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
pmolettiere commented ·

7 Answers

Smart battery connect shows low battery voltage

Hi so I have a smart battery protect installed between my bank and an inverter. The back shows almost full charge, however as soon as I turn the inverter on the batter protect shows the battery at 9.5 volts.

I can't seem to connect to the battery protect via Bluetooth unless it's throwing up am error warning so I can't check whether it's a fault with the inverter drawing too much or a fault with the SBP.

I have the positive on the bank going to the SBP in and the SPB out going to the inverter positive and then the negative from the inverter going back to the bank. The ground is connected to a ground spike.

Any help much appreciated!

Angus Tobey asked

0 Answers

why can I not use a smart battery protect between battery and inverter?

Hi all,

Just bought a battery protect (the larger smart one/forgot the details, sorry).

Thought I could hook it up between battery and loads and have it turn off current in case of battery-low-voltage. As a safety measure thing.

Then I`read:

you cannot use this device between your batteries and an inverter (...)

Is this for real?

Of course I have an inverter! Don't we all?

How am I going to battery (lowvoltage) protect my system?

My set-up is 4x 160W panels, MPPT 100/20, 12V system

thanks for any advice,


westen asked
gallaxial answered ·

2 Answers

smartbattery protect 220 amps

I read Some place in Forum that can not Connect the smart batteryprotect 220 amps

Directly to a Inverter and some suggest to use the Function (The SWITCH to put on/off the Inverter) but did not found device doing this function , and nobody suggest anything Exist

Any Suggestion :?

gallaxial asked

0 Answers

LiFePo4 Smart and Battery Protect on the charger side going into short circuit after restart

I had a scenario where the batteries told the ve.bus BMS "allow to charge:NO" because the battery temperature was below 5°C - well one battery was, see my unanswered question here: https://community.victronenergy.com/questions/34077/smartlithium-battery-temperature-sensor-believable.html

Since I never got an answer for this, I am using the BMS and the temperature of the battery as measured internally as the "source of all knowledge" to control the chargers, rather than the temperature reported by the BMV-712.

This in turn turned off the battery protect on the charger side (I have 1x BlueSolar 150/70 and 2x SmartSolar 150/35 there)

All good so far.

However, when the temperature increased, and the BMS changed to "allow to charge:YES" the Battery Protect (configured in Li-ion mode) eventually went to error E1 - short circuit.

When I measured the voltage on the charger side of the BP it was ~30V - battery side was ~26V.

I then disabled the chargers using Victron Connect, restarted the battery protect by removing and replacing the remote connection from the BMS, waited until the BP had configured, then restarted the chargers one by one.

The system came up.
Obviously I don’t want to have to do this every time the system shuts down due to low temperature.

Any help appreciated.

jasontav asked
howard-t commented ·

2 Answers

2 Mppt on Battery Protect?


I would like to connect the two charging current outputs of my two Mppt controllers to the input of my battery Protect 65 A. And from there go to the collective plus rail. Is that possible? Or do I destroy the battery protect with it?

Can I also use it to switch the death strand?

razer05 asked
razer05 answered ·

4 Answers

Victron Superpack 200 ah

Recently I had installed 3 x 200ah superpack lithium in parallel (series not allowed). In this case max amp draw will be 210amp max continues. ( all cables same length)

In this setup there is a 220Amp Victron battery protect on the main.

I'm wandering about the use of the battery protect, when I consider adding 1 more 200ah to upgrade the max continues draw to 280amps. This battery protect will limit the system.

Does the Powerpack need a battery protect? Since it has an integrated BMS.

jkbon asked
Tom edited ·

1 Answer

Smart Battery Protect

I connected a Battery Protect 100A incorrectly and it burned up. I connected the IN to the positive busbar and the OUT to the negative busbar thinking this represented the loads.

I have ordered another smart 200A and don't want to make the same mistake.

I am going to connect the IN directly to the battery and I am not sure whether to connect the OUT to the Positive or Negative busbar. Looking at the wire colour coding in the manual, I am thinking it should go to the positive busbar. Both busbars are connected directly to the positive and negative terminals of the battery and the negative connection has a smart shunt.

