Victron is Over-priced Eurotrash. Why would anybody buy Victron over an AiO?

[sunshine_eggo]

Insulated at all? Throw a 9k BTU mini split in there . Set thermostat to 80°

Not even a little. I have a floor to ceiling blackout shade separating the front 10' from the remaining 30'... probably about R0.5.

I am tempted to do something like that. I actually picked up a Midea portable 12k mini-split portable for $120, and it's really tempting to cut a duct sized hole in the container. If it was also a heat pump unit, I would have already done it.

 

[Crowz]

Insulated at all? Throw a 9k BTU mini split in there . Set thermostat to 80°

That's what I did for my workshop.

Shows $479 right now. I got it on a lightning deal sale for $340

Free shipping too. Love amazon.

12k btu heatpump

Amazon.com

 

[sunshine_eggo]

Not sure any amount of BTU can put a significant dent in the R.002 walls of the container. Thing is nearly thermally transparent when you take solar heating effects out of it.

 

[HRTKD]

Paint it white?

 

[sunshine_eggo]

Paint it white?

But then it's too cold in the winter...

 

[NC_hydro]

Get some of those black mesh tarps that are like shade cloth and stretch them taught 8” or so away from the container

 

[Brucey]

Not even a little. I have a floor to ceiling blackout shade separating the front 10' from the remaining 30'... probably about R0.5.

The "gloryhole" partition....

 

[BerndL]

So basic mppt question, but I'm curious about victron's implementation.

When you're clipping, the SCC limits input by controlling the resistance it applies across the + & - of the panels.
From what I've seen a victron increases the resistance, decreases the current, and lets the input voltage rise closer to Voc.
At noon I often see ~76V 6A in, 14V 30A out.

During clipping you don't care about wire losses, so the only effect is that the SCC is now converting >80V down to as low as 12-13V, which means more switching losses and heat in the unit.

Would it be possible for them to instead decrease resistance, increase current, and let input voltage drop closer to battery voltage?
You could have 43V 9.9A instead of 76V 6A with the same output, wouldn't that mean less heat generated where it matters (inside your electronics) and more where it doesn't (your wires and panels)?

Or am I retarded and reducing input current is always better for heat than keeping the input-output voltage closer?

 

[ricardocello]

Would it be possible for them to instead decrease resistance, increase current, and let input voltage drop closer to battery voltage?

I believe the load variation on an SCC can vary from dead short (0 power) to full open at Voc (also 0 power).
However, on a victron SCC the input voltage must be 5 volts above the battery voltage to start, and then 1 volt over to run.
Which cuts it about as close as possible for a buck converter.

They find the load that maximizes overall power (including switching losses), and that voltage isn’t necessarily close to the battery voltage.
But if it was, that’s where it would stay.

 

[BerndL]

They find the load that maximizes overall power (including switching losses), and that voltage isn’t necessarily close to the battery voltage.
But if it was, that’s where it would stay.

Right, but when its output is maxed out, it picks a non-optimal current and voltage to reduce the input. I'm curious why victron picked "higher voltage, lower current" over "lower voltage, higher current" if both do the same thing, a smaller gap between PV and battery voltage is more efficient.

 

[NC_hydro]

Right, but when its output is maxed out, it picks a non-optimal current and voltage to reduce the input. I'm curious why victron picked "higher voltage, lower current" over "lower voltage, higher current" if both do the same thing.

More current I would imagine mean more heat than higher voltage lower current.

 

[Crowz]

Right, but when its output is maxed out, it picks a non-optimal current and voltage to reduce the input. I'm curious why victron picked "higher voltage, lower current" over "lower voltage, higher current" if both do the same thing.

Sounds like a cooling it down decision for sure. They get VERY hot at the top of their charging output.

 

[sunshine_eggo]

Right, but when its output is maxed out, it picks a non-optimal current and voltage to reduce the input. I'm curious why victron picked "higher voltage, lower current" over "lower voltage, higher current" if both do the same thing.

