[RE-wrenches] EG4 v HomeGrid battery systems update?

Jason Szumlanski jason at floridasolardesigngroup.com
Fri Sep 5 02:43:53 PDT 2025 

This has also been my experience. I don't know if it's EG4 listening to
customers and understanding what we are up against. It might be dumb luck
that their batteries work this way. but I have never had an issue with
firmware mismatch with EG4 in an open-loop setting, even when the batteries
are communicating with each other, just not with an inverter.

It's too bad their batteries don't play nice with Sol-Ark. More accurately,
probably, Sol-Ark doesn't play nice with EG4.


Jason Szumlanski
Principal Solar Designer | Florida Solar Design Group
NABCEP Certified Solar Professional (PVIP)
Florida State Certified Solar Contractor CVC56956
Florida Certified Electrical Contractor EC13013208


On Thu, Sep 4, 2025 at 10:04 PM Jay via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> I had to talk to eg4 today.
> I asked them about the necessity for firmware updates on batteries.
> They said the batteries will work without correct firmware. They might not
> be compatible of communication with the inverter but will work.
>
> So if you had to add another battery to a few older ones it would work
> fine.
> Yes best to do a firmware update but not necessary
>
>
>
> On Sep 4, 2025, at 3:53 PM, Jason Szumlanski via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
> 
> Ok, I have some information about the latest shutdown of HomeGrid. I just
> went out to the island today and spent the entire day resolving the issue
> (hopefully).
>
> First, I want to clearly state how incredibly knowledgeable, helpful, and
> patient HomeGrid technical support was today (shout out to Armando Rolden).
> I was lucky enough to have all of the right cables with me, and the EMS
> Tools preloaded on my Windows laptop, and we worked together to diagnose
> and resolve things.
>
> I'll cut to the chase: there were two potential issues that might have
> caused the shutdowns.
>
> 1. On one stack of batteries we had previously bypassed a pack
> (HomeGrid calls the individual batteries a pack). This was months ago and
> we did it because somehow it became out of balance, meaning one of the 15
> cells internally had a significantly lower voltage. We do not know why this
> happened, but presumably it was not being cycled enough to 100%, which
> HomeGrid insists is absolutely necessary to prevent issues like this. The
> moral of the story: don't undersize a PV array with HomeGrid, or at least
> have an auxiliary charging source to get batteries to 100% at least weekly.
> I seriously doubt this was the reason for the recent shutdowns because we
> had been running two uneven stacks for months (one with 7 and one with 8)
> without any issues.
> 2. We added a stack of 8 to the original two stacks a month ago. For three
> weeks, everything worked fine. Then we started getting these random
> shutdowns. We discovered today that four of the eight packs had a different
> software version. This is the more likely reason, in my opinion, that we
> experienced issues. Incidentally, the shutdowns always happened when the
> batteries were at 100% for a few hours. This points to issues with
> differing charge limits between the different software versions according
> to HomeGrid.
>
>
> So where does this leave me? I'm hopeful that the software updates and
> manual rebalancing of the unbalanced pack will resolve the issues at this
> site. But it reiterates that these sytems are not ideal for off-grid
> applications when issues like these can take down the whole system. And I
> was fortunate that the property was unoccupied today, because I had to shut
> down the system many times. We had to un-parallel stacks, reconfigure
> things, and re-parallel at the end. I did not have a generator functional
> at the time, so I could not keep power on to the home, so we lost Internet,
> which made remote support difficult. We had to run off of one stack for a
> while to make it happen, so that also required some reconfiguring.
>
> All of this takes a LOT of time. As I said, I spent all day on this. Part
> of the problem was that I called HomeGrid at 9:00 am EST and didn't get a
> call back until 11:00 am, but I had already left the site! I had to turn
> the boat around to go back. I didn't know how long it was going to take, so
> I wasn't going to wait all day, but fortunately they caught me in time.
