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Forum section: electronics / general

author: Simon
author_rank: Unknown
timestamp: December 20, 2019, 12:45:20 pm
content: I am having the pile of garbage that is my solax battery system returned for a refund as the system is awfully crude and won't do what they incited it could.So, what should I replace it with? My electrician is not that knowledgeable in batteries (hence he got taken it by solax) so it's feeling like a desperate search for a replacement system that is actually worth having.What I ideally want is a system that will charge up with any excess solar power I am producing, supplies me when solar in insufficient and allows me to charge at set time and discharge at set times. Ideally it should work with IFTTT.Am i asking too much ?

author: fourtytwo42
author_rank: Super Contributor
timestamp: December 20, 2019, 01:50:58 pm
content: Are you allowed to say what the solax did not do ?What is the scale of your system in terms of installed panel capacity ?Personally I calculated I could not justify the cost of batteries so store energy as hot water instead but then I only have a 1Kw system.

author: Simon
author_rank: Unknown
timestamp: December 20, 2019, 02:27:01 pm
content: Well solax appears to be able to discharge into the grid but most of it's settings are meaningless, unapplicable and for future development. Basically they are still turning out prototypes and selling them. they are hopeless. their UK base company is full of their own chinese people so while you get duped into thinking that here is a UK company prepared to recognise a chinese one you instead get the full chinese experience.The website for managing the thing is so flaky and the last 2 updates just made matters worse. they clearly do not have a clue what they are doing or care. It has taken a year to get them to come and look at my system, they had to hand install a firmware update versions newer than what I bought it with and still the exact problems they claimed to have solved have not been fixed.For me now it's a matter of trust. If the system stays as is it could be decent but I suspect it will only get worse as their farcical attempts to improve things only make matters worse. For example if I want to setup a timed charge (which they call "forced use" which sounds like a discharge to me) I have to set 4 settings, I have to save these individually not change all 4 and then press save. As their website is so dodgy often one or more of the settings fails leaving a half cocked setup. What an intelligent person would have done is to have you enter the four settings, hit save and then send all 4 to the unit. So if it fails you left with the last good setup. It's just amateurish shit like this that drives me mad. They are as crude as you could get. There are loads of more problems but if I carry on this will be a book. suffice to say: save your sanity, never touch solax, ever!I'm looking around 10kW. With my octopus tariffs i can make money from the battery itself by charging at 1-6p at night and discharging at 12p during 1600 and 1900 on top of providing me with power in the evenings. My tariff follows the wholesale prices with a premium between 1600 and 1900 so I get low prices all day long, really low at night and high between 1600 and 1900. when we had a lot of overnight wind we were paid 1p/kWh to use it and for one half hour period this went up to 4.5p/kWh

author: ahbushnell
author_rank: Frequent Contributor
timestamp: December 20, 2019, 02:38:55 pm
content: Electricity is a lot cheaper in the UK. In California it's about .35 $/kW-hr. or .27 pounds/kW-hr. A little off topic.

author: Simon
author_rank: Unknown
timestamp: December 20, 2019, 02:45:56 pm
content: Well I am also working on the assumption that in years to come it will go up so want to be prepared.

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 21, 2019, 01:02:07 am
content: Surplus EV battery + BMS + inverter/charger. There are many commercially available inverter/chargers that will do what you're looking at (unless you want "zero export" to the "input" side using external sensors, in which case the list narrows to just one - Sol-Ark) or you can build one based on a Prius inverter as I'm planning to do. Some hackers have figured out that you can swap the control board for your own control logic.https://openinverter.org/forum/viewtopic.php?f=14&t=51

author: Simon
author_rank: Unknown
timestamp: December 21, 2019, 01:18:20 am
content: Well so long as the inverter charger can be commanded to charge or discharge by a certain amount then an external power sensor and control circuitry can make it do the neccessary. I am really looking for off the shelf stuff. Victron seems to be well regarded, it's what to control the victron with.

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 21, 2019, 03:18:38 pm
content: Just make sure whatever you get supports external control via some well documented protocol - RS485, CAN, Ethernet, or even analog signals. Download and read the manual before buying.I would suggest a Raspberry Pi or other single board computer as a controller. Easy to program and plenty of room for expansion.

author: Simon
author_rank: Unknown
timestamp: December 21, 2019, 03:53:04 pm
content: Yea I have been wondering if i need to end up with my own system. But I have no experience in talking protocols so was hoping all off the shelf.

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 21, 2019, 06:28:52 pm
content: Maybe check if there's already a Python library written to communicate whatever protocol the inverter uses? I suspect a lot of them would use Modbus.

author: Simon
author_rank: Unknown
timestamp: December 21, 2019, 07:47:05 pm
content: modbus is common particularly for the power sensor connections but victron talk about CAN and RS232 alot as well.

