Legion Solar - Bypass All Regulations! - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: October 09, 2019, 10:45:58 pm
content: Lets just bypass all regulations for home solar install, that'll do the trick!https://www.kickstarter.com/projects/plxdevices/legion-solar-4-permission-free-energy-and-storage

author: EEVblog
author_rank: Unknown
timestamp: October 09, 2019, 10:56:54 pm
content: Just plug right into your power point, no worries!https://legionsolar.com/tutorials.htmlI actually know someone who's developing a new battery storage solution that plugs into your mains powerpoint that will be trialed in Australia soon, and there are HUGE design challenges and red tape involved.

author: fourfathom
author_rank: Super Contributor
timestamp: October 09, 2019, 11:04:04 pm
content: Providing no utility backfeed gets around (some of) the regulations. They way they provide "night time offset" is with the extra-cost "stage 3" and "stage 4" battery bank and charger. Let's see the amazingly fast ROI for that stage-4 setup! (it's going to be pretty bad.)

author: EEVblog
author_rank: Unknown
timestamp: October 09, 2019, 11:58:57 pm
content: Quote from: fourfathom on October 09, 2019, 11:04:04 pmBut you are still backfeeding through the power point.

author: fourfathom
author_rank: Super Contributor
timestamp: October 10, 2019, 12:21:29 am
content: Quote from: EEVblog on October 09, 2019, 11:58:57 pmIf true, this would violate all kinds of regulations. I was just looking at their video showing no backfeed.I used to have a gas generator with a "suicide cord" that let me backfeed my house wiring. If I forgot to open the mains breaker I could have killed a lineman. I suspect that in fact the heavy load would pop the generator breaker virtually instantly, but that's not something you want to rely on.But there has to be some sort of backfeed prevention! I don't see it, but how could there not be??? I suppose I could always read the rest of the website material, but I'd rather not.

author: Circlotron
author_rank: Super Contributor
timestamp: October 10, 2019, 12:38:29 am
content: Quote from: fourfathom on October 10, 2019, 12:21:29 amNot trying to derail the thread, but a safer solution in your case would have been to use a normal unmodified single phase induction motor as a generator. When they lose mains connection they have no source of reactive power for excitation and so the output stops.For those that are unfamiliar, when an induction motor is connected to AC mains it wants to rotate at very nearly synchronous rpm. Apply a load and it resists slowing down and AC power is drawn from the mains and mechanical power is delivered to the load. Conversely, if you try and rotate the machine faster than synchronous speed it resists being sped up and mechanical power is absorbed from the external source and AC power is delivered to the mains. One situation is the mirror image of the other. Also, no synchronization issues either, just turn on the breaker and away you go.Now, back to the thread...

author: EEVblog
author_rank: Unknown
timestamp: October 10, 2019, 01:55:21 am
content: Quote from: fourfathom on October 10, 2019, 12:21:29 amI think that's exactly how it works.Although it might have some extra detection and cutout protection or something. But it's designed to be user installed and it looks like they are saying just plug the male plug into a mains outlet.QuoteMe neither, it just sounds completely dodgy though. Just asking Joe Average to install solar panel themselves on their own roof is going to statistically come-a-gutsa big time.

author: fourfathom
author_rank: Super Contributor
timestamp: October 10, 2019, 02:10:11 am
content: Quote from: EEVblog on October 10, 2019, 01:55:21 amSure, what could possibly go wrong?

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 10, 2019, 02:49:20 am
content: A properly designed grid tie inverter should automatically switch off when disconnected from mains. Even the "simple" one I designed for senior design class had several mechanisms for that - voltage and frequency checking and N-G continuity checking.Quote from: EEVblog on October 09, 2019, 10:56:54 pmIsn't that a UPS? If you mean it backfeeds the mains wiring, then it would need the installation of a relay to isolate the grid connection in order to be useful, largely defeating the point of making it plug in in the first place.

author: fourfathom
author_rank: Super Contributor
timestamp: October 10, 2019, 06:24:16 am
content: Quote from: fourfathom on October 10, 2019, 02:10:11 amThe more I think about this (not actually reading the marketing material, just thinking), I refuse to believe that anybody with the brains required to tie their own shoelaces would attempt to sell a product with a hot plug. Even if it had some kind of "probing" circuit that would energize only briefly to check whether it was plugged in or would see an overload, it would still be too dangerous to sell.

author: Circlotron
author_rank: Super Contributor
timestamp: October 10, 2019, 06:44:34 am
content: Quote from: fourfathom on October 10, 2019, 06:24:16 amProbably as dangerous as a motorcycle, chainsaw, lawnmower, lathe etc. But at least those things might have users with some degree of training, or at least awareness of the risks. If there is money to be made, someone will make it, regardless of the consequences to others. Atomic bombs, crystal meth, melamine in infant's milk. Q.E.D.