>
> The bottom line is I think HomeGrid has a good product. When it works, it
> works. But the premium price and the off-grid resilience and serviceability
> issues make it unsuitable for my applications.
>
> If issues persist at this site, I am going to have to run the three stacks
> in open-loop. That will not help the intra-stack issues, but it might help
> with redundancy by keeping two of three stacks going in the event of a
> fault. Of course, there are serious downsides to this, given that the SOC
> estimating from Sol-Ark is poor and Voltage mode will need to be used for
> the AGS as a result. I really hope that the system will keep humming along,
> but I'm sure it is only a matter of time before I'm called back out.
>
>
> Finally, I also need to backtrack on something I said before. You CAN
> connect to individual battery packs with a computer and use the HomeGrid
> EMS Tools. It requires a differnet RS232-USB cable with a RJ11 connector on
> one end. It allows you to monitor the battery pack in real time, but not
> perform updates (which requires RS485). However, the battery pack has to be
> turned on, and if it is in a stack and has a fault, the stack will probably
> error out and not function as a result. So the same problem exists in that
> you can't service a pack within a stack while the rest of the stack
> functions normally.
>
>
> P.S. If you work with HomeGrid with EMS Tools, make sure you record the
> password for the software interface for future reference. If you can't
> reach HomeGrid, you will need it to even open up the software. It's not a
> standard default password.
>
>
>
> I hope this helps others!
>
>
> Jason Szumlanski
> Principal Solar Designer | Florida Solar Design Group
> NABCEP Certified Solar Professional (PVIP)
> Florida State Certified Solar Contractor CVC56956
> Florida Certified Electrical Contractor EC13013208
>
>
> On Wed, Sep 3, 2025 at 1:18 PM Jason Szumlanski <
> jason at floridasolardesigngroup.com> wrote:
>
>> Nothing like a coincidence...
>>
>> A client on an island with three stacks of 8 HomeGrid batteries has just
>> called me to report that the entire system is down. All of the battery BMS
>> module displays are dark. I have mySolArk data from three inverters there
>> that show the batteries were topped off and just idling along with solar
>> covering the load at 5:00 pm last night when the power suddenly went out,
>> killing the Starlink connection. I'm going for a boat ride tomorrow to
>> check it out. Ugh.
>>
>> I will report my findings. Not sure if it's a battery or inverter issue,
>> but the customer's handyman reported nothing on the battery screens, which
>> seems strange to me. Even an error should not turn the display off, as far
>> as I recall.
>>
>> P.S. No power loss notifications from Sol-Ark is a frustrating loss of
>> functionality. I heard a rumor on Facebook that they are fixing this
>> in mySolArk this month, but I'm not holding my breath.
>>
>>
>> Jason Szumlanski
>> Principal Solar Designer | Florida Solar Design Group
>> NABCEP Certified Solar Professional (PVIP)
>> Florida State Certified Solar Contractor CVC56956
>> Florida Certified Electrical Contractor EC13013208
>>
>>
>> On Tue, Sep 2, 2025 at 4:31 PM Jason Szumlanski <
>> jason at floridasolardesigngroup.com> wrote:
>>
>>> We have some stacks of HomeGrid out there in various capacities, from
>>> the smallest with five in a stack, up to four fully populated stacks of
>>> eight. In total, I oversee around 150 Stack'd batteries, including many
>>> that I installed and some that were installed by others. I will say that
>>> they are easy to install, have a nice bold visual interface, look good, and
>>> perform up to expectations. They communicate flawlessly with Sol-Ark 15k.
>>> However...
>>>
>>> I believe there is a fundamental design flaw in this stackable battery
>>> architecture. Here is why I am no longer offering HomeGrid in a nutshell:
>>>
>>>    - When one battery in a stack has a fault, the entire stack faults
>>>    out, which renders the stack non-functional until you either:
>>>       1. Remove the battery from the stack or turn the circuit breaker
>>>       off, and:
>>>       2. Reconfigure all of the dip switches to remove the battery from
>>>       the communication loop, then:
>>>       3. Reprogram the master BMS to recognize the new stack members
>>>       and their positions.
