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Marine Electronics System Design & Installation Help / Periodic Resource

Hi Folks,

Long time listener first time caller... : ) Have been lurking here for the last year plus and thanks for the support and community here.

I bought and live aboard a 37ft sailboat as of a year and a half ago. Have been doing projects and making upgrades in anticipation of cruising the boat long term / off grid. I've grown increasingly interested in electrical systems, have already made some upgrades to the boat here including a Multiplus II and some other upgrades and reconfigurations, and really I'm really eager to continue to gain more competency here.

I've learned a lot so far, but I consistently find myself up against knowledge gaps - especially with electrical - that end up burning way too much time and way too much energy spinning my wheels reading manuals and haphazardly trudging through misc online resources to try and answer questions and decision make toward a clear path forward... often ending up without clear answers or a path forward.

As of this winter my existing AGM batteries are toast. I need to make some moves here in the near term as I'm moving back aboard ASAP and getting the boat back in the water. I'm leaning toward a move to LifePo4 house bank and the requisite system upgrades to build, charge, operate, and maintain the system safely and efficiently. I'm making progress on my own - I think - putting info for system design together but have again found myself wasting too way too much time on questions that I'm sure are quite simple for the right person.

Is there a qualified marine electrician or marine electrical company out there familiar with Victron products than can provide periodic consultation services while I design and build my system?

I'm more than happy to pay for this, it would save me so much time and give me so much more confidence. I'm enjoying the research, diagramming, and learning thats coming with this and am trying to be as thorough and organized as possible - but I'm painfully aware that I need some expert advice to move this forward safely and confidently.

System currently includes: 30A shore power, 3.5kw Generator, Multiplus II 12/3000/120, Victron BMV, 2 - 30A Blue Sea Distribution Panels, Blue Sea DC Distribution Panel, 420 Ah of (toasted) AGM batteries split between house / start, 1500W Lofrans Windlass, Raymarine Instruments, Refrigeration / Compressor, Misc other DC consumers.

Upgrades I have and are not installed, or plan to buy install: LifePO4 Cells, REC or Orion Jr BMS, Tyco Contactors / Disconnectors, Victron Orion DC >> DC Charger, 400W - 600W of PV Array, Victron MPPT Controllers, Balmar Alternator, Balmar or Wakespeed Alternator Regulator, Galvanic Isolator, 30A Blue Sea ELCI.

If there are existing resources out there you can recommend, please do. If you're an individual out there that might be the right fit to help guide me through this I'd love to connect and try to figure out a way to work together toward designing and me executing on this.


// Phil

panema asked

0 Answers

shunt install 4 serial/parallel batteries
My RV has four 6v AGM batteries wired in series/parallel.  Two 
batteries (connected serially) are in the front engine compartment, two batteries (presumably also connected serially) are in a tray 
underneath the chassis at the back of the RV (difficult to 
see/access).  The batteries in the front are grounded to the 
chassis and there is no wire from a negative post back to 
the back of the RV.  I assume the back batteries are grounded to 
the chassis in the rear.

Can I install the shunt on the negative to ground wire on just the front two batteries and get meaningful data from the monitor?  If I configure the monitor with the capacity of just two (instead of 
four) batteries, will I effectively get usage data reflecting all 
four, since they are all connected together anyway?  It seems to me that both the front pair and rear pair of batteries should show 
equivalent draw/charge data, equivalent voltage, etc.  If the front two batteries are low, then the rear two batteries are low too. 
Would there be any distortion of monitoring data in this case?

toddbender asked
kevgermany answered ·

1 Answer

MultiPlus in AC passthrough only during staged RV install?

Will be upgrading a 5th wheel from FLA to LFP batteries, along with a MultiPlus 3000VA 12v 120a replacing the current AC/DC converter and 1200w inverter.
Completing the install in stages would make things easier and maintain RV use during nice weather.

Any issues with connecting AC In/Out to the Multiplus without being connected to batteries, and will the transfer switch pass-through AC power?
I'll do the same thing during short storage intervals with a disconnect switch to maintain batteries below 100% SOC, while allowing AC to a residential fridge.
If this works fine, what position should the panel switch on the Multiplus be in when disconnected from batteries?

offroad asked
offroad answered ·

1 Answer

Battery Protect Connection

On my attached schematic what port in the BP100 should the load stop from the CL 12/100 go to?
Same question re the BMV, what port from NO to the BP65?

