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battery connection

Multiplus II 48/5000 defective series? Not sure before connecting

I bought two Multiplus II 48/5000/70. On both inverters, the connection terminals to Battery missing(or not?) connection plate. Please check attached photo.
Unusual design of the battery connection terminals or a incomplete series.
Never before seen that type of connection. Is it ok or defective series?


janusz-sebek asked
john-gordon edited ·

2 Answers

Replace the batteries from gel to lithium

I would like to buy these lithium batteries: "16 pcs 3.2V 280Ah lifepo4 battery 280AH" to replace my "8 Ultracell UGT 275 Ah 12V" now exhausted, for my 7.4 KWh system with VICTRON 3 kwh Multiplus 48/3000 INVERTER , Color Control GX, BMV-702, .....

Can they be compatible and easily configurable?

marinolab asked
marekp commented ·

4 Answers

Which battery cabling to prefer?

Hey there,

I've already done a couple of installations which all runs fine. I always stick to the "Unlimited wiring" guide for best DC / AC cabling. Normally there is plenty of space to have one big battery bank with equal DC lengths (f.e. multiple Pylontech + Victron Lynx).

Now I will install a bigger bank on a boat (catamaran) and would like to know which way would be best. Both options have pros & cons, maybe there is a third option I don't have in mind.

There is a bit space in each hull and in the middle of the catamaran. Which makes me have 4 spaces for the batteries.

Each battery pack will have it's own BMS. In total the battery will consist of 144x 280Ah Lifepo cells.

Keep in mind that in the schematic are no fuses and kill switches. Surely they will be add in the installation.

The normal use during driving will most likely draw only 2-4 kW in total. But the system has to be capable of maintaining 6kW to both engines over a couple of hours if necessary.

Left Option like Page 19 at wiring unlimited "Diagonally":


- should make equal current on all banks

- only one battery monitor (shunt)


- horrible long cables, about 28m for each + and - cable to the bus bar. Another 9m for each engine (just 125A)

- a couple of volts drop even with 120mm2 cable

Right Option like Page 19 at wiring unlimited "Busbars":

In this case the cable itself is the busbar.


- shorter cables


- 4 batteries in Victron System (not a problem at all, monitoring will be through (modified) MarineMFD App on a Raymarine MFD)

- unequal usage of batteries
- batteries in hulls will be discharged faster and get less charge than center batteries!?

I think (hope) last point shouldn't be a problem when laying on anchor the banks should be equalling themself, right?

Anyone tested this?

I also had the idea to build real separate banks and use Orion 48/48 to charge the banks for the engines. But the Orions are really getting only near 90% efficiency and I think that is a bit to much inefficient as the engines will be the biggest consumers.



klandos asked
klandos commented ·

0 Answers

Cyrix-Li-Ct not connecting batteries

I put a Cyrix-Li-Ct between starting (lead acid)and house batteries (LFP). But the Cyrix never connect the two batteries even when the alternator and the starting battery is at 14.4V!!! Same thing if the house battery is at 14.4V by the Victron MPPT on solar panels.

Of course when I push on the "start assist" the Cyrix connect for 30 seconds.

As my LFP battery is not Victron's one the BMS is hidden inside, so I cannot connect the BMS on the Cyrix-Li-Ct!

Any chance to fix this problem?

piou asked
piou answered ·

2 Answers

XLR adapter

Is there such thing as an XLR adapter for the victron blue smart chargers?

aksel227 asked
wkirby answered ·

1 Answer

Broken Bat- screw on Multiplus-II 3k: how to fix?

While rewiring a Multiplus-II installation, I broke the Bat- screw, not by over-tightening it (I use a dynamometric wrench), but probably while guiding the 35mm2 wire and rotating it many times. I thought the nut was sufficiently hand-tightened to prevent the wire from moving, but apparently not...

Here is the result:



My plan to repair this is either:

  1. carefully drill the remaining of the screw, re-thread the remaining of the soldered nut on the other side, and screw what's left (second photo), probably adding a bit of solder
  2. unsolder the remaining, as it appears to be a soldered nut on the bottom of the PCB, and replace it with a new brass bolt, to be also soldered

What do experts thing about that? What kind of soldering iron do I need (20W, 50W, more)?

Since this setup allows for 35A sustained charging, 50A sustained discharging, and 115A peak discharging (PylonTech battery at 48V), I hope that will be OK...

nhuillard asked
sharpener commented ·

3 Answers

It makes any sense have an isolator after a single output from a Victron IP22 12V 20 (3)?

My boat had installed an old battery charger with 3 outputs but was only using one of them connected to an isolator, which was feeding 3 lead-acid batteries 120 Ah. The battery charger collapsed and I substituted by a IP22 12 V 20(3) Victron charger. There is any reason that I should keep this type of connection or should I eliminate the isolator and use the 3 output to charge individually each battery?

