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What would the best possible charge controller be like??


Ben
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Seems msb controllers are having "problems"
From every thing i know of msb is the only "cheap" controllers
But are they truly cheap if all info is considered?

Could a higher voltage controller help pay for its self by saving copper wire cost?
Is there a better way than MPPT?
A better than MPPT or not as good but simple way of turning high voltage to low voltage?
Nothing is 100% efficient but how close can a controller be?
To the dreamers if you could have it do anything explain what that would look like?
What features are must haves?

From the way its looking msb may not be a good the best way to go

So most people like me dont have a clue what to even look for to even know what is a good deal!

I hope this post will make it easy to make a better choice!

 I hope everyone who reads this will add there TWO CENTS from what they use to what would be nice to have!
Even if some one has already said what you would say please say you second what has already been said! That will let the reader !
I hope the pros from all around or under the world chime in along with reg people like myself and definitely the dreamers!

Dreamers are the start of ALL the good stuff even though the pros would like to kick them in the head to shut them up! LOL LOL
I will start this by saying wire can add a very big cost to off grid solar.   

How much money can be saved by high voltage panel setup?

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3 hours ago, Ben said:

Could a higher voltage controller help pay for its self by saving copper wire cost?

Very subjective...depends on how much more the "higher voltage controller" costs!

Worth noting that what's most fun to calculate is the percentage of power loss across your solar wires (wire resistance per 1k feet against the solar panel "short circuit amps" for a worst-case calculation).  The longer the wires between the panels and MPPT, the higher your losses here will be.  Bigger wire is obviously considerably more expensive--and at some point, you will break even with a higher voltage MPPT.

 

I find the MSB's voltage rating to be very limiting especially with the newer higher wattage panels, which run significantly higher voltages than the older ones.  You simply can't put more than 2 of the bigger panels in series with an MSB--which puts you barely above battery voltage (if 48v).

 

3 hours ago, Ben said:

Is there a better way than MPPT?

No, not for solar panels anyway.  In short, solar panel current remains very stable (based on the amount of light), while the voltage can be taken from no load to a short circuit--meaning that the "maximum power point" is going to be at the highest voltage.

The reason "solar panel voltage" is not a defined constant, is because it is highly variable based on the solar panel temperature--so a "sweeping maximum power point tracking" method is the quickest and simplest way to try to get the most power out of a panel.

 

3 hours ago, Ben said:

A better than MPPT or not as good but simple way of turning high voltage to low voltage?
Nothing is 100% efficient but how close can a controller be?

So "MPPT" is the term used for the regulating methodology.

The actual conversion topology is generally a non-isolated synchronous buck converter.  (Some random smaller Chinese units sometimes are designed around boost topology--but that's highly specific to a particular small usecase.  And of course, most uber-cheap Chinese "MPPT" units are just outright fakes, with no buck conversion circuitry whatsoever.  Basic PWM chargers.)

Most "industry standard" MPPT units run >99% efficiency, often reaching or exceeding 99.6%.  For example, my Morningstar Tristar TS-MPPT-60 will run a happy 3,200W at full load--with no fans, and a heatsink that's warm (but not scorching hot) to the touch.  If 99.6% efficient, that's a paltry 12W of heat.

Worth noting that the enemy of MPPT is amperage--which is why they tend to limit out at 60/80/100A.  The more current, the more heat generated--which is why an MPPT that can do 3,200W at 48v can only do 800W at 12v.  Same 60A.

 

3 hours ago, Ben said:

From the way its looking msb may not be a good the best way to go

They are a cheap way to get started, for sure.  I can't say that their MPPT function is the world's best (or anything close to it)--but a lot of people seem to like them.  I personally have never used one (I have Morningstar Tristar and Epever Tracers), as I prefer MPPTs without fans if I can!

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with msb one and one half batt voltage is what your shooting for on panel input to controller   

why so low why not 4 or 500 volts on the solar input to the controller is it just a safety issue   

 could a controller work like a low freq inverter but stepping voltage down not up with a steel core tranny 

seems like the high amp stuff could be done by a tranny

a tranny can be very efficient i know the cost of low freq tranny would be crazy high just wandering 

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If no shading would high voltage  on controller input charge batt in lower light or is there not much benefit?   

