired in parallel, a SmartShunt operating in Battery Monitor mode, a Smart Solar MPPT 150/45 solar charge controller, and a Cerbo GX with GX Touch 50 connecting everything. I also have a battery disconnect switch that currently disconnects all of the non-Victron loads in my system. I have some questions about best practices with respect to wiring each of these components and would greatly appreciate your help!


I have my SmartShunt wired into the negative side of my circuit, directly between the negative terminal on my battery bank and all other loads. I have the Vbatt+ terminal wired directly to the positive terminal of my battery bank using the optional battery temperature sensor (with black wire connected to the aux terminal and configured correctly). I don't think I have any questions or concerns here. The manual is very clear about how to wire everything. This results in the SmartShunt being "always on" regardless of the battery disconnect switch position.


I have my MPPT charge controller wired to the battery bank's positive terminal directly (always connected, even if battery disconnect switch is turned to off) currently unfused, but in reading the manual more closely, it looks like I should add a 50A fuse to this connection. The negative connection connects to the load side of my SmartShunt. Regardless of fuse, is it recommended to have the MPPT connected directly to the battery, as I do now, or should I put it on the "load" side of the battery disconnect switch, such that if that switch was turned off, no power would be able to go into the batteries from the MPPT (assuming solar power was supplied)? Or is it a personal preference? I see pros and cons either way, and don't think it would make a huge difference for me in either case, but would love to hear your thoughts.

Cerbo GX (main question)

I currently have my Cerbo GX powered directly from the battery bank's positive terminal with the supplied fused cable such that if I turn off the battery disconnect switch, the Cerbo GX remains powered up. (Negative side goes to load side of SmartShunt.) This has the downside that turning off my battery disconnect switch does not get rid of the power draw on the battery of the Cerbo GX (which appears to be ~3-5W). This has the upside of always keeping the Cerbo GX on and monitoring. My main question is: Is it problematic to turn off the Cerbo GX when I turn off the rest of my loads in my RV? This is usually when it is in storage and not in active use. While the idea of having the tracking of temperature sensor data and battery voltage is nice during storage, it doesn't seem critical to me. I just can't find anything within the manual that specifies whether it is better to keep the Cerbo GX "always on" or if it's okay to disconnect when not in use. Compared to say, the SmartShunt, which is "always on" but has such a small power draw that it seems like a non-issue. Any guidance on this would be greatly appreciated! (I unfortunately just accidentally drained down my battery, I believe in part due to the draw of the Cerbo GX, which is why I am wondering if I should remove the parasitic drain.)

Thanks kindly for your reading and assistance!

stefprez asked
stefprez commented ·

1 Answer

VE.Direct cable minimum bend radius?

I'm having a hard time finding a minimum bend radius listed for the ve.direct cables in any documentation. The installation I'm working on uses some 2x2 inch (51mm) wire trough and some 2x1 inch. The ve.direct cables are all too long for the raceway runs (using shortest possible lengths) so I'd like to coil up the excess inside that trough, but am concerned about damaging it. Does anyone know the limit or have experience with either successful tight coils or with damaging them by coiling too tightly?



ramahsolarguy asked
kevgermany answered ·

1 Answer

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