diy solar

diy solar

Midnite Solar Announced their new 10kw AIO at Intersolar Today

Bob was posting about this the other day:


That would have been Robin. I am in AZ right now recuperating from some health issues. Working while recuperating of course !
I love my little lab here !

boB
 
It does, when referring to a single leg surge.


Yes, a transformer can transfer power from 240V to 120V or vice versa. So could give 2x if big enough.
But it doesn't store energy to any appreciable degree or otherwise help with surge.

I think the most dramatic effect is in a true low-frequency configuration like MSW.
A utility transformer spec'd 3% regulation might deliver 0A at 123.6V, 100A at 116.4V. If you short-circuit the output, it could deliver 3000A or more.
Similar the surge capability of MSW, if the transistors could carry the current.

Anything HF uses SMPS to store energy in an inductor. What it can do is limited by stored energy and switching frequency.
 
Yes, a transformer can transfer power from 240V to 120V or vice versa. So could give 2x if big enough.
But it doesn't store energy to any appreciable degree or otherwise help with surge.
Correct
I think the most dramatic effect is in a true low-frequency configuration like MSW.
A utility transformer spec'd 3% regulation might deliver 0A at 123.6V, 100A at 116.4V. If you short-circuit the output, it could deliver 3000A or more.
Similar the surge capability of MSW, if the transistors could carry the current.

Anything HF uses SMPS to store energy in an inductor. What it can do is limited by stored energy and switching frequency.
I'll just take your word on most of this. It's over my pay grade. lol
 
Excellent news Robin & Halfcrazy.
I don't care where it's made, as long as it is made well & to robust specs.
I found the "Art-Deco" comment funny... I like Art-Deco myself, it's COOL ! Architects should bring it back with a modern twist IMO.

Dang thing about it.... Those of us who have Classics & are all setup would have to swallow a Big Chunk to convert over... I dunno many who'd want to sacrifice a few grand worth of SCC's that work amazingly well.
There needs to be an option from them with ALL the capability of this inverter without the built in chargecontroller..
 
As far as I know, every battery based inverter out there have a transformer at least between battery side and HV inverter grid side.
The PWM that makes the sine wave is always high-ish frequency. Usually greater than 20 kHz so it falls outside of the human hearing range.

"Low Frequency" just refers to the transformer being a heavy 50Hz or 60Hz type which is BIG compared to a "High Frequency" inverter which uses a smaller transformer. Low Frequency transformer inverters have typically been said to have a higher surge than HF inverter types but there is no technical reason for this to be the case.

boB
 
We will be looking for the best places to give away the first 20 units. We need to get the most out of these marketing units as there is a ton of competition. Some of it is pretty good, but a lot of it misses the mark.
Feel welcome to send one my way. I will be adding solar to a Sol-Ark 15k with a battery. It is a unique use case for the MS Inverter, but would serve as a demonstration for the general concept:

The MS inveter would attach as AC Solar Input to the Sol-Ark. The 10kW rating of the MS inverter is perfect for my situation.

The Energy Storage Solutions (ESS) program in CT pays a fee (incentive payment) based upon how much your battery supports the grid during "Events" set by the Utility (3 hour window on a specific day when they expect peak demand). Battery ability is after PV production.

My batteries can max out the sol-ark 15k inverter output for that 3 hour window. If I add DC PV, then that cuts into inverter capacity available for the incentive payment.

Why not add a 2nd 15k? Because the utility (Eversource, or ES) limits export to 25kW. Two 15k's can exceed the limit. ES doesn't care about software limits (grid export limit), ES is concerned with hard limits.

Adding 10kW of AC PV would be allowed - the rated AC output of the MN15 (I think I can ignore the peak output of 11kw).

Any excess PV (over 10kW) could be used to charge the batteries (offset power being drawn by Sol-Ark to export power). ESS program only sees what the Sol-Ark inverter is doing, not where the battery power comes from.

Why would MS care about this special case? It could demonstrate that the MN15 could serve as UL1741SB compliant AC PV input to another inverter that can modulate AC PV input.

Bonus if MN15 priority of Solar PV can be: Load, Export, Recharge Battery. And, if Export is Frequency Limited, then excess PV is sent to Batteries. Only when batteries are fully charged would PV production be throttled back.
 
I'll just take your word on most of this. It's over my pay grade. lol

Simple calculation is just ohms law, current limited by winding resistance.
Beyond that is what the core can transfer, I'm not real clear on it.

 
Simple calculation is just ohms law, current limited by winding resistance.
Beyond that is what the core can transfer, I'm not real clear on it.

I wasn't referring to the transformer stuff.
The electronic stuff is beyond my expertise.
 
Do these AIO's allow battery charging with the inverter portion off, both from an a/c source and of course the MPPT?
 
I don't have the full spec sheet, but Midnite has a very impressive unit on the way. I spent about an hour at Intersolar talking to the brains behind the operation and was very impressed. Unlike some competitors, the Midnite team was very humble and pleasant to talk to and they didn't belittle the small businesses they work with. We agreed to get one of these AIO units at the end of February when inventory arrives and will use this thread to share everything we can learn about this machine.

Some specs:
PV Input voltage up to 600VOC, MPPT operating range of 70V to 550v (this is a higher top and lower bottom than SA and EG4)
3 MPPT inputs
48v battery input
100A passthrough/transfer switch
15kW solar input
10kW continuous inverter
Surge: 13kW on a single leg (WOW!)
Field serviceable! First AIO to have this ability.

To get things started, a picture!

View attachment 189615
Good news, I've been researching inverters for my shop solar system. This is a serious contender.
 
Yes. At surge power levels HF transformer efficiency gets worse and heat becomes exponential. Same happens to LF transformers.
Absolutely.
If it is a transformer that is providing surge capacity.
I don't think that it's been confirmed either way, yet.
But I would expect it to be the case.
 
You could comfortably run 18s packs...
~2KWh additional capacity per 305ah pack.

Will there be a pre-order available?
I'm perfectly happy with what I have but this is a solid unit with excellent specs.

I bet one could make a very popular youtube video putting this head to head with some other popular AIOs...
 
Transformer and power transistors can limit the surge power due to their ESR. (Effective Series Resistance)

Heat dissipation, which is related to the resistance of components, ESR, is more of how long the power can stay up there. That is strictly from thermal time constants. A low frequency transformer is bigger and so its time constant is longer than the small transformer.
BUT, the FETs or IGBTs for either version is about the same time constant. HF inverters usually have larger inductors which can be another time limiting component.

Transformers are not an energy storage device though. At least they are not supposed to. They just transfer power and energy.
If they DO store energy, then that means the transformer has leakage inductance and can manifest itself with big voltage spikes which need to be dealt with.

I'm not sure how every inverter limits their output power except by turning off. They can reduce the AC output voltage but you don't want that.
ESR and time pretty much. ESR is where the heat comes from of course.

boB
 
You could comfortably run 18s packs...
~2KWh additional capacity per 305ah pack.

Will there be a pre-order available?
I'm perfectly happy with what I have but this is a solid unit with excellent specs.

I bet one could make a very popular youtube video putting this head to head with some other popular AIOs...
I’m gonna start calling you my brother from another mother because at the end of the day our systems are going to be mirrors. Backups included ?
Get off my lawn and back away slowly from my inverter
 
Back
Top