GoodWe has just released what could most simply be called a solar battery charger, the GoodWe BP. If you want to sound a little more informed called a charge controller. Big deal. How many solar hybrid inverters are out there at the moment and why should we care about GoodWe’s?
Who is GoodWe?
The name GoodWe is a strange one. It reminds me of when I was living in the Lakes District in England with a French lady called Antoinette. One day she decided to go out into the garden and collect escargot to prepare and cook for dinner.
As I swallowed my first snail she smiled and asked
“Good, Oui ?!!”.
“Wee”, I said in my best French accent – I lied.
GoodWe is a Chinese inverter manufacturer with a reputation for quality. The inverter has been rebadged by companies such as Renesola (Replus) and Zeus Appolo. More recently it is being used as the guts of Redback Technology’s Hybrid inverter and the Ampetus Energy Pod. In December 2015, GoodWe was listed on the “National Equities Exchange and Quotations”, more commonly known as the “Chinese NASDAQ.” Not a bad effort for the Chinese company that sprang into existence in 2010.
The Emerging Battery Storage industry
If you haven’t heard the news, the latest thing in solar is to store your excess solar power in batteries, then use that power at night. It’s a rapidly growing market as consumers are fed up with getting paid diddly squat for sending their valuable solar power back to the grid. It’s going to revolutionise energy generation and distribution – but the industry is just in its infancy.
While trying to understand this emerging solar storage industry, there is one bloke who is unarguably a leader. Glen Morris has lived off-the-grid with solar in a community in the Yarra ranges outside of Melbourne for the last 20 years. He’s the Vice President of the Australian Solar Council and Vice President of the Energy Storage Council. The bloke is genuine solar-storage royalty, complete with an enviable beard and castle on a hill. Last week while I was in Melbourne, Glen gave me an hour of his time to show me around his training facility at Moora Moora.
Glen’s gentle enthusiasm was infectious as he showed me around his uber man-cave next door to his idyllic hay-bail home. The training facility consists of a bunch of old sheds and a purpose-built boat house that he has converted into an in-service micro-grid generation station. I struggled to keep up as he walked me through the toys that manufacturers had sent him to test and destroy. As we walked past a GoodWe inverter, I asked him what he thought of GoodWe as a manufacturer.
“Oh, have you seen this one Mark.”
‘Well no, not this particular GoodWe inverter …. but….”
“It’s not an inverter. You gotta check this out” Glen insisted.
The following 2 minutes were a blur of excitement – I’d be lucky if I retained 50 percent. But I got the gist. Glen likes it, so I need to look into it. When I got back to Brisbane, I called Bill Allison from one stop warehouse to help me interpret Glen’s excitement.
How to charge a solar Battery
There are two main ways to connect a solar system to a battery. AC coupled, or DC coupled.
AC coupled
AC coupled is a great retrofit solution. If you already have a solar system, and you wanted to connect batteries, then connect the battery to the output of any inverter and charge your batteries with the solar power after it has been “inverted”. The down-side to this is efficiency losses. It requires converting the DC power on the roof to AC (through the inverter) then to DC to charge the battery, then back to AC to feed your house. Every time you convert from AC to DC looses efficiency. There are some bad examples of AC coupled systems like the Enphase Battery with a charge and discharge rate that renders it all but useless. SMA recently released more interesting examples in the SMA storage. The down-side to the SMA is that its cost increases ridiculously if you are using any inverter other than an existing SMA.
DC Coupled
DC Coupled is the preferred option. This way you use the DC power from your roof to charge the batteries before it is inverted to AC. At night time, when you want to use the battery power, it sends DC battery power to the inverter, to invert it to AC power. The DC to AC conversion only happens once. It’s much more efficient and elegant. Until now, the downside to DC coupling has been that you need to have a hybrid inverter. If you were retrofitting an existing system, you would throw out your existing inverter and replace it with an expensive hybrid inverter. Again this is costly.
Enter the GoodWe BP
GoodWe explains that “BP” stands for “Battery & PV”. PV stands for PhotoVoltaics, the fancy name for solar power. If that’s too hard to remember, remember that the GoodWe BP is a vibrant yellow, a similar colour (one might imagine) to the honey making insect’s urine. If I had my way, I’d call it the “GoodeWe DC Coupled Retro-Fit Solar Battery Charge Controller” – or the “GWDCCRFSBCC”.
It’s not a hybrid inverter. It’s not even an inverter. It’s simply a device that sits between your existing panels and inverter to charge your solar battery. The genius of the GoodWe BP is that it can be installed onto an existing system, and it works with most solar panels, most solar inverters, and a growing number of batteries.
The GoodWe BP pro’s
- It’s cost effective. Around $1500 cheaper than using an SMA Storage or retrofitting with a hybrid inverter.
- It can be retro-fitted to any inverter.
- It can, in theory, be coupled to any battery – lithium, gel or lead acid. This is in theory only. The battery manufacturer has to test the integration and approve the use of the GoodWe to validate your battery warranty. GoodWe tell me that batteries that are currently approved include the LG Chem, Pylontech and BYD lithium batteries, and the Shoto lead acid battery. The compatibility of the GCL battery is currently being tested. Considering the GoodWe is a few weeks away from arriving in Australia, this an impressive start.
- The current model can take 6kw of solar power in, and it can charge and discharge the inverter at 2500w
- It has WiFi Monitoring, albeit modest.
The GoodWe BP cons
- It can probably only use half of your solar. Most solar inverters are broken into two parts or two “trackers”. This means about half of the panels run on one of the inverter’s trackers (think “engines”), and the other half run on the other engine. The GoodWe inverter can only use one of your inverter’s trackers. So you will probably only be able to use about half of your panels to charge the battery.
- It can’t run when you have a blackout. Your existing inverter will not allow it. Many hybrid inverters will also not allow this, but if you are paying a premium for a battery, I think you deserve the luxury of having a bit of power in a “blackout” and have the luxury of using the power that your panel are producing during the day.
Conclusion
The GoodWe BP Series is an interesting concept from a reputable Chinese inverter manufacturer. The biggest advantage is that it makes retrofitting any battery more economical. While it has a decent 6kW solar capacity, and a reasonable charge and discharge capacity, it is limited by the fact that it will often only be able to be connected to about half of your solar panels, i.e. one string. If you loose grid power, your battery won’t be able to be used as backup. However given the right application, the GoodWe BP seems pretty Good, … Oui?
