Solar Assistant (Possibly) Voids Warranty on EG4 Inverters?

[Brett V]

I'd really like to see someone from SS chime in here and verify that the statement you received from tech support is the official company policy.

I'm not an attorney but that statement sure looks like a violation of the Magnuson-Moss Warranty Act to me.

 

[wildbillpdx]

I'd really like to see someone from SS chime in here and verify that the statement you received from tech support is the official company policy.

I'm not an attorney but that statement sure looks like a violation of the Magnuson-Moss Warranty Act to me.

I just want an official answer from both SS and SolarAssistant regarding this blanket statement that the combination destroys the communication card in the inverter. SA seems to be in the dark about any such problem.

 

[Brett V]

I just want an official answer from both SS and SolarAssistant regarding this blanket statement that the combination destroys the communication card in the inverter. SA seems to be in the dark about any such problem.

I looked at your photo again and "technically" you're not connecting the SA Pi to the inverter, you're connecting a USB to serial converter to the inverter.

 

[400bird]

Just remember that the Raspberry Pi is connected to the same communication line and has the similar voltage thresholds for failure. If the Pi was putting 32 volts on the comm lines into the inverter it would also see 32 and not survive either.

 

[Crowz]

Sounds like another stellar "expert" from SS. There isn't a 32 volt line in the pi as mentioned to do that. The serial converter is all that is actually talking to the inverter in the first place. If a computer is allowed to connect to it to do firmware updates then there is no issue what so ever since amazingly a pi is a computer, imagine that.

I thank my lucky stars I went with sungold with every SS thread I run across.

 

[wildbillpdx]

I looked at your photo again and "technically" you're not connecting the SA Pi to the inverter, you're connecting a USB to serial converter to the inverter.

You are correct that there is a converter in the middle...but SS didn't give any specifics about exactly "how" the Pi fries the communication card or whether it was a Raspberry Pi, Orange Pi, or...

 

[Skypower]

I could possibly see an issue depending on how Eg4 wired the com card. The Solar Assistant DC to DC converter and my 10 amp 5V converter both have non isolated negative(passes right through). The giant wall wort (at top) may be the way to go for DC isolation for pi /power hub or beyond. I have DIY batteries so I don’t have the problem. I went away from the SA DC to DC as part of a problem eliminating scheme and they were hot. The big wall wort worked fine but I didn’t want any potential interruption so I went with the big DC to DC. Will the wall wort be safe SA + Eg4 batteries? I- DO-NOT-KNOW. Just mentioning negative pass through on the DC to DC devices is common.

 

[400bird]

Ok, fair enough, they could have a different 0 volt reference. But, there's a ground pin in the communication connection right? That should bring the ground planes in line. Maybe the SolArk comm card uses a 0 volt reference that is 32 volts above whatever is passing through from the wall wart, to the Pi, to the RS 232 adapter and this pass through ground reference is blowing out their artificially elevated ground referenced communication card.

The solution in that case would be to sure only a fully isolated power supply for the Pi and connect the signal ground.

 

[zanydroid]

Ok, fair enough, they could have a different 0 volt reference. But, there's a ground pin in the communication connection right? That should bring the ground planes in line.

It is still quite likely (and known to happen for other non isolated interfaces) for ground current to fly through the ground pins from the higher voltage side through the cable and into the driver. This happens for example in the cases where the reference to the voltage source is positive and not negative. Then this voltage source will fight to keep its negative output at a non zero voltage.

I don't think the EG4 network card can solve this unilaterally in a rock solid way without isolating data lines and floating its DC supply. That costs extra money.

 

[Hedges]

For Ethernet, there are galvanic isolators

https://www.amazon.com/EverStar-MI-300-EN60601-1-Compliant-Healthcare/dp/B08ZSY88CL

Network isolator - Wikipedia

en.wikipedia.org

Other things like USB, opto-isolated (and extender) solutions.

Probably not the low-cost solution you want.

If nothing else connects to earth, not even through a supposedly isolated power supply, that ought to let you use a battery-powered laptop and battery powered everything else (including solar assistant), with just the EG4 grounded. No current flow if no path.

 

[Tulex]

So, EG4 is the only device to discover/have this issue with SA? Seems odd.

 

[Watts Happening]

So, there's another post here where Signature Solar made up something similar about Solar Assistant putting 12v into that comm port.
Feels like they have two issues: tech knowledge and trying to get out of all warranty.

