Maxim Integrated panel

Maxim optimiser review. Maxim Integrated panels are my latest find. Maxim is a brand of solar panel optimiser that is going to challenge the conventional optimiser market. In this review, I’ll first explain why optimisers are needed, what optimiser options are currently available, and finally why Maxim optimisers are the next generation in an exciting technology known as Module Power Electronics (MLPE).

 

Maxim optimisers shade proof your solar. Shade resistant solar? Seriously? Let me explain by starting with why solar panels are so drastically affected by shade.

Solar in the perfect world

(Just read the italics quote below if you hate maths)

Solar panels are designed to work together. When we install 20 solar panels on a home, we usually run the first 10 in a “daisy chain” (in series) and the other 10 in another “daisy chain”. We call this “2 strings of 10”.

At lunchtime on a sun-shining day, a standard 250W panels will run at about 33 volts and 7.6 amps. If you multiply 33 x 7.6, you get about 250 watts. (volts x amps = watts)

When we string ten of the panels together, we multiply the 33 volts by the ten panels and get 330 volts. The amps (current) however, remains the same at 7.6 amps. When we multiply the 330 volts by 7.6 amps, we get 2500W.

Two of these strings give us 5000W or 5kW of power.

This was at lunchtime on a good day. At 8 am that morning when the sun was not so strong, we would still have about 33 volts per panel, but we may have (for example) only 3 amps. So 33 volts x 3 amps x 10 panels = 990 watts.

So earlier in the morning, voltage stays the same. However the current is less, and the power is less.

The current of a 1 panel is the same as the current of 10 panels in a string. 

Screen Shot 2016-09-29 at 1.03.48 PM

The real world problem

Enter the bad guy: Shady shade. Let’s say one panel is partially shaded by a tree at 8 am in the morning. When there is less sunshine on a panel, we have fewer amps (or current). Instead of 3 amps at 8 am we only have two amps.

The problem with a “daisy chain” of panels (in series) is that if one panel is shaded and running at 2 amps, then all of them will run at 2 amps.

Because just one panel is shaded, we only have 2 amps (instead of 3 amps) running through the entire string. 2 amps x 330 volts is only 660 watts. Partially shading just one 250w panel has lost us 330 watts! If we could just chop down the neighbours damn branch, knock down the next door’s building, or move that mountain, we would be back to our 990 watts.   The one shaded panel “drags down” the power in the rest of the string.

Even if there is not a tree or building in sight, this entire string loss can occur when one panel is dirtier than the other. It also happens when one panel operating slightly lower than the others because of a variance in panel degradation and manufacturing mismatch.

Because the current in one panel is the same as the current of all 10 panels in that string, partially shading just one 250w panel (and ruducing the current of that one panel) has in turn lost us 330 watts – or, 1/3 of our production in that string of 10 panels.

Solar with shade

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The solution

We need a way to make each panel to work independently of each other. There have been ever-improving methods of solving the shading problem. The solutions are collectively called “Module Level Power Electronics” or MLPE. In other words – we fix this problem at the solar panel with some type of electronics. Module level power electronics can come with several other advantages:

  1. It allows every panel to work independently of each other. One dirty, shaded or mismatched panel will not affect the next.
  2. It allows for much greater design flexibility. For example, if we need to install 3 panels on the North and 7 on the East, we can only achieve that with some type of MLPE.
  3. It can allow for individual panel monitoring. This way, if one panel is particularly shaded, dirty, or faulty – we can pick that up remotely and be proactive about fixing it.
  4. It can allow for a higher degree of safety by switching off the power at the panel on the roof rather than at the inverter on the ground. This is a great advantage in case of a fire.

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MLPE Evolution

Module level power electronics is evolving. These are the stages of the evolution as I see it.

