Benefits of Closed Loop Comms?

[rrambo]

I like the idea of closed loop for SOC.. with my current frankensystem I've noticed "interesting" differences in charging with my 2 chargeverters, one which is open loop and one that is closed loop. When my new batteries come in and I install my 12000xp however I plan on closed loop between the 12000xp and the batteries leaving the chargeverters open loop.

 

[rrambo]

I will add that at least in my situation, the closed loop I have now between my one chargeverter and my eg4 batteries are rock solid.

 

[Osmethne]

This stuff needs to be turn-key. Buy an inverter, snap in some solar panels, snap in some batteries, connect the power and go. The last thing i want to do is fiddle around with some manufacturers battery tool to 'balance' my batteries. The fact that 'closed loop' has generally sucked really bad is not an indictment of the idea, it's simply an indictment of the quality of the communiction around it. My inverter and the BMS on them should be managing my batteries not me, or some 3rd party tool. The BMS built into your battery should be able to make the best decision for the life and health of that battery period. If it does not, then the problem is not the closed loop communication.

They most definitely need to get it together with their protocols. The state of the industry is awful regarding this. I think it's the biggest reason why so many people are hostile to the idea of battery communications.

 

[ksmithaz1]

If someone comes up with an inverter that will allow rolling firmware updates in parallel, and not lose it's mind if it can't talk to it's batteries, and puts out 50A or more, and are as robust, I will seriously consider dumping these silly 18kpv's. None of this crap has resilience in it's design, which is the one thing that drives me absolutely bat poop. I just can't believe nobody has managed to get this sh-t together, and we are even discussing open vs closed loop. Of course you want your inverter to talk to your batteries, what you don't want is your inverter having a panic attack for no reason, or frying your batteries because of something stoopid.

 

[SunDave]

This is interesting to see. There is a negativity toward comms, and a lot of "I can do X without" justifications.

I can set my inverter to error on problems, or to ignore the comms and carry on. So just having it doesn't hamper anything that i know of. (ksmithaz1 maybe the 18kpv has that or could add it).

If you don't want communications, no problem. Why the non-comms crowd isn't live and let live as well is a mystery to me.

 

[empowered]

This is interesting to see. There is a negativity toward comms, and a lot of "I can do X without" justifications.

I can set my inverter to error on problems, or to ignore the comms and carry on. So just having it doesn't hamper anything that i know of. (ksmithaz1 maybe the 18kpv has that or could add it).

If you don't want communications, no problem. Why the non-comms crowd isn't live and let live as well is a mystery to me.

i havent seen anyone try to shove 'no comms' down anyone's throat here...

 

[SunDave]

DATA, i wouldnt go as far as calling it GOOD data. my SOC readings when i was in closed loop were ALL OVER the place, had nothing in common with what my bms readings were. garbage.

No big deal. If I didn't like the info, I wouldn't use it either. I wonder what the heck it's reporting if it's not what the BMS is showing.

Some work better obviously. My inverter tracks with what the BMS says, so I'm happy with it.

 

[fmeili1]

For my setup, yes there's a good reason I use it. I use an NHX-10k and I have an EV TOU plan. Peak hours are 3-8pm. Before closed loop coms I would charge it up to 100% before 3. This would waste a lot of solar power. Now it's programmed to keep it to a progressively higher SOC before 3 so I make use of much more solar power.

Yes, but you could achieve this without closed loop comms between battery and inverter.

In my case, I get the battery data (incl. SOC) via RS485 into SolarAssistant and from SA via MQTT into my smart home system. A smart home rule can now control the grid charger (in my case I'm using DIY chargeverters with CAN bus control for grid support) to pre-charge exactly to the required SOC to make it over the next on-peak TOU time frame without grid usage.

 

[SunDave]

i havent seen anyone try to shove 'no comms' down anyone's throat here...

So, saying they are for idiots, training wheels, and for people who don't understand batteries is completely neutral. Got it. Thanks. I don't care where the conversation goes. All I said is that there was negativity toward coms. No sense in pretending otherwise.

 

[ksmithaz1]

sure you can, just extrapolate SOC to voltage...

Doesn't work super great, The problem is voltage can vary quite a bit because of load. You are now guessing based on variations of tenths of a volt which can work OK in a steady state, not so much in a dynamic one. The BMC is tracking current flow and voltage and is making educated guesses based on advertised capacity, rate of discharge and voltage, and temperature, etc, etc. Does your inverter have a setting that says turn off at 50.5v unless the load is over 50%, in that case make it 50.0v? Mine doesn't.

 

[Tulex]

i havent seen anyone try to shove 'no comms' down anyone's throat here...

Nor have I, there's just an aura of arrogance maybe.

 

[ksmithaz1]

Yes, but you could achieve this without closed loop comms between battery and inverter.

In my case, I get the battery data (incl. SOC) via RS485 into SolarAssistant and from SA via MQTT into my smart home system. A smart home rule can now control the grid charger (in my case I'm using DIY chargeverters with CAN bus control for grid support) to pre-charge exactly to the required SOC to make it over the next on-peak TOU time frame without grid usage.

Now you created a dependency on yet another system, but yes you can do this.

 

[Cmiller]

Sounds like Big Lithium propaganda...

Nope. Not propaganda at all. I have lithium batteries at home myself. I have been in the industry since 2011 and have worked with tons (quite literally, haha) of lead batteries, and now in the last 5-6 years we are doing mostly lithium. I see the PV production logs from systems that had lead and switched to lithium, and their production always goes up! We also don't have the service calls anymore related to corrosion causing bad connections! We also don't have people calling because their battery has reduced capacity, then you discover they haven't equalized for a year, so you explain for the 4th time how to equalize..... To be fair, we do get some calls related to closed loop issues and BMS issues.... lol. But overall our service call-to-installed systems ratio is way better with lithium!

