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Is this a bad joke? Signature Solar creating specs requirements to avoid defective inverter costs?

Old_Skewler

Solar Enthusiast
Joined
Jul 30, 2021
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505
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NYS
This has just been a very disappointing experience, considering that I specifically chose the vendor based on their sales and technical support claims. Yes, the fact that they have members actively participating in these forums also led me to believe that they would stand behind their products. My experience has been quite the opposite, with them actually grasping anything out of thin air to avoid responsibility with their product.

I have recently purchased from them the following equipment:

- Growatt 8kw DVM-MPV
- 48V 100AH EG4
- Battery Cables
- AC Disconnect

The equipment above was purchased after a long back and forth conversations with their sales team, clarifying questions and compatibility with my existing condition (off grid with a 14kW LPG Kohler generator and 240V split phase panel). This being my very first DIY energy system, I can assure everyone that I tried to cover all angles and asked many questions during those calls:

- Will it work with my 240V split phase?
- Will it be able to turn on the generator automatically?
- How long would it take to charge the battery with the generator?
- Would I need any other equipment for this to fully work?
- Will I be able to simply add more energy storage as I please?


And the list of questions goes on, but at no point during any of the sales calls Signature Solar mentioned or raised questions regarding the compatibility of my $5,000 14kW Kohler generator with their inverter. To be quite honest, their attitude was quite the opposite: this is the package you need, everything will work, we are here to support it.

Well, this hasn't been the case. After installing the system I was only able to operate it in UTI mode, where if I turn the generator (manually) the power switches from battery to generator power and when generator is turned off, power goes back to battery source.

When trying to operate in the correct mode (SBU) the unit simply does not transfer between battery source to generator source. Additionally, the dry contact for the AGS does not click appropriately once the battery hits the SOC setpoints.

After a few unsuccessful calls with Signature Solar tier 1 technician, they bounce me to a tier 2 technician who basically is stating that my generator is not compatible with their unit and it is my fault to have purchased their inverter. They even went to say that their inverters are NOT compatible or meant to be used with generators, which was a shock considering they mentioned off-grid solutions, their inverters have a AGS contact and the inverter user manual explicitly mentions generator application.

But guess what is nowhere to be found anywhere in their website or inverter manuals? The "new generator requirements" they have recently created in order to avoid dealing with their defective products.

They are basically saying the inverter is not defective and the problem with my setup is due to the following:

1. My generator being only "14kW" instead of the allegedly required 16kW.
2. My generator only guaranteeing "up to 5% THD" when their inverter allegedly only works with 3% THD.

I had asked them to point me to where these requirements live but they were not able to produce anything concrete.

To be continued.
 
I'm sorry to hear that you are having such a problem.
I'm not sure what the parameters are around your system combination. But, I'm sure that there's a way to make it work. If I get some free time to dig into the manual, I'll try to help you find a solution.
 
I think that the simple solution would be a SOC monitor with a set of contacts to start the generator.
Set the inverter to utility, and it should work perfectly.
 
Wow, that's terrible. It should be instantaneous. Within micro seconds.
Unless you are referring to generator startup delay.
I'm referring to the fact that an inverter will wait for a while to find out if the PV input is going to come back before it switches to grid input.
If grid disappears, yes they all switch to battery mode in short order (4-20ms)
 
I'm sorry to hear that you are having such a problem.
I'm not sure what the parameters are around your system combination. But, I'm sure that there's a way to make it work. If I get some free time to dig into the manual, I'll try to help you find a solution.

The manual is surprisingly vague and does not go deep in the modes of operation of the inverter - actually, it barely mentions them.

I have tried all modes of operation and the only time it behaves correctly is under UTI setting and manually turning on/off the generator. Not a great long term solution.

If you have any idea how to set this up, I'm all ears.
 
Are you still within time limit for credit card disputes?
That ought to teach them a lesson.
I'm very much aware of it and considering filing a claim.

Just waiting for final position from vendor on how they intend to responding to my defective claim. As of now, they are still claiming the inverter is functioning correctly.
 
Sorry to hear about your bad experience with Signature Solar and their 'tactical tech team'. Join the club.

Sounds like you did your due diligence and asked all the right questions. That only goes so far when you are getting bad answers. That's exactly what happened with me and part of the reason my experience with them was so disappointing.

That 14kw Kohler isn't the issue. It's a good generator with clean power.

Luckily, there are a lot of smart, helpful people here that will likely come up with a workable solution. Good luck!
 
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I think that the simple solution would be a SOC monitor with a set of contacts to start the generator.
Set the inverter to utility, and it should work perfectly.
And what would happen once I install the PV panels?

My understanding is that the inverter needs to be setup under SBU mode to fully work with the PV + Generator.
 
That 14kw Kohler isn't the issue. It's a good generator with clean power.
I told them that. Not to mention that the transfer works fine under UTI mode.

They were clearly looking for a spec in the generator to blame for the inverter behavior.
 
I'm very much aware of it and considering filing a claim.

Just waiting for final position from vendor on how they intend to responding to my defective claim. As of now, they are still claiming the inverter is functioning correctly.

Based on other experiences I've read here, I suggest lighting a fire under them. If you get a refund and buy something else, you've washed your hands of the problem.

