Midnite Solar Announced their new 10kw AIO at Intersolar Today

[Hedges]

So, HyperVoc was just a gimmick name for the difference between the top of the usable range and the VOC?
The same thing that every MPPT on the market has.

Sounds like they just listed the VOC as lower than it actually was.

No gimmick, a clever design.

When > 600V is applied to PV input, the switching transistor sees Voc - Vbattery.

When the switching transistor closes, connecting inductor to input capacitor, it sees zero volts.
As soon as the transistor opens, input voltage of the inductor flies negative at ground or battery(-). The transistor now has Voc on one side, zero on the other.

I think HyperVoc means detect voltage is above max (150V, 600V, whatever), and don't switch. Then it can survive Vbattery + 150V, or +600V.
It looks to me like capacitors have to handle the higher voltage, but transistor benefits from this design.

 

[timselectric]

No gimmick, a clever design.

When > 600V is applied to PV input, the switching transistor sees Voc - Vbattery.

When the switching transistor closes, connecting inductor to input capacitor, it sees zero volts.
As soon as the transistor opens, input voltage of the inductor flies negative at ground or battery(-). The transistor now has Voc on one side, zero on the other.

I think HyperVoc means detect voltage is above max (150V, 600V, whatever), and don't switch. Then it can survive Vbattery + 150V, or +600V.
It looks to me like capacitors have to handle the higher voltage, but transistor benefits from this design.

Sounds similar to a SPD.

 

[Hedges]

Surge protection device?
That's a voltage clamp, like a Zener, with limited power dissipation. It prevents voltage from going very high.

A buck converter has an inductor with one side at output (battery in this case) voltage.
Other side of inductor is connected by a switch to input of buck converter (PV voltage and capacitor).
Not operating, the switch only experiences PV Voc - Vbat.
Operating, voltage is applied to inductor and current ramps up. When switch turns off, inductor flies negative. It is clamped to negative rail of PV and negative side of battery, allowing current to circulate.
The switching process repeats, producing a sawtooth current flow (current not dropping to zero in some operating modes.)

If the switch is not operated after sun comes up, it never sees more than PV Voc - Vbat.
if switch is operated it sees the full PV Voc.

I think most MPPT just start switching.
I think HyperVoc suppresses switching, avoiding the inductive kick and application of full Voc to the switch.

If battery was disconnected, so inverter capacitors with zero volts were on output of MPPT, then I don't think the protection works.

 

[JoeHam]

All I know, for certain, is that if you exceed max voltage on a Victron MPPT the magic smoke comes out .

Although it was an accident it seems I gotta learn everything the hard way.

Hyper gimmick may have helped in this moment of stupidity.

 

[realpinochet]

No. HyperVoc is actually the input voltage that the Classic will tolerate (not operate) at ABOVE its rated operating input range.

For example, the Classic 150, which runs and starts up at 150V and below can tolerate (but not turn on) at the nominal battery voltage PLUS 150V.

If you had a 48V nominal battery voltage then the Classic 150 would guarantee to not break at 150 + 48 = 198 V.

If 12V battery then HyperVoc max is 150 + 12 = 162V maximum. These can happen in cold climates where the design of the system is marginal.

No other MPPT charge controller does this AFAIK and I do not think that the ONE has it either ?

Yes, it is a marketing feature. I suppose you could call it a gimmick. I remember in my TV fixing days there was usually, in an old tube TV schematic, a component called a gimmick. I think it was two wires twisted together to create a small capacitance. Now I can't even find that in a Google search.

boB

View attachment 209205

Do you guys ever plan on releasing any of your inverters with high voltage DC input for the battery side? It seems like there's a little movement in the market for this but it's so slow. Aims has one with I believe 300V input now. I'm not sure on the Schneider home but they said high voltage battery input. The old argument of high voltage is dangerous has really lost it's merit when we're running 600V DC from the panels.

 

[SpongeboB Sinewave]

Do you guys ever plan on releasing any of your inverters with high voltage DC input for the battery side? It seems like there's a little movement in the market for this but it's so slow. Aims has one with I believe 300V input now. I'm not sure on the Schneider home but they said high voltage battery input. The old argument of high voltage is dangerous has really lost it's merit when we're running 600V DC from the panels.

Maybe...
Would love to do that ! 380V I think is the future for higher power stuff, at least. Some of these systems can get pretty big !

Sure it can be dangerous. I don't know how they handle that now but a few years ago, we had a HV LG lithium battery and one of our techs had to fly to California for a day or two and get educated on it before they would let him work with it. I don't think that particular LG battery (it hung on the wall) ended up going anywhere, market wise.