I would appreciate guidance on this from your wisdom.

zofo58 asked
zofo58 answered ·

2 Answers

Orion-TR Smart - input and output to same source

Background: I'm considering a boat setup where an Orion-TR non-isolated would charge a Lithium house battery from the lead/acid starter battery (standard setup, per Victron docs). The house battery is also charged by an Victron MPPT Controller/solar panels. I would like the solar/mppt to charge my starter battery in an emergency. I think I can achieve this by (a) disconnecting the Lion House batt and (2) setting my 1-2-both connector to "both". These two steps together would connect the MPPT to the starter battery and isolate the house battery, giving the starter battery the full solar charge.

This emergency setup would leave my Orion in-line and out-line both connected to the same battery terminal (the starter battery positive). Is this safe to do? The manual says that all models are short circuit proof, so I'm thinking yes, but I'm not sure this situation is actually a short circuit.


jfhbc asked
jfhbc commented ·

2 Answers

battery input shorted - fuse constantly blowing

I have had a successful small solar setup with the Victron 100/20 Bluetooth enabled controller and three 100w panels in series to make 60v PV input and 80AH worth of lithium-ion batteries and so the highest voltage charging was set to 12.5v, this setup lasted about half a month with no problems. I come home today to a blown fuse and the battery terminals shorted to almost 0ohms. I can still access the controller from Bluetooth and resetting to factory default changes nothing. when i checked the history tab on the controller the highest PV voltage was 126v and considering three 20v panels in series can not possibly create that much i feel inclined to believe it may be defective - although checking the current voltage still says 59v... any help would be appreciated

Shamus Ploegman asked

0 Answers

Charging 2 Lithium banks with MPPT


I'm looking for a way to charge my 2 lithium banks with MPPT and keep them isolated a the same time.

Here is a picture of what I have so far.

The starter has a switchable circuit to keep the Argos energise circuit live and prevent the MPPT shutting down each evening and messing with the history metrics and also give the MPPT a voltage reference when charging as I don't believe it will get one from the Argos input terminal (please confirm if I'm wrong on that). I understand that this will draw around 0.05A to have the Argo and MPPT active, which will be easily replaced by the solar charge going to the starter battery.

The 2 65A BPs are configured to lithium settings and will disconnect using the BMS charge disconnect going via the BMV relay.

This will not be an approved setup, but will it work as I've gone through serveral designs and this is the only one I haven't spotted any problems with - yet.... :)

If you have a better and supported setup for doing this I would be very interested in the details :)



stocksy asked
pim answered ·

1 Answer

Battery protect : only 1.7V on output

I installed a BP 100 with 2 LiFePo4 batteries in 24V. I programmed the BP 6A. When I put back the remote connector, the screen flips between number 3 and 4. I mesured 26V on the IN and 1.7V on the OUT. Same situation with load connected or not.

michelbuyckx asked

0 Answers

Battery Discharge Protection - Inverter

I have a mobile (Caravan) system that is Lithium based but I DO NOT have Victron Lithium batteries. My batteries also do not have an accessible BMS. They are a Renogy 170 AH lithium batteries.

My system is charged via a Victron 100/50 Smart Solar MPPT and a Victron 30 amp AC charger. I also have fitted a BMV712, smart battery sense and a 65 amp Smart Battery Protect.

I am about to install a NON Victron Inverter 2800/5600 watts to see how much I can do via 240v instead of gas. Induction cooking etc.

my question is about how I best protect my batteries from over discharge whilst using the inverter.

I have read that you should not use a Smart Battery Protect on an inverter. Is this correct?

if you can then the 220 amp model it may be a bit small (2640 watts).

Can I use the BMV712 to activate a relay to disconnect the inverter?

Are there any other alternatives?


strop asked
joep commented ·

3 Answers

BatteryProtect 220A

Hi All,
I would like to kindly ask you some information about the BatteryProtect 220A.

I would like to protect the battery from the deep-discharge and I am thinking to put the battery protec between the battery and the inverter (2500W inverter).

From the manual it is not very clear if I can do this or not.

