Re: [RE-wrenches] off-grid AC coupling feasibility

[Jerry Shafer via RE-wrenches]

An all DC side charging is preferred and will have the simplest charging
system. Flex net DC shunts, easy to monitor.  Last l heard FM 100 were
pushed out till late in the year
Fun times

On Sat, Jul 30, 2022, 1:37 PM Kirk Herander via RE-wrenches <
re-wrenches@lists.re-wrenches.org> wrote:

> Jerry-
> The pole mount does not exist for a few more weeks, so I have time to
> think about DC or AC coupling for it only. To clarify, the old roof 1.8 kw
> array is functional and has been charging the new blue ions through an old
> Outback pre-hub 60A controller(replacing it soon with a new FM60). So I do
> have existing dc-coupling already to get around dark start issues for the
> most part.
>
> Right now I'm starting to lean towards 100% DC coupling, hooking the new
> pole-mount array to an OB FM100 300vdc max 100A charge controller *IF* I
> can find one in time. At least then I can see everything on one dashboard
> (OpticsRE). Both Mate3s and hub 10.3 are already installed.
>
> One of the other things influencing my decision is the request from my
> customer to have it "grid-ready", which to them means the house is easier
> to sell when the time comes, if the buyer wants to bring in the grid power.
> I won't go into it, but it is a simpler solution (in terms of local
> hardware requirements) to AC-couple the new array with these utility rules
> in mind.
>
> So there is no fits-all solution to AC vs. DC coupling, as someone said.
>
> On Sat, Jul 30, 2022 at 3:58 PM Jerry Shafer via RE-wrenches <
> re-wrenches@lists.re-wrenches.org> wrote:
>
>> Its not clear to me if you will actually have a DC side coupled
>> connection in talking about the pole mount. If so then it does work but if
>> not then no, the big question is how would you restart the inverter to
>> restart the SE to start the charging process on the AC side, answer, you
>> can't in most cases. Example, SMA SI coupled with SMA 4K's, you have a dead
>> battery, you need to bring up the VDC to wake up the inverter to wake up
>> and count down the 4K's the trick here is to alter programming to instant
>> start the 4K upon getting VAC and hertz instead of the 300 sec count down.
>> Something else,  LFP does not relax and get any parasitic voltage back to
>> even start the SI so changing the timers may still not work. Best bet is to
>> have at least some DC side PV to charge a dead battery without the
>> inverters at all. I did ac coupling with Trace and SMA 20 plus years ago
>> and SMA said then it was not possible. How the world has changed. fun times!
>>
>> On Sat, Jul 30, 2022, 9:31 AM Kirk Herander via RE-wrenches <
>> re-wrenches@lists.re-wrenches.org> wrote:
>>
>>> All,
>>> Anyone out there successfully AC-coupled inverters in an off-grid
>>> system? Advantages vs. pitfalls?
>>>
>>> In my case I'm thinking of its practicality with a Solaredge inverter
>>> AC-coupled to an OB Radian inverter. OB firmware makes this pretty easy
>>> now. So effectively the Radian is always operating in a grid-backup mode.
>>>
>>> I already upgraded the system to the Radian, and soon to add 5kw of
>>> pole-mounted PV(currently only 1.8kw of 22-year old PV on the roof). This
>>> system also just got 16kwh of Blue Ion LFP batteries.
>>>
>>> This is a last-minute thought I have instead of investing in additional
>>> DC charge controllers for the new array.
>>> Cost-wise there's not much of a difference between several high-quality
>>> charge controllers and a smaller SE inverter w/optimisers. Thanks.
>>>
>>> --
>>>
>>> *Kirk Herander / **kirkh@vermont.solar *
>>>
>>> *Owner|Principal, VT Solar, LLC*
>>>
>>> *Celebrating our 31st Anniversary 1991-2022!!*
>>>
>>> *www.vermont.solar*
>>> 
>>>
>>> dba Vermont Solar Engineering
>>>
>>> 802.863.1202
>>> ___
>>> List sponsored by Redwood Alliance
>>>
>>> Pay optional member dues here: http://re-wrenches.org
>>>
>>> List Address: RE-wrenches@lists.re-wrenches.org
>>>
>>> Change listserver email address & settings:
>>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>>
>>> There are two list archives for searching. When one doesn't work, try
>>> the other:
>>> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
>>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>>>
>>> List rules & etiquette:
>>> http://www.re-wrenches.org/etiquette.htm
>>>
>>> Check out or update participant bios:
>>> http://www.members.re-wrenches.org
>>>
>>> ___
>> List sponsored by Redwood Alliance
>>
>> Pay optional member dues here: http://re-wrenches.org
>>
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>>
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Re: [RE-wrenches] off-grid AC coupling feasibility