Lastly does it matter which cables go into/out from the inverter switch on this schematic.


james-ward asked
steffen-graap edited ·

1 Answer

UK ESS Self-install MCS certification


I am looking to install my own ESS - Multiplus II with Pylontech US3000C batteries, solar on MPPTs on the DC side. I am happy to do all the design and install work myself, however I would ideally like to find someone who is MCS certified to sign it all off afterwards and give me a shiny certificate.

Does anyone know of anyone that would be willing to do this kind of thing in the South East of the UK?

dangos asked
pau1phi11ips edited ·

2 Answers

Multiplus 3000 General question and buzzing in float mode


I have installed my Multiplus in place of an older Xnatrex 2500 whose transfer relay failed. She was a good old girl but had to be put out to sea so to speak. Would have made a great anchor for a small boat! Anyway, the installation went fine and the unit is operational with updated firmware on the CCGX display and the inverter.

Question 1: if the inverter is off, all the circuits on the inverter are also off. I seem to recall on my Xantrex that when it was off the default was for the unit to pass power thru the inverter. That does not seem to be the case or did I miss something in the installation?

Question 2: With shore power on, inverter on, and it in float mode there is a low-level buzzing sound coming from the inverter. Is that normal? The unit is located in a cabinet (with vents for heat release) right outside the main solan so will be an issue trying to sleep.

Thanks for any help you can offer.

topcorner18 asked
topcorner18 answered ·

2 Answers

Technische Frage zum AllInOnePV Angebot GreenAkku

Guten Abend, ich bin neu hier im Forum und auch relativ neu in der PV Ebene.

Mein Vorhaben ist so autark wie möglich zu werden. Ich bin auf das Angebot von GreenAkku gestoßen.


Meine Frage dazu. Benötige ich noch irgendwas für die Installation?

Mein Vorhaben: Am Anfang ca 6,2Kwp an Modulen aufs Dach. Vorwiegend Süd- und Ostseite.

Ich möchte gerne den Akku nutzen und an sonnigen Tagen überschüssige Energie einspeisen wenn der Akku voll ist.

In den Darstellungen ist leider keine Vorschau für genau dieses Angebot. Auch dazu wird in einer Darstellung ein MPPT Regler oder ein PV Inverter gezeigt.

Ich bin etwas verwirrt. Vielleicht könnt ihr mir weiterhelfen.

Mit freundlichen Grüßen und vielen Dank im voraus

dremi666 asked
steffen-graap edited ·

9 Answers

Kontrolle und Inbetriebnahme Inselanlage

Hallo Liebe Victron Community

Bin neu hier im Forum, also habt Rücksicht mit mir. Zuerst zu mir, ich bin gelernter Elektroinstallateur.

Nun habe ich für meinen Camper ein Inselsetup zusammengestellt und installiert.

Bestehend aus Solarladeregler, Lifepo4 Batterie 160Ah, DC-DC Wandler, Multi-Wechselrichter, Cerbo GX, Smart Shunt und Battery Protect.

Nun wurden mir die Geräte von einem Grossisten empfohlen, welcher aber lediglich ein Händler ist und nicht selber installiert. Mein Setup läuft nun seit ein paar Tagen und ich habe sogleich zwei Probleme.

Einerseits gibt der Battery Protect kein Spannung aus am Out, obwohl über die High und GRND Klemme 12/13V anliegen vom BMS. Programmiert sollte er meiner Erkenntnis richtig sein.

Zudem habe ich das Setup nun über 6 Tage eingeschaltet und ohne Erzeuger laufen lassen. Aber auch ohne Verbraucher. Gemäss VRM Portal floss auch nie gross ein Storm und trotzdem, fiel die Batteriespannung heute Nachmittag plötzlich auf unter 11.5V.

Wie kann es sein, dass kein Strom fliesst und es doch Ah verbraucht??



Vielleicht hat jemand von euch gerade eine Idee hierzu?

Allenfalls macht es doch noch Sinn, das Ganze bei einem erfahrenen Installateur zu prüfen. Kennt ihr jemand in der Gegend von Zofingen, Sursee (Schweiz)? Spielt auch keine Rolle, falls etwas weiter weg.

Vielen Dank schonmal für eure Unterstützung!!