Could you please help me?
Thank you very much in advance for your time and help.
Best regards

bambinz asked
Matthias Lange - DE answered ·

1 Answer

How to reset the bluetooth PIN to connect with Victron Smart BatteryProtect 12/24V-100A

Hi all,
I've searched all questions but haven't found an answer yet:

Two years ago I've purchased a Victron Smart BatteryProtect for my RV and I seem to have changed the default PIN (000000, six zeros) to connect my iPhone via bluetooth with the BatteryProtect. Now I bought a new iPhone and can't remember the PIN I've changed it to and can thus no longer connect to the device.

How can I reset that code? I've checked this page (https://www.victronenergy.com/live/victronconnect:start#bluetooth_smart_-_resetting_the_pin_code), but the BatteryProtect is not mentioned.
Thanks for your help!


gaston-buiten asked
gaston-buiten commented ·

1 Answer

Battery Protect 220A + Phoenix Smart IP43 problem

Ι have a Battery Protect 220A on a LIFePo4 system that controls the charging

The Battery Protect is set at Li-ION mode

The BMS is not Victron

The charger of the system is a Phoenix Smart IP43 50/3

The problem is as follows

The Battery Protect is off (via the BMS – charge is complete)

Connect the Phoenix Smart to mains power

Enable the Battery Protect (The BMS thinks it is time to recharge)

The Battery Protect throws error E1 (Short Circuit Detected)

The above is not the case with other charger (but the charger is 25A – not 50A as the Phoenix Smart)

If the Battery Protect is enabled before the Phoenix Smart is connected to mains power, then no error on Battery Protect. Everything works as intended

The battery protect has a peak current of 600A, so I was not expecting this

Any suggestions?


ppet asked
ppet answered ·

3 Answers

Sudden low voltage disconnect LifePo4

The 100Ah Lifepo4 battery in my camper has suddenly disconnected itself due to low voltage.

The BMV 712 however still shows a SOC of nearly 100%.

(A couple of days before the BMV got an update, which “failed”. The SOC showed by the BMV after the update was 100%, while it was 97% before the “failed update”.)

I don’t understand what might be wrong. How is it possible that the BMV still indicates that the battery is (nearly) fully charged? Can it be explained by the prevailing low temperature of mines 4 degrees of the battery?

southwick asked
southwick answered ·

3 Answers

Smart Battery Protect Wiring

I recently installed a solar power system on my Class A motorhome. It consists of Victron components: 150/60 MPPT solar controller, Cerbo GX, Touch 50 and a 3000w inverter/charger all in 12 volts. I have four Battle Born 100Ah lithium batteries. The controller is wired to charge the batteries directly. My dealer/designer/tech company is adamant that I should install the SBP to protect my expensive lithium batteries. As he put it, “Do you know how many people have “grave-yarded” their lithium batteries? Everyone at least once.”

In reading about the product, I now understand that it doesn’t do REVERSE CURRENT. In my technologically challenged mind and from reviews of users of this product, it is clear that you can’t wire this inline between the batteries and an inverter/charger because of the no reverse current limitation. Additionally, the diagrams in the manual do NOT show an inverter, only batteries and a load with the SBP in between.

So I’m wondering how to wire the SBP in a system with lithium batteries and an inverter/charger or whether it can be used in such a system. I’m wondering if I could wire the SBP “around” a wire that serves as a charging conduit. I use 4/0 welding cable wired off the batteries through a 400A slow burn fuse and then through a Blue Sea Switch to the coach and inverter/charger. My thinking is that I’d put the SBP between the fuse and switch, leaving the existing cable between them in place and simply creating a short route around this connection.

The questions are: 1) would this isolate the SBP from a reverse current condition and 2) would it work? Any takers on answering this idea?

Hans asked
nebulight answered ·

3 Answers

Coonection between Smart BP-65 and BMV712

I am a little confused and have read my tips which sometimes have been conflicting and confused me more.

If feasible I would like to have a Battery protect to prevent a charge from dc-dc orion, MPPT and the IP22 charger. The intention is to set up the relay parameter in the BMV712 and when the temperature or voltages are outside certain parameters ( below 5 degrees) the Battery protect, using the remote feature, would turn off.

I would like to know if this is feasible?


and if this is ok which connections do I need to make?

The objective is to protect my lithium battery against charging at cold temperatures.

I have included a diagram of my setup which does not have the BMV to Battery protect relay connection.

Also attached is my current setup, which shows the 2nd BP-65 not connected and this will remain like this until I can found the correct safe solution.