As always i am full of questions but i think others would be wondering also so not a waste if answered where all can freely read 

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I find the MSB's voltage rating to be very limiting especially with the newer higher wattage panels, which run significantly higher voltages than the older ones.  You simply can't put more than 2 of the bigger panels in series with an MSB--which puts you barely above battery voltage (if 48v).

I  try connecting  4  solar panets at 60 VOC  in series and parallel   and the MSB  blow up  and melted the terminal  it got so hot in the summer .     My  other  6  MSB  been working good  with  just 2 solar panels connected  and  producing  under 500 watts per hour for each  MSB  for 5 hours of sunlight  now .       One MSB been working for 3 years .    

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12 hours ago, Ben said:

with msb one and one half batt voltage is what your shooting for on panel input to controller   

why so low why not 4 or 500 volts on the solar input to the controller is it just a safety issue 

Firstly, RdsOn (on resistance) in FETs significantly increases with higher-voltage parts.  Higher on resistance = more heat at the same current.  And the more heat generated, the lower the system efficiency.

IGBTs are generally used for high voltage switching--as their "saturation voltage" can often result in lower losses than a comparable MOSFET.  Worth noting that SiC-based FETs (silicone carbide) have significantly narrowed the gap between MOSFETs and IGBTs.

 

12 hours ago, Ben said:

 could a controller work like a low freq inverter but stepping voltage down not up with a steel core tranny 

seems like the high amp stuff could be done by a tranny

a tranny can be very efficient i know the cost of low freq tranny would be crazy high just wandering 

Cost, weight and efficiency demands for an MPPT pretty much rule out low-frequency iron-core transformers!  Worth noting that the one thing an MPPT cannot provide (because of the solar panels!) is any sort of surge power.  This makes them ideal for HF-style designs.

I've looked into the possibility of making a GS MPPT--but unfortunately due to the PJ fiasco, I've got CONSIDERABLY more important things on my plate right now!

In short, my plans specced a dual-input 200-400v panel voltage range, utilizing a forward/flyback (isolated) topology, and providing 4 isolated "12v" outputs that could be series/parallelled for full output at 12v, 24v, or 48v if desired.  (No other MPPT on the market offers this.)

Due to the topology, it wouldn't work with low voltage panel systems--it just won't turn on.  And yes, it would be based around an HF core design to significantly reduce wire losses (which in my experience account for more than 90% of the losses of an LF transformer!)

Just think about it: if you need 200 turns of wire around a large LF core, that's a pretty significant resistance.  But if you can take that same thickness of wire...you'll only need 20 turns on a suitable HF core--meaning that you now have 1/10th the resistance.  And that means that you have 1/10th the losses--well, apart from the black magic of high-speed switching.  Which among other things includes the "skin effect" of wires starting to become hugely important at higher frequencies!

 

But like I've said, I've got MUCH bigger things that need attention right now!

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As stated above, high voltage mosfets are miserable devices with much higher Rds On.

Suppose you have a mythical buck converter that transforms 500v down to 50v at 50 amps.

Current at the high voltage input might then be only 5 amps (assuming an impossible 100% efficiency).  The problem is, the mosfet has to supply 50 amps and also switch at 500 volts.  It gets hit with the worst extremes of both voltage and current.  There are two choices, either build something that is going to get very hot and be inefficient, or build something very expensive, with a rather large number of high voltage mosfets. 

Neither approach has much appeal, either technically, or commercially which is why its not done that way.

 

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Totally agreed, for the typical non-isolated synchronous buck converters.

My thought was to utilize a forward/flyback topology with synchronous rectification on the output instead.  This topology is commonly used in SMPS units easily exceeding 2kw per unit (think server rack PSUs).  Most often, they internally run from a 400v (PFC) DC bus...using a HF transformer to do the "dirty work" dropping 400v down to the 12v @ 220A continuous output.

Yes, efficiency on those units generally is just under 90%--which is a considerable efficiency loss when normal "low voltage" MPPTs tend to near 99% efficiency levels.  (Pretty simple if you think about it I guess--the less "work" being done, the more efficient it likely is to be!)

 

It is definitely possible to attain reasonable efficiency at said levels...as Morningstar Corp offers a 600v MPPT with a "peak" efficiency of 97.9%.  (Of course, "peak" is by no means indicative of "average" or even "full load"...gotta love marketing!)

