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battery connection

Can I change the connection from VE.Can to BMS-Can on the CERBO GX


this is my first time on this forum and I hope someone can answer this question:

My installer has connected the Pylontech US2000C (to CERBO GX and Multiplus II) to the VE.Can port.

However, I would like to connect them to the BMS-Can as recommended.

Can I simply change the connector and the terminator from VE.Can to BMS-Can?

What is the procedure?

Thank you in advance and greetings


klaus-gorka asked
Mark commented ·

2 Answers

MPii (3kVA 48V) DC input terminal question

Hi, All

I am a new owner of a 3kVA Multiplus II (48VDC, 220VAC 50 Hz), and I have a few basic questions about the DC input terminals on these units.

1. My unit's positive terminal is a big shiny hunk of metal, whereas the negative terminal looks to be just a wide piece of tinned PCB track.

This looks a bit flimsy, considering that the OEM recommends a 125 A DC breaker on this line, and that at a moderate load we expect tens of amps to pass through this connection. Am I missing something here?

2. Following on, I have done a temporary setup for configuration and testing, passing only 4 to 8 amps or so with a temporary battery connection consisting of a 1.5 mm**2 cable (10 A fused) looped around the post and clamped under the nuts, and today I was sorting out something more permanent with crimp lugs. When I removed the old connection on the negative terminal, I noticed that where the copper has been in contact with the tinned PCB track, the track looks a matt grey colour instead of the shiny tin of the rest of the strip. The contact resistance is very small (fraction of a millivolt with a few amperes flowing) but I am concerned I might have damaged something during my temporary setup period. Any thoughts?

Thank you in advance!

bob-bobson asked
bob-bobson edited ·

2 Answers

Battery connection MPPT RS 450/200




I can’t find instructions on the connection for battery/48V. The torque is specified to 14 Nm, but am I supposed to remove both nuts (as delivered the terminal bolt has nut-washer-spring washer-nut)?

Is the cable shoe supposed to be connected on top of the first nut or directly on the terminal with two nuts?

calle asked
calle commented ·

1 Answer

Cable to BlueSolar overheated

Lately I noticed a burning smell so today I checked with the infrared thermometer the battery cables on the chargers and the + was much hotter than the negative that was just 25c. So once the sun was down I turned off and removed the cable. It looks like burned. Checked all bolts. The negative on the bush bar took a bit of tightening (1/4 of turn max). Any idea what might caused it?

These are 50mm2 H01N2-D cables (recommended is h07v-k 35mm ) on a Bluesolar Mppt 70A and an oversized array of 2.7kw, so it runs for maybe 2hrs at maximum output 2KW 70A.I have an external fan hitting the device with a timer since installation,given it does does have any fan of its own. Since the cables were too thick to fit the terminal, I chopped off enough strands to fit. I have not used a terminal because it looks like the terminal of the BlueSolar is some kind of clamp pressuring like square? the cable so if I put a cylindrical terminal there will be less contact??

System is operating since July 1st 2022, this happened


last week.

Minas Papageorgiou asked
Minas Papageorgiou commented ·

1 Answer

Connecting 3x JKBMS to Cerbo possible?

Hi is it possible to connect 3x JKBMS to a Cerbo for BMS control?

At the moment i just connected them via BT (ESPHome) to HASS, but that just gives me alarms.

Would be nice to get slow down charging and other features as well.
I got three 8S Packs in Parallel. If it's not possible, maybe someone knows other ways to get it to work.

mryoshii asked
Phil Gavin answered ·

2 Answers

8 x Winston Cells = 400ah in series (24v) – separate Batterybank – Different Cable lengths

Hi everybody,

first of all, sorry for my english.

Im Gian from Switzerland, building an Expeditions-Mobile of a Bucher Duro (Ex-Swiss-Military-Truck).

I bought 8x 400ah Winston Cells with REC BMS which is compatible to all the rest of my Components which are from Victron: 5000W Multiplus II, Orion, Buckboost and so on.

Due to space limitations, i would like to separate the batterybank in 2 blocks.
The cells will be connected in SERIES to achieve 400ah on 24v.

Someone told me to look after exact same cable lengths and that its not good to separate the cells in two blocks because of the much bigger Reststance between block 1 and 2.

I then tought its only a problem if wired in parallel but he told me NO. Its the same issue when connected in series.

So whats correct? I dont wanna risk anything.
The two blocks would have a distance of about 70cm (27.5").

The the cells will be connectet with the original winston linkbars which are very short. Except of the two blocks which are connected then with a 70cm long cable.

Is this a Problem or not?

If not, what cable size for the 70cm should i use?

thank you very much for your help.


rodeo asked
klim8skeptic commented ·

3 Answers

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 commented ·

5 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


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