>>>    - If you have multiple stacks, you have to do all of the above, and
>>>    in addition:
>>>       1. Remove a battery from each additional stack to balance them,
>>>       then perform all of the above steps on each stack.
>>>       2. But before you reprogram each master BMS you have to take the
>>>       stacks out of parallel communication, then reprogram the parallel stacks
>>>       before operation again.
>>>       3. Making each stack equal is per HomeGrid support, but in
>>>       practice, I don't know if it is necessary, especially if you are losing one
>>>       of eight (12.5%). If you have smaller stacks, this might be a bigger issue.
>>>    - To diagnose a battery issue with a laptop and cable and get
>>>    warranty support, you can only do that with the master BMS because each
>>>    battery does not have a comm port. That means you have to have the entire
>>>    stack non-functional while you perform diagnostics, which is not ideal for
>>>    off-grid settings, especially if there is only one stack.
>>>    - If a battery fails to balance and becomes depleted, causing a
>>>    fault, there are no simple terminal bolts to connect an external charger.
>>>    I'm not sure how you would even accomplish a manual charge without opening
>>>    up the case.
>>>
>>> The EG4 server rack batteries work in a fundamentally different way.
>>> Each battery has an independent BMS. When there is an alarm in a stack or
>>> stacks of batteries, the entire battery bank does not fault out. You can
>>> physically take a battery out of the stack without changing any dip
>>> switches on the other batteries. You can shut one down or experience
>>> a fault on one battery without any others shutting down. I have tried this
>>> with the LifePower4 batteries, even when there are multiple communication
>>> strings of 16 batteries connected to a communication hub. The rest of the
>>> batteries just keep on working, which is the way it should be! The
>>> communication hub will just show zero values for the battery that is
>>> missing from the stack. I cannot confirm if this is the case with the LL
>>> batteries, but I suspect it would be. In a way, this is like having the
>>> batteries in an open loop in terms of resilience, with all of the benefits
>>> that closed-loop battery communications offers. I have had a small variety
>>> of battery issues with EG4, and not once has the whole bank of batteries
>>> been affected by one battery's issue.
>>>
>>> Side note about another server rack option: I can confirm that Pytes
>>> Ebox V1 batteries in a communication stack will shut down all batteries if
>>> one has a fault, at least confirmed by one situation I had. This is despite
>>> each battery having it's own BMS and console port to communicate with the
>>> batteries. The situation in my case was a battery that had no "Barcode"
>>> programmed into it, which was causing a parallel communication fault and
>>> shutting down the whole stack. In this case, physically bypassing the
>>> battery with the issue with a Cat5 coupling worked fine. There are no dip
>>> switches to set, and the master battery reconfigures the communication
>>> stack automatically. With Pytes' support, I was able to manually code in
>>> the Barcode to the BMS with a console cable, and the problem went away. I
>>> am not sure if all varieties of faults would have the same effect with
>>> Pytes EBoxes, but this communication issue definitely caused the whole
>>> stack to fault out.
>>>
>>>
>>> The phenomenon of the new breed of LFP batteries lacking
>>> reliability/redundancy inspired a blog post that I did just a couple of
>>> weeks ago:
>>> https://floridasolardesigngroup.com/homegrid-stackd-batteries-the-redundancy-fallacy
>>>
>>>
>>> A couple of other notes on HomeGrid:
>>>
>>>    - They do not have any way to connect conduit to the BMS. You
>>>    wouldn't want to anyway, especially with rigid conduit, since you might
>>>    need to remove the BMS for service. The BMS should be at the bottom, in my
>>>    opinion, for this reason. You can only run positive and negative battery
>>>    cables out of the provided strain relief glands in free air, and it
>>>    requires that the batteries be about 4 inches away from the wall. There is
>>>    no suitable way to protect 100% of the battery cables.
