sonnen Reviews 3,268

If I could give it a zero I would. We had it installed 5 years ago and have had nothing but problems. They keep replacing parts only to have the replaced parts fail. Rinse and repeat. It has probably worked correctly 25% of the time. Their customer service is horrible. We had a second Enphase System installed and it has been flawless. DO NOT BUY A Sonnen system.

I've had my Sonnen backup system for two years and in that time I've had to power failures. The system failed to work on either occasion. My installer will be replacing the system again which will now make my third installation. When my system fails, my basement floods because my sump pumps can no longer operate. My refrigerators shut down, and my house has no heat. I paid $18,000 for the piece of mind of knowing I'd be covered in the event of a power failure, and Sonnen has let me down every time.

In this last episode, I was told that my initial replacement was actually a refurbished unit. When you buy these batteries, you go into it knowing that the lifespan will be 10 years. I have no idea what the lifespan is on a refurbished unit since nobody ever consulted me on this and I wasn't able to ask the question. I overheard the technician tell the installer that my replacement unit was a part of a known "bad batch" and it needed to be replaced anyway. This means that Sonnen intentionally waited for a critical failure before making the installer and customer aware of the issue.

When selecting your backup battery system, steer well clear of Sonnen. They are absolutely non reliable, and their business practices border on shady.

Faulty inverter it’s meant to be a premium product!
So less than 10 months into operation, my premium product developed a glitch the inverter would drop and not provide power. Sonnen via the installer advised they would need to investigate and a replacement would be required. My initial research indicated that Sonnen was a premium product. Still awaiting a response for a replacement unit.

This is the 2nd time I have had problems with the Sonnen battery not working.
1st time took 3 weeks to be repaired.
2nd time, I contacted Sonnen twice last Tuesday 14/11 and had to leave messages for a call back. Called again twice on Wednesday 15/11 and had to leave messages for a call back. Finally got a call that afternoon with instructions to reboot the system. However this failed and was advised a technician from the Support Team would be in touch as there appeared to be a hardware problem.
Sent email this Tuesday 21/11 to follow up on what was happening to my dedicated support person, it is now 1 day later 22/11 and still no contact.
Really Sonnen this is NOT good customer service.

I would rate a MINUS 1 star.

I bought these batteries in 2019 and have had nothing but problems. I live in a fire prone area of California where PG&E frequently shuts off power during the fire season. I rely on these batteries. Every time the power shuts off, one or both of them stops working and it is a whole production to get them up and running again. Sonnen continues to tell me that they have a fix on the way, yet three years later, the issues continue.
My installer told me that at one time Sonnen was refunding customers with these issues, but have since stopped. The installer has several customers who are in the same situation. Unfortunately, the installer is a small to midsized local company that cannot afford to refund everybody. So I am stuck with batteries that continue to fail while Sonnen makes promises that it cannot keep.

Battery stopped operating in April 2023 (under 5 years old) and still under warranty. It took 8 weeks for new parts to arrive but these were apparently 'faulty' and could not fix the problem. Service support team have now stopped answering all communications - no solution and no hope! Avoid!

Hi, I have an issue with my Sonnen battery. I will n9 discharge below 25%, so in the mornings I buy electricity despite still having stored power overnight. I cannot get a response from my local support. Thanks in advance for you response. James

I have a sonnenBatterie 10 22kWh, installed on 2022-02-25. It consists of 2 battery modules of 11kWh each, placed in a "cascade" stacking system. (#172848 and #172853)

My battery is not working and Sonnen is unable to find a solution. I am a very, very unhappy client.

The problems started on 2022-07-25: once in a while, the cascade stacking status of one of the battery modules would change from "working" to "not ready". The battery would then stop charging or discharging. Basically, the battery stops working completely. After a while, one of the battery module light indicators would change to red. The temporary fix is to restart both battery modules. This issue was never solved.

Since 2023-04-25, the issues got worse: EVERY DAY, around 4-5AM in the morning, one of my battery modules loses the cascade, leading to the battery in a whole to fail. EVERY DAY, in the morning, I have to restart my batteries so they continue to work.