Thank you

antquin asked
kevgermany answered ·

1 Answer

Connecting Multiplus-II, Cerbo GX, Pylontech batteries and a Fronius Primo

While trying to connect everything I realise I made a mistake on the first cable, so I'm trying to make sure I got everything right before returning the wrong cable and buying the right ones.

Cerbo-GX <--> Pylontech US2000C : I need a "VE.Can to CAN-bus BMS type A Cable 1.8m" from "BMS.Can" port to "A/CAN" port right?

Multiplus-II 5000 <--> Cerbo GX : I need a RJ-45 UTP cable right from MP's "VE.Bus" port to Cerbo's "VE.Can" port right ? Is this just a standard Ethernet cable?

Fronius Primo <--> Cerbo GX : I just need both device connected to the same network through their LAN ports? Is it enough if both devices are on the same WiFi network?

Thanks for the help !

zeron asked
zeron commented ·

1 Answer

3parallel Multiplus Battery to lynx busbar cable size


I have 3x multiplus 5's connected to a 48V lead acid bank.

What is best option/ way to wire from battery bank to lynx distributor? Cable size req works out to 185mm for 600A surge power? Seems too big an hard to work with?

Any tips?


eyrere asked
eyrere commented ·

2 Answers

BlueSolar PWM-DUO LCD-USB - Two Different Ah Banks

Currently have 2 of the BlueSolar PWM-DUOs rigged up in parrallel, so each one has a connection to battery bank 1 output and battery bank 2 output.

Is it acceptable for bank 1 and 2 to have different Ah capacities?

Specifically 10Ah 24V on one and 32Ah 24V on the other.

R asked
kevgermany answered ·

1 Answer

MPPT 100/20 load output ok for DC-AC inverter and DC 24 V Motors (10A max draw)

I need to connect an AC inverter to a system with 400W solar (24V) and 100AH battery (24V) to source some DC pumps (24V, 5A max) and a DC-AC inverter supplying 20W @120V AC..

Can these go to the load output of the controller or do I need an external load dump relay and is there a control from the MPPT 100/20 controller? How to connect? Can i use the Victron Battery Protect 12/24-volt 65AMP?



joncrowell asked
kevgermany answered ·

1 Answer

Charge Controller Load Port Reverse Flow?

I have a 17' travel trailer. We use the battery only for some basics, mostly to pump shower water in the evening, run the fridge thermostat and sometimes to run the heater fan at night. I am adding a 100W ground solar panel and a Victron SmartSolar MPPT 75/15 controller. My thinking is to take the cables that currently connect to the trailer battery and connect that to the load of the new controller. Of course, the battery and panel will then connect to the controller. However, when I plug the trailer into shore power or the trailer is being towed, current is sent to the battery to charge it. With my proposed setup, the shore or tow power would need to enter the controller's load port and make its way then to the battery. Will that work? If not, do I need to instead have the trailer's current wiring hook up directly to the battery, thus bypassing the charge controller?

vomund asked
kevgermany answered ·

1 Answer

How do I connect my Smart Shunt to monitor my 4x 6V batteries (2 serial and then 2 parallel)

I searched everywhere but could not find any information for my battery configuration which is a fairly common for RV. Please see below. My RV has 4 x 6V batteries and I do serial for 2x6V to get 1x12V and then I do parallel to get 2x12V.

My question is: if I want to monitor the battery charge of my both "12V" batteries, which positive should I connect the power cable from AUX to? I already connected VBatt+ to the positive of my 1st "12V". Currently I connected AUX to the positive of 2nd "12V". Is this correct? Please see my wiring diagram below.

Thank you!


ly8 asked
ly8 answered ·

2 Answers

Using 2 BlueSolar MPPT 100/50 in parallel

Hello dear community,

Wish you a happy new year!

I am an electronic engineer, but completely new to solar stuff.

I have 2 BlueSolar MPPT 100/50 connected:

1) 4x similar solar panels in parallel, each panel about 250 watt, vmp about 30vdc, imp about 8.4A

2) 4x of same solar panels, but different connection, combination series-parallel - 2 + 2 in series and both groups in parallel, delivering about 60vdc (2x vmp).

Battery bank is 24vdc, not sure about capacity.

Question is - can I connect the OUTPUTs of both MPPT 100/50 in parallel to the same battery bank?

Thank you, Puiu

puiu-chiselita asked
puiu-chiselita answered ·

3 Answers

How best should 5 x 3.5 US3000 Pylontech and 10kVA MP II connected?

Hello everyone.

I have an off-grid customer who did a DIY install of 5 x 3.5 US3000 Pylontech batteries and a 10kVA MP II. He used the Pylontech 2m battery cables to the inverter and correctly followed the Pylontech connection instructions. I however advised him to rather use a suitable busbar setup and cable rated well above the 120A of the supplied Pylontechs given the high rating of the charger. He started charging his batteries at the 140A 10kVA 48V MP-II capability, because the Pylons shows he can do 185A so he took it very literally.

I much stand by my advice, but will value a sanity check from any large system installers out there.

Thank you in advance.



ejrossouw asked
nickdb commented ·

1 Answer


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