contactor vs. shunt trip breaker

[400bird]

When you re-introduce the string wouldn't the other strings simply transfer energy into or out of the introduced string fairly quickly to get them back in sync?

Depends on how far apart your cell voltage drifted. There's almost no resistance in the circuit, so the amperage flow from battery to battery could be very high for an extended period. It's not exactly a safe process to parallel multiple packs at different voltages.

Because Batrium is designed to provide 'a pulse' for a shunt-trip. For example, I have the "Critical Fault" event associated with Relay #1 and this sends a pulse when the system detects a Critical Fault. Its does not send a continuous current as you would need for a regular relay or contactor - you'd have to figure something out.
View attachment 93394

I'm not sure you've got the correct option selected there. I think you want "Critical Pulse Off (CB trip)"

I think the one you have shown would close the relay when a fault is present. But, I'd have to check the help pages to find it.

 

[OffGridInTheCity]

I'm not sure you've got the correct option selected there. I think you want "Critical Pulse Off (CB trip)"

I don't use this.

I think the one you have shown would close the relay when a fault is present. But, I'd have to check the help pages to find it.

Yes - that's how mine works - e.g. Relay 1 on the Expansion board allows current to pass thru (to the shunt-trip coil)) when 'Critical Fault' occurs. Have tested it several times and it's gone off a couple of times

Batrium

support.batrium.com

 

[jtvt]

When you re-introduce the string wouldn't the other strings simply transfer energy into or out of the introduced string fairly quickly to get them back in sync?

That's the problem.
I have 4 strings. 1120 AH total. Say one drops, then reconnects. Then I potentially have a 840AH battery (the other 3 strings) feeding a 280AH string which has a limited charge rate.

 

[Supervstech]

What about the locking relays?

 

[rhino]

That's the problem.
I have 4 strings. 1120 AH total. Say one drops, then reconnects. Then I potentially have a 840AH battery (the other 3 strings) feeding a 280AH string which has a limited charge rate.

That makes sense.. There must be some amount of voltage difference between strings for it to dump large amount of amps into the string.. i.e. if it is only 0.5V difference would it send 1C into that string? In any case I could see why having a shunt on each string would then be useful so this is something that could be monitored for and prevented if setup in that way.

 

[toms]

Thanks to everyone that has responded in this thread with their experiences and knowledge - it has been very helpful.

 

[copec]

When I setup my Nuvation BMS in 2019 I couldn’t find any of those ABB 400A breakers for less than $500, so I went with tyco contactors and a 400A fuse, it does have contactors on the negative and positive facing the same direction so it can open or close the contactor with the forward polarity first. I did all sorts of hammering on it testing it out.

 

[toms]

You should start a thread on that BMS. I just had a quick look at the operating manual and it is the most comprehensive i have seen.

 

[Solar Steve]

Wonder if anyone has a link to DC specifications for the ABB SACE breakers - all I can find is AC

 

[OffGridInTheCity]

Wonder if anyone has a link to DC specifications for the ABB SACE breakers - all I can find is AC

It's not an easy read - but this document covers ABB SACE models, including AC and DC ratings. It's down lower in the tables for the specific family/models. https://library.e.abb.com/public/76885b8d9881c6cfc1256d3b004b5d77/1SDC210003D0201.pdf

 

[rhino]

Worth noting, the Midnite 250A RT breaker also has a remote trip functionality with the proper trigger. I also was finally able to locate AND order Noark 150A and 250A DC breakers in the USA that have capability of adding remote trip. Was $224 for the 250A version. Those are similar to the ABB breakers. Datasheet for the Noark ones is here: https://na.noark-electric.com/wp-content/uploads/MCCB-Datasheet-NOARK.pdf

 

[100FUEGOS]

I don't use this.


Yes - that's how mine works - e.g. Relay 1 on the Expansion board allows current to pass thru (to the shunt-trip coil)) when 'Critical Fault' occurs. Have tested it several times and it's gone off a couple of times

Batrium

support.batrium.com

View attachment 93443

You should re-check your choice to trip the MCCB, all you need is a pulse to activate the coil that trips the breaker. No need to maintain the coil energised once it has tripped the breaker. My choice is "Critical Pulse Off (CB Trip)" as suggested above and it does exactly what I need.

 

[OffGridInTheCity]

You should re-check your choice to trip the MCCB, all you need is a pulse to activate the coil that trips the breaker. No need to maintain the coil energised once it has tripped the breaker. My choice is "Critical Pulse Off (CB Trip)" as suggested above and it does exactly what I need.

