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Sol-Ark - Disconnect Strategy?

solardad

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Apr 13, 2020
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I think I have ironed out a disconnect / safety strategy with my hybrid setup, Sol-Ark 12k.
Goal is to trigger a relay via BMS (Batrium) when either cell voltage is too high, low or a single cell starts to fail based on relative voltage delta.

Today my system is setup to do "grid zero" via limited to home as long as I have PV / Bat. capacity to meet my household loads and if loads exceed system setup then the grid supplies the short fall.

The challenge is two fold after confirming with Sol-Ark

1 - Damaging the inverter if you disconnect the battery under a load. Sol-Ark confirmed that using a relay to disconnect the battery is a "no no". If there is any significant load (they are unable to define significant) then having an emergency disconnect (breaker) could damage the inverter.

2 - The built in RSD relay is only for PV (mppt controllers) and does not shut down the inverter. I was hoping it would shut down everything but the main purpose is to just meet 2017 code for panel level shutdown.

Soo here is my thinking on how to tackle the scenarios...

1. High voltage scenario or Large cell voltage delta -need to stop any charging taking place so I would leverage RSD via relay from the BMS. This would kill any charge and allow the batteries to drain down with existing loads. I would have to manually reset the RSD though I think (Sol-Ark was not clear on how to reset).

2. Low voltage scenario or Large cell voltage delta - 4 pole shunt trip breaker (ex. ABB s5n) on the AC side. This scenario would also require a manual reset but it would kill any inverter demand and as such allow the batteries to charge if there is PV.

I think I am covered and outside of the inverter failing the high and low scenario should never take place given the limits I have set within the inverter. The real benefit or coverage would be for a large cell delta.

Thoughts?

What are others doing given the Sol-Ark limits?

Thanks
 
Note: some of this all depends on where u live. IE) disconnect requirement established after a fire dept refused to put out a fire because was no absolute means to turn off the solar electricity.

So now, many places do not care about an inverter being damaged. They want to see a big OFF switch at the batteries.
 
Agree. This is a post install item in that my system has already been approved and in place as is. I have a ground mount so no panel level shut down is required in my area.
 
There may be ways to cut charging by using the remote temperature sensor input, a fixed resistance to simulate 25°C run over a normally open contact of a relay driven by the BMS, this would put the SCC in an out of parameter condition, thus shutting down charging ,this method depends on the model of SCC used, Morningstar support endorses this as a means to achieve charging shutdown with their controllers, it may work with others. With Schneider SCC's it is possible to achieve the same results using the PV ground fault circuitry, fooling the controller into believing there is a ground fault, this is not endorsed by Schneider, the RTS method may also work

Having the SCC settings slightly below maximum battery voltage would reduce the chance of a single cell runaway in the first place, but having a secondary means would prevent overcharging should a MOSFET fail in a short condition.

To cut the inverter output what I use is my main distribution breaker, which is a residual current circuit breaker (RCBO ) or " ground fault " type, a resistor connected over a normally closed contact of the same relay used to kill charging, this leaks enough current, >30mA to ground thus tripping the breaker, this doesn't shut down the inverter but if used in conjunction with the DC disconnect, would prevent damaging the inverter as both input and output are disconnected similtaniously.

There may be other ways of inducing a fault to allow a safe shutdown, in both SCC and inverters, often the best place to start is in the fault section of the trouble shooting section of the manual, then simulating a fault.

The point of this post, which may not be directly related to your particular equipment, it is however aimed at thinking outside the box, using available methods in an unconventional way, consider this as a collection of thoughts, nothing more.
 
To cut the inverter output what I use is my main distribution breaker, which is a residual current circuit breaker (RCBO ) or " ground fault " type, a resistor connected over a normally closed contact of the same relay used to kill charging, this leaks enough current, >30mA to ground thus tripping the breaker, this doesn't shut down the inverter but if used in conjunction with the DC disconnect, would prevent damaging the inverter as both input and output are disconnected similtaniously.

