Where is @Will Prowse?

[rmaddy]

That is right along the lines of my post earlier today!

I saw that earlier today. Your post and this post came together at the right time to motivate me to post up my suggestion. I've wanted to see a proper comparison for a while since we so many questions here about "should I wire my panels in series or parallel?".

 

[timselectric]

Shading is only an issue for location of panels.
With bypass diodes built into every panel, these days. You wire the panels for efficiency. Highest safe voltage strings possible. Paralleled to desired amperage.

 

[Will Prowse]

That is exactly why I was suggesting you break away from the rest of the YouTube pack and start doing more detailed analysis of Inverters and how they perform. Just looking at the effieceny curves of "typical" Inverter designs has got me really wondering at what Wattage are these Inverters efficiency being rated at. How effiecent is a an LV6548, Growatt or Sol-Ark at full load versus 40% load? That is one of those values you can see instantly with that Fluke Meter and a bunch of heaters for loads. Then we have the whole THD question. Lots of new Angles to test the equipment you already have.

I thought about your suggestion of using a power analyzer with various inverters, and I do not think the results would help people that much (especially beginners). What I care about most with an inverter is reliability and the software. That is what you're paying for. Posting an efficiency gain of a few percent over another inverter really does not help people (it is fascinating though, and I want to see the results as well).

And if someone wants to run large inductive loads repeatedly, they should do so with a high quality LF inverter. What the results would show is that if you need higher efficiency and better performance, you need to spend more money.

The THD question is interesting. I lost interest with THD after I realized even my cheapest inverters have a lower THD than grid. I still need to test under load as you stated. But at what point does a high THD affect the life of a device? I know anything with a coil will run hotter. And I have burned out quite a few motors in my day. But is there data for me to draw conclusions? Can I draw a conclusion that could be useful for everyday people with those results?

Even the budget LV6548 has fantastic efficiency figures, but awful idle consumption. So again, I would tell people my usual "spend more money, because you get what you pay for" line. The quality of the components and the software all improve when one spends more money on a victron, for example.

 

[Will Prowse]

Shading is only an issue for location of panels.
With bypass diodes built into every panel, these days. You wire the panels for efficiency. Highest safe voltage strings possible. Paralleled to desired amperage.

Yes I agree. Just wire them to the highest voltage possible. Paralleled to desired amperage. Well said.

If someone has shading issues, they need to fix the shading. Remove object that is causing the shade to be cast on the panels.

 

[Will Prowse]

Well, I replied to the YT post asking for such ideas but i'm especially curious as to how prevalent repackaged used cells are in supposedly new prebuilt batteries, such as the TimeUSB battery you took apart. I think you've basically already established that most of the cheap batteries that DO use new cells don't particularly suck, and depending on how you look at it pretty much range from 90% good to 100% good to the point that you've combined multiple battery dissections into one video lately because they're.. predictably just fine.

But used cells in 'new' batteries.. What known instances are out there? Would some things to look out for be, odd aH sizes that don't correlate with multiples of common cell sizes, suspiciously small BMS current ratings, unusually pessimistic cycle life claims (2000 or less vs typically higher claims), etc?

And couch this in, when does it stop mattering? How steep is the 'non-linearity' of capacity drop off after lifepo4 hits 80% of original capacity anyway? How cheap does something like that have to be to still be better than a spanking new lead-acid, for example? Is it even realistic to care about claimed cycles past 2000 etc when the battery has multiple cells and they ALL have to make it to 4000 for a battery that claims 4000 to actually get there, with daily cycling, in 10+ years!? Does 'sudden cell death' which might be more pragmatic of a concern (is it?) than the difference between 2000 and 4000 cycles, become more common after that 80% capacity mark, or are used cells likely to be essentially as 'reliable' as new but with quicker capacity deterioration? And what kind of uses would likely NEVER find the difference between 80% of 120 and 100% of 100 because they'll likely never cycle them often or deeply enough to find drastic differences, and is that a surprisingly large umbrella that covers a whole lot of people who would say they would not consider used cells but in all likelihood would still be happy with them?