author: fourtytwo42
author_rank: Super Contributor
timestamp: October 10, 2019, 07:27:04 am
content: From there ad "Utility company only sees less consumption from you, not a grid tied solar system. As a result, it is not necessary to seek interconnection permission pertaining to utility company approved grid-tied solar systems. "In the UK at least ALL grid connected installations must meet BS7671 that prohibits plug & socket connections for generators and ALL GTI's must meet G83.It is irrelevant that this companies systems aim not to export to the grid, the fact that they are grid connected brings all the regulations into play.Again here in the UK there are various further requirements such as building regulations regarding panel mounting.Finally like in many other countries a qualified electrician is required to make changes to the fixed wiring.Most of the marketing material of this company is either written from a position of ignorance or is deliberately misleading.Shouldn't this thread be in dodgy tech where it belongs!

author: phester
author_rank: Contributor
timestamp: October 10, 2019, 09:55:46 am
content: I think from the quick pic of the manual you can see a picture of the micro grid inverters. So the video is showing the grid connection to the microinverter. IMO it does not break some of the code as it would still prevent anti islanding etc. and so it would not become a suicide cord either. But you could potentially overload a ring main from the breaker.

author: Marco
author_rank: Super Contributor
timestamp: October 10, 2019, 10:49:43 pm
content: In the Netherlands 500W is allowed for plug in solar on an existing group ... a bit anemic.If you can get to the group before it branches you are allowed to put in a separate distribution board to use the full power of the group for solar as well.

author: NiHaoMike
author_rank: Super Contributor
timestamp: October 11, 2019, 04:15:38 am
content: Quote from: fourtytwo42 on October 10, 2019, 07:27:04 amA more workable idea, if the goal is to allow anyone to install a "grid tied" solar power system by simply plugging stuff together, is to make a box similar to a UPS that plugs into the wall and then loads plug into the box. The solar can power the loads or charge the batteries (if present) but cannot backfeed the building wiring.

author: SiliconWizard
author_rank: Super Contributor
timestamp: October 15, 2019, 10:12:21 pm
content: But it's got AI!

author: MagicSmoker
author_rank: Super Contributor
timestamp: October 16, 2019, 12:04:14 pm
content: Although this product is dodgy as hell - backfeeding AC into a wall outlet is never a good idea, really - I am not a big fan of the anti-islanding requirement simply because it solves an unrealistic problem. I mean, the goal behind such legislation seems reasonable on the surface - prevent utility workers from getting electrocuted from a solar PV + inverter system backfeeding to the grid - except it totally fails to acknowledge that even a relatively massive 10kVA system would be immediately overloaded if the mains dropped out. A more practical solution that would allow the system to act as backup power in the event of an outage is a fast-acting overcurrent trip that requires manual resetting and, perhaps, also notifying the user to open the main circuit breaker before doing so (via, say, a message on an LCD front panel or the like).

author: Kleinstein
author_rank: Super Contributor
timestamp: October 16, 2019, 01:11:57 pm
content: In most cases back-feeding the grid that went down would cause overload to the weak device. However there can be rare cases where is does not - especially in the US with relatively small distribution transformers there may not be many devices connected. Another problem could be if there was something like an arc that caused all arc fault protectors to trip. In a new build neighborhood this could mean essentially all loads disconnected.

author: ejeffrey
author_rank: Super Contributor
timestamp: October 16, 2019, 03:21:50 pm
content: Even if the common case a island will be too big for a typical PV system to energize that isn't always the case or for the entire duration of a failure/repair. You wouldn't want an inverter recovering/restarting when utility workers have shut off a bunch of feeds to isolate a fault. The anti islanding feature is also the easiest and best way for non storage systems to comply with emergency services requirements that the utility power can be shut off with one or a minimum number of switches. The main service disconnected automatically stops the inverter.

author: MagicSmoker
author_rank: Super Contributor
timestamp: October 16, 2019, 03:36:48 pm
content: Emergency services needing a sure way to disconnect power is a good point, but protecting line workers isn't because SOP is to either treat conductors as live or else ground them out while undergoing work.An arc fault will still present a massive overload before the recloser opens so the typical 5kW esidential inverter will almost certainly trip, but if if it doesn't then see above.Automatic reclosers are also a non-issue because, again, see above.Note that I said the inverter needs to trip on an overcurrent (which includes trying to supply the whole neighborhood with power) and then should ideally notify the user to open the main circuit breaker between the meter and house before resetting the overcurrent fault.Are there ways in which this could still be a hazard to utility workers? Sure, but being a lineman is a dangerous job in the first place. The second you forget that you are likely to meet an untimely end.