AIOs with Configurable Input Priority - Do They Power the Load and Charge the Batteries at the Same Time?

[forbin]

I know a bunch of the all-in-ones can support batteryless operation (while only in single and not stacked topology), I would only operate like that in a bind, perhaps in a mobile or emergency situation. Even if I didn't want batteries, I would at least install some small ones, and it can greatly add to the surge capacity for starting motors (even though it wouldn't have much capacity behind it), it would help settle out the peaks and dips, which seems to me it would help things last longer, and not put your AC output circuits at the same risk for surges or brownout type behavior which could be harder on appliance loads.

Ian at watts247 had a nice demo of this on an LVX6048 batteryless video on You Tube I liked, he showed batteryless, and then with some small batteries, and it handled surges better for starting motor loads. Batteries help the inverter input to handle inrush load better as it provides a good buffer, like a shock absorber in the circuit...

That's just my rough opinion on running batteryless.

Thanks. I agree, true batteryless operation would be for unusual situations. I used the term more generally as a shortcut to indicate the ability of an AIO to power loads directly from the panels, but my assumption is that the system would still have batteries. It just would not draw from them if there was enough power coming directly from the panels.

 

[Samsonite801]

Mpp Solar works the same.
2400 watts from the panels, 800 watts load, 1600 watts charging.
Solar/battery/utility output mode, solar first charging priority.

I have some of the LV6548s I'm provisioning soon, and in my build here, I am adding in 2 AIMS AC-to-DC 48v standalone battery chargers into the system, so I don't have to flip inverters to bypass in order to add supplemental AC charging (which on MPP Solar requires the generator also power house loads as well as charging).

So this way, say I'm getting some Sun on a cloudy day, batteries are charging from solar too slow, I can run the generator to only the standalone chargers to charge on the batteries faster, while inverters are running.

I might even buy 2 more of those standalone chargers to have 4 total, if I find I want better charging speed / efficiency...

 

[Samsonite801]

Thanks. I agree, true batteryless operation would be for unusual situations. I used the term more generally as a shortcut to indicate the ability of an AIO to power loads directly from the panels, but my assumption is that the system would still have batteries. It just would not draw from them if there was enough power coming directly from the panels.

Yeah, I totally caught your drift there, even before I wrote all that, it just seemed like I felt some urge to add in all that stuff about it I suppose

 

[Mattb4]

I know a bunch of the all-in-ones can support batteryless operation (while only in single and not stacked topology), I would only operate like that in a bind, perhaps in a mobile or emergency situation. Even if I didn't want batteries, I would at least install some small ones, and it can greatly add to the surge capacity for starting motors (even though it wouldn't have much KWh capacity behind it), it would help settle out the peaks and dips, which seems to me it would help things last longer, and not put your AC output circuits at the same risk for surges or brownout type behavior which could be harder on appliances.

Ian at watts247 had a nice demo of this on an LVX6048 batteryless video on You Tube I liked, he showed batteryless, and then with some small batteries, and it handled surges better for starting motor loads. Batteries help the inverter input to handle inrush load better as it provides a good buffer in between, like a shock absorber in the circuit...

That's just my rough opinion on running batteryless.

The one thing about batteries is they can put out a lot of current and voltage quickly. You could run your cars electric system on a battery charger but starting the car needs that oomph that only a battery can provide.

 

[meetyg]

That device must communicate with the battery to isolate it. Probably uses the batteries BMS to accomplish the task.

You have the option to interface with the BMS, but you can also choose not to and rely on voltage thresholds, as opposed to battery SOC.

 

[Mattb4]

You have the option to interface with the BMS, but you can also choose not to and rely on voltage thresholds, as opposed to battery SOC.

Interesting. Since the battery is charged based on voltage of the DC bus how does the SCC know the SOC?

 

[meetyg]

Interesting. Since the battery is charged based on voltage of the DC bus how does the SCC know the SOC?

Again, you can choose whether the thresholds are SOC or voltage based.
For SOC, you must have an interface to the BMS. For voltage based, you don't.

I'm quoting from the MUST inverter manual, but I'm guessing it's the same for MPP/Voltronic, since the MUST is a clone of those brands:

 

[Mattb4]

Thanks, as I said it needs to communicate with the BMS or it simply defaults to standard voltage on the common DC bus. Voltages in parallel are how most of these devices control charging. Your model allows controlling the BMS shutoff point.

 

[Samsonite801]

Interesting. Since the battery is charged based on voltage of the DC bus how does the SCC know the SOC?

Yeah, the SCC is just an intelligent buck converter. I think of it like a normal battery charger, where instead of having an AC power source, it uses the buck converter and MPPT algorithm to control the input side of it, but it only pulls the power off the panels it needs to hold the designated output amps/voltages (depending on CC or CV), on the charge profile...

So when you turn on a bunch of loads in the house, the inverter draws down the volts on battery bank, so the SCC works its input circuit to hold the voltage on its charger output based on the charge profile stage (bulk, absorption, float) that it is currently operating in.

If the BMS has comm connection to the AIO, then the MPPT controller can use SoC as influence, to control more than just by voltages alone, as any normal charger would operate.

 

[Mattb4]

Yeah, the SCC is just an intelligent buck converter. I think of it like a normal battery charger, where instead of having an AC power source, it uses the buck converter and MPPT algorithm to control the input side of it, but it only pulls the power off the panels it needs to hold the designated output amps/voltages (depending on CC or CV), on the charge profile...

So when you turn on a bunch of loads in the house, the inverter draws down the volts on battery bank, so the SCC works its input circuit to hold the voltage on its charger output based on the charge profile stage that it is operating in.

If the BMS has comm connection to the AIO, then the MPPT controller can use SoC as influence, to control more than just by voltages alone, as any normal charger would operate.

Nicely explained.

 

[Samsonite801]

Nicely explained.

Yeah thanks, I just generally try to always find some simple layman terms way to point stuff out because that's what it took for me to wrap my head around things back when I was trying to understand back in the day (until I was ready to dive even deeper say). Keep It Simple Silly (or Keep It Silly Simple) is the way I like to operate as I learn. The brain will then open up to the complexities later when the time is ripe

 

[Mattb4]

Yeah thanks, I just generally try to always find some simple layman terms way to point stuff out because that's what it took for me to wrap my head around things back when I was trying to understand back in the day (until I was ready to dive even deeper say). Keep It Simple Silly (or Keep It Silly Simple) is the way I like to operate as I learn. The brain will then open up to the complexities later when the time is ripe

I try that but often I run afoul of what seems so simple to me is Mandarin Chinese to the person I am trying to explain it to.

 

[Samsonite801]

I try that but often I run afoul of what seems so simple to me is Mandarin Chinese to the person I am trying to explain it to.

I totally get you there... Sometimes I tend to oversimplify (in worry that the listener/audience might miss something critically important I'm trying to articulate), and then they all give me the eye like, 'dude, we already knew that like 10 years ago, like duh, can you move on to the next point please'...

Then I'm like sorry, I didn't think you're all like children, I just wasn't sure what level of information you were on when you got here hehe.

It's a delicate balance I guess, trying to imagine what you think they might already know or don't know is a challenge sometimes, because I wouldn't want to offend anyone, but also don't want them to miss important information that could really be helpful in their learning either...

It's the challenge of us all trying to get on the same page together in this complicated world where we all know lots, but of different things hehe...

So I always tell people, 'hey if you already know this part, please disregard' hehe...