Solution 1: Bypass diodes

Bypass diodes have been in solar panels since Adam was a boy. They exist in just about every solar panel. If a tree is completely shading one panel, that panel will just be bypassed, as if it was no longer in that string. So if you threw a blanket over one of the ten panels, the other nine would work as normal. The problem that bypass diodes are only designed to kick in when there is a serious shading issue on one-third or more of a panel. While shade can sometimes completely blank out just one solar panel, panel mismatch due to soiling and degradation only partially affects the panel. Bypass diodes do not help solve soiling, mismatch or scattered shade.

 

Solution 2: Micro-inverters

Some clever cookie came up with micro-inverters to solve the problem. Instead of “daisy chaining” 10 panels together and sending 330 volts down to an inverter on the wall, they made ten small inverters and put them behind each panel. The panels are no longer daisy chained so the problem is solved. The added benefit with micro-inverters is that we can monitor every panel individually. If one of your panels is running 10 percent less, then you know you have a problem with shade, dirt, or (less likely) your panel needs to be replaced under warranty.

The problems with micro inverters are complex, and I discuss Enphase micro-inverter limitations in this blog. In short, micro inverters often cause significant design limitations which will decrease your power production. It’s also reasonable to assume that putting so many electronics in a little case on a hot roof will be less reliable than having those components in a central location in the shade and on the ground.

On the odd occasion, miro-inverters will help us with the best design at an affordable price. In these cases, we strongly recommend Enphase micro-inverters over their nearest rival APS.

 

Solution 3:  First Generation Optimisers

Optimisers solve the issue by dividing the inverter. They place part of the inverter on the roof, but they want the other part on the ground. A typical solar Inverter is primarily made up of 2 parts: the MPPT and the inverter itself.

  • The MPPT or “Maximum Power Point Tracker” is the part that tracks the slightly changing voltages and rapidly changing currents, and adjusts so it gets the maximum power out of the panels.
  • The inverter “inverters” (transforms or changes) the solar panel DC power into 240v AC power so it can be used by our appliances.

To solve the issue of having too many parts on the roof, companies like SolarEdge and Tigo use what is called “panel optimisation”. Instead of putting the entire inverter on the roof, they just put the MPPT on the roof and leave keep the inverter on the ground.

Solar with shade and optimisers

There are several manufacturers doing this, the two I choose to work with are SolarEdge and Tigo.

  • SolarEdge offer a whole solution. They sell the optimisers go behind each solar panel and a simple SolarEdge inverter without the MPPT. The system comes standard with individual panel monitoring. Solar Edge also has a higher level of safety because the panels shut down to a safe voltage in case of emergency.
  • Tigo just sell optimisers. They are “inverter agnostic”. In other words, we can use any brand of inverter we like. In fact with the Tigo TS4 solution, if only a few panels are likely to be shaded, you can just purchase a few optimisers, reducing the overall cost of your solar system. They call this selective deployment. To reduce costs further, individual panel monitoring and safely isolating the DC power comes as an optional extra. Read my Tigo TS4 optimizer review.

Both of these solutions are great. SolarEdge is more expensive and is better. Tigo is more affordable if you use selective deployment and leave out individual panel monitoring and “Safe DC”.

Now, there is now another solution

 

Solution 4: Maxim Integrated panels

If I had my way, I would install a complete Tigo & Fronius systems or SolarEdge system on every roof with shading issues. Panel optimisation increases solar production in every situation. The fact that we can monitor individual panel production, and shut the solar panels down in case of a fire geeks me right out. But solar is about a return on investment. It’s for this reason that we have introduced the more affordable Maxim integrated panels to our line-up.

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What is Maxim?

Maxim is the second generation of panel optimisation. It’s a simple and cost effective solution that does one thing, and one thing extremely well – panel optimisation. While Enphase, SolarEdge and Tigo all give the option of individual panel monitoring and a higher degree of safety, Maxim focuses on the main problem : not all panels in a string will always operate at the same current.

How Does Maxim Work?