This all sounds like the same “tech support” and “engineers” that worked on my 18kpv :/

 

[Crowz]

Its usb to a serial adapter to a cable running to the eg4. I have serious doubts it is going to pass thru all of that in a negative way. If its that fragile its not going to be fit to do firmware updates.

 

[zanydroid]

Its usb to a serial adapter to a cable running to the eg4. I have serious doubts it is going to pass thru all of that in a negative way. If its that fragile its not going to be fit to do firmware updates.

If they provide an official USB adapter that includes the necessary isolation and DC DC magic then it's fine.

If you updated with a non official USB adapter not configured the right way and something goes wrong then they can rightfully tell you to go pay for the repair.

For the common case of using a laptop to update it is very unlikely for the DC reference to not match up. Or probably a desktop, the main question there would be how the USB shield is bonded and whether that busts the AC DC isolation in the PC power supply.

The problem is in using DC DC converters to power the host device since they are not obligated to be isolated like AC DC supplies are. And it's very unlikely for a PC to be powered that way, yet somewhat likely for a SA or RaspPi to be. You can corroborate this by searching on the forum for how many people might have a 48V to USB DC DC converter going into a Pi or Cerbro

Or search more broadly for 48V PoE to non isolated power extractor disasters. It's a known issue, you can see complaints on misc Amazon pages for non isolated extractors, Unifi forum (since at one point they used non isolated extractors), etc

 

[zanydroid]

For Ethernet, there are galvanic isolators

https://www.amazon.com/EverStar-MI-300-EN60601-1-Compliant-Healthcare/dp/B08ZSY88CL

Network isolator - Wikipedia

en.wikipedia.org

Other things like USB, opto-isolated (and extender) solutions.

Probably not the low-cost solution you want.

If nothing else connects to earth, not even through a supposedly isolated power supply, that ought to let you use a battery-powered laptop and battery powered everything else (including solar assistant), with just the EG4 grounded. No current flow if no path.

I was on a thread recently where I recommended looking into RS 485 isolators, and Amazon happens to have reasonably priced modules for that from random companies. RS 232 is single ended vs differential on RS485 so I'm not sure the same isolators are compatible

I believe USB 1 full speed (12 Mbps) isolation is pretty affordable too. Stuff gets real for 480 Mbps and up.

 

[zanydroid]

Given that isolation of power converter and signal lines is not onerously expensive for the power levels and data rates we are talking about I'm not sure why this thread hasn't simply converged on the consensus of isolation being cheap idiot proof insurance...

 

[Quattrohead]

I think the crux of the problem is people using cheap and nasty switching power supplies for the Pi that have no actual isolation hence all kinds of weird voltages could be present on the communication line, especially the ground.

 

[Watts Happening]

I think the crux of the problem is people using cheap and nasty switching power supplies for the Pi that have no actual isolation hence all kinds of weird voltages could be present on the communication line, especially the ground.

I don’t doubt that at all. For reference this thing is working great with my Sol-Ark. I’m not shocked at the responses of the SS team, but I’d still be quite surprised if this somehow magically created extra voltage and shocked their inverter.

Just connect this straight to the positive and negative battery cables inside the inverter, then plug your pi into it and you’ve got a 48v to USB power supply. No nonsense solution.

https://www.amazon.com/gp/aw/d/B076ZLHLD3

 

[Adam De Lay]

I'm sorry, I would have to see proof and see what components were used to perform the test which "burned up 100% of the EG4 inverters we've connected".

If this was the case, it seems like it would happen across the board because I doubt any of the different inverters supported by SA could handle an injection of 32v over the com port. I would think that SA would be the first to stop recommending usage in that case because their hardware would be the ones "toasting" these inverters.

Where's all the "burned up" MPPs, Sol-Arks and Growatts?

 

[Tulex]

I'm sorry, I would have to see proof and see what components were used to perform the test which "burned up 100% of the EG4 inverters we've connected".

If this was the case, it seems like it would happen across the board because I doubt any of the different inverters supported by SA could handle an injection of 32v over the com port. I would think that SA would be the first to stop recommending usage in that case because their hardware would be the ones "toasting" these inverters.

Where's all the "burned up" MPPs, Sol-Arks and Growatts?

That's my question. Why is this only "happening" to EG4 units? SA is used on all sorts of batteries and inverters. I haven't heard of this issue with any of them.