As a conclusion, I paid an enormous amount of money for a battery that is not working and Sonnen is unable to fix the issues.

If not fixed in the very short term, or Sonnen doesn't provide me with a new battery, I will start legal action.

Installed the 16kwh version 3 years ago.
Inverter broke after 1year. Was replaced by the newer revision which overheated after 5min of use. Was replaced again after a few months by me contacting support/ local installer as an additional full time job...or it felt like it.
The new Inverter was already used (showed signs of wear) and had the same issue, overheating after 5min. Made the installer call sonnen onsite, they said this was normal..... I contested. Nothing more happened. Kept nagging, the installer then claimed his warranty only covered the first 2years and he was out.
Contacted Sonnen again, this time they made me redo all trouble shooting steps until they also concluded that the Inverter was faulty and needed replacing.
That was 10 months ago. 2 months ago (and 50 emails in-between) was Contacted by their instalation partner that the case would be transferred to a partner company which was closer to me...Nothing since.
Yesterday the Inverter died.
Waiting....

Communication from this company is very poor. I have had generic communications advising that my Eco 8 battery was offline and given instruction to self-reboot so they can assess the problem. This is after speaking with a representative on 20 January who had already diagnosed there would need to be a technician to replace parts. The same thing happened 12 months ago.

The representative was polite enough (John) but
Sonnen now do not answer their phone lines and whilst emails are replied to, the message is the same. (John: "As soon as we can get a date from our suppliers as to the supply of parts we will inform you")

It has been over 2 months and I think it is now becoming 'an unreasonable wait time' - particularly when summer is a high generation and consumption period. This is costing me money.

I would like to remind management at Sonnen that under Australian Consumer Law, amongst other things:
When purchasing goods or services, under the Australian Consumer Law (ACL).

Goods will:
• be fit for their disclosed purpose;
• have spare parts and repairs available for a reasonable amount of time after purchase unless otherwise stated; and
• honour any warranties.

Services will:
• be provided with due care, skill and technical knowledge.
• be fit for any disclosed purpose.
• be completed (or provided) within a reasonable time; and
• take all necessary care to avoid loss or damage.

Maybe this review will elicit a better response. I share the feelings of many more reviewers who are equally frustrated on getting regular updates.

Purchased a Hybrid 9.5.3 15kWh system (serial no. 216785) which got installed 29th November 2022. 17th January 2023 the inverter went defect and the system was down until 22nd February 2023. The inverter was replaced with a new and then the expectation was that now the defective parts was replaced there should be no worries for years to come. Unfortunately 5th March 2023 the system is going into defect mode again. Restarted the system 3x and every time it end up with red colored circle. It is understandable that a defect occur but this time my patience is gone - await input from your DK reseller Viasol.

We had a solar system with a Sonnen back up battery installed on June 20th, 2022.
As of this writing 11/30/22 the battery portion of the system has never been functional.
The customer service and technical support has been abysmal.
They sent a new part out which took several weeks. It arrived without the cables. When they sent the cables a couple of weeks later it only had 4 out of 5 cables. We never got the 5th cable.
Their scheduling reservations for tech support available to speak to the installer have no openings for over a month.
We started out patient, understanding that mistakes and oversights happen but that understanding and patience was not met in kind with prioritizing in any way our case as the weeks turned to months. We finally stated about a month ago to them and installing company that we expected it to be made right or have the battery removed and a full refund by December or we would look to outside regulatory agencies and legal counsel if necessary.
This caused things to finally over 5 months after installation to be escalated to "Tier 3 support"
A week ago we were told an order had been put in for necessary parts. As of today they have still not even shipped them.
We already missed out on a summer of credits to our electric bill from drawing off battery during peak hours. We are now heading into winter with no backup power source if we lose power. We have medications that require refridgeration and medical equipment that require power. At this point we want our significant monetary investment refunded so we can pay off the loan we have been paying on for 6 months now and just buy a generator

Battery pack installed in June . Installers put CT on wrong cable took 3 weeks to get corrected. Battery pack stopped charging on 8 Sept took 2 weeks to establish part required which is apparently on way to installer. This might take up to 4 weeks still not arrived. Absolutely useless customer service just hope the part solves the problem. Battery now been out of operation since instal for 64 days approx and only achieved 38 charge cycles not good enough. Had a similar system installed for my daughter but that was not without its problems tripping breakers that shut off the freezer and fridge not a good outcome. Phone call today it’s charged from mains, no sun, and then gone off.
Currently not impressed with their operation they can fault find the pack, apparently over the internet and then it all comes to a halt
Update 24 Nov - request from more information from Sonnen provided phone number but to date no contact again not impressed and no word of parts!

