Contactor? SSR? Or rely on Batrium and Victron communication

[Rui Ponte]

To add extra protection to my DIY 48V 560Ah battery, I was thinking on adding a low/high voltage disconnect, controlled by the Batrium BMS.

Question 1:
I noticed that a lot of people recommend the Gigavac EV200/GV200
Here, €125+Shipping https://evshop.eu/en/relays-fuses/13-gigavac-gv200qa-contactor-48v-external-economizer.html

Could these two be viable (cheaper) alternatives?
Dianqi ZJ200A ($25,3+VAT) https://aliexpress.com/item/33001621718.html
SSR-200DD ($25,23+VAT) https://aliexpress.com/item/4000295498163.html (does this SSR have the specs I need?!)

The battery will be fused at 200A.

Question 2:
My Victron Multiplus II and Batrium can talk to each other via can bus, namely in regard to charge and discharge limits:
(more details: https://support.batrium.com/article/111-how-to-control-victron-venusgx-with-watchmon)

Additionally, the Victron inverter also has “allow charge” and “allow discharge” external contacts that, I believe, can be controlled by the Batrium.
(more details: https://www.victronenergy.pt/upload...battery-systems-to-Multis-and-Quattros-EN.pdf)

I still haven’t configured the two together but, If everything works seamlessly together, will I be wasting my money on the above mentioned contactor?
Or one can never be to safe, and it would be a good idea to add the contactor as a failsafe, in addition to the Batrium-Victron communication?


Thanks, and sorry in advanced if I’m asking something stupid ?

 

[DW SD]

Rui,
I bought the Gigavac from EVwest.com for around $135 shipped. It does have the economizer circuitry so the draw is lower. That is good for 500A +.
electriccarparts.com had some similar ones for $85, which I found after.
Chargery also sells contactor relays with their BMS for modest cost.
I can't comment on the aliexpress ones. Does seem like you want a quality unit.

Assuming Batrium is BMS ...It does seem like you can get the same functionality by disconnecting charge and load (assuming Victron gear is your only load and charger) w/o the contactor.

Doug

 

[Jejochen]

i use the multiplus 2 with batrium. works flawless

 

[Rui Ponte]

Thanks for your inputs guys!
Yes, I think I'll also abandon the ideia of having a contactor, because the Victron and Batrium BMS should work well together.

@Jejochen , because your system is very similar to mine, some questions:
1) Are you using Victron MPPTs? If so, are you also remote disconnecting them using the Batrium? Or only the Multiplus II?

2) I think you installed your 48 cells in three parallel 16S banks, right? If so:
2.1) Do you have 48 blockmons to monitor all the cells?
2.2) How are you ensuring the three packs remain balanced?
To minimize the number of blockmons needed and to avoid balancing the packs, I'm planning on installing my 32x280Ah cells into a single 16S2P battery.

 

[Jejochen]

Till today i use a grid tied inverter with solar panels wich operates indepenent from the multiplus. The multiplus however reads through a smart meter the solar input. Tomorrow i'll get a victron mppt 250/85. This will come in handy as it will charge the battery straight away, and also in case of power failure (very rare in my area), and empty battery, a bit of sun can charge the battery until it has enough power to start the system, wich includes the other inverter with solar panels. Without this the system is in a dead loop, if no grid power available.
2/ yes
2.1/yes
2.2/ the packs remain balanced, they are all connected together on a positive and negavtive busbar. the batrium bms keeps all cells at the same level
I preferred to have a blockmon on each cell, to monitor each cell, so if one behaves badly, i'll notice it right away. Logically the 'leveling power' is higher if each cell has its blockmon. If the cells are matched and new, paralleling them shouldnt be an issue however.

I'll propably order another 32 cells to increase my bank. Then i'll have 50 kWh

 

[Rui Ponte]

Till today i use a grid tied inverter with solar panels wich operates indepenent from the multiplus. The multiplus however reads through a smart meter the solar input. Tomorrow i'll get a victron mppt 250/85. This will come in handy as it will charge the battery straight away, and also in case of power failure (very rare in my area), and empty battery, a bit of sun can charge the battery until it has enough power to start the system, wich includes the other inverter with solar panels. Without this the system is in a dead loop, if no grid power available.
2/ yes
2.1/yes
2.2/ the packs remain balanced, they are all connected together on a positive and negavtive busbar. the batrium bms keeps all cells at the same level
I preferred to have a blockmon on each cell, to monitor each cell, so if one behaves badly, i'll notice it right away. Logically the 'leveling power' is higher if each cell has its blockmon. If the cells are matched and new, paralleling them shouldnt be an issue however.