Should we be crying wolf to the whole idea of derated used cells being sold 'retail' in new batts, or should we just be hounding them down to a lower price point, or forgoing the shamelessly easy Amazons return policy on 'pre-assembled' batteries and buying used raw cells cheaper through some other marketplace which would likely offer NO realistic chance of returns/support?

Sorry, as a car mechanic one of my main hobbies is finding out (on my own stuff) just how far and how long parts will go beyond their design intent. With lifepo4 I don't have the patience to wait all the years to figure any of this stuff out with my own testing, but would sure like to hear someone who's been watching and using them since closer to 'the beginning' give highlights of their accumulated knowledge, even if half of what i've asked for here might be considered vague generalizations and conjecture. I understand that it's easier to receive and find the value of such things, than it is to put yourself up to spreading it when you hold yourself to high standards. Or..maybe you've been JUST WAITING to rile up half of everyone by making any assertions along any of these lines.

The tough part with this is we really have no idea what they were used for previously. So if I find a paper covering degradation, I have no way to compare how they were used. Getting a lifepo4 pack to 80% degradation is not easy. I wonder what physical changes occur in a lifepo4 that has been cycled heavy for a short time. Could be changes in SEI layer or fractures in the anode. As usual. But there is no way to measure these phenomena unless I tear it apart and use an electron microscope. But again, the pack history could differ, so the results of me doing a long term test on one could get a false representation for these used cells. Sudden cell death seems to be rare with this chemistry as well. Especially compared to lead acid.

Especially considering the price. These packs, or at least the one I just tested, is nearly the same cost as a brand-new pack for which I can give solid recommendations and cycle life estimates. I have no real way to draw conclusions or give recommendations on used, heavy cycled cells.

With that said, I am charging my car with B grade cells that are heavily degraded. They work great!

 

[Hedges]

That is exactly why I was suggesting you break away from the rest of the YouTube pack and start doing more detailed analysis of Inverters and how they perform. Just looking at the effieceny curves of "typical" Inverter designs has got me really wondering at what Wattage are these Inverters efficiency being rated at. How effiecent is a an LV6548, Growatt or Sol-Ark at full load versus 40% load? That is one of those values you can see instantly with that Fluke Meter and a bunch of heaters for loads. Then we have the whole THD question. Lots of new Angles to test the equipment you already have.

But would that appeal to the demographic of majority of Will's audience?
Bolt things together and have a functioning system, to appeal to many users.
As soon as you get into losses vs. load, engineering aspects, it will go over the heads of many and only appeal to a few.

Even among engineers, getting into a different discipline or different area of their discipline, a presenter will lose many of them. There is a market for deep technical presentations in various fields, but viewers select themselves for interest in that. Science shows on TV deliver a bit of content with lots of animated graphics for appeal.

Efficiency - no-load power consumption of inverter may be most important, especially for mobile systems. A percentage of used power being lost is one thing, but no-load consumption requires bigger battery and more panels just to keep system running so it can power loads when desired. Video could have graphic of pie charts superimposed showing how much of a battery and how much of a PV array is wasted on that, vs. available for user's loads.

THD - what could matter is how well inverter handles poor power-factor loads. LF inverter may be better for inductive motor loads. Many loads have rectifier/capacitor front end, e.g. power adapters and non PF-corrected motor drives for fridge or A/C (apparently European models are better in that regard than U.S.) Try operating inverters heavily loaded with such products.

 

[Will Prowse]

My latest 48V system was the most fun I have had in the last year on the channel. And I am trying to think of ways to improve that system. It seems perfect. I am running 13kW daily intermittently daily (two ac's and the ev charger) at high efficiency, and not a single hiccup. The system has been running 24/7 since I built it, and I just hit 2 mega Watt hours. I love it. Especially for the price versus a sol ark or victron. I still have not been able to kill a MPP or any other all in one unit. They just keep on working. I have destroyed inverters in the past too, but these units have not given me issues.

I think modular 12V systems that can fit in a van (think milk crate system on steroids) may help a lot of people. I saw some van life systems last week and people may need more help in that area. Most of the youtube videos covering van systems are super boring and there is zero new information being posted on this topic. Might be fun to think of a new way to build those systems.