Maxim simply works by taking those old fashioned bi-pass diodes out of the panel and replacing them with Maxim chips – or fairy-dust. It’s a bit above me how fairy dust works, but I can tell you what it does. It increases the current of a shaded panel to match the current of the others. It does this by lowering the voltage of the panels. If it didn’t lower the voltage, that little chip would be generating power all by itself, and we all know only Tinkerbelle’s fairy-dust can do that. And I don’t believe in Tinkerbelle.

The solution is elegant and affordable. There no increase in the number of components on the roof, so less parts to potentially fail. Even better, it means I can still use the Fronius inverter, that, although it does not have individual panel monitoring, it has a fantastic individual string monitoring and load control with the Fronius Smart Meter as I explain in this post.

But Maxim is even better!

I promised that Maxim would be “the closest thing to shade proof solar”. Here’s why:
Micro inverters and first generation optimisers both work at the panel level. If a bird makes a mess on one cell, the production of the whole panel is affected. But panels have always been divided up into three groups of cell-strings. As mentioned earlier each of these strings have always been protected by bypass diodes. Because maxim removes these 3 diodes and replaces them with Maxim fairy-dust, a maxim panel works at the cell-string level or one-third of a panel. If a bird does his business on one of your cells, then the whole panel is not affected – just one-third of the panel. So the Maxim panels actually work more efficiently than micro-inverters or SolarEdge optimisers.

Maxim cell optimiser

Is  Maxim fairy dust real?

My specialty is not electronics. But after reading the Maxim Optimisers White Paper, I’m convinced enough that I have ordered a container of these fairy dust embedded panels from my local solar wholesaler. I’ve waited 7 long months for this delivery, and as soon as it comes, an array of panels will be on my warehouse roof to make sure they work as the whitepaper says. If not – I’ll return them and have a quiet cry.

But if Maxim works as described – and I’m confident they will – then we’ll be introducing the next step in the evolution of solar panel optimizers to the Australian market.

Update. It took me six months, but my test results are in! Jump over to my Maxim test results to find out how it went. As a hint, we’re still installing Maxim.

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Conclusion

Solar is an exciting industry to work in. The problems of shade have already been adequately solved by Enphase, SolarEdge and Tigo. If individual panel monitoring is high on your wish list, then you’ll need to fork out more and stay with the earlier models of Enphase, Tigo, or SolarEdge. But if optimisation and value for money are key, then Maxim are offering an affordably priced superior optimiser.

What are your thoughts on Maxim Vs other solutions for MLPE? Leave a comment and let us know your experience.

Mark

28 Comments on Maxim optimisers – the closest thing to shade proof solar.

Mark C said : administrator Report a month ago

Thanks, Andrew! Yes, a guy that used to work for me now sells and installs in Newcastle. If you email me at mark@mcelectrical.com.au, I can pass on your details.

Andrew Molloy said : Guest Report a month ago

Well done with your site extremely helpful and informative. I don't suppose you can recommend a good installer in Newcastle with the same knowledge and dedication you have.

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Mark Cavanagh said : administrator Report 2 months ago

Thanks, Adrian, the way you explain that makes it obvious. I had that mixed up and no-one else had noticed to date! Yes, we are a bit more limited with design of Maxim/Fronius as we really need to make sure we are keeping that string voltage high.

