Almost seems like its better NOT to have inverter communication?

[Alkaline]

Lots of threads with issues with inverter comms and batteries, Almost seems like it would be better not to setup communication? Hakuna-Matata?

 

[Ampster]

I don't have it with my BMS and Inverter without communications. A lot of the issues can be handled with appropriate settings on both devices.
If I had the perfect system I would have them communicate but I am reminded by the saying, do not let perfect be the enemy of good.

 

[Horsefly]

I've been vocal here before: I currently do NOT have any battery-to-inverter communication, and I really have a hard time thinking it is such a great thing. People seem to be clamoring for it without really understanding why they want it. There is some advantage to having your BMS manage the charge current into the battery, but I'm not sure it is that big of an advantage. There are other things that have been discussed, but I don't really see it. I'd say it is better to keep it simple.

 

[Ampster]

In the EV world it is important to have the BMS integrated with the power plant (inverter) but less so in the stationary storage market. I actually like seeing two independent estimates of my SOC, one from my inverter and another from my BMS.

 

[Don B. Cilly]

IMO all the inverter needs to know about the battery is its voltage.
And to a lesser extent, all the battery needs to know about the inverter is its draw (duh ;·)
No particularly sophisticated form of communication is needed for that, is it.
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[robby]

When both the battery and Inverter have software properly written to communicate with each other it's a great feature. The Inverter always knows which packs are running and the SOC of each pack plus temp and production or charging requirements the packs needs. If one pack goes offline the Inverter knows how many Amps it just lost from the system and it will prevent the other packs from being overloaded or tripped.

 

[toms]

I think it’s one of those things that you either do right, or don’t do at all.

My main system is fully integrated - my auxiliary system isn’t. It really depends on your use case. For a main house system i would always go with an integrated system. It is actually a lot simpler than making sure a collection of individual components plays nicely, and when you want to switch in aircons and hot water systems etc based on SOC as well as use AC and DC coupled chargers, not having the BMS in control becomes a headache.

If your system is simpler without the BMS being in control - then there’s not much point having comms just because you can.

 

[A.Justice]

I keep mine separate, with no communication.

If five devices all communicate with the same central "hub", then in my mind, I have no redundancy structures. If all five devices are separately monitoring voltage, current, etc, then I would consider that to a level of monitoring redundancy.

 

[timselectric]

I had no problems with communications. It was nice in the beginning, when I didn't have the knowledge to set everything up myself. Once I learned enough, I cut the cord. Now, my system does what I set it to do.

 

[JoeHam]

Cou

Lots of threads with issues with inverter comms and batteries, Almost seems like it would be better not to setup communication? Hakuna-Matata?

Couldn’t agree more, well said.

To take simplicity a step further, I see no need for built in precharge either.

Precharge is stupid simple to do with a cheap resistor when you commission your system and then you may not need to do it again. But I leave the resistor laying around in case I ever need to.

Everything should have a cost-benefit analysis before being added to the system IMHO. Simplicity, and a reduced number of components to fail is valued here and I believe adds to system robustness.

 

[OzSolar]

Totally agree and I was just thinking about this yesterday. In particular I was wondering how well today's batteries will talk to inverters in the future. Forward compatibly?

I'm faced with needing to replace my tired 2v FLA battery bank soon but my old Trace 4048 inverters are doing just fine so there's no reason to replace them yet.

Given how much trouble people ~seem~ to be having getting and keeping today's batteries working with today's inverters it seems foolish to assume you'd stand a chance of getting your 10 year old batteries to talk but more importantly work with you new inverter.

 

[Sanwizard]

Lots of threads with issues with inverter comms and batteries, Almost seems like it would be better not to setup communication? Hakuna-Matata?

What about extended vacations away from home? Do you trust your system to take care of itself while you are away?
I leave my Grid tie, no battery system alone all the time, but I always have a nagging doubt something may go wrong with my battery connected system I built myself, if left for days on end to just do its thing. That's why I am looking forward to getting comms working, so the Inverter has more control of the complete system, and its settings will dictate what happens.
Am I being paranoid? Or is that a valid concern? What do you guys do if you leave home for two weeks or more?

 

[Alkaline]

What about extended vacations away from home? Do you trust your system to take care of itself while you are away?
I leave my Grid tie, no battery system alone all the time, but I always have a nagging doubt something may go wrong with my battery connected system I built myself, if left for days on end to just do its thing. That's why I am looking forward to getting comms working, so the Inverter has more control of the complete system, and its settings will dictate what happens.
Am I being paranoid? Or is that a valid concern? What do you guys do if you leave home for two weeks or more?

I would trust the BMS to protect the battery, I would not trust the inverter to fix issues that the BMS could not do better.

 

[Zwy]

Lots of threads with issues with inverter comms and batteries, Almost seems like it would be better not to setup communication? Hakuna-Matata?

Increase in complexity, increase in failure points.

I deal with this on a daily basis.

 

[JoeHam]

What about extended vacations away from home? Do you trust your system to take care of itself while you are away?
I leave my Grid tie, no battery system alone all the time, but I always have a nagging doubt something may go wrong with my battery connected system I built myself, if left for days on end to just do its thing. That's why I am looking forward to getting comms working, so the Inverter has more control of the complete system, and its settings will dictate what happens.
Am I being paranoid? Or is that a valid concern? What do you guys do if you leave home for two weeks or more?

I leave my system for more than a month at a time. Yes, I trust a properly designed and implemented system.

I also ignore it when I’m home, no difference.

I think you’re being paranoid. But then again, “they” may be out to get you. ?

 

[Ampster]

Am I being paranoid?

Just because you are paranoid does not mean Murphy is not lurking in the shadows. The two most important failsafe settings are Low Voltage Cutoff and High voltage setting. Communications can fail but if those settings are in the inverter and BMS you should be safe.

 

[toms]

Increase in complexity, increase in failure points.

I deal with this on a daily basis.

I agree, simplicity is exactly the reason i use a BMS that controls the whole system.

 

[Sanwizard]

I leave my system for more than a month at a time. Yes, I trust a properly designed and implemented system.

I also ignore it when I’m home, no difference.

I think you’re being paranoid. But then again, “they” may be out to get you. ?

Thanks Joe. I'm not worried about "they". I am worried about "Murphy" and "Me"?

 

[toms]

Given how much trouble people ~seem~ to be having getting and keeping today's batteries working with today's inverters it seems foolish to assume you'd stand a chance of getting your 10 year old batteries to talk but more importantly work with you new inverter.

My ten year old LiFePO4 have been happily talking to the SMA canbus on my Sunny Island their whole life. What makes you think the next decade will be any different?

What might seem foolish to you has been accomplished with ease by many thousands of DIY LiFePO4 systems.

 

[400bird]

I've got inverter to BMS comms. I primarily use it to provide a "limp" mode if the cell voltage gets too high or low (stop charge or discharge) or limit current if the cell temps get high or low or completely cut off off it is passes the second threshold.

Like others said, set hard limits in the inverter separately.