 

[Will Prowse]

But would that appeal to the demographic of majority of Will's audience?
Bolt things together and have a functioning system, to appeal to many users.
As soon as you get into losses vs. load, engineering aspects, it will go over the heads of many and only appeal to a few.

Even among engineers, getting into a different discipline or different area of their discipline, a presenter will lose many of them. There is a market for deep technical presentations in various fields, but viewers select themselves for interest in that. Science shows on TV deliver a bit of content with lots of animated graphics for appeal.

Efficiency - no-load power consumption of inverter may be most important, especially for mobile systems. A percentage of used power being lost is one thing, but no-load consumption requires bigger battery and more panels just to keep system running so it can power loads when desired. Video could have graphic of pie charts superimposed showing how much of a battery and how much of a PV array is wasted on that, vs. available for user's loads.

THD - what could matter is how well inverter handles poor power-factor loads. LF inverter may be better for inductive motor loads. Many loads have rectifier/capacitor front end, e.g. power adapters and non PF-corrected motor drives for fridge or A/C (apparently European models are better in that regard than U.S.) Try operating inverters heavily loaded with such products.

Absolutely! You hit the nail on the head here.

 

[Koldsimer]

@Will Prowse I would love to see a video highlighting the differences in the pre-charge function amongst the rack mount style batteries. Things like resistor sizing, ways to initiate the feature, how to bypass, duration of pre-charge etc. would be good to know and have documented. The hard part would be getting all the different batteries together but i believe you have that covered!

 

[SacRV]

I'm always present here or checking the channel. Trying to think of a new fun direction to take with the videos. Have done a few hundreds videos now and I feel like I'm repeating myself. I actually filmed some videos this month, but didn't post them because they were not very useful.

Will, I think a real world from design-to-completion trailer install would be helpful to new viewers.

 

[Cyanlite]

My fun videos get downvoted. Or if I share opinions or entertain. Technically, instructional videos get the upvotes, and I'm here to appeal to the masses. Need to find the next thing that can really help people. I don't want to entertain. I want to help people. Without wasting their time.

I'd love to see a series of videos on a full-blown DIY solar set up that fully passes electrical inspections, and your experience going through the inspection process. Everything from the permit application to ground mounting to engineering stamping to dealing with the inspector on-site.

To my knowledge, no other YouTuber has done anything like that. Other smaller projects like installing a Reliance generator transfer switch to work with a Growatt/EG4 inverter.

And I do get your point about being repetitive. I've seen so many YT'ers out there doing weekly tear downs of the latest Chins-clone battery from Amazon.

 

[robby]

But would that appeal to the demographic of majority of Will's audience?
Bolt things together and have a functioning system, to appeal to many users.
As soon as you get into losses vs. load, engineering aspects, it will go over the heads of many and only appeal to a few.

Even among engineers, getting into a different discipline or different area of their discipline, a presenter will lose many of them. There is a market for deep technical presentations in various fields, but viewers select themselves for interest in that. Science shows on TV deliver a bit of content with lots of animated graphics for appeal.

Efficiency - no-load power consumption of inverter may be most important, especially for mobile systems. A percentage of used power being lost is one thing, but no-load consumption requires bigger battery and more panels just to keep system running so it can power loads when desired. Video could have graphic of pie charts superimposed showing how much of a battery and how much of a PV array is wasted on that, vs. available for user's loads.

THD - what could matter is how well inverter handles poor power-factor loads. LF inverter may be better for inductive motor loads. Many loads have rectifier/capacitor front end, e.g. power adapters and non PF-corrected motor drives for fridge or A/C (apparently European models are better in that regard than U.S.) Try operating inverters heavily loaded with such products.

Yes it would appeal to them once you start doing the Videos and producing Data and put it into context.
It does not matter how technically inclined the Audience is. They will all quickly know that high THD is bad and you can see from his previous videos the numbers from other Inverters. They know that they want good efficiency, especially at the load levels their house is typically consuming power at. Well here is an Inverter that delivers great efficiency right at the levels your using. It's all about taking the educating level of the Audience up by another notch, if not your just going to be doing the same stuff over and over and the Truth is it really tells you nothing about the Quality of the product you are buying. Yes Growatts produce the same power as other Inverters but it was not until I looked at a more technically inclined video that I saw that the Output Voltage had major issues with it. You did not need to be a rocket scientist to understand something was wrong because the guy compared it to the Grid and it was obvious that the power was distorted and Glitching.