I tried to look up THD spec for utility grid but haven't found it.
If generator delivers power within spec for grid, inverter ought to accept it.
Generator may run higher than 60 Hz under no-load, if it is just electromagnetic not inverter. Loading it down could help.
Some inverters have wider limits when operated on generator, tighten to limits quoted in UL-1741 or UL-1741-SA when on-grid.


If you want to spend the money, 2x Sunny Island or 1x Sunny Island + transformer could work well.
They can be had for about $3000 each. Not cheap, I know, but the best stuff available anywhere.
They've been doing inverter/generator interaction for decades.

 
The inverter will take 1-2 minutes to switch to utility input.
The dry contact output is not usable to start a generator on its own, you need an interface to handle the generator start system.
SS have plenty of sales people and not enough tech people.
I have NO experience with AIO inverters, but, the "1-2 minute time to switch to Grid power", might be, that the inverter is syncing its AC output to the Grid;s sinewave. The inverters here take time to sync to our gensets. This can take at least 30 seconds for many inverters ... just a thought.

FWIW, POD
 
Based on other experiences I've read here, I suggest lighting a fire under them. If you get a refund and buy something else, you've washed your hands of the problem.

I tried to look up THD spec for utility grid but haven't found it.
If generator delivers power within spec for grid, inverter ought to accept it.
Generator may run higher than 60 Hz under no-load, if it is just electromagnetic not inverter. Loading it down could help.
Some inverters have wider limits when operated on generator, tighten to limits quoted in UL-1741 or UL-1741-SA when on-grid.


If you want to spend the money, 2x Sunny Island or 1x Sunny Island + transformer could work well.
They can be had for about $3000 each. Not cheap, I know, but the best stuff available anywhere.
They've been doing inverter/generator interaction for decades.

From what i remember, typical utility grid thd is between 2 and 5%. I could be wrong.

And Signature will likely offer you a full refund. You just have to send it all back on your dime.

x2 on the Sunny recommendations.
 
The inverter will take 1-2 minutes to switch to utility input.
I'm referring to the fact that an inverter will wait for a while to find out if the PV input is going to come back before it switches to grid input.

I'm using 2 different Chinese inverters as UPS / backup (no PVs), one (12v - inverter + AC charger only) switches almost instantly while the other one (24v - with AC charger + PV input) takes its time.

Unfortunately the one that switches instantly is already dead and I'm talking to the seller. We haven't had any mains power loss since I bought it around 2 months ago, and I'm only cycling it once in a while.

Switching instantly might have been too fast for comfort for the fella.
 
Based on other experiences I've read here, I suggest lighting a fire under them. If you get a refund and buy something else, you've washed your hands of the problem.
I'm open to any solution that accepts the fact the inverter is the problem as opposed to blaming the generator.
I tried to look up THD spec for utility grid but haven't found it.
If generator delivers power within spec for grid, inverter ought to accept it.
Very good point. Also please note the technician has even stated the inverter is not meant for off grid applications or to be paired to a generator. It is just absurd because the literature on their website and even the installation manual describes generator applications
If you want to spend the money, 2x Sunny Island or 1x Sunny Island + transformer could work well.
They can be had for about $3000 each. Not cheap, I know, but the best stuff available anywhere.
I remember we talked at the beginning of my journey and I checked into SMA, it is just out of my budget.
 
And Signature will likely offer you a full refund. You just have to send it all back on your dime.
I'm not open to pay for return shipping on a defective product.

Please keep in mind that i already paid exactly $320 to have this package shipped to me.
 
Just to confirm:

When SBU mode is selected (Program 01 = SbU)
AND
When battery voltage is under 46.0V (or whatever Program 12 is set to)
AND
This has been in that state for more than 5 minutes (undefined time, it's not settable, and Growatt doesn't document it - but it's intended to prevent generator starts for short term heavy load conditions)

THEN
You do NOT see NO & C connected together on the dry contact port?

If that is the case, then the unit has failed and must be repaired. It isn't following the manual on Page 11, "Dry Contact Signal". Also note the use of the word "Generator" on that same page - they should not be claiming the growatt doesn't work with generators.

Further, the dry contact is rated 3A/250VAC, so should be capable of starting the Kohler Generator. Just connect Growatt Dry Contact NO and C to Kohler Generator terminals 3 & 4. Per page 20 of the Kohler manual (CONFIRM THIS MATCHES YOUR GENERATOR BEFORE USING MY TERMINAL NUMBERS) - https://apelectric.com/content/PDF/Kohler/14rca(l)_operation_manual_2019.pdf . Do note that the generator requires a 2 minute no-load cooldown, and the growatt probably doesn't provide that. You may be shortening your generator life if you don't add additional equipment. That may be as simple as a time delay relay between the growatt and the generator.

As far as Signature Solar... They are not a good source of technical information or assistance, pre or post sale. Still better than most overseas vendors on Alibaba, but not by a whole lot. I only recommend them to DIY'ers who know enough to build their own system, and will only need support if a product is clearly faulty and under warranty. This is not intended to be a dis-recomendation, just acceptance of the cost/support tradeoff. I'll still purchase from them when they're the best price for the equipment I'm looking at, and they often are.
 
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