[Kirk Herander via RE-wrenches]

Jerry-
The pole mount does not exist for a few more weeks, so I have time to think
about DC or AC coupling for it only. To clarify, the old roof 1.8 kw array
is functional and has been charging the new blue ions through an old
Outback pre-hub 60A controller(replacing it soon with a new FM60). So I do
have existing dc-coupling already to get around dark start issues for the
most part.

Right now I'm starting to lean towards 100% DC coupling, hooking the new
pole-mount array to an OB FM100 300vdc max 100A charge controller *IF* I
can find one in time. At least then I can see everything on one dashboard
(OpticsRE). Both Mate3s and hub 10.3 are already installed.

One of the other things influencing my decision is the request from my
customer to have it "grid-ready", which to them means the house is easier
to sell when the time comes, if the buyer wants to bring in the grid power.
I won't go into it, but it is a simpler solution (in terms of local
hardware requirements) to AC-couple the new array with these utility rules
in mind.

So there is no fits-all solution to AC vs. DC coupling, as someone said.

On Sat, Jul 30, 2022 at 3:58 PM Jerry Shafer via RE-wrenches <
re-wrenches@lists.re-wrenches.org> wrote:

> Its not clear to me if you will actually have a DC side coupled connection
> in talking about the pole mount. If so then it does work but if not then
> no, the big question is how would you restart the inverter to restart the
> SE to start the charging process on the AC side, answer, you can't in most
> cases. Example, SMA SI coupled with SMA 4K's, you have a dead battery, you
> need to bring up the VDC to wake up the inverter to wake up and count down
> the 4K's the trick here is to alter programming to instant start the 4K
> upon getting VAC and hertz instead of the 300 sec count down. Something
> else,  LFP does not relax and get any parasitic voltage back to even start
> the SI so changing the timers may still not work. Best bet is to have at
> least some DC side PV to charge a dead battery without the inverters at
> all. I did ac coupling with Trace and SMA 20 plus years ago and SMA said
> then it was not possible. How the world has changed. fun times!
>
> On Sat, Jul 30, 2022, 9:31 AM Kirk Herander via RE-wrenches <
> re-wrenches@lists.re-wrenches.org> wrote:
>
>> All,
>> Anyone out there successfully AC-coupled inverters in an off-grid system?
>> Advantages vs. pitfalls?
>>
>> In my case I'm thinking of its practicality with a Solaredge inverter
>> AC-coupled to an OB Radian inverter. OB firmware makes this pretty easy
>> now. So effectively the Radian is always operating in a grid-backup mode.
>>
>> I already upgraded the system to the Radian, and soon to add 5kw of
>> pole-mounted PV(currently only 1.8kw of 22-year old PV on the roof). This
>> system also just got 16kwh of Blue Ion LFP batteries.
>>
>> This is a last-minute thought I have instead of investing in additional
>> DC charge controllers for the new array.
>> Cost-wise there's not much of a difference between several high-quality
>> charge controllers and a smaller SE inverter w/optimisers. Thanks.
>>
>> --
>>
>> *Kirk Herander / **kirkh@vermont.solar *
>>
>> *Owner|Principal, VT Solar, LLC*
>>
>> *Celebrating our 31st Anniversary 1991-2022!!*
>>
>> *www.vermont.solar*
>> 
>>
>> dba Vermont Solar Engineering
>>
>> 802.863.1202
>> ___
>> List sponsored by Redwood Alliance
>>
>> Pay optional member dues here: http://re-wrenches.org
>>
>> List Address: RE-wrenches@lists.re-wrenches.org
>>
>> Change listserver email address & settings:
>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>
>> There are two list archives for searching. When one doesn't work, try the
>> other:
>> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>>
>> List rules & etiquette:
>> http://www.re-wrenches.org/etiquette.htm
>>
>> Check out or update participant bios:
>> http://www.members.re-wrenches.org
>>
>> ___
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: RE-wrenches@lists.re-wrenches.org
>
> Change listserver email address & settings:
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> There are two list archives for searching. When one doesn't work, try the
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Re: [RE-wrenches] off-grid AC coupling feasibility

