[RE-wrenches] ~5,000 amps @ 48 volts

[david quattro]

Qty 12 of SolArk 18K is the thought.
I’m thinking about 400-500kWh battery.  I have been in deep, careful
conversations with all branches of AHJ such as Planning, Building, and
Fire. They all support this design. Fire Dept was the key, as they had
final say as to whether they’d allow it. I was pleased to hear that Fire
dept prefer this design over 5 disparate systems of 80kWh each and 5 small
generators; their logic is that it’s safer to have all the generating
equipment in one spot.
   Understandably they will require a separate Utility Building constructed
of fire proof materials, with adequate ventilation, fire suppression, and a
heat alarm that’s internet monitored by me.  cool idea.



On Fri, Dec 19, 2025 at 12:13 PM Jason Szumlanski <
jason at floridasolardesigngroup.com> wrote:

> I don't have a definitive answer for you, but I do have additional
> questions! Have you looked into containerized battery solutions that may
> have integral bussing? I am not familiar with this market, but it seems
> like it would be the path of least resistance.
>
> What inverters are you planning to use? With the max parallel Sol-Ark 15K
> inverters (12) or FlexBOSS21 inverters (16), you would "only" reach about
> 3,300 - 4,000A on the DC side. You could probably get this down
> programmatically without losing much functionality, if any.
>
> This DC ampacity rating suggests a very large battery bank. Are you
> subject to NFPA 855 residential limitations? I am looking for guidance on
> how to comply with Chapters 4-9 for residential installations in the
> easiest, unambiguous way possible. We have many clients interested in large
> battery banks, but I have resisted taking these jobs because of the
> seemingly onerous requirements.
>
>
>
> 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 Fri, Dec 19, 2025 at 1:13 PM david quattro via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
>> Hi everyone,
>>    I am still helping an uber wealthy owner determine if he really wants
>> this much power. If he does, do any of you have experience sourcing a 48v
>> battery-combiner on the order of 4500 to 5000 amps?
>>   I also want to get clear on how to best wire from batteries to
>> combiner, and from combiner to inverters. I read here on the Wrenches list
>> about some electricians who strategically sized conductor AWG so that
>> resistance matches, which seems straightforward once we get our components
>> mounted and accurate distances can be determined. Can anyone on list
>> provide feedback about that, I really appreciate it!
>> Thank you
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