[RE-wrenches] Grid-Tied Radian Force Discharge

Fri Apr 26 05:37:15 PDT 2024

Maverick and Mac

I am using Flextime here so that we are only using Grid Zero mode from
2-6am, when there is no solar coming in. The rest of the time, the system
is in Grid tied mode so that we can take advantage of as much solar as
possible. But the battery bank is two strings of the NSB190 FT Blue+
batteries, for 404AH. The typical load overnight is only about 400watts
from what I can tell through Optics. Since the system is grid tied it is
getting to absorb every day.

There is no Flexnet on this one. When we set it up, I was thinking that the
Flexnet would just give bad SOC readings and confuse the customer since the
batteries are not often cycled. However, it is frustrating that remotely, I
can only see hourly voltage readings, which does not give much detail.
However, I think I just noticed something interesting. I was about to say
that the low reading is not accurate, because yesterday it showed the low
being 49.2V. I noticed right now that the "temperature compensated target
voltage" was 2V lower than the actual voltage.  Optics seems to display the
actual voltage (since I see right now that the batteries are hanging out 2V
above the float setting. Anyway, if the system is using temperature
compensated voltage for the cutoff, then seeing 49.2V was actually the LBCO
cutoff voltage (since the settings was 47.2V). And I had the Grid Zero DOD
V set to 48. So, I had 0.8V difference between the settings, but I need it
to be >2V difference (on a chilly morning).

Also, frustrating, is that these batteries want a 2mV per cell temp
compensation. But the Radian can only do 5mV per cell. So on these cold
mornings, the Radian is probably overcompensating for the cold
temperatures.