Any help much appreciated


vango-sho asked

0 Answers

Batterylife algorith option for Bluesolar MPPT

Hi all,

i have an off grid system with a 150/70 BlueSolar MPPT, a BMV700 and a 24/1600 Phoenix Compact inverter. I am having issues in understanding the Battery Life algorithm option on the MPPT. There is no information on the MPPT manual whereas the Victron Connect manual refer to the manual. I have got some information on the ESS and understood the functionality but i wonder if it is applicable to the MPPT.

If the Batterylife option is enabled on the MPPT, what SOC reference will it take as there is no option to set a SOC?

Thanking you for your return on this.


ashley asked
solguy answered ·

3 Answers

Danger Reverse Current when using Battery Protect for charging

Hi together,

I have a question concerning using a BatteryProtect (BP) to disconnect the charge source in a Lithium Battery System with VE.bus bms.

In the BP manual Figure 5 illustrates how to connect the BP for charging situation and it states that "uncontrolled reverse current will flow through a Battery Protect if Vout > Vin."

Now I wonder what happens, when the Voltage of the charger (Vin) drops, i.e. Solar charger when there is no sun or any other charging source that is swithched of. Wouldn't then the Voltage of the Battery (Vout) be higher and thus reverse current flow causing danger?

THanks a lot for your comments, I am abit affraid of burning down my RV...

cheers, Daniel

danielk asked
Justin Cook - Bay Marine Supply USA commented ·

6 Answers

Question About batteries

I'm struggling to understand batteries, I have a small solar installation SmartSolar 100/30, SmartShunt and Smart battery protector in exhibition trailer which is currently being used as test rig, I was using two Flooded leisure batteries in parallel 220AH effective. I Run a 3.9A (Lights and network switch) I calculate that at 3.9A (4A.) 220AH/4 which I estimate should run for 55hrs, runs for about 2hrs before the BatteryProtect kicks in.

I have purchased AGM battery for testing cos I'm looking at replacing my 2 x 110AH flooded leisure batteries with VE 110AH AGM batteries in a slightly more complex installation in the camper and wanted to do some comparisons.

I am thinking the flooded batteries are no longer serviceable although the indicator display is green on both.

The 110AH AGM battery I would estimate 110AH/4 = 27hrs running time and not even coming close to that. What sort of running time would you normally expect with such load?

What is the maximum discharge point for AGM batteries? 80% AGM and 50% for flooded, but other websites saying 50% for AGM and 80% for flooded, which is correct?

What setting for battery protect would you recommend?

Thanyou in advance

southsideph asked
marc-de-montreal answered ·

1 Answer

does smart sense cold tem shut down ,communicate with smart Battery Protect

280 amp lithium battery, 100/50 victron charge controller, smart BP 100 amp, battery sens

smoketest asked
smoketest answered ·

1 Answer

Lithium Smart Batteries protected individually?

The Lithium Smart battery range require an external BMS and low/high voltage/temperature protection. We are looking at connecting 4 x 200Ah batteries in parallel. However if you use 1 x smallBMS and daisy chain the leads, then if 1 battery in the bank has a fault, the BMS will shut down the batteryProtect and no power will be available.

Is it possible to add a smallBMS and some BatteryProtect/Cyrix devices to each battery to create what is similar to a superpack. The pack would have a separate charging and load connector.

Note: Superpack batteries will not fit in our enclosure.

The following image is taken from the battery protect manual.

If we assume the following:

- "Battery Charger" is a RED keyed Anderson for charging input

- "DC Load" is a GREY Anderson connector for load outputs

Would it be possible to connect 4 of these in parallel. Or would the main 220A Battery protect have to be changed to a Cyrix module as there may be reverse current connecting the batteries in parallel.

The BatteryProtect manuals state: Caution: uncontrolled reverse current will flow through a Battery Protect if Vout > Vin. Therefore never use a Battery Protect for battery to battery charging.