I appreciate the comment! as I wasn't aware of this nuance.
However, in my ABB SACE S3 case - there's no ongoing current to the coil until "Critical Fault" condition occurs closing Batrium Relay 1 which then allows current to the ABB SACE coil to trip it. Once the ABB SACE is tripped, it also breaks the connection to the coil - so the current is momentary.

 

[Solar Steve]

Thanks OffGrid for lots of useful information in the link (as well as Rhino for the alternate part). This is a great forum!

 

[100FUEGOS]

I appreciate the comment! as I wasn't aware of this nuance.
However, in my ABB SACE S3 case - there's no ongoing current to the coil until "Critical Fault" condition occurs closing Batrium Relay 1 which then allows current to the ABB SACE coil to trip it. Once the ABB SACE is tripped, it also breaks the connection to the coil - so the current is momentary.

That may only be possible if the current from the Batrium to the trip coil goes through an auxiliary contact inside the MCCB. The Auxiliary contact inside the MCCB is in NC state and the moment the current pass through it and trips the MCCB the contact changes state and it opens the circuit. In any case, the relay in the expansion board will be closed until the critical fault ends.

This is not the right way to wire the shunt trip coil. If for any reason the auxiliary contact fails the coil inside the MCCB will be damaged. This only adds another possible point of failure.

Please let me know if I am mistaken.

 

[OffGridInTheCity]

That may only be possible if the current from the Batrium to the trip coil goes through an auxiliary contact inside the MCCB. The Auxiliary contact inside the MCCB is in NC state and the moment the current pass through it and trips the MCCB the contact changes state and it opens the circuit. In any case, the relay in the expansion board will be closed until the critical fault ends.

This is not the right way to wire the shunt trip coil. If for any reason the auxiliary contact fails the coil inside the MCCB will be damaged. This only adds another possible point of failure.

Please let me know if I am mistaken.

Will respectfully disagree with respect to ABB SACE S3 shunt-trip breakers.

 

[100FUEGOS]

And I respect that obviously. But I do not want you to only disagree I want to learn how it works. How possibly the S3 can cut power to the coil inside if there is no auxiliary contact involved?

 

[OffGridInTheCity]

And I respect that obviously. But I do not want you to only disagree I want to learn how it works. How possibly the S3 can cut power to the coil inside if there is no auxiliary contact involved?

I disagree that's it's risky / incorrect to use an ABB SACE S3 this way. Of course a breaker can fail, including the main power contacts, but ABB SACE has as good a reputation as any. How it works internally - I don't know. I did take one apart once, but it's an amazingly complicated piece of equipment - multiple layers of contacts

 

[100FUEGOS]

Sure they are top quality but the coil only needs a pulse to trip and nothing else. What would be the purpose of having a relay engaged in the expansion board sending power to the MCCB all the time when there is a function specifically designed for this? Simply put it is not the right function to pick from the list on the Batrium tool kit.

Understand I only want to know if the S3 does not work with the pulse.

 

[OffGridInTheCity]

Sure they are top quality but the coil only needs a pulse to trip and nothing else. What would be the purpose of having a relay engaged in the expansion board sending power to the MCCB all the time when there is a function specifically designed for this? Simply put it is not the right function to pick from the list on the Batrium tool kit.

Who said that power flows thru the Batrium relay 1 continuously? Once the shunt-trip disconnects the battery, in my case ALL loads are disconnected, including the power thru the relay that tripped the shunt (and battery power to the Batrium). That's the point of a shunt-trip in my setup.

"Crictical Fault" a popular choice for overall 'emergency shut off' from what I've seen. BUT this is 1000% a DIY (personal choice) decision. Not a mandate or recommendation.

Understand I only want to know if the S3 does not work with the pulse.

Current -> Cut-off = Pulse. Pulse -> Cut-off = Pulse. Both are pulses. I guess one could ask - is the 'pulse' sent by Batrium long enough to trip the mechanism or too long and causes coil contact failure you're thinking of. I don't know.

To me, you're over-thinking this - even if current was trying to flow continuously after the trip. You're focusing on 1 aspect of an ABB SACE shunt-trip and ignoring other aspects. If the whole thing (trip mechanism AND contactors) don't work as advertised, then there's trouble. Much more likely (in my view) that the contactors (high current) won't work / disconnect the battery from the load than the coil mechanism (low current) will fail.

Perhaps this is a concern for other models of shunt-trip?