Midnite Solar Rosie on sale

[hwy17]

Hey one more question, if you don't mind, LOL. I'm just realizing that the Hawkes Bay is single MPPT charge controller. The Max Input Voltage is 600vdc, but I can't find the Max InPut Current anywhere on the documentation. Do you have information on this by any chance?

That would be very midnite of them to not list one, because MPPTs don't really have a max current on the panel side. It will only draw what it wants from the panels current wise.

You could post the array specs you're thinking of using. As long as it's not like a crazy over panel ratio it should work fine.

 

[koppted]

That would be very midnite of them to not list one, because MPPTs don't really have a max current on the panel side. It will only draw what it wants from the panels current wise.

You could post the array specs you're thinking of using. As long as it's not like a crazy over panel ratio it should work fine.

Seems like a massive oversight. I was hoping it was listed so I know what the hard limit is on amps flowing the MPPT so I would know how to wire my panels, and what sort of wire to use from the Panels/combiner box to the Controller. This is sort of a bummer. I don't want to over panel without knowing how much is being clipped of by the controller. This seems crazy to me. I could put 9 of the q-cell 485watt panels in series and I would be fine, but for shading reasons I'd like some combination of series-parallel.

 

[hwy17]

[Deleted]

Deleted because I'm not actually sure what your design direction is or the implications of fat arrays into high voltage CCs. If you're wanting to run like 4s2p q cells 485 into the Hawkes Bay I don't know the limitations of that.

If you're running 6-8s/1-3p then I think you can be pretty confident you're only going to hit the output current limit, not the input.

 

[koppted]

[Deleted]

Deleted because I'm not actually sure what your design direction is or the implications of fat arrays into high voltage CCs. If you're wanting to run like 4s2p q cells 485 into the Hawkes Bay I don't know the limitations of that.

If you're running 6-8s/1-3p then I think you can be pretty confident you're only going to hit the output current limit, not the input.

Ok, thanks for your help

 

[400bird]

If you're not happy with internet answers, call Midnite, they answered quick and can get info that isn't in the spec sheet.

I'd say that hwy17 is right, long as you aren't trying to put in 50amps @ 100v. Once you get up onto the 500v range, it's probably fine for any input current within reason.

 

[hwy17]

I found this video last night that has some fairly clean audio of the Rosie (for those of us particularly interested in that) and an actual overload. I don't know what the hell kind of air compressor he has but he says not even two XW's can start it either.

Oh and a really cool scope shot of an inverter syncing to grid input and falling off it.

He talks a bit about the potential grid input circuitry difference between an XW and a Rosie that I'm not sure anyone here is still really sure of and I'm not either. He says it parallels the grid to the inverter output. Does an XW not also parallel in essence? Anyway, not a design concern that I have.

 

[Hedges]

Seems like a massive oversight. I was hoping it was listed so I know what the hard limit is on amps flowing the MPPT so I would know how to wire my panels, and what sort of wire to use from the Panels/combiner box to the Controller. This is sort of a bummer. I don't want to over panel without knowing how much is being clipped of by the controller. This seems crazy to me. I could put 9 of the q-cell 485watt panels in series and I would be fine, but for shading reasons I'd like some combination of series-parallel.

It likely can process PV current up to its output current, if PV voltage is low.
But we normally run PV voltage higher. Lower PV current is converted to higher battery current.

Panel wiring ampacity should support Isc x 1.56

SCC output current can be up to rating of SCC. Wire ampacity should support that current x 1.25, as should breaker (or if larger breaker, size wire to that.

SCC won't draw from panels more than its current rating x battery max voltage, plus its inefficiency loss.
But panels usually produce less than their STC rating, so you overpanel.

Shading would lose the voltage of the shaded panels or diode-bypassed sections of panels.

If you parallel PV strings of different orientations, their wattage/current with sun off-angle is what they produce. You could reasonably overpanel to 140% without clipping this way.

 

[Cheap 4-life]

Stop making up theories of how an inverter operates that you have no idea about.
You also don't get to define grid interactive based on your own opinion.

Not making up theories. Simply reading the same information that’s available to everyone. Then using my electrical back round and experience with many other inverters to make intelligent conversation about an inverter. If you don’t want to here what I have to say you are more than welcome to block me..
I’m certainly not trying to redefine grid interactive. Simply giving my opinion that if the inverter can’t interact with the grid/main panel directly then it isn’t very grid interactive is it..

 

[Cheap 4-life]

Manual says,

"Current Transformer (CT) Terminals (#3) Two terminals available for remote current transformers to measure AC branch or grid-connect currents. (Not yet active, future firmware release.)"

sounds great. Maybe I will be getting a Rosie instead of a Victron when the time comes.
i hope having terminals for CTs also implies that the AC input will be bidirectional so the inverter can use the AC input terminals as an output to the main panel. I can’t think of any reason to have CTs on the homes mains unless it’s for letting the inverter know how much power the homes main panel is using so it can cover that load. Only internal CTs would most likely be used instead if CTs were only needed for the inverters AC output to the sub panel

 

[koppted]

It likely can process PV current up to its output current, if PV voltage is low.
But we normally run PV voltage higher. Lower PV current is converted to higher battery current.

Panel wiring ampacity should support Isc x 1.56

SCC output current can be up to rating of SCC. Wire ampacity should support that current x 1.25, as should breaker (or if larger breaker, size wire to that.

SCC won't draw from panels more than its current rating x battery max voltage, plus its inefficiency loss.
But panels usually produce less than their STC rating, so you overpanel.

Shading would lose the voltage of the shaded panels or diode-bypassed sections of panels.

If you parallel PV strings of different orientations, their wattage/current with sun off-angle is what they produce. You could reasonably overpanel to 140% without clipping this way.