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 21, 2019, 08:06:22 pm
content: Does the documentation say how to send commands over RS232? I would have to guess it would be Modbus.

author: Simon
author_rank: Unknown
timestamp: December 21, 2019, 08:08:42 pm
content: How do you mean they are modbus? they are either one or the other and RS232 is clearly stated, not mention of modbus. I have not looked around for any further information but I expect it is out there.

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 21, 2019, 09:32:24 pm
content: Modbus is a high level protocol, which runs on top of some lower level protocols like RS232/485 or TCP/IP.https://en.wikipedia.org/wiki/Modbus#Modbus_RTU_frame_format_(primarily_used_on_asynchronous_serial_data_lines_like_RS-485/EIA-485)

author: Simon
author_rank: Unknown
timestamp: December 21, 2019, 09:35:46 pm
content: I see, well quite likely then.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: December 21, 2019, 11:24:21 pm
content: Quote from: Simon on December 21, 2019, 08:08:42 pmRS232 and CAN bus are hardware specificationsMODBUS is software. You can implement MODBUS on serial links.

author: Simon
author_rank: Unknown
timestamp: December 22, 2019, 10:29:03 am
content: Yes we just did that bit

author: Kibi
author_rank: Unknown
timestamp: January 02, 2020, 10:36:04 pm
content: In the Victron world there are several communication protocols in use depending upon the product.VE.Bus is their proprietry protocol wich works over a RS485 hardware layer. VE.Bus is used for their inverters / inverter/chargers to talk amongst one another when several of them are configured for three phase, split phase or multiple units stacked in single pahse. It is possible to have six units per phase, 18 units maximum. There is not very much public information about this protocol.Solar charge controllers use a 5V TTL level serail communication (BMV battery monitors are 3V3 TTL). The protocol on top of this is the VE.Direct HEX protocol.Victron's whitepapers section contains publications on the VE.Direct protocol. The larger solar charge controllers include, in addition to the VE.Direct port, a CANBUS port over which runs the VE.Can protocol. VE.CAn is onlr really necessary for larger installations where up to 25 charge controllers can communicate on the same bus.The CANBUS port can also be configured to operate with various battery munfaturers.Battery compatibility list:https://www.victronenergy.com/live/battery_compatibility:startWhitepapers:https://www.victronenergy.com/support-and-downloads/whitepapersIn particular "Communication with Victron Energy Products":https://www.victronenergy.com/upload/documents/Whitepaper-Data-communication-with-Victron-Energy-products_EN.pdfWhen composing a system of the various Victron parts and you want grid interaction then you need to use some sort of hub to tie the components together and publish data to their "VRM" site. VRM is free to use - no subscriptions.There are various hub products to use which run a linux based OS called VenusOS. VenusOS even runs on a RaspberryPi and is well maintained. Off the shelf products range from the VenusGX up to a CerboGX depending upon how many components you want to connect. In most cases a VenusGX or a CCGX (with colur LCD) will serve just fine. VenusGX has sligtly better connectivity but lacks an LCD. Anytthing that you could see or configure on the LCD is available on a locally served web page.A VenusGX has VE.Can, VE.Bus (to talk to the inverters), two VE.Direct, tank level inputs, digital inputs, a set of relay contacts and a USB port. A USB hub can be connected if more USB ports are needed.The RaspberryPi route is ideal for small setups. You need to buy USB dongles to connect anything up. People like us can make up a digitally isolated USB to TTL 5V converter to get around this, but as soon as you need to buy a VE.Bus dongle then it starts to get the price up a bit.Having said that, most Victron owners who like to get their hands dirty will have a VE.Bus dongle to hand anyway. Some have been known to carry one when on holiday - just in case.I did end up needing it, so it was all good.MODBUS-TCP and MQTT are available on the Venus devices. Digging around in the OS is OK, usual caveats apply of course.Modbus-TCP register list is available in the whitepapers section. You need to provide an email address for the download link for this document for some reason.Venus range:https://www.victronenergy.com/panel-systems-remote-monitoring

author: Simon
author_rank: Unknown
timestamp: January 03, 2020, 07:28:11 am
content: Well i am looking at the GivEnergy system. It's plug and play and they seem to be serious.

author: mikeseaman3000
author_rank: Newbie
timestamp: August 24, 2020, 12:07:35 pm
content: Hello.Just seen this article online and thought i'd join.Did you get the GIVEnergy System Simon? I gained a dual AC3.0 Inverter System and having lots of issues with it.Trying to integrate to my Modbus Automation system with no success.Anyone got anything else running?ThanksMike,

author: Simon
author_rank: Unknown
timestamp: August 24, 2020, 12:13:39 pm
content: Hi Mike, no I decided that given that electricity prices are unlikely to rise enough to justify the cost. Clearly the battery market needs to standardize before i touch them again. I can't use an all in one inverter for solar panels and batteries because my system is 550V, Joju solar are a bunch of idiots who did not tell the electrician as they claimed to put them in two parallel strings and apparently thought you could do that with 15 panels..... fucking pen pushers.Is your's a givenergy system? I doubt they warrant you fiddling with the modbus, does the actual system work?