This way, if one of the packs fails and the BMS switches one off, then the other three would still be able to function.

stefanh asked
offshore commented ·

4 Answers

Protecting BP65 from overcurrent


don’t need to protect a bp65 itself from overcurrent or can I use it as a „fuse“? Eg it sits on a rail which has an 80a fuse from the battery and down the BP im running a line which should allow the 65A. If there’s a short / overload I want the BP to shut down the line and not blow the 80A fuse upstream. Do I need a second fuse just before the BP e.g. 60A or am I good with just the main 80A fuse?


max32 asked
markus answered ·

2 Answers

BP100 showing E1 (short circuit) error code, but I don't believe I have a short circuit -- possible bad unit? How to test?

I just updated my 12v 400Ah lithium battery system, reusing many components including my BP100 -- the BP100 worked previously but now is giving me an E1 (short circuit) code when I connect the battery positive to it. I have done a lot of testing and don't believe I have actually have a short circuit. Can you tell me what reasons would lead to the E1 fault so I can rule them out? Or is there a way to test if the BP100 is definitely faulty?

Scenario 1: If I remove the "out" load cable from the BP100 and connect the battery to the "in" the BP100 will not give an error.

Scenario 2: If I have the load cable connected to the "out" and turn on the battery, the BP100 will give the E1 error and not provide power to the "out" post, however if I use a jumper wire with a 15A fuse in line and touch it to both the "in" and "out" posts on the BP100, it will provide power to my house, not blow the 15A fuse, and I can also remove the jumper cable and the BP100 will work as normal, continuing to provide power to the "out" post without any error codes.

bryantroll asked
geon1 answered ·

13 Answers

How can I quickly get paid Victron installer help in the Las Vegas area?

greetings, Im currently in Vegas with homemade tiny house on wheels (box truck called the SnakPak) . Im in dire need for someone with Victron expertise to help complete the hook up of all my components ( CCGX, multi control, bms, battery protect, etc)! having issues currently with adding assistant to multiplus for the bms. I will more than compensate anyone who would like to help with $, Booze, etc. !!! thank you and I promise you will get a kick out of my build!! you can see my build @ spanky301 on IG :)

mark-pankey asked
nebulight answered ·

3 Answers

E1 error Smart BatteryProtect 220

Hello all,

I have a Smart BatteryProtect 220. When I activate the Smart BatteryProtect without any load on the output, I get the error E1 (short circuit).

Only with a load on the output I can activate the Smart BatteryProtect.

Is this a normal behavior? It is definitely not a short circuit, only an open output.

Thank you very much.

Best regards

felixsteinbeis asked
Alexandra commented ·

1 Answer

Battery BMS Triggers Short Circuit Protection when connecting Multiplus

tldr: When I turn the battery on with the Multiplus connected it registers a short circuit protection event. Help!


I've read thru the Battleborn thread and wondering if I'm suffering from the same issue, but its a little different.


I have 3 RJ Lithium 24V 300AH 150 cont/300 peak batteries and a Multiplus 24/3000/50/120

I wanted to use the multiplus to charge them up equally to parallel them.

I wired everything with a single battery powered "off" (charge and discharge disabled, FETs Locked)

The battery cable is 2ga and 26 inches long and feeds to a Lynx Distributor ->Lynx Shunt -> Lynx Distributor 2

I installed 150 mega fuses everywhere that needed one just to get the Multiplus configured and the batteries charged and paralleled.

The inverter cable is 1/0 and 5 feet long

When I turn the battery on without the multiplus connected, I measure 26.4v at the Lynx Distributor 2.

When I turn the battery on with the multiplus connected the BMS registers a short circuit protection event and shuts down.

The Multiplus is OFF.

I've attempted to precharge the Multiplus by hooking up AC as in the Battleborn thread and this did NOT change things.

I have not tried a different battery.

I have not tried connecting the multiplus directly to the battery using the 1/0 wire.

In general the "short circuit" has me freaked out.

Anything glaring above that would help sort this out?

Thanks for reading.

Ambot asked
alan commented ·

3 Answers

Smart Battery Protect and Orion DC-DC

Hi, I'm planning to connect Orion DC-DC 24-12 into my lithium setup to support 12V loads and I was planning to connect that _after_ the Smart Battery Protect. Having thorough look into the SBP manual, it says that "The short circuit protection of the BP will be activated if you try to directly connect loads with capacitors on their input (eg inverters)". Does Orion have capacitors that could cause short circuits, or is it fine to connect it as I intended?


bezda asked
sponk answered ·

2 Answers