[RE-wrenches] Odd battery charging behavior with Outback inverters

[Steve Higgins]

Good Morning Everyone,

The graphs look like something is bypassing the absorb timers.   I haven't
been at Outback for a long time now, but from my experience, this can be
caused by the FNDC, end amps programming of the FM Controllers,  or the
operating mode of the inverter.

On the FM Charge Controllers:

In the Advanced menus are the End Amps settings; this should be programmed
to about .5 to 1% of the battery bank capacity at the most.  If the absorb
timers are over 4 hours, I would defeat this setting altogether, especially
if they charge lead batteries.   The issue with this setting is most lead
manufacturers want the current going into the battery under charge to fall
to less than 2-3% for 60 mins.   The timer in the FM's is only 3 mins and
is not programmable.

On the FNDC:

Still, to this day, I find FNDC installations that are not correctly
programmed, even from experienced installers.  It does not help that the
FNDC was a very misunderstood product.

The FNDC has 5 Settings that Matter: Battery Capacity, End Amps, Parameters