This wasn't a conscious choice. It is how physical laws work.

The voltage and current relationship is dictated by the load. If you pull less than max load, the voltage is higher. This relationship is stable and predictable. It is also advantageous in that there is less losses, i.e., higher voltage and lower current result in less wiring losses.

 

[sunshine_eggo]

You know what... I think I've made things better...

At this point only about 1 foot of the container roof will EVER see sunlight. that was a 95% reduction in exposed roof since last summer.

Looking at the winter and summer solstices:

The south face receives winter sun with negligible losses due to panel overhang. Trig says the panel overhang obscures less than 8" of the south face at winter solstice.

There's what it looks like a couple weeks before the equinox - about a foot and a half off the top, so even less shaded at the winter solstice:



The south face will be partially shaded by the panel overhang... Trig says over 5 feet of it on the summer solstice, and I've added that additional shade over the rest of the south face.

In generalities:

I have a notable reduction of key surfaces when heat is a concern.

I have a notably smaller reduction of key surfaces when heat is desired.

Is this fixed? No, but I think I've notably mitigated summer heating issues without significant adverse effect on desired winter heating.

 

[Crowz]

Careful there is an evil tree thing in front of it

 

[sunshine_eggo]

Careful there is an evil tree thing in front of it

LOL... That's not a tree. It's a giant shrubbery (juniper).

In the WORST case, there is a partial shadow across the bottom row of cells one rack at a time. I've never noticed it affecting performance, but it probably does a wee bit.

 

[sunshine_eggo]

LOL... absorption hit at 8:32am... "full" (75% SoC) by 9:45am.



num num num num num....

 

[Crowz]

LOL... That's not a tree. It's a giant shrubbery (juniper).

In the WORST case, there is a partial shadow across the bottom row of cells one rack at a time. I've never noticed it affecting performance, but it probably does a wee bit.

Kill it ! Kill it with fire !

All trees are evil and their cousins the shrubs are mini me evils of them !

 

[sunshine_eggo]

Kill it ! Kill it with fire !

All trees are evil and their cousins the shrubs are mini me evils of them !

We are of the same tribe. I'm sure that once I'm on-site permanently, I'll be giving that bugger a trim!

 

[740GLE]

Kill it ! Kill it with fire !

All trees are evil and their cousins the shrubs are mini me evils of them !

Look around the rest of his land, I’d say anything tall is naturally eliminated or just never grows.

 

[green mountain boys]

We are of the same tribe. I'm sure that once I'm on-site permanently, I'll be giving that bugger a trim!

I like to call it, basal pruning.

 

[sunshine_eggo]

Look around the rest of his land, I’d say anything tall is naturally eliminated or just never grows.

8-15' juniper "trees" and 10-20' Pinon Pines in a ~85/15% ratio. They often grow together for some symbiotic reason I forgot.



Occasionally we'll get a heavy rain and EVERYTHING turns green... but then its days of weeding...

Oh looky... rain!

 

[JoeHam]

LOL... That's not a tree. It's a giant shrubbery (juniper).

Perhaps the knights will cut it down for you :

 

[740GLE]

8-15' juniper "trees" and 10-20' Pinon Pines in a ~85/15% ratio. They often grow together for some symbiotic reason I forgot.

View attachment 284771

Occasionally we'll get a heavy rain and EVERYTHING turns green... but then its days of weeding...

Oh looky... rain!

View attachment 284776

You call that trees???? cute

I’m surrounded by 75-120ft white pines that are true warts of the land and need to be obliterated!

Sadly they do provide some shade in the summer that keeps the house cooler and decent screening from the neighbors, just horrible for PV production.

 

[sunshine_eggo]

Perhaps the knights will cut it down for you :

I was hoping someone would get the reference!!!!

You call that trees???? cute

I’m surrounded by 75-120ft white pines that are true warts of the land and need to be obliterated!

Sadly they do provide some shade in the summer that keeps the house cooler and decent screening from the neighbors, just horrible for PV production.

I said "trees"...