Adrian Hawke said : Guest Report 2 months ago

Hi Mark, Nice MLPE write-up. MLPE is most definitely the future of PV. Just a correction to your post mate - the Maxim chip doesn't increase the voltage of a shaded module or cell string, it actually REDUCES the voltage in order to maintain the current. As electricians, we all know that in a series circuit, the current is common, which is why any loss of production on a module in a PV String, causes losses for the whole string. The Maxim chip is a Buck converter, meaning that instead of simply bypassing the shaded/impacted cell string, it allows the string's reduced output to contribute what it can to the rest of the module. Ohms Law says that in order to maintain the module/cell string current, the voltage must be sacrificed. An increase in voltage would result in reduced current, which would have a negative effect on module performance. As you know I am a big fan of MLPE, and it is my job to continuously study and understand these things. Maxim has benefits for tight packed tilt-framed systems, where spacing is reduced due to limited area, as the Buck process allows extra yield over conventional diodes for when the modules shade each other during the day. The NREL doc shows this: http://www.nrel.gov/docs/fy14osti/62024.pdf Ideally, a system would be installed where the modules do not shade the ones behind, especially between the hours of 10am-2pm, as required in Australia, but if there is minimal area for modules, a tighter configuration with the Maxim chip will not see the same losses as conventional diodes. So to be clear, Maxim chips are Buck converters, that will allow mismatched cell strings to contribute current to the module, albeit at a sacrifice to the voltage. With this in mind, it is necessary to ensure the inverter is still running within it's Pmax voltage range to achieve optimum performance, and therefore conventional string design is still required. Maxim, along with other MLPE products (SolarEdge of course...) are providing benefits that would otherwise be unreachable in the market. MLPE technology is definitely worth researching to understand the benefits, options and differences they all bring to the system owners/operators.

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Mark C said : administrator Report 2 months ago

Hi Jozsef. Thanks for commenting from Budapest. You can't monitor panels with Maxim, and I'm told you can't use Maxim and solarEdge or Tigo. The "boost-buck" function of each optimizer would fight against each other and be counter-productve. If individual panel monitoring is the most important thing, I would use solarEdge. Solaredge is still a very good system. If shading is really bad, (as in some panels shaded most of the day) you may even consider using Enphase microinverters. Roof types are different in different countries, so i would talk with your local installer about that.

Jozsef said : Guest Report 2 months ago

Dear Mark, You may be surprised that I write you from Budapest (Hungary), but I read a few very nice article from your blog. I shortly would like to ask your advice: I want to install 30 Jinko Maxim 265 panel with Fronius Symo 10.0 inverter. As a customer (not expert at all) I learned from your writings that Jinko Maxim with Fronius will provide me probably the best "optimization". My question is: how can we have a monitoring system as well to monitor each panel? What else I need to order from the installer? I understood something like "Tigo"?? Do I need Tigo TS4-R-O (yellow??) and Tigo Gateway and Tigo Cloud Connect? Is this what I need or something else. Pleae give me a list I need to order on top of the Jinko MAxim panels and Fronius Symo. Another expert told me that Jinko Maxim can work with SolarEdge optimizer?? I do not know anything, can you help me? Another question: What kind of frame is good for Gerard (Decrabond) roof? Thank you in advance for your kind help. Jozsef

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Mark C said : administrator Report 5 months ago

Hi Garry, No Maxim and SolarEdge are entirely different products - competitors. Maxim is a simpler more cost effective and more efficient way of optimising. I'm just uncertain about the durability of solarEdge embedded optimisers. The HD wave does look interesting, but time will tell.

Garry said : Guest Report 5 months ago

Mark, were the SE optimiser failures only in relation to MAXIM panels or other branded panels had failures too? Do you see any common characteristics in the failures of solar edge? Do you recommend the Solar Edge HD Wave Inverter's which i believe are coming out this year?

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Mark C said : administrator Report 5 months ago

Hi Gary, We've had 8 Solaredge optimisers jobs have had failures (inverters or optimisers) of only 47 solar edge jobs installed. While that's only a small percentage of components fail, it's a high percentage of jobs we have had to go back to. I've talked to other installers that have also had more than their fair share of failures. Given the 20 year warranty on the optimiser, and 12 on the inverter, I'm a little concerned!

Mark C said : administrator Report 5 months ago

Hey Peter, Maxim are good - but not that good.

Peter said : Guest Report 5 months ago

These Maxim modules sound good. Will they solve inverter problems. Like one needing a Hybrid inverter(s) that work with wet and dry cell batteries and diesel generation in a 3Phase grid connection under West Australia regulations. This is what I need!!