When something is DIY, I personally will deal with a lot more issues than I will with something that I paid a professional to install! So from an installer perspective, it doesn't really make sense to sell lead to people unless they specify that is what they want, and we can't explain to them the benefits of lithium. New lead is about the same price as new lithium these days...

 

[empowered]

So, saying they are for idiots, training wheels, and for people who don't understand batteries is completely neutral. Got it. Thanks. I don't care where the conversation goes. All I said is that there was negativity toward coms. No sense in pretending otherwise.

there's negativity, sure, because as is, its not very accurate/good information. nobody is trying to force ANYONE to use open loop... you're making an elephant out of a fly.

 

[Haysdb]

I use closed loop with a Deye inverter with two Seplos BMS batteries and it has worked perfectly from day 1. I have tried open loop but my inverter has a very primitive charge controller that hits the absorption voltage and then just says I’m done and I’m outa here and let’s SOC drop. With closed loop my batteries stay at 100% until the sun goes down. I’ve lowered my target voltage to 54.4 so that the batteries aren’t held at a high voltage.

I have no experience with batteries prior to this. In my world closed loop “just works”.

 

[ksmithaz1]

This is interesting to see. There is a negativity toward comms, and a lot of "I can do X without" justifications.

I can set my inverter to error on problems, or to ignore the comms and carry on. So just having it doesn't hamper anything that i know of. (ksmithaz1 maybe the 18kpv has that or could add it).

If you don't want communications, no problem. Why the non-comms crowd isn't live and let live as well is a mystery to me.

Really? What inverter? All the ones I've seen are all or nothing. If you set for closed loop they do not work at all without comm.

 

[SunDave]

there's negativity, sure, because as is, its not very accurate/good information. nobody is trying to force ANYONE to use open loop... you're making an elephant out of a fly.

?
By saying use whatever you want and questioning the negative stance toward comms? I don't even think I made a fly

 

[Chuck2]

?

 

[Tulex]

?
By saying use whatever you want and questioning the negative stance toward comms? I don't even think I made a fly

Dumbo could fly, and now that I think of it, maybe more entertaining....

 

[SunDave]

Really? What inverter? All the ones I've seen are all or nothing. If you set for closed loop they do not work at all without comm.

Sol-Ark 15k
There is a BMS_err_stop setting that I disable if I ever want to mess with batteries. I don't want the whole system shutting down or glitching out because I wanted to re-wire the battery that the comms cable goes to.

I do run with it on though, because I like the idea of the inverter stopping should the batteries actually have a problem. Relying on breakers to save the day is not something I am as comfortable with.

 

[ksmithaz1]

I use closed loop with a Deye inverter with two Seplos BMS batteries and it has worked perfectly from day 1. I have tried open loop but my inverter has a very primitive charge controller that hits the absorption voltage and then just says I’m done and I’m outa here and let’s SOC drop. With closed loop my batteries stay at 100% until the sun goes down. I’ve lowered my target voltage to 54.4 so that the batteries aren’t held at a high voltage.

I have no experience with batteries prior to this. In my world closed loop “just works”.

If you are in closed loop all of the inverters I've looked at closely will honor the battery BMS request and ignore other hard settings, from voltage all the way to maximum charge rate. Are you sure your Deye's are behaving differently from that? Can anyone here confirm this type of behavior on their inverter in closed loop?

 

[Osmethne]

Yes, but you could achieve this without closed loop comms between battery and inverter.

In my case, I get the battery data (incl. SOC) via RS485 into SolarAssistant and from SA via MQTT into my smart home system. A smart home rule can now control the grid charger (in my case I'm using DIY chargeverters with CAN bus control for grid support) to pre-charge exactly to the required SOC to make it over the next on-peak TOU time frame without grid usage.

I can't. I officially can't with this inverter and SA. For this inverter SA can't enable or disable charging via solar or the grid. It only allows me to enable charging and charge amperage.

For example; If I tell it to charge at 50 amps and only 30 amps of solar are available then it'll draw the other 20 from the grid. If I want to charge to 90% and stop then it'll disable charging from both sources. I can't tell it to only charge to a certain percentage but also keep charging if there's excess solar.

But with closed loop comms it works beautifully.

 

[ScrodusGargleRotten]

If you are in closed loop all of the inverters I've looked at closely will honor the battery BMS request and ignore other hard settings, from voltage all the way to maximum charge rate. Are you sure your Deye's are behaving differently from that? Can anyone here confirm this type of behavior on their inverter in closed loop?

I think you are right. Bms overrides inverter

 

[ScrodusGargleRotten]

I can't. I officially can't with this inverter and SA. For this inverter SA can't enable or disable charging via solar or the grid. It only allows me to enable charging and charge amperage.

For example; If I tell it to charge at 50 amps and only 30 amps of solar are available then it'll draw the other 20 from the grid. If I want to charge to 90% and stop then it'll disable charging from both sources. I can't tell it to only charge to a certain percentage but also keep charging if there's excess solar.

But with closed loop comms it works beautifully.

What inverter? Id like to stay away from it

 

[ksmithaz1]

Sol-Ark 15k
There is a BMS_err_stop setting that I disable if I ever want to mess with batteries. I don't want the whole system shutting down or glitching out because I wanted to re-wire the battery that the comms cable goes to.

I do run with it on though, because I like the idea of the inverter stopping should the batteries actually have a problem. Relying on breakers to save the day is not something I am as comfortable with.

Damn, I may just look into SolArk again as pricey as they are. I think they allow for rolling firmware updates as well.