I have worked with several 120V battery banks though. Weren't a lot of 120V inverters around. Pretty much just the Exeltech. Wonder if they still make that ? They were made in Texas. No charger in this unit though. You could take two (2) MPPT charge controllers and put each one across 60V worth of battery to get 120V solar. There was the Classic 250KS (Kangaroo Special) for a while that was 120V battery MPPT. Still out there AFAIK.

It looks like there are quite a few inverters that work with HV batteries, aren't there ? Seems I just saw a list of inverters (AIO ?) that said they work up there in the 300-500 volt range and there were quite a few. We had one at the shop around a year ago but we did not connect up batteries to it. Just PV input. GroWatt ? Something like that. Can't remember now.

boB

 

[littleharbor2]

Didn't (doesn't) the Tesla Powerwall come in high voltage? They originally were going to have a 48 volt version as well but stopped that. I was bummed at that because I saw Off-Grid potential with the 48 volt version.

 

[JoeHam]

hehehhe...my first in-progress video is demonstrating the serviceability. Essentially I am taking it down to a sheet metal case with nothing in it, guts spread across two workbenches, then putting it back together and installing it.

You’re killing me Smalls.

Where’s that video ?

I’ll have to rewatch Sandlot to keep me busy .

You’re Killing Me Smalls – Meaning, Origin and Usage - English-Grammar-Lessons.com

Anyone that grew up in the late 1990s to the early 2000s has likely seen the well-known movie, The Sandlot. Whether you chose to watch it on your own, or a

english-grammar-lessons.com

 

[NC_hydro]

Don't rush him, it will come out when it comes out

 

[Cmiller]

The biggest issue/risk that I see with high voltage batteries (other than........ well...... high voltage...... ) is cell imbalance issues. There don't seem to be many battery manufacturers that have active cell balancing. And from what I have seen, in the long term you normally (nearly always, almost every time.... etc....) end up with cell imbalance issues on batteries that are getting cycled regularly! (Note the cycled regularly part!) The passive balancing in most BMSs is often simply not enough to keep up! Even with very high quality cells, you will eventually end up with capacity differences within the unit, and therefore cell imbalances! And this is all just on 16S (51.2V)! Now what will happen on say, 96S (307.2V)? I love the idea of higher battery voltage and less amps, but there's a whole lot more that has to be right in order for it to work right on the battery side!

 

[Mahendra Gomanie]

The biggest issue/risk that I see with high voltage batteries (other than........ well...... high voltage...... ) is cell imbalance issues. There don't seem to be many battery manufacturers that have active cell balancing. And from what I have seen, in the long term you normally (nearly always, almost every time.... etc....) end up with cell imbalance issues on batteries that are getting cycled regularly! (Note the cycled regularly part!) The passive balancing in most BMSs is often simply not enough to keep up! Even with very high quality cells, you will eventually end up with capacity differences within the unit, and therefore cell imbalances! And this is all just on 16S (51.2V)! Now what will happen on say, 96S (307.2V)? I love the idea of higher battery voltage and less amps, but there's a whole lot more that has to be right in order for it to work right on the battery side!

This is true

 

[G00SE]

Day 89 of refreshing the Midnite website to see if there’s a price yet
(They could make a lot of ad revenue off of me hitting refresh alone)

 

[realpinochet]

The biggest issue/risk that I see with high voltage batteries (other than........ well...... high voltage...... ) is cell imbalance issues. There don't seem to be many battery manufacturers that have active cell balancing. And from what I have seen, in the long term you normally (nearly always, almost every time.... etc....) end up with cell imbalance issues on batteries that are getting cycled regularly! (Note the cycled regularly part!) The passive balancing in most BMSs is often simply not enough to keep up! Even with very high quality cells, you will eventually end up with capacity differences within the unit, and therefore cell imbalances! And this is all just on 16S (51.2V)! Now what will happen on say, 96S (307.2V)? I love the idea of higher battery voltage and less amps, but there's a whole lot more that has to be right in order for it to work right on the battery side!

This is why they make active balancers, in fact there's HV 10A 15A ones that are on the market now. There's too many pros to HV to not move forward in the industry.

 

[Hedges]

EVs have HV batteries. Have they had a problem getting out of balance?

Passive balancer is a small resistor to bleed off small amount of current. Whether that can keep up depends on how badly imbalanced and length of time held high enough for imbalance to be observed.

I think LiFePO4 spends less time on steep part of curve above knee where balancing gets performed. The chemistry in most EV probably allow balance during much of the charge. Slow charge of course allows more - 8 hours overnight vs. 20 minute Supercharge in middle of SoC.

