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Battery Protect

Grounding the Neutral of the Battery

We have a 3-phase ESS 5KVA multiplus-ll inverter installed it's using a Freedom Won 53V Battery.

The connection is battery to Bus-Bars. Bus-Bar to circuit breakers to inverters

My question is, must the neutral of the battery be grounded also?

Lindsay asked
nickdb answered ·

1 Answer

Grounding Battery's Neutral in ESS system

In Wiring Unlimited by Victron the ESS system's battery is grounded from the neutral (refer to image below)


Now I have a 3-phase ESS system using a Freedom Won 53V battery due to conflicting opinions, I'm not sure if I must ground the battery's neutral.

My connection is from Battery to Bus-Bars, Bus-Bar to circuit Breakers, Circuit Breakers to inverters.


Lindsay asked
nickdb answered ·

1 Answer

Can we Parallel the Smart Battery Protect Remote Signal of two or more separate units?

I am working on a project with a customer who wants to have 2 x Smart Battery protect 48V-100 in parallel because his solar panel MPPT load is higher than the 100A capacity of the switch. The MPPT's are not Victron and cannot be controlled with a GX product to stop the charge if required. Each Switch input is going to separate MPPT controllers group, the output connected th the BMS Load side bus.

The BMS only has one normally open contact output used as an Allow to charge signal. We normally use this contact to drive the Remote Signal of the Protection relay. In this case can we drive both remote signal with a single contact and in effect paralleling the two control circuits or do we have to use a relay with multiple sets of contacts?

Jmarc asked

0 Answers

Where is lowbat cutout on Cerbo GX or do I need a Victron Smart Battery Protect?

I have a 24v system using these components:

  • 24v system, comprised of twelve 6v 235ah batteries in series and parallel, flooded lead acid
  • VE Multiplus 24v 3000w inverter
  • VE Smartshunt (external bat monitor hooked up here)
  • VE Cerbo GX
  • VE 100/50 MPPT Charge Controller
  • 11,500 starting watts, 9,000 running watts generator
  • 4 Longi 370w 75 cell panels

I'm curious about the lowbat cutout and how to set this, and also how to set an alarm that the low bat cutout is approaching AND for the alarm to inform me in some personal way, via SMS if at all possible. So, my question is am I setting up the lowbat cutout when I'm selecting the Discharge Floor percentage? If so, how do I setup the alarms and notifications to myself, OR do I need to purchase and install a Victron Smart Battery Protect instead? What is the advantage to installing that product or does the Discharge Floor percentage already let me do the same things that the Victron Smart Battery Protect will let me do?

Thanks Community! You're the best part of Victron (oh, and the tech).

allswell asked
kevgermany answered ·

1 Answer

BP65 remote port power supply voltage


i've got a BP65 and was going to use the power supplied by the remote port on a 2-stage switch to switch both the BP65 via remote (first stage) and then in addition a 12V relay (second stage). I was assuming the remote+ port would deliver 12V but after wiring everything up and the relay not switching I measured it and only got 5.xV readings from the port.

(The switch connects3 terminals A (input) and B (output 1) at the first stage, then A, B and C (output 2) at the second stage. The relay is connected to terminal C and chassis ground and does not have an integrated resistor or diode.)

It seems, I have blown the remote port at some point during wiring it up, though, as I'm now having the symptom where the BP65 circuit now remains closed even if I completely unplug the remote port connector. So I'm wondering if the lower voltage is standard or a symptom of a blown remote port controller?

Thank you,


wyrfel asked
Matthias Lange - DE answered ·

1 Answer

Disconnecting Large DC Loads

Hi! I've been searching here, but haven't found any discussion around this question.

I'm looking at setting up a large lithium house bank on a boat (800Ah) to drive both DC loads and a multiplus inverter and a VE.Bus BMS. I understand that the BMS should be able to switch the load off under certain conditions. The suggested route is to use a BatteryProtect, and the remote option on the Multiplus.

Switching the Multiplus seems straightforward, but switching the large DC load less so. Max DC ampacity for the load is roughly 600A, although the highest current draws are very intermittent — windlass (100A), electric winches (200A x 2). Even so, my understanding is that I need to switch everything off when indicated by the BMS.