Idle consumption is definitely a measurement that is needed but that is already being done. I think efficiency is just as important on large systems as small mobile systems. an extra 5% loss in efficiency can be a real blow if your trying to figure out how to get off grid or how many batteries do you really need to achieve your goal.

It's up to Will, he can keep wiring up Inverters and cracking open batteries or move the technical level up several notches.

 

[FilterGuy]

Wow!! I started the thread as just a fun little question but it has turned into an interesting discussion of possible videos for Will. I like it.

 

[ncsolarelectric]

My latest 48V system was the most fun I have had in the last year on the channel. And I am trying to think of ways to improve that system. It seems perfect. I am running 13kW daily intermittently daily (two ac's and the ev charger) at high efficiency, and not a single hiccup. The system has been running 24/7 since I built it, and I just hit 2 mega Watt hours. I love it. Especially for the price versus a sol ark or victron. I still have not been able to kill a MPP or any other all in one unit. They just keep on working. I have destroyed inverters in the past too, but these units have not given me issues.

I think modular 12V systems that can fit in a van (think milk crate system on steroids) may help a lot of people. I saw some van life systems last week and people may need more help in that area. Most of the youtube videos covering van systems are super boring and there is zero new information being posted on this topic. Might be fun to think of a new way to build those systems.

Does your system have Rapid Shutdown per NEC 2017? It would be interesting to see what is required to make that work with your EG4 setup. I think you need both the TS4 on the panel AND a pair of DC contactors at the inverter to de-energize the wires. The inverters are not equipped with the contractor or a breaker, like the Sol-Ark is.

 

[Supervstech]

Does your system have Rapid Shutdown per NEC 2017? It would be interesting to see what is required to make that work with your EG4 setup. I think you need both the TS4 on the panel AND a pair of DC contactors at the inverter to de-energize the wires. The inverters are not equipped with the contractor or a breaker, like the Sol-Ark is.

Only required if panels are residence roof mounted.

 

[ncsolarelectric]

Only required if panels are residence roof mounted.

I thought Will's system was on his roof. No?

 

[robby]

I thought Will's system was on his roof. No?

Nope, not the ones you see in videos used for testing Inverters etc.
He does have panels on the roof for his home system, but that is never used for testing purposes.

 

[cs1234]

I thought Will's system was on his roof. No?

I thought he has some panels on his roof, an installed to code grid tie system installed by somebody else.

Then the stuff he does for our benefit on youtube are just sitting on his driveway in his fenced in area? Not that I have a problem with it. I only wish I could get away with it.

 

[SparkyJJO]

I know! A new how to DIY build your very own inverter from nothing but copper wire, and old horseshoe, a cardboard box, and duct tape!

 

[Will Prowse]

I thought he has some panels on his roof, an installed to code grid tie system installed by somebody else.

Then the stuff he does for our benefit on youtube are just sitting on his driveway in his fenced in area? Not that I have a problem with it. I only wish I could get away with it.

Tesla solar installed my grid tie system. I do not like installing panels, especially with the health issues I have with my feet from when I was disabled. I would love to build ground mount arrays but I don't have room on my property. Still trying to find someone to sell ballast ground mount system, but no one has come to market yet.

My panels are on the ground so the fire safety codes don't apply. I have them secured with a stainless steel cable. Very easy to swap panels out for testing. The insulation of PV wire is thick, and my wires are on concrete, so it is good to go.

I personally want to stick to Offgrid lifepo4 systems. I just don't care about grid tie, and there's thousands of companies installing it now for cheap. Not very diy friendly with the permits either.

And I prefer independence from the grid.

Low voltage DC seems not to be covered much (if at all) in NEC. Pretty unfortunate. I was expecting something that could help me design my systems. Not really. Just a bunch of ac wiring configurations for various applications and environments. Not sure why people reference it when it serves little use in large battery systems being charged with solar. Even the grounding recommendations for mobile systems is non existent.

Typically I use marine low voltage DC recommendations, such as ABYC. It is a million times more useful than NEC.