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

[Jason Szumlanski]

I am envious of this opportunity. Keep us up to date on it! I forgot that
the 18K is coming out with the 350A DC charging capability.

I'm still thinking that a containerized battery might be something to
consider.

If using Sol-Ark, presumably you are looking at one of their battery
partners. Maybe they can assist with bus options.


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 3:32 PM david quattro <david at quattrosolar.com>
wrote:

> 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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