The largest constant current ampacity I see for the BatteryProtect is 220A. While some loads are intermittent, when in use, they may be used for minutes at a time, so I think I must remain within the continuous current rating for the Battery Protect.

What's the best way to switch this DC load?

I've considered paralleling several BatteryProtects, both on the load and on the signaling circuits, but I'm currently leaning towards a 600A contactor with 4000A surge rating, despite the appearance that the signal from the BMS will likely need to drive a relay to provide the necessary current to the contactor.

Please advise.



pmolettiere asked
stgermain45 answered ·

8 Answers

BatteryProtect does not allow 12v refrigerator to start

We have a BP-65 connected to two 110 Ah batteries driving some lights, a vhf radio and a 12v refrigerator. The protector does not allow the fridge to run. I imagine the starting current of the compressor is kicking in the protection... Should I try to program the protector to a lower disconnect voltage or? The fridge also has a protection circuit which shuts off the fridge when the voltage drops low, but it then cycles back on and continuously when the voltage source rises again and then falls.

glstromeyer asked
glstromeyer answered ·

5 Answers

Victron BP Load and Charging


I have a similar setup as per the below diagram:


I would like to connect a Victron IP65 charger to the battery directly.

Is this allowed? I see the manual states "but not both currents at the same time".

Does one have to switch the BP off first and then switch on the charger?

Can one have the charger on as well as a load on at the same time across the BP?

Forgive the dumb questions, I really am struggling to understand all of this.

I have the charger connected ATM to the battery with no BP and a small load of 500-800ma. I know a load can affect the charging algorithmic behaviour etc. (overcharge?).

Thank you.

ephemeric asked
Paul B answered ·

1 Answer

Intermittent fault with Smart Battery Protect

I have a Smart Battery Protect 12/24 100A being used as part of a lithium system with a VE.Bus BMS and an Orion 24/12- 70. Basically, I am using the Smart Battery Protect in Li-ion mode which is controlled by the load disconnect on the VE.Bus BMS, this circuit is the supply for the DC House panel.

The problem I am having is that there is an intermittent fault where the Smart Battery Protect gets stuck on “Attempting to activate” (in Victron connect) and causes the RV interior lights to constantly flash on and off. Occasionally after being stuck on “Attempting to activate” for a while, it will display an E1- Short circuit error (both on the unit and in Victron connect); however, I am 100% certain that there is no short circuit. Sometimes it will work fine for hours, and then if the breaker for the house panel is switched on and off it will then get stuck in this fault and it is nearly impossible to get it working again.

So far, we have tried a second DC-DC Converter, a second working battery protect and are still getting the same fault. The cable runs to the input and from the output of the battery protect are appropriately sized, and the BMS is in the same compartment so the ground wire and the load disconnect to Remote H on the battery protect are only approximately 0.5m. We have since discovered that we can trick the battery protect into working every time it gets stuck in this fault by briefly touching a 24V supply on the output of the battery protect.

Has anyone experienced this problem before and discovered a solution?

linky asked
Bruno M answered ·

5 Answers

BP40 - charging by reverse current in my old motorhome - blocking diode?

Hi all. My 25 year old motorhome has the house battery at the front and a Power Management System (PMS) at the rear where the 240V hook-up lives. The PMS handles 12V distribution but also has a transformer in it to provide battery charging (14V-10A) when hooked up to 240V. It contains the 240V consumer unit too as it happens but not relevant here. Charging happens by reverse current using the wiring between the battery and the PMS unit (the load). I want to protect the house battery from over discharge using a Victron BP40 but the back-charging arrangement will apparently set the BP40 alight! So here's the question: Can I just use a blocking diode (45V-20A) in parallel with the BP40 to facilitate safe back-charging? Will be adding solar panels in due course (10A max) but essentially it's the same problem. Would love to hear from anyone who has seen this before but all comments will be gratefully received. Thank you all in advance for your thoughts.

pablo-kontiki asked
pablo-kontiki edited ·

0 Answers

BatteryProtect 12/24V-100A - SMART get's hot!


input Voltage


output Voltage


Voltage drop

Hi! I have huge problems with my BatteryProtect 12/24V-100A SMART. For some time now, it has been getting extremely hot in operation, even if I only constantly consume arond 60-70W. The voltage drop between the input of the BatteryProtect and the output is approx. 5 volts!!! According to the thermal imaging camera, the BatteryProtect gets 56°C.
Something can't be right there, right? does anyone know the problem?
The annoying thing is that my BatteryProtect, which was still under warranty at the time, broke about 2 years ago and the replacement device seems to be causing problems again. So far I've actually always been satisfied with Victron...