Thanks for the suggestion.
 
i made my batrium talk to sol-ark via canbus and solark listens to it (sol-ark doesnt talk back or batrium doesnt understand it) if you want this let me know i might do a small write up.

other problem that you have with shunt trip (i had the same problem) but im jsut adding 5kw battery that i had from before in front of it (shunt trip breaker) with its own bms so if batrium trips the shunt sol-ark still has some battery and wont have a heart attack (extra battery is not mounted yet on the floor)

as im adding more 280ish amp packs im planning on adding the victron distributor thing with fuses for each 16x pack

(pardon the mess was moving stuff around lately and its temporary permanent work in progress)
 

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i made my batrium talk to sol-ark via canbus and solark listens to it (sol-ark doesnt talk back or batrium doesnt understand it) if you want this let me know i might do a small write up.

other problem that you have with shunt trip (i had the same problem) but im jsut adding 5kw battery that i had from before in front of it (shunt trip breaker) with its own bms so if batrium trips the shunt sol-ark still has some battery and wont have a heart attack (extra battery is not mounted yet on the floor)

as im adding more 280ish amp packs im planning on adding the victron distributor thing with fuses for each 16x pack

(pardon the mess was moving stuff around lately and its temporary permanent work in progress)
This is an interesting setup. I am in the process of building the same setup Batrium with Sol-ark and that same Shunt Trip.

It will be great if you can share your experiences and how you made Batrium to Sol-Ark.
 
see below, i did a quick write up so someone else might find it if they need to

 
see below, i did a quick write up so someone else might find it if they need to

Thank you!
 
the only thing that might be bad is if that 5kw battery goes dry (if batrium trips the breaker), but im going to try and figure out a good low battery voltage minimum ion sol-ark so the bms should never disconnect, also theres a setting in sol-ark that says stop on bms error (not sure if that actually works with current hack, will try to test that this weekend
 
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the only thing that might be bad is if that 5kw battery goes dry (if batrium trips the breaker), but im going to try and figure out a good low battery voltage minimum ion sol-ark so the bms should never disconnect, also theres a setting in sol-ark that says stop on bms error (not sure if that actually works with current hack, will try to test that this weekend
Did you try this? If so did it work and if not what did you learn?
I now have my Sol-Ark, 16s4p power wall connected and communicating with Batrium.
Looking for disconnect option that works but doesn’t hurt Sol-Ark .
 
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Did you try this? If so did it work and if not what did you learn?
I now have my Sol-Ark, 4P16S power wall connected and communicating with Batrium.
Looking for disconnect option that works but doesn’t hurt Sol-Ark .
How did you make Batrium communicate with Sol-Ark?
 
How did you make Batrium communicate with Sol-Ark?
@audreez made a thread about how he did it.


I used a CAT5 cable, stripped out the extra wires, added ferrells to the blue, blue/white and green wires, and connected them to the canbus port both on Batrium and Sol-Ark.
Change settings in Sol-Ark for lithium battery integration.
It wasn’t easy to figure out but eventually you will. In Batrium, in the remote settings you’ll need to set voltage, charge amps.
I just got mine working yesterday so I still have a lot to learn myself but some of it was trial and error. There were a lot of errors lol
 
@audreez made a thread about how he did it.


I used a CAT5 cable, stripped out the extra wires, added ferrells to the blue, blue/white and green wires, and connected them to the canbus port both on Batrium and Sol-Ark.
Change settings in Sol-Ark for lithium battery integration.
It wasn’t easy to figure out but eventually you will. In Batrium, in the remote settings you’ll need to set voltage, charge amps.
I just got mine working yesterday so I still have a lot to learn myself but some of it was trial and error. There were a lot of errors lol
Please share your experience, thanks!
 
@Shawn Hayes Great job! I have not looked into it yet but you should be able to control rapid shut down functionality in the Sol Ark via one of the Batrium relays. I believe that is really the only way to shut down the inverter versus a shunt trip breaker on the battery. something I’m gonna investigate this fall.
 
@Shawn Hayes Great job! I have not looked into it yet but you should be able to control rapid shut down functionality in the Sol Ark via one of the Batrium relays. I believe that is really the only way to shut down the inverter versus a shunt trip breaker on the battery. something I’m gonna investigate this fall.
Thanks I appreciate it. Yes, when I get a little more time I’m gonna try to investigate further a shut down option that will not give the Sol-Ark a heart attack!
Just wondering if you’re willing to help me answer a few questions about Batrium as well?
So far the most misunderstood part of the settings are in the remote settings that help send signal or control factors to the Sol-Ark.
In my Batrium remote comms control logic settings, under charging and discharging targets, I have voltage and current settings plugged in. But under power, (high/low - VA) I still have a zero. How do I determine what those numbers for the power VA setting should be and what does it affect?
12F53216-E934-4085-8026-42BBFE854297.jpeg

I played around with some of the settings this morning and I changed it from high limited original to, high limited advanced and changed some of the numbers in the scaling option. It changed the numbers in the charge profile and begin sending lots of current to the batteries.
So after that I went back to the original settings that I had started with and things went somewhat back to normal. I would like to know more about what the settings do and how it affects everything, so I’m hoping those that have some experience with that could share their information?
 