I'll propably order another 32 cells to increase my bank. Then i'll have 50 kWh

Thanks!
Regarding the Victron MPPT, you'll have (like I'll have) to disconnect it using the BMS, to avoid overcharging the battery banks.

And I'm on the same boat: my 32 x 280Ah are still en route (still ~3 weeks to go) and I'm already planning to order another 32
I'm okay with monitoring each 2 cells, since they'll be new and matched.
If/when I order the additional 32 cells, then I'll make a second battery, and parallel it to this first one.

 

[Jejochen]

yeah, my ess is set-up, normally pluging in the mppt with ve.direct should be almost plug-and-play

 

[Jejochen]

yep, that was a easy setup! just receievd the mppt, and hung it on the wall. just connected with a temporary wire to have a look at the settings. I literally had to do nothing, except plugin the ve.direct cable. Appeared right away in the screen, and took all the setting. It now is controlled by the batrium. Dude, these systems are not cheap, but they are awesome! Love the high quality stuff!

 

[gnagflow]

Hi Rui,
i am searching onthe internet for hours to find an answer for exactly the same question you asked. I want to buy a can-bus bms like Batrium to control my Multiplus 2. But I want to use a disconnector controlled, if the CANbus makes a problem. I want to use the AUX1, AUX2 to switch off/on the Multiplus (not using an extra disconnector if i can use the Victron built in relays). But if i use the ESS assistant at the Multiplus i can only choose either can-bus bms or two wire bms and dont know how to utilize the internal charger/inverter disconnecter?
Did you find a solution therfore?

thank you

 

[gnagflow]

To add extra protection to my DIY 48V 560Ah battery, I was thinking on adding a low/high voltage disconnect, controlled by the Batrium BMS.

Question 1:
I noticed that a lot of people recommend the Gigavac EV200/GV200
Here, €125+Shipping https://evshop.eu/en/relays-fuses/13-gigavac-gv200qa-contactor-48v-external-economizer.html

Could these two be viable (cheaper) alternatives?
Dianqi ZJ200A ($25,3+VAT) https://aliexpress.com/item/33001621718.html
SSR-200DD ($25,23+VAT) https://aliexpress.com/item/4000295498163.html (does this SSR have the specs I need?!)

The battery will be fused at 200A.

Question 2:
My Victron Multiplus II and Batrium can talk to each other via can bus, namely in regard to charge and discharge limits:
(more details: https://support.batrium.com/article/111-how-to-control-victron-venusgx-with-watchmon)

Additionally, the Victron inverter also has “allow charge” and “allow discharge” external contacts that, I believe, can be controlled by the Batrium.
(more details: https://www.victronenergy.pt/upload...battery-systems-to-Multis-and-Quattros-EN.pdf)

I still haven’t configured the two together but, If everything works seamlessly together, will I be wasting my money on the above mentioned contactor?
Or one can never be to safe, and it would be a good idea to add the contactor as a failsafe, in addition to the Batrium-Victron communication?


Thanks, and sorry in advanced if I’m asking something stupid ?

Hi Rui,
i am searching onthe internet for hours to find an answer for exactly the same question you asked. I want to buy a can-bus bms like Batrium to control my Multiplus 2. But I want to use a disconnector controlled, if the CANbus makes a problem. I want to use the AUX1, AUX2 to switch off/on the Multiplus (not using an extra disconnector if i can use the Victron built in relays). But if i use the ESS assistant at the Multiplus i can only choose either can-bus bms or two wire bms and dont know how to utilize the internal charger/inverter disconnecter?
Did you find a solution therfore?

thank you

 

[Rui Ponte]

Hi Rui,
i am searching onthe internet for hours to find an answer for exactly the same question you asked. I want to buy a can-bus bms like Batrium to control my Multiplus 2. But I want to use a disconnector controlled, if the CANbus makes a problem. I want to use the AUX1, AUX2 to switch off/on the Multiplus (not using an extra disconnector if i can use the Victron built in relays). But if i use the ESS assistant at the Multiplus i can only choose either can-bus bms or two wire bms and dont know how to utilize the internal charger/inverter disconnecter?
Did you find a solution therfore?

thank you

Hi
Since the Victron Inverter/MPPTs will only use the battery if there's an "ok" from the BMS (DCL/CCL > 0), ended up choosing a non-controlled DC breaker.

I started by using a ANL 200A fuse. Even though it did it job, I noticed it was getting too hot for my tasting (>70ºC).
So I changed to a "waterproof 200A" thingy a lot of people are buying and using. Don't know why (don't see other people complaining!) but the sucker tripped every time I had current surges, even when below 100A.
So, this weekend I swapped that out for this Carling Technologies 150A fuse. It's expensive as hell (96€+VAT) and massive/heavy, but it's performing beautifully, even at high amperages:

 

[gnagflow]

Hi
Since the Victron Inverter/MPPTs will only use the battery if there's an "ok" from the BMS (DCL/CCL > 0), ended up choosing a non-controlled DC breaker.