 

[realpinochet]

EVs have HV batteries. Have they had a problem getting out of balance?

Passive balancer is a small resistor to bleed off small amount of current. Whether that can keep up depends on how badly imbalanced and length of time held high enough for imbalance to be observed.

I think LiFePO4 spends less time on steep part of curve above knee where balancing gets performed. The chemistry in most EV probably allow balance during much of the charge. Slow charge of course allows more - 8 hours overnight vs. 20 minute Supercharge in middle of SoC.

Current thought by some running HV is that sodium ion batteries will resolve some of these concerns. Thoughts?

 

[Hedges]

I have no detailed knowledge about sodium ion. Does it self-equalize?

Lead-acid of course gets equalized with over-charging. Even AGM can have that done on occasion.

Seems to me balancing electronics can be dirt cheap compared to the $50 ~ $100 LiFePO4 cells we see. But most HV batteries use smaller cheaper cells, need cheap balancers (zener, transistor resistor, ~$1?)

 

[realpinochet]

It looks like there are quite a few inverters that work with HV batteries, aren't there ?

I'm only aware of Sandi and Aims for us DIY folks. The others like what outback and schneider have on the market are only AC coupled so they do not work without the grid. They're are a few guys running the sandi inverters, they are low frequency and built like a tank and are industrial quality from what I've read with mitsubishi guts. Sandi has HV battery now where it's plug and play. I was hoping to see American made inverters chalanging these soon, I'd rather support a American company.

https://www.cnsandi.cn/

 

[realpinochet]

I have no detailed knowledge about sodium ion. Does it self-equalize?

Lead-acid of course gets equalized with over-charging. Even AGM can have that done on occasion.

Seems to me balancing electronics can be dirt cheap compared to the $50 ~ $100 LiFePO4 cells we see. But most HV batteries use smaller cheaper cells, need cheap balancers (zener, transistor resistor, ~$1?)

I'm not sure, I'm looking for more info on this myself. From what I heard they are easier to configure in HV application for some reason. I think they are more resilient on internal balancing. You can also charge them in freezing temps without damage and discharge to zero without any degradation according to a video on youtube I watched last year. Thermal runaway and more stable chemistry seems to be something they talk about..don't know. The Chinese are putting them into their EV/s now.

 

[Hedges]

StorEdge, Sunny Boy Storage, Sunny Boy Smart Energy are HV battery inverters for consumers.
SolArk has a 3-phase HV inverter (think that one is 277/480Y).

What we don't have is protocols or BMS for HV DIY.
I'm curious about what could be done with an EV. Let it be your AC coupled battery for peak shaving and backup usage (only when left at home, of course.)

Given how much salt is in the ocean, and low toxicity/good safety (once reacted) the opportunity to use sodium in a battery is very attractive.

AGM fits for my backup purposes, but at $0.50/kWh isn't competitive with grid. Possibly FLA can be, but I think it is still well above cost of LiFePO4. What is sodium ion cost per kWh of cycle life?

 

[realpinochet]

Maybe...
Would love to do that ! 380V I think is the future for higher power stuff, at least. Some of these systems can get pretty big !

Sure it can be dangerous. I don't know how they handle that now but a few years ago, we had a HV LG lithium battery and one of our techs had to fly to California for a day or two and get educated on it before they would let him work with it. I don't think that particular LG battery (it hung on the wall) ended up going anywhere, market wise.

I have worked with several 120V battery banks though. Weren't a lot of 120V inverters around. Pretty much just the Exeltech. Wonder if they still make that ? They were made in Texas. No charger in this unit though. You could take two (2) MPPT charge controllers and put each one across 60V worth of battery to get 120V solar. There was the Classic 250KS (Kangaroo Special) for a while that was 120V battery MPPT. Still out there AFAIK.

It looks like there are quite a few inverters that work with HV batteries, aren't there ? Seems I just saw a list of inverters (AIO ?) that said they work up there in the 300-500 volt range and there were quite a few. We had one at the shop around a year ago but we did not connect up batteries to it. Just PV input. GroWatt ? Something like that. Can't remember now.

boB

A few more questions. Rosie has a five year warranty right? This new AIO has ten? Why? It would appear Rosie is a superior inverter made in the USA? How does the surge compare between the two? Finally, why does any inverter I can find that has 100A pass through relays are AIO? I thought Rosie had that but it's 60A? The 100A seems like it would make it a easier install...although it seems like a lot of homes now are going 400A services for EV/s.