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garry said : Guest Report 5 months ago

" We're really liking them and are finding they work well when designed well. At the same time, we are finding concerns with SolarEdge. I've started the Maxim test result blog " Hi Mark, thanks for the update...what were the SolarEdge concerns you were finding in relation to the MAXIM panel ?

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Mark C said : administrator Report 5 months ago

Hi Lawrence, a sneak peek, yes they work as advertised! We're really liking them and are finding they work well when designed well. At the same time, we are finding concerns with SolarEdge. I've started the Maxim test result blog - and I really need to make time to wrap it up soon! Mark

Lawrance said : Guest Report 6 months ago

Looking for an update on these Maxim optimised 265W panels. Are they as "shade proof" as their marketing material say? Interested in following your blog, just not sure if you've started it yet.

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Mark C said : administrator Report 6 months ago

Hi Filip When cells within the module get shaded, the Maxim optimizer reduces current pulled through the 20 cells in the cell-string to match that of the weakest cell. This weakest current is then delivered to the output by transforming a high voltage / low current power source into a low voltage / high current power source matched to the series current of the rest of the string. In contrast, a conventional panel requires excess current to flow through the bypass diode which is only activated by forming a large reverse voltage across the weak cell. This reverse voltage causes a large power dissipation (i.e. the hot-spot). So not only does the Maxim optimizer improve reliability by preventing the hot-spot from forming, but also produces more energy by not wasting the power available from the affected cell-string.

Filip Kaszubowski said : Guest Report 7 months ago

Such a good article! Maxim seem to be a really prosperous technology. One thing got me thinking though. Bypass diodes are designed mostly for neutralisation of negative effects of reversed bias. In shaded cell temperature can increase very quickly and hot-spot is likely to occur. Of course there are modules like SunPower in which MAXEON cell technology is a solution for the problem itself, but what about conventional panels? Aren't they more likely to heat up too much, having these bypass diodes replaced by Maxim chips? Is Maxim able to even current flows in different cells somehow to prevent a shaded cell from switching bias? If so, do you know how exactly is it executed? Best regards from the other side of the Earth, Filip.

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Plu42jiKoyh said : administrator Report 7 months ago

Hi Chris, The Maxim test on my roof is doing really well. I'll blog about it soon, but they definitely work well on a cell string level. Currently, we can only get 265W panels, and i can't see 70 cell format (logner footprint panels) coming in the near future. Mark

Christopher Staples said : Guest Report 7 months ago

How goes these MAXIM panels ? any for sale yet ? any in the long format? looks like 2x of the standard 1.65m panels will not fit on my roof so needing the 2m long panels instead , which will just barely give me 6kw I was hoping for 10kw+ oh well

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Plu42jiKoyh said : administrator Report 11 months ago

Hey Jack, Bugger. I was just at Solar Power International in Vegas and I'm sure I saw Kako there. I missed it! I noticed you are from the USA. It may be something that's first suited for USA with your "rapid shutdown" regulations. I know Kako only because Selectronics import Kako string inverters to operate with their SP Pro in Australia. But that's all I know about Kako! I'll be at our solar conference in Melbourne in a couple of weeks and I'll be sure to look out for it there! If they are going to be coming down-under, I'll look into them.

Plu42jiKoyh said : administrator Report 11 months ago

Thank's Paul!