I started by using a ANL 200A fuse. Even though it did it job, I noticed it was getting too hot for my tasting (>70ºC).
So I changed to a "waterproof 200A" thingy a lot of people are buying and using. Don't know why (don't see other people complaining!) but the sucker tripped every time I had current surges, even when below 100A.
So, this weekend I swapped that out for this Carling Technologies 150A fuse. It's expensive as hell (96€+VAT) and massive/heavy, but it's performing beautifully, even at high amperages:

View attachment 14937
View attachment 14938

 

[gnagflow]

Hi
Since the Victron Inverter/MPPTs will only use the battery if there's an "ok" from the BMS (DCL/CCL > 0), ended up choosing a non-controlled DC breaker.

I started by using a ANL 200A fuse. Even though it did it job, I noticed it was getting too hot for my tasting (>70ºC).
So I changed to a "waterproof 200A" thingy a lot of people are buying and using. Don't know why (don't see other people complaining!) but the sucker tripped every time I had current surges, even when below 100A.
So, this weekend I swapped that out for this Carling Technologies 150A fuse. It's expensive as hell (96€+VAT) and massive/heavy, but it's performing beautifully, even at high amperages:

View attachment 14937
View attachment 14938

Hi Rui, thank you for your answer. Damn this is a big circuit breaker! My plan was to use a normal victron fuse and to switch off with the disconnector, if a CAN Bus error occurs. Did you read about those "pre-charger" units, or did you use one? If you switch on with your circuit breaker, i read, that the capacitors of the inverters surge a high current, wich will be solved by the pre-charger?

 

[Rui Ponte]

Hi Rui, thank you for your answer. Damn this is a big circuit breaker! My plan was to use a normal victron fuse and to switch off with the disconnector, if a CAN Bus error occurs. Did you read about those "pre-charger" units, or did you use one? If you switch on with your circuit breaker, i read, that the capacitors of the inverters surge a high current, wich will be solved by the pre-charger?

Yes, I've read about the pre-charger circuit. However, I didn't implement one, because:
i) Lazy
ii) Didn't find any mention to it on Victron's user manual or Victron's brilliant "Wiring Unlimitted".
iii) Before connecting any DC charges, I powered the inverter with the AC Input, hoping that would pre-charge the capacitors. I then followed Victron's connecting procedures: inverter off, AC supply off, connect the MPPTs and battery.

Don't know.... maybe I'm assuming a lot of crap / being dumb. Maybe not. I'll let the experts be the judge of that

 

[gnagflow]

Yes, I've read about the pre-charger circuit. However, I didn't implement one, because:
i) Lazy
ii) Didn't find any mention to it on Victron's user manual or Victron's brilliant "Wiring Unlimitted".
iii) Before connecting any DC charges, I powered the inverter with the AC Input, hoping that would pre-charge the capacitors. I then followed Victron's connecting procedures: inverter off, AC supply off, connect the MPPTs and battery.

Don't know.... maybe I'm assuming a lot of crap / being dumb. Maybe not. I'll let the experts be the judge of that

Hi, this is exactly what i could find in the internet, that maybe if you turn on the AC that the capacitors could be loaded.
What I absolutely not understand ist this Victron instruction, to turn off the AC before connect or disconnect the battery. I cannot find an explanation for that. The question is, if you use an automatic contactor, it is always the opposite, the contactor does connect and disconnect although the AC is connected. The question is, if in this case you could damage something, or why does victron give this connection procedure. ....
Do you have any clue?

 

[nebster]

On a Multiplus, if the AC input is powered, the buffer capacitors are charged immediately. On a Quattro, that is true only for AC input 1.

I can't think of a reason to avoid connecting the battery when the unit is powered up on AC. I suspect during a restart procedure that you're overlooking, that would be fine.

However, the buffer caps hold their charge for some time (0.5 to 3 minutes, in my tests -- it likely varies by inverter size/model). You could follow the rules, disconnecting AC and connecting DC, and as long as you did it in under thirty seconds or so, there won't be much inrush.

 

[jwelter99]

Just an update here:

1) You can now get a Smartsolar with the VE.CAN ports in the larger models.
2) The Cerbo GX is out and it has both a VE.CAN bus as well as a BMS.CAN bus.

With the Batrium you needed to set the VE.CAN to normal CanBus 500Kbit mode which disabled the VE.CAN functionality. The nice thing is with the Cerbo that is no longer needed.

The VE.CAN devices use the VE.CAN bus, and the Batrium plugs into the BMS.CAN, and everything does what is expected.