>>>    - Along the same lines, if you ever plan to expand the system, make
>>>    sure you leave enough battery cable length to reach a higher level.
>>>    - The lack of busbars is a really nice feature (until you get into
>>>    larger systems).
>>>    - The discharge rate supports the maximum input for a Sol-Ark 15K
>>>    with, I believe, just three batteries.
>>>    - I love their "busbar pair" designed specifically for the Sol-Ark
>>>    15K. I order a pair with every inverter, regardless of what battery I am
>>>    using (although I am not actively selling Sol-Ark right now).
>>>    - You can't monitor the condition of individual batteries with Solar
>>>    Assistant, or any other tool remotely to my knowledge. You can't even
>>>    monitor the condition of paralleled stacks.
>>>    - The "app" for the batteries is mind-bendingly useless – unless I'm
>>>    really missing something.
>>>    - For some firmware and hardware versions, over-the-air updates are
>>>    not possible, and HomeGrid will need to send you an update tool. To be
>>>    fair, I think this is also the case with EG4 and some other manufacturers.
>>>    - Once we received a shipment where three of eight batteries were in
>>>    the right boxes, but there were no guts in the batteries at all! It was
>>>    just an empty steel battery shell. We had to send them back to our
>>>    supplier. The boxes actually said 13 Kg on the labels rather than 52 Kg,
>>>    but nobody at the factory caught it. Strange.
>>>    - HomeGrid Support is very competent, I would say among the best in
>>>    terms of knowing their products inside and out, but it's 50/50 whether I
>>>    get someone on the phone or get a call back in a timely manner that allows
>>>    me to complete a service call. They are willing to schedule assistance if
>>>    you have an off-grid situation that requires help.
>>>
>>>
>>> Is this a vote for EG4? Not necessarily, but it's hard to argue with the
>>> price and the superior reliability/redundancy aspects of the LifePower4/LL
>>> batteries. One battery fault should not shut down an entire system unless
>>> there is a legitimate safety hazard. It's possible that these are UL issues
>>> that require system shutdowns, but EG4 appears to have overcome the
>>> problems I've seen with other manufacturers' products.
>>>
>>> Like others mentioned, I prefer to go with the 14.3 kWh / 16 kWh sealed
>>> batteries. I feel they have better build quality (other than my recent rant
>>> about rust on the MNP PowerFlo16), and keeping components sealed up better
>>> just makes sense to me, especially in challenging environments. Of course,
>>> if you want more modularity in terms of expansion options and less impact
>>> if a single unit goes down, 5 kWh units might be a better option. There is
>>> no right or wrong option, I guess – sometimes it just comes down to
>>> priorities, space, mounting options, and price.
>>>
>>>
>>> Jason Szumlanski
>>> Principal Solar Designer | Florida Solar Design Group
>>> NABCEP Certified Solar Professional (PVIP)
>>> Florida State Certified Solar Contractor CVC56956
>>> Florida Certified Electrical Contractor EC13013208
>>>
>>>
>>> On Tue, Sep 2, 2025 at 10:41 AM Christopher Warfel via RE-wrenches <
>>> re-wrenches at lists.re-wrenches.org> wrote:
>>>
>>>> Hi Wrenches, I went through the archives and read the comparison
>>>> between
>>>> these two.  The HomeGrid manual was in such a mess (or my pdf reader
>>>> was
>>>> defunct), that I started looking at other options. If anyone has a
>>>> strong opinion of either of these two, or something better, I would
>>>> appreciate.  We traditionally install small systems, and this would be
>>>> one (@15kWh).  I would prefer to use a racking system with the BMS as
>>>> part of the packaging. Solark 12kPV multimode.  Thank you, Chris
>>>>
>>>> --
>>>> Christopher Warfel, PE
>>>> ENTECH Engineering, Inc.
>>>> PO Box 871, Block Island, RI 02807
>>>> (401) 447-5773
>>>>
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