Battery not charging or discharging , going on for over two months , Communication with Sonnen very very poor . Promising product but appalling customer service, Very slow in finding resolutions to any problem . Constantly been ignored when looking for updates.

UPDATE:
Issue has still not been resolved. What more needs to be said.

Contracted with Sunshine Renewable Solutions Houston Texas, per Sonnen sales representative for installation of an EcoLinx 18 in Austin TX home. Install began in January 2022 and unit today still isn't fully operational, e-stop doesn't work and whole house monitor isn't installed correctly. Installer and Sonnen point to each other for the reason this isn't resolved, but I blame both. Sonnen tech support has been out a few times to correct issue unsuccessfully and cancelled most recent scheduled visit in October. I own an eco and ecoLinx. I guess that I need to push the situation on social media, local TV consumer affairs and seek legal counsel.

Sonnen service for Puerto Rico is very poor, I never recomend these batteries because of my service experiences and the installer company is no longer selling sonnen.
I own two systems, for the residence and a beach villa.
Now, in Puerto Rico there is one service tecnician but l can’t call him. I have to call US and wait for an email with instructions, which both times
did’t work and last time I had to wait 3 months for the service.
During storm Fiona there was no grid and no sun for several days and batteries went stand by. I followed instructions given by email and couldn’t charge by sun or grid. I called again a week ago an still waiting for a tecnitian to open a service claim in PR. Service is for #68503
Roberto Sein

Battery was installed in 2018, worked fine until July 2022. Reported the issue of battery not charging from July 2022 to the installer who opened a case at sonnen. NOTHING happened so far, no direct communication from the company to the customer, no real guidance on what to do in the web portal, no help at all. Living in a sunny region but can't use the solar power for 2 months and with heavily reduced sonnenFlat allowance due to their new contract, it is forseeable that we will need to pay for extra energy. Absolutely apalling.

Another update this time unfortunately I downgrade my rating back down. It has been a month since the company found a local provider to assist me. I have been in contact with the local provider but the issue now remains unsolved. The reason being SONNEN, a part apparently is faulty. I was notified a month ago that the part has been ordered internally. After four weeks I write to the company to get an update and he's told the exact same thing. Energy prices has exploded and my problem remains unsolved. The company cannot even provide an update as to when I can't expect the parts to be shipped. Warranty is great but if things doesn't get fixed it doesn't matter!

Update. Fair is fair. While initially in panic mode the company has responded to emails and is now trying to locate a local partner to address the issue. I am now hopeful that the review initially written can be changed even further.

The battery is such is great. On paper the warranty is also great. The problem is when the installer company goes insolvent and there's no one to provide the service under the warranty. So now I got a beautiful battery system the sun is shining and I got nobody to call and a battery that doesn't work after two years and not after 10,000 cycles despite numerous installers being available here in Denmark. I would probably say go with the cheap companies in the future as opposed to buying the expensive with a high degree of warranty.

Update. And I will keep updating this the issue is ridiculous. Trustpilot notified me yesterday that son required more information including a service number. For obvious reasons as they don't reply to emails that doesn't exist. When checking their website for support inquiries they write "Please contact the installer who initially installed your system for any service enquiries." which is all well and fine if it wasn't for the fact that the installer is insolvent and no longer in business a fact sonnen is quite aware of as it is reflected when checking the status on my.sonnen.de in effect rendering the warranty useless if there's no one to take the service inquiry.
As stated you're better off buying a cheap battery as opposed to trusting the warranty from this company.