Freundliche Grüsse und frohe Ostern


cyrill-schuerch asked
Matthias Lange - DE answered ·

1 Answer

BMV 712 Smart Monitor dosnt work


Hey ,

I have Problems with my BMV 712 . Im Sure that i haf install everything correct, but the Monitor dosnt work.

Energy flows.

The battery Pol of the Shunt is connected with the minus Pol and the load Site of the Shunt is connected to the System ground.

+B1 -> Battery1 +, +B2 -> Battery2 +

I send the Monitor back, but the seller says it Works. He Send another Shunt, Same Problem ...

I Switch the phone cable, still nothing.

I tyried ist with other cables for the +B1/B2, also nothing.

now i Test the „Energy Flow“.

Shunt - to Shunt +B1/B2 has no Connection, i was mit able to get the 12.8V.

Anybody and idea ? What did i wrong?

Sorry for my english, thanks for help !



northernlightss asked
klim8skeptic commented ·

6 Answers

US Certification for Victron Inverters

I'm trying to figure out if Victron inverters are US certified?

My solar installer is saying he can't use Victron because it won't pass inspection in Washington state (US).

I found the below certificates on victron's site, but my installer says he doesn't see a listing for US or at least one that Washington State recognizes so he can't legally install it.

I sent a mail to Victron to ask for clarification, but figured I might post here as well just in case someone here was able to help figure this out.

Quattro 15kVA Certificate,-5kVA,-8kVA,-10kVA-and-15kVA.pdf

Battery Inverter Certificate,-48-3000-35-50-No.-SAA162783.pdf

oliman asked
hydrogen edited ·

4 Answers

Multiplus II installation options


I'm installing a Multiplus II with Pylontech batteries.

I have a SMA SunnyBoy 5000TL-24 AC grid inverter.

Wiring diagrams show two installation options: parallel to the MP2 or connected to AC-out.

What's the best option?

In case of a grid failure, the MP2 would create an island on AC-out, would the inverter still work to support the esential loads and let the MP2 charge the battery? Assuming there was battery power left as the grid failure occured of course.


frame77 asked
marekp edited ·

1 Answer

New Multiplus-II Cycling Absorption Charge On and Off

Got a new installation: Multiplus-II 12/3000 2x120, Cerbo GX, and SmartShunt 500. There are three Battle Born LiFePO4 batteries connected via a Lynx Distributor. All settings are defaults except for Absorption voltage which is set at 14.4, the midpoint of Battle Born's range.

The Multi goes through Bulk charge okay, but then cycles charging amperage -- not the status light --on and off when in Absorption. The absorption light on the Multi stays on constantly, but the charging amperage goes from 0.8 to none based on the voltage. When the Multi is charging at 0.8 amps, the voltage climbs in a minute or so to 14.1. The charging current then stops despite the Absorption light staying on. After a couple of minutes, the small drain from the Cerbo GX causes the voltage to drop to 14.39 at which point the Multi starts charging again at 0.8 amps.

I watched this behavior for just over an hour and the Multi never entered Float stage. I suspect there's a setting...or combination of settings somewhere that need to be adjusted.




jm0278 asked
dray22 answered ·

3 Answers

Dual Parallel MultiPlus AC Wire Size Advice

230 volts 50hrz boat with shore power and generator with a separate AC source panel and AC Distribution panel.

I am installing 2 MultiPlus 1600/70 unit in parallel (location constraints close to the battery bank made it optimal to install 2 smaller units).

Question: what would be the optimal wire size to run from a: The AC source output to the multiplus(s) and b: from the multiplus(s) back to the AC distribution panel?

The distance between the panels is approximately 3-3.5 meters one way. At what point would you add the junction box to split the AC in wires, the AC out wires and would you keep the same wire size throughout.

Thanks in advance for any advice,

graham-perry asked

0 Answers

Multiplus 3000 not showing on victron connect app

Updated Firmware and ve.config through VRM portal. when I'm charging the red grid square is blank and I dont see my multiplus as a device on the list? Did i install wrong?

ak9009 asked
snoobler answered ·

1 Answer

Issues connecting MK3 to USB

I have screwed up the proceedure of hooking up the MK3 to USB installation and now cannot get passed finding a com port. I hooked up the device prior to installing the driver to the MK3. I have lithium batteries and cannot utilize my multiplus charger until I change parameters. Can someone help this newbe to the Victron world what to do?



ricko asked
kevgermany commented ·

2 Answers


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