[Jerry Shafer via RE-wrenches]

Its not clear to me if you will actually have a DC side coupled connection
in talking about the pole mount. If so then it does work but if not then
no, the big question is how would you restart the inverter to restart the
SE to start the charging process on the AC side, answer, you can't in most
cases. Example, SMA SI coupled with SMA 4K's, you have a dead battery, you
need to bring up the VDC to wake up the inverter to wake up and count down
the 4K's the trick here is to alter programming to instant start the 4K
upon getting VAC and hertz instead of the 300 sec count down. Something
else,  LFP does not relax and get any parasitic voltage back to even start
the SI so changing the timers may still not work. Best bet is to have at
least some DC side PV to charge a dead battery without the inverters at
all. I did ac coupling with Trace and SMA 20 plus years ago and SMA said
then it was not possible. How the world has changed. fun times!

On Sat, Jul 30, 2022, 9:31 AM Kirk Herander via RE-wrenches <
re-wrenches@lists.re-wrenches.org> wrote:

> All,
> Anyone out there successfully AC-coupled inverters in an off-grid system?
> Advantages vs. pitfalls?
>
> In my case I'm thinking of its practicality with a Solaredge inverter
> AC-coupled to an OB Radian inverter. OB firmware makes this pretty easy
> now. So effectively the Radian is always operating in a grid-backup mode.
>
> I already upgraded the system to the Radian, and soon to add 5kw of
> pole-mounted PV(currently only 1.8kw of 22-year old PV on the roof). This
> system also just got 16kwh of Blue Ion LFP batteries.
>
> This is a last-minute thought I have instead of investing in additional DC
> charge controllers for the new array.
> Cost-wise there's not much of a difference between several high-quality
> charge controllers and a smaller SE inverter w/optimisers. Thanks.
>
> --
>
> *Kirk Herander / **kirkh@vermont.solar *
>
> *Owner|Principal, VT Solar, LLC*
>
> *Celebrating our 31st Anniversary 1991-2022!!*
>
> *www.vermont.solar*
> 
>
> dba Vermont Solar Engineering
>
> 802.863.1202
> ___
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: RE-wrenches@lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> There are two list archives for searching. When one doesn't work, try the
> other:
> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
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>
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Re: [RE-wrenches] off-grid AC coupling feasibility

[Howie Michaelson via RE-wrenches]

Hey Kirk,
This is something I've done a few times with success, although I've used an
XW pro instead of the Radian, with OB charge controllers. Having the mix of
DC and AC coupled is ideal, as the solaredge will do the bulk of the
charging, but then charge controllers will do the finish taper charge
instead of a relay switching the solaredge on and off (which as far as I
know, solaredge removed frequency shifting for tapering the finish charge
several years ago). It is also helpful in cases where the inverter shuts
down on low voltage, as the DC coupled array will bring the battery voltage
up enough to allow the inverter to turn on and start the solaredge again.
>From my point of view, the combination of AC and DC coupling is the ideal
off grid scenario.
Howie

On Sat, Jul 30, 2022, 12:31 PM Kirk Herander via RE-wrenches <
re-wrenches@lists.re-wrenches.org> wrote:

> All,
> Anyone out there successfully AC-coupled inverters in an off-grid system?
> Advantages vs. pitfalls?
>
> In my case I'm thinking of its practicality with a Solaredge inverter
> AC-coupled to an OB Radian inverter. OB firmware makes this pretty easy
> now. So effectively the Radian is always operating in a grid-backup mode.
>
> I already upgraded the system to the Radian, and soon to add 5kw of
> pole-mounted PV(currently only 1.8kw of 22-year old PV on the roof). This
> system also just got 16kwh of Blue Ion LFP batteries.
>
> This is a last-minute thought I have instead of investing in additional DC
> charge controllers for the new array.
> Cost-wise there's not much of a difference between several high-quality
> charge controllers and a smaller SE inverter w/optimisers. Thanks.
>
> --
>
> *Kirk Herander / **kirkh@vermont.solar *
>
> *Owner|Principal, VT Solar, LLC*
>
> *Celebrating our 31st Anniversary 1991-2022!!*
>
> *www.vermont.solar*
> 
>
> dba Vermont Solar Engineering
>
> 802.863.1202
> ___
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: RE-wrenches@lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> There are two list archives for searching. When one doesn't work, try the
> other:
> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
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>
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Re: [RE-wrenches] off-grid AC coupling feasibility

[Jason Szumlanski via RE-wrenches]

Hi Kirk,

I have not done this personally, and this does not pertain to your specific
situation, but related to this subject is the Sol-Ark 15k has a massive AC
coupling capability even with maximum DC connected PV. I really like this
idea for people that want a huge PV array but only need the continuous AC
output of a single inverter. You lose some redundancy compared to dual
inverters, but this could be a cost effective strategy. Mixing DC and AC
coupling does have its advantages.

Jason Szumlanski




On Sat, Jul 30, 2022 at 12:31 PM Kirk Herander via RE-wrenches <
re-wrenches@lists.re-wrenches.org> wrote:

> All,
> Anyone out there successfully AC-coupled inverters in an off-grid system?
> Advantages vs. pitfalls?
>
> In my case I'm thinking of its practicality with a Solaredge inverter
> AC-coupled to an OB Radian inverter. OB firmware makes this pretty easy
> now. So effectively the Radian is always operating in a grid-backup mode.
>
> I already upgraded the system to the Radian, and soon to add 5kw of
> pole-mounted PV(currently only 1.8kw of 22-year old PV on the roof). This
> system also just got 16kwh of Blue Ion LFP batteries.
>
> This is a last-minute thought I have instead of investing in additional DC
> charge controllers for the new array.
> Cost-wise there's not much of a difference between several high-quality
> charge controllers and a smaller SE inverter w/optimisers. Thanks.
>
> --
>
> *Kirk Herander / **kirkh@vermont.solar *
>
> *Owner|Principal, VT Solar, LLC*
>
> *Celebrating our 31st Anniversary 1991-2022!!*
>
> *www.vermont.solar*
> 
>
> dba Vermont Solar Engineering
>
> 802.863.1202
> ___
> List sponsored by Redwood Alliance
>
>
>
___
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[RE-wrenches] off-grid AC coupling feasibility

[Kirk Herander via RE-wrenches]

All,
Anyone out there successfully AC-coupled inverters in an off-grid system?
Advantages vs. pitfalls?

In my case I'm thinking of its practicality with a Solaredge inverter
AC-coupled to an OB Radian inverter. OB firmware makes this pretty easy
now. So effectively the Radian is always operating in a grid-backup mode.

I already upgraded the system to the Radian, and soon to add 5kw of
pole-mounted PV(currently only 1.8kw of 22-year old PV on the roof). This
system also just got 16kwh of Blue Ion LFP batteries.

This is a last-minute thought I have instead of investing in additional DC
charge controllers for the new array.
Cost-wise there's not much of a difference between several high-quality
charge controllers and a smaller SE inverter w/optimisers. Thanks.

-- 

*Kirk Herander / **kirkh@vermont.solar *

*Owner|Principal, VT Solar, LLC*

*Celebrating our 31st Anniversary 1991-2022!!*

*www.vermont.solar*


dba Vermont Solar Engineering

802.863.1202
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