Cheers,
Dave

On Fri, Apr 26, 2024 at 7:45 AM Mac Lewis via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> Hello Dave,
>
> Be sure you calibrate the flexnet and the inverter voltage.  My gut
> feeling is that the Delta voltage you have is too tight.  If you have the
> system on Optics, I'd set the LBCO pretty low, then observe how much
> voltage sag (or where your voltage cliff is) you are getting at
> the discharge SOC you are going for, then you can work your LBCO back up.
>
>
>
> On Thu, Apr 25, 2024 at 8:47 PM Maverick Brown via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
>> Dave
>>
>> What is the size of the battery bank and what is the typical load, let’s
>> say at night or some other peak time?
>>
>> Bank size, SOC and demand can influence voltage. LBCO at 47.2 could be
>> too high under smaller bank higher load situations.
>>
>> Also, with the AC coupled solar in an off grid case, what is the
>> likelyhood of reaching Absorb daily or at least a couple times a week?
>>
>> The bottom line is to know the likely solar production kWh. The load kWh
>> and try to use just a bit of the battery storage kWh to keep the batteries
>> viable and reduce the electric bill without sacrificing the backup
>> capacity. OpticsRE can help fine tune these settings.
>>
>> Thank you,
>>
>> Maverick
>>
>> Maverick Brown
>> Off-Grid Solar Commander since 2006
>> Maverick Solar Enterprises, Inc.
>>  • Solar Commander Remote Power
>>  • SunFlow Systems Cathodic Protection
>> maverick at mavericksolar.com
>> 512-460-9825
>>
>>
>>
>> On Apr 25, 2024, at 5:57 PM, Dave Tedeyan via RE-wrenches <
>> re-wrenches at lists.re-wrenches.org> wrote:
>>
>> 
>> A minor update here. I had the grid zero DOD volts set to 48, and the low
>> battery cut out was set to 47.2v. But the homeowner told me that their
>> loads cut out at some point. Does anyone know whether it is possible that
>> Outback would be using a temperature compensated voltage for one of those
>> setpoints and a non-temperature compensated voltage for the other one?
>>
>> Thanks!
>> -Dave
>>
>> On Wed, Apr 24, 2024, 3:33 PM Dave Tedeyan <dave at sungineersolar.com>
>> wrote:
>>
>>> Maverick and Steve,
>>>
>>> Thank you much for pointing me in the right direction here. I was
>>> looking at the Radian setting and not the Mate3S settings. I've decided to
>>> use the flextime schedule to have it go to grid zero mode at night when we
>>> will not be exporting any solar power anyway. It really does not matter in
>>> this case whether the batteries get recharged by the grid or from the AC
>>> coupled solar.
>>>
>>> Cheers,
>>> Dave
>>>
>>> On Tue, Apr 23, 2024 at 5:25 PM Steve Higgins via RE-wrenches <
>>> re-wrenches at lists.re-wrenches.org> wrote:
>>>
>>>> Yes, Grid Zero would work, but the customer wouldn't be selling power
>>>> to the utility.   You could program the Radan to sell more power by
>>>> lowering the sell voltage. I would get aggressive with it for at least
>>>> 20-30 cycles to see if you can recover some capacity. Ideally, to recover
>>>> lost capacity from lead batteries, you want to do 50-80% cycling for at
>>>> least 5-10 cycles.
>>>>
>>>> I would be cautious about HBX mode, its issue, and why this mode should
>>>> have died with the old Trace Eng inverters... HBX mode tends to kill
>>>> battery banks if left there too long or you are not getting the battery to
>>>> 100%. The problem with HBX mode is that there is no way to control absorb
>>>> timers, so the batteries get to the 80-85% range but never get to full; if
>>>> the batteries are lead, this is going to create sulfation problems, and if
>>>> AGM will end up in severe swelling.    If I remember correctly, you can
>>>> adjust the delay timer for HBX, which should be equal to the programmed
>>>> Absrob timers, but I don't know if they killed this in the new firmware.
>>>>
>>>>
>>>>
>>>> <http://www.rollsbattery.com> <http://www.rollsbattery.com>
>>>> <http://www.rollsbattery.com> <http://www.rollsbattery.com>
>>>> <http://www.rollsbattery.com> <http://www.rollsbattery.com>
>>>> <http://www.rollsbattery.com> <http://www.rollsbattery.com>
>>>> <http://www.rollsbattery.com> <http://www.rollsbattery.com>
>>>> <http://www.rollsbattery.com> <http://www.rollsbattery.com>
>>>> <http://www.rollsbattery.com> <http://www.rollsbattery.com>
>>>> <http://www.rollsbattery.com> <http://www.rollsbattery.com>
>>>> <http://www.rollsbattery.com> <http://www.rollsbattery.com>
>>>> Steve Higgins ⋅ Technical Services Manager
>>>> t +1.902.597.4020  m +1.206.790.5840
>>>> f +1.902.597.8447  e steve at surrette.com
>>>> <http://www.facebook.com/RollsBattery>
>>>> <https://www.youtube.com/user/RollsBattery>