Thanks hedges your expertise on these topics is something I always look forward to.

 

[Halfcrazy]

I'm a little hung up on the reports of Midnite equipment requiring an Android device to update nowadays?

I don't need iOS or Mac support but I would rather see at least decent computer based support. I don't have any android devices and I try to keep it that way. I have a windows laptop dedicated to managing my solar equipment.

Edit: Seems like maybe they do have an iOS app on the store now. That's not my preference, I'd rather not have my phone or bluetooth involved at all. But it's better than android only.

MNBLE UPDATE

Update MidNite Solar's newest products including displays, charger controllers and inverters. Pre-download firmware for off network updates. Find out if you are running the most current firmware for your MidNite device. Search the web, update your social media or use other phone applications...

apps.apple.com

Currently the firmware update is via Android or Ios, Direct from laptop updates are currently being worked on but I do not have a time to market on the firmware for that

 

[Halfcrazy]

It might not shut down. As I said it would then need the grids power to pass thru the inverter to the loads that are moved to a separate panel. Which is very inconvenient. Real grid interactive imo means it can power the loads in the main panel and stop itself from selling back to the grid if desired.. otherwise it’s just grid power passed thru the inverter, possibly at the same time the inverter is supplying those loads.. and then the only way for the inverter to cover all the homes loads up to its max output (to zero the electric bill) is to move all the homes loads to a subpanel

Correct, If Rosie is in a grid support situation and powering loads from the battery and ignoring grid (IE grid last or grid zero style) and the loads exceed her capability she will pull the extra from the grid

 

[Halfcrazy]

Seems like a massive oversight. I was hoping it was listed so I know what the hard limit is on amps flowing the MPPT so I would know how to wire my panels, and what sort of wire to use from the Panels/combiner box to the Controller. This is sort of a bummer. I don't want to over panel without knowing how much is being clipped of by the controller. This seems crazy to me. I could put 9 of the q-cell 485watt panels in series and I would be fine, but for shading reasons I'd like some combination of series-parallel.

There is no hard limit, The MPPTs self regulate on output current and allow for over driving so in theory one could put an array with an ISC of 100 amps and a VOC of 595vdc on the Hbay and it will simply produce the 120A out it is limited to. This of course would be extremely wasteful, so we suggest no more than 2x its rated wattage

 

[AntronX]

Wowza at 9m42s that sounded (and looked like on scope) like some bad relay chatter during overload that should be fixed. Needs soft start voltage bucking implemented in software. Paging @SpongeboB Sinewave

 

[SpongeboB Sinewave]

Wowza at 9m42s that sounded (and looked like on scope) like some bad relay chatter during overload that should be fixed. Needs soft start voltage bucking implemented in software. Paging @SpongeboB Sinewave

Yeah, it's OK. Just noisy and connected to a load it should not be hooked up to without a slave Rosie connected.
Try that with any other similarly rated inverter. Not sure how long they all wait until they turn off ?

The Rosie turned off because it let the output current go too high for too long. Doesn't hurt anything and is there for protection.
And it did not limit until the power section got HOT. Notice you did not hear the limiting until the very end of all that grunting and trying to deliver all the current that compressor would take.

I will admit it is kind of annoying but it's OK. BTW, it's not "oscillating" per se' but just limiting fast while letting the load TRY to start. It's part of the magic of Rosie except for that noisy side effect

boB

PS. Soft Start voltage ramp up MIGHT be an option and it can certainly be done but for large surges, it might now.
We could play with something like that but this situation and test is MEANT to torture inverters.

 

[AntronX]

BTW, it's not "oscillating" per se' but just limiting fast while letting the load TRY to start. It's part of the magic of Rosie except for that noisy side effect

Is there a reason why it does not drop voltage level once max AC current is reached? Momentarily dropping voltage wound also drop locked rotor current below inverter max current cutoff and motor may spin up similar how soft starters work. If it does not spin up in 1 - 2 seconds then cut power.

 

[SpongeboB Sinewave]

Is there a reason why it does not drop voltage level once max AC current is reached? Momentarily dropping voltage wound also drop locked rotor current below inverter max current cutoff and motor may spin up similar how soft starters work. If it does not spin up in 1 - 2 seconds then cut power.

Inverters are usually supposed to regulate their RMS AC output voltage.
It would have to be another operational mode. But I like it !

How often would you connect a many time higher load requirement product like this compressor to your too small inverter ?

We like the David and Goliath -ness of the Rosie as far as a small-ish inverter driving too large of loads. (I just made that up)

So, another mode that does soft voltage ramp might not be a bad idea ! Eventually might be able to look into doing that !
It's just SMOP ! Simple Matter Of Programming
boB

 

[AntronX]

So, another mode that does soft voltage ramp might not be a bad idea ! Eventually might be able to look into doing that ! It's just SMOP ! Simple Matter Of Programming

Yes, exactly. Just drop PWM width to hold max AC current for few seconds. Maybe make it menu item adjustable time window until trip point. I would even experiment with dropping frequency to 50Hz at the same time. If this works good enough to eliminate external soft starters then it a valuable feature. The only issue it may stall already running HVAC compressor if this mode activates. May want to include that as a disclaimer.

 

[AntronX]

How often would you connect a many time higher load requirement product like this compressor to your too small inverter ?

All the time. That's why soft starters exist and are expensive for what they are (fancy light dimmers). Even look at Will's videos where he gets excited if some small solar generator box starts his car lift.

 

[SpongeboB Sinewave]

All the time. That's why soft starters exist and are expensive for what they are (fancy light dimmers). Even look at Will's videos where he gets excited if some small solar generator box starts his car lift.

If it's just triacs, they could build that into the motor drive themselves if it helps their product starting up.

I'm not sure if you are talking about compressors or maybe something else, BTW ?

boB