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

Fri Dec 19 20:26:07 PST 2025

Interesting exercise here,
5000 amps at 48 vdc, this would be 20+ Fortress evault max 48 vdc cabinets
and l dont think you can put that many on the BMS.
What service does he have, a 3 phase 120/208, 277/480, a 120 208 3 phase it
would be around 600 + meter main, single phase close to a 1000, amps. You
may want to consider a commercial solark inverter as l recall they are high
voltage DC, It would be more efficient, smaller and less copper wire even
with a transformer to step it down. Get more info on this existing service,
voltage, phases, gets us all out of our boxes and thinking.
Fun times

On Fri, Dec 19, 2025, 2:49 PM Kirk Herander via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> I do think the Electrician tried to balance the loads in the three 240 V
> panels, but how close he really came especially with add-ons down the road
> I don’t know. It does work fine, and the system is 5+ years old now without
> any issues.
>
>
> *Kirk Herander / **kirkh at vermont.solar <kirkh at vermont.solar>*
>
> *Owner|Principal, VT Solar, LLC*
>
> *Celebrating our 34st Anniversary 1991-2025!!*
>
> dba Vermont Solar Engineering
>
> 802.559.1225
>
>
> On Fri, Dec 19, 2025 at 5:46 PM david quattro <david at quattrosolar.com>
> wrote:
>
>> Kirk,    it sounds like phase imbalance is not a problem
>>
>> On Fri, Dec 19, 2025 at 2:42 PM Kirk Herander <kirkh at vermont.solar>
>> wrote:
>>
>>> Hi,
>>> I’ve done one large off grid system with 480 -3 - phase inverters and 1
>>> mwh, 850 vdc LFP storage.
>>>
>>> We created 240vac  by stepping each 480v L-L phase down to 240 through
>>> its own transformer of proper size.
>>> So we have three 240/120 VAC panels for typical household loads.
>>>
>>>
>>> *Kirk Herander / **kirkh at vermont.solar <kirkh at vermont.solar>*
>>>
>>> *Owner|Principal, VT Solar, LLC*
>>>
>>> *Celebrating our 34st Anniversary 1991-2025!!*
>>>
>>> dba Vermont Solar Engineering
>>>
>>> 802.559.1225
>>>
>>>
>>> On Fri, Dec 19, 2025 at 5:25 PM david quattro via RE-wrenches <
>>> re-wrenches at lists.re-wrenches.org> wrote:
>>>
>>>> I’ve thought about HV and 60K model, but my loads are 240 Single phase,
>>>> across 5 separate contiguous parcels.  all these homes already have their
>>>> own utility meters.  There is one owner.  The plan is to have an ATS at
>>>> each meter.
>>>>    Regarding 3 phase offgrid, I’ve been concerned about phase
>>>> imbalance. Maybe I don’t need to worry about that.
>>>>
>>>>
>>>>
>>>> On Fri, Dec 19, 2025 at 1:51 PM Michael Morningstar via RE-wrenches <
>>>> re-wrenches at lists.re-wrenches.org> wrote:
>>>>
>>>>> A couple or three Discover HVs and Sol-Ark 60ks. Done quickly
>>>>>
>>>>> On Fri, Dec 19, 2025 at 1:00 PM Kirk Herander via RE-wrenches <
>>>>> re-wrenches at lists.re-wrenches.org> wrote:
>>>>>
>>>>>> Why 48v, why not commercial DC, like 850? What are you looking at for
>>>>>> kwh storage? A1000vdc buss, homemade or otherwise, would drop the buss
>>>>>> rating down to about 300 A. Commercial grade  inverters, such as 3-phase
>>>>>> Delta PCS inverters are spec'ed for these situations.
>>>>>>
>>>>>> 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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>>>>>>
>>>>>> --
>>>>>>
>>>>>>
>>>>>> *Kirk Herander / **kirkh at vermont.solar <kirkh at vermont.solar>*
>>>>>>
>>>>>> *Owner|Principal, VT Solar, LLC*
>>>>>>
>>>>>> *Celebrating our 34st Anniversary 1991-2025!!*
>>>>>>
>>>>>> dba Vermont Solar Engineering
>>>>>>
>>>>>> 802.559.1225
>>>>>> _______________________________________________
>>>>>> List sponsored by Redwood Alliance
>>>>>>
>>>>>> Pay optional member dues here: http://re-wrenches.org
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>>>>>>
>>>>>
>>>>> --
>>>>>
>>>>> Michael Morningstar
>>>>>
>>>>>
>>>>> Morningstar Electric Inc
>>>>>
>>>>> PO Box 1494
>>>>>
>>>>> Mount Shasta, CA 96067
>>>>>
>>>>> 530-921-0560
>>>>>
>>>>> CSLB 1116835
>>>>>
>>>>> mjmorningstar at gmail.com
>>>>>
>>>>>
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