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56 minutes ago, Sid Genetry Solar said:

Totally agreed, for the typical non-isolated synchronous buck converters.

My thought was to utilize a forward/flyback topology with synchronous rectification on the output instead.  This topology is commonly used in SMPS units easily exceeding 2kw per unit (think server rack PSUs).  Most often, they internally run from a 400v (PFC) DC bus...using a HF transformer to do the "dirty work" dropping 400v down to the 12v @ 220A continuous output.

Yes, efficiency on those units generally is just under 90%--which is a considerable efficiency loss when normal "low voltage" MPPTs tend to near 99% efficiency levels.  (Pretty simple if you think about it I guess--the less "work" being done, the more efficient it likely is to be!)

 

It is definitely possible to attain reasonable efficiency at said levels...as Morningstar Corp offers a 600v MPPT with a "peak" efficiency of 97.9%.  (Of course, "peak" is by no means indicative of "average" or even "full load"...gotta love marketing!)

I have not given any of this much thought, but one way to do this would be to build a "voltage reduction front end" to drive a conventional MPPT controller of your choice.

Step down the very high solar voltage to something much lower, say 600v down to 150v or something, whatever is required.

An efficient way to do that would be with a fixed duty cycle forward converter and a 4:1 transformer.  No mppt, no control of any kind required.  Just a 4:1 (in this example) voltage reduction. The forward converter always operates at high voltage and low current, and the transformer always operates at full duty cycle, so it could all be made to operate at reasonably high efficiency.

The output current is increased x4 (in the above example), and that is done via a transformer. All the clever mppt stuff could be done after that.

Not too difficult or complex.  Any voltage ratio would possible. Maybe 800v down to 18v ?

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31 minutes ago, Warpspeed said:

I post on several different Forums as Warpspeed. 

I am me and nobody else.

I was never questioning your identity...just noting that Ben has multiple times asked me if I'm not somehow Warpspeed.  I keep assuring him that I'm not--so there's nothing like a thread with Ben, theRealWarpspeed and myself in it for proof....

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16 minutes ago, Warpspeed said:

I have not given any of this much thought, but one way to do this would be to build a "voltage reduction front end" to drive a conventional MPPT controller of your choice.

Step down the very high solar voltage to something much lower, say 600v down to 150v or something, whatever is required.

An efficient way to do that would be with a fixed duty cycle forward converter and a 4:1 transformer.  No mppt, no control of any kind required.  Just a 4:1 (in this example) voltage reduction. The forward converter always operates at high voltage and low current, and the transformer always operates at full duty cycle, so it could all be made to operate at reasonably high efficiency.

The output current is increased x4 (in the above example), and that is done via a transformer. All the clever mppt stuff could be done after that.

Not too difficult or complex.  Any voltage ratio would possible. Maybe 800v down to 18v ?

Definitely a feasible idea, one that I hadn't considered either.

One thing to keep in mind is that the more "conversion levels", the lower the total system efficiency--as a "voltage reduction front end" would also still require switching -> filtered DC rectification on the output circuit.  Use of a standard rectifier diode is very inefficient at any significant current levels (at least by MPPT standards!), requiring huge heatsinks, etc.  Synchronous rectification is a fun little trick to implement--but drastically more efficient!  (Thinking <40mV drop instead of >1,200mV at 100A!)

And if an efficiency of a "voltage reduction front end" of >95% could be achieved, there's no reason it couldn't be implemented as an MPPT.  Coding an MPPT can't be that hard...

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i never thought you was warpspeed   

warpspeed is a truly awesome person old school cool to the max!! 

i thought you may have been poida 

 poida and you sid are truly gifted and have a way of making me understand unlike anyone else i have ever known   

 warpspeed would lead me to the water over and over and over and over but he would not drink it for me 

i think he wanted me to do things for myself so i could better understand

i truly appreciate warpspeed them guys down under are hard to beat  

you have a man with a  life time of wisdom chiming in on here 

 it makes me very happy to see warpspeed on here

Hey warp ALL my esg002 inverters are running strong you i have had zerro problems!

One of them is my buddys only power running day and night 24/7 

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Thanks for you in put dickson i have to argree with you     

We now have the worlds best old school and the worlds best new school thinking things through

WOW WOW WOW!! 

  Some thing great will have to happen!!

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