Please share your experience, thanks!
I will try to give a better account of what it took to go through all that either later tonight or maybe early tomorrow morning. We are in the final stages of moving furniture and finishing touches so that we can get moved into a new place. My priority these last four days have been getting my 16s4p power wall connected to Sol-Ark, getting the Batrium to talk to Sol-Ark and ironing out those wrinkles.
 
Please share your experience, thanks!

I’ll be happy to share a few things, but if you have specific questions, just ask? I’ll do my best to answer what I’ve experienced so far.
However this is the Sol-Ark/Batrium disconnect strategy thread, if we’re gonna talk about Sol-Ark and Batrium communication, it’s best to do it in the thread located in the link below. That is where I will respond with my experience, so far.

 
Thanks I appreciate it. Yes, when I get a little more time I’m gonna try to investigate further a shut down option that will not give the Sol-Ark a heart attack!
Just wondering if you’re willing to help me answer a few questions about Batrium as well?
So far the most misunderstood part of the settings are in the remote settings that help send signal or control factors to the Sol-Ark.
In my Batrium remote comms control logic settings, under charging and discharging targets, I have voltage and current settings plugged in. But under power, (high/low - VA) I still have a zero. How do I determine what those numbers for the power VA setting should be and what does it affect?
View attachment 101301

I played around with some of the settings this morning and I changed it from high limited original to, high limited advanced and changed some of the numbers in the scaling option. It changed the numbers in the charge profile and begin sending lots of current to the batteries.
So after that I went back to the original settings that I had started with and things went somewhat back to normal. I would like to know more about what the settings do and how it affects everything, so I’m hoping those that have some experience with that could share their information?
Hmm. So I have not played around with that option screen but I do have some thoughts.

1 - When you are sending 'lots of current' I view that as a good thing in that you are maximizing the efficiency of the inverter and the available solar. Remember with two 12ks you could theoretically send 360a total (180a per 12k). At 360a a single 16s 280a cell battery is only 22a per cell or less than .1c, well within the limits of a 280a cell. I believe you have 4 sets of 16s so divide that number by 4 and you will quickly realize that you are just tickling the cells even at full charge output (360a or only 5.6a per cell (assuming you have 64 cells)).

2- I have my charge / bulk setting at 55v, 49v for low cutoff and 48v for shutdown.
 
Hmm. So I have not played around with that option screen but I do have some thoughts.

1 - When you are sending 'lots of current' I view that as a good thing in that you are maximizing the efficiency of the inverter and the available solar. Remember with two 12ks you could theoretically send 360a total (180a per 12k). At 360a a single 16s 280a cell battery is only 22a per cell or less than .1c, well within the limits of a 280a cell. I believe you have 4 sets of 16s so divide that number by 4 and you will quickly realize that you are just tickling the cells even at full charge output (360a or only 5.6a per cell (assuming you have 64 cells)).

2- I have my charge / bulk setting at 55v, 49v for low cutoff and 48v for shutdown.
Yes you are correct, I have 64 cells, 4 packs of 16 each. I have my max charge set at 360 A in Batrium. I will have to recheck my math but based upon my calculations I am charging at approximately a .32C rating. 360a/1120ah = .3214. Did I miss something or using the wrong calculator?
Currently my charge is 53.8, 50.4 for low and 48 shutdown, aiming for that 90-ish% to 15-ish% range.
I’m playing with my settings to see what changes and also using my volt meter to see how accurately Batrium is reading the batteries.
One thing I have noticed so far, Batrium is sending the charged % to the Sol-Ark. I have noticed that it is not accurate. I know you can go into Batrium and change your percentage number manually. Ive seen an option for recalibration of percentage charged. I am trying to adjust that recalibration percentage so it will hopefully make the SOC percentage more accurate.
 
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