cyborgxxl asked
cyborgxxl edited ·

0 Answers

Connecting a charger to Load (Out) side of a BatteryProtect


I have two questions:

  1. is a BatteryProtect able to handle reverse current when connected as shown below in case of the BP220? Reverse current would be up to 30A while charging, and Vout >Vin.
  2. In case 1. is possible, let's now now assume the BP220 disconnects due to cell under voltage ( and thus BMS Load Disconnect output being set free floating). When connecting the charger (14.2 or 14.4V) thereafter, what would the voltage drop between Vout and Vin be? Can the BP220 handle 30A reverse current in that case, up to the point when it connects again after 30sec?

Note: the design intent of the layout below is to protect the SmartLithium battery from standby current drawn by the charger in case of cell under voltage. With the original design from the manual, this could only be achieved by a main switch (or pulling the fuse) between battery+ and BP. I cannot use a Cyrix-Li-Charge because my charger applies a IU1oU2oU3 charging characteristic with U3 being below the Cyrix-Li-Charge 13.7V engagement level.


Image: BatteryProtect Manual figure 5, modified (second BP out connected to 1st BP out instead of 1st BP in as in original diagram).



stefancs asked
Matthias Lange - DE commented ·

14 Answers

Battery Protect Amp Ratings

Is the BP220 rated for 220 Amps at 12 volts and thus 440 amps at 24 volts? Or is it 220Amps at 12 or 24 volts.

Just making sure... ;-)

Patrick asked
Alexandra answered ·

1 Answer

MPPT Completes Bulk and Absorption with Zero Charge Current. Is this normal?

Hi my MPPT went through bulk and absorption cycles today while disconnected from the batteries. I am trying to determine if this is normal behaviour. I would have thought that once the batteries were reconnected bulk charging would resume.

System set up

  • Two 12.8V lithium smart in series feeding 24/3000 Multi-plus operating off grid
  • 1.2kW solar PV fed through a 100/50 MPPT
  • Battery protect between the MPPT and the batteries
  • VE Bus BMS charge disconnect wired to battery protect to prevent charging due to high cell voltage or low temperature.
  • Raspberry PI using Venus SW is logging data to the VRM.

Temperature dropped to -2C overnight for the first time but warmed up to a high of +14C by 2pm

The site is 200+ km away but looking at the VRM data, I noticed the MPPT battery current remained zero throughout the morning presumably due to low temperature shutdown.

I have the MPPT absorption voltage = 28.4V and fixed absorption period of 15min.

You can see in the chart that the MPPT battery voltage reached 28.4 at 7:12am and stayed there for 15min, then dropped at 7:27am. The MPPT battery current was zero during this time. (Lower right corner of the chart below)


Here is a zoomed view of the absorption cycle:


It seems the MPPT completed its absorption cycle at 7:27am and then switched to float, without actually feeding any current to the batteries.

At 13:04 the batteries had warmed up enough for the BMS to trigger the battery protect to close the circuit and you can see the MPPT battery current begin flow, but the MPPT remained in float.

Is this normal behaviour in this situation? I would have thought that once the batteries were reconnected, bulk charging would resume.


abegweit asked
abegweit commented ·

3 Answers

Appairage BatteryProtect HQ2132JXTXE et Orion Smart HQ2137XNUMZ par Bluetooth


Mon installateur m'a installé BatteryProtect HQ2132JXTXE et Orion Smart HQ2137XNUMZ.

Sous son contrôle, j'ai installé l'appli Victron Connect. Lors de la première utilisation dans son garage mon téléphone Galaxy A20 ne s'est pas appairé par le Bluetooth avec les 2 appareils.

Arrivé chez moi, j'ai reussi à appairé mon téléphone avec les 2 modules et j'ai pu changer les 2 mots de passe et voir les informations.

Depuis, j'ai renouveler l'accès plusieurs fois sans succès...

Merci pour toute information.

pri asked
Thiemo van Engelen (Victron Energy staff) commented ·

0 Answers

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