>>>> <https://www.youtube.com/RollsBatteryEngineering>
>>>> <https://www.youtube.com/RollsBatteryEngineering>
>>>> <https://www.youtube.com/RollsBatteryEngineering>
>>>> <https://www.linkedin.com/company/rolls-battery-engineering>
>>>> <https://www.linkedin.com/company/rolls-battery-engineering>
>>>> <https://www.linkedin.com/company/rolls-battery-engineering>
>>>> <http://www.instagram.com/RollsBattery>
>>>> <http://www.instagram.com/RollsBattery>
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>>>>
>>>> On Tue, Apr 23, 2024 at 1:53 PM Maverick Brown via RE-wrenches <
>>>> re-wrenches at lists.re-wrenches.org> wrote:
>>>>
>>>>> You can do it in one of several easy ways.
>>>>>
>>>>> HPX mode on the Mate. High Battery transfer. When the battery voltage
>>>>> and/or SOC is above the setpoint drop the grid. When the battery voltage or
>>>>> state of charge goes below the setpoint pick up the grid. This case the
>>>>> Mate  is doing the driving.
>>>>>
>>>>> Also available is Grid Zero mode where the inserter decides to zero
>>>>> the loads based on battery voltage and AC amp load. Then you would set the
>>>>> ReBulk set point on the inverter charger to trigger charging the batteries
>>>>> instead of zero AC loads.
>>>>>
>>>>> The third choice is to program something called FlexTime where you set
>>>>> the schedule of the AC input mode from grid tide to red zero or off grid,
>>>>> etc.
>>>>>
>>>>> It’s the system is on OpticsRE, you can adjust the settings fine-tune
>>>>> to get the best performance out of those Northstar batteries.
>>>>>
>>>>> I just decommissioned a 36 battery group of Northstar batteries after
>>>>> 13 years and most of them are still viable.
>>>>>
>>>>> As a precaution, For AC coupling, I also install a high battery AUX
>>>>> port controlled relay that drops the AC coupling input circuit.
>>>>>
>>>>> Thank you,
>>>>>
>>>>> Maverick
>>>>>
>>>>> Maverick Brown
>>>>> Off-Grid Solar Commander since 2006
>>>>> Maverick Solar Enterprises, Inc.
>>>>>  • Solar Commander Remote Power
>>>>>  • SunFlow Systems Cathodic Protection
>>>>> maverick at mavericksolar.com
>>>>> 512-460-9825
>>>>>
>>>>>
>>>>>
>>>>> On Apr 23, 2024, at 3:36 PM, Dave Tedeyan via RE-wrenches <
>>>>> re-wrenches at lists.re-wrenches.org> wrote:
>>>>>
>>>>> 
>>>>> Hi All,
>>>>>
>>>>> I have an AC coupled Radian that is used to back up certain loads when
>>>>> the grid is down. It is paired with the Northstar Blue (Outback) batteries.
>>>>> The system sits in float nearly all the time. During a recent grid outage,
>>>>> the batteries had less than half the capacity that I would have expected,
>>>>> and they are only about 3.5 years old with very few cycles on them.
>>>>>
>>>>> I tried to talk to Outback about it, which seems to not be possible
>>>>> anymore. I did talk to Northstar, and they recommend not leaving the
>>>>> batteries in float all the time.
>>>>>
>>>>> I am wondering if anyone knows of a way to force the Radian to
>>>>> automatically discharge the batteries to a certain voltage ideally once a
>>>>> week, but could do daily. Essentially, I would like to utilize a time of
>>>>> use schedule where I can force the radian to not use the grid and just use
>>>>> the battery to power the loads for a little while. Ideally this would be
>>>>> automatic, and not require the customer to go through the grid breaker
>>>>> every once in a while. It seems that from the manual, I need to keep the
>>>>> Radian in Grid Tie mode in order for it to be able to sell excess PV back
>>>>> to the grid. Any ideas?
>>>>>
>>>>> Thanks!
>>>>> -Dave
>>>>>
>>>>> --
>>>>> [image: Logo] <https://www.sungineersolar.com/>
>>>>> Dave Tedeyan, P.E.
>>>>> Owner | Sungineer Solar
>>>>> p: he | him | his
>>>>> a: 1653 Slaterville Rd. | Ithaca, NY 14850
>>>>> w: www.sungineersolar.com <http://www.sungineersolar.com/>
>>>>> c: (607) 270-0370
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>>>
>>> --
>>> [image: Logo] <https://www.sungineersolar.com/>
>>> Dave Tedeyan, P.E.
>>> Owner | Sungineer Solar
>>> p: he | him | his
>>> a: 1653 Slaterville Rd. | Ithaca, NY 14850
>>> w: www.sungineersolar.com <http://www.sungineersolar.com/>
>>> c: (607) 270-0370
>>>
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>
> --
>
>
>
> Mac Lewis
>
> *"Yo solo sé que no sé nada." -Sócrates*
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-- 
[image: Logo] <https://www.sungineersolar.com/>
Dave Tedeyan, P.E.
Owner | Sungineer Solar
p: he | him | his
a: 1653 Slaterville Rd. | Ithaca, NY 14850
w: www.sungineersolar.com <http://www.sungineersolar.com/>
c: (607) 270-0370
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