Plu42jiKoyh said : administrator Report 11 months ago

Hi Paul, Thanks. I've never used Talesun - Tigo say are integrating with heaps of panels including; ET Solar Hansol, JA Solar, Jinko, Lightway, Luxor, Perlight, RECOM, Silfab, Solartec, Sunpreme, Sunerg, Sunage, Trina, Upsolar and IBC and probably others that are not updated on their website. I know the industry isn't a fan of Bloomberg, but I think a panel must be on the Bloomberg list for me to even start looking into it. Maybe that's just a cheats way of getting a short list but I'm not sure where else to start! Do you install Talesun? What do you like about them compared to any other Chinese panel? Mark

Plu42jiKoyh said : administrator Report 11 months ago

Thank's Peter. I agree, my preferred option would be Fronius with TS4 with the Tigo monitoring and safety options. The Fronius is hands down the best inverter and it's load control function and user-friendly monitoring, Ten-year warranty, robust Austrian build, I could go on.... Solar edge is a close second and have some exciting load control functions coming soon. While we are waiting for the Fronius Primo-Hybrid, Solar edge is the best for a single phase battery option with Tesla Powerwall. I haven't heard about a larger Symo Hybrid. You probably know (in Energex area) you can couple a 5 symo-Hybrid with a 5 Symo, and install a total of 13.2kW of panels (or more with batteries). When the Maxims arrive (in a few weeks), I'll run some tests on my roof for sure. We are a mixed array of panels with Tigo at the moment, and I'll mix it up a bit. I'm thinking Maxim and Tigo would be doubling up (apart from individual cell-string mismatch)- but it will be an interesting test for sure! Thanks for your comments, I'm a hotel at Disneyland with my kids atm. Happy days!

PeterT said : Guest Report 11 months ago

Another great article ... thanks Mark! Whilst the Maxim solution appears highly attractive for all the reasons stated, there remains significant value in being able to monitor and interrogate each panel to ensure that you can address any soiling/shading problems, and to further ensure that each panel is performing as per the manufacturer's performance warranty. With this in mind, I tend to think at first blush, that perhaps a Maxim enabled solar module with a Tigo TS4-S (i.e. safety and monitoring junction box) strapped on would provide a superior solution ... though I accept this would be a little more expensive. Interestingly enough, I do wonder if Jinko Solar (at the very least) might have already thought this through and are potentially offering cell level optimisation already with their Tigo Smart Module offering, because on their Tigo webpage for this module (i.e. http://www.jinko-smart.com/tigo.html) they state, and I quote: 'With the help of cell optimizer, Jinko Smart can entirely eliminate hotspots, the main source of module failure.' In any case, if you were so inclined Mark, I would be interested in your prospective analysis of the Maxim Modules with perhaps at least a strings worth of Tigo TS4-S' to see if: 1. The TS4-S would be compatible with a Maxim Module, and 2. If so, then to analyse if there is any noticeable performance improvement in the overall string or array. Anyway, I hope this finds you well and that you and your family are having lots of fun in Vegas mate ... Cheers Peter PS Any goss from Fronius on any new 3 phase hybrid offerings? I am mighty keen to see something bigger and better (say 10KW) than their current 5KW Hybrid Symo offering.

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Paul Clark said : Guest Report 11 months ago

Hi Mark. There is also another brand of panel with the built in optimiser. Talesun has produced a panel with a built in Tigo optimiser. It would definitely be worth considering. I believe they are available in Australia. Cheers

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Jack Castiglione said : Guest Report 11 months ago

Can you review and comment on the new MLPE technology from KACO? German firm KACO new energy Inc. launches breakthrough MLPE solution to a newly expanded distribution network 09/09/16, 03:49 PM | Solar & Wind, Energy Storage & Distribution | KACO new energy Inc. San Antonio, TX: KACO new energy, one of the fastest growing solar companies in the North American utility-scale market, today announced that it is shipping an updated version of its residential MLPE solution, the blueplanet Ultraverter™ to an expanded distribution network.

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Paul said : Guest Report 11 months ago

Well done on an accurate description of shade/current/power. Not too often I see it.

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Plu42jiKoyh said : administrator Report 11 months ago

Hi Carl, We'll have them in about 2 weeks time. I'm told our container is the first container into Australia. I don't know when the rest of the market will cotton on.

Carl said : Guest Report 11 months ago

Hi Mark, These optimisers sound very interesting. Do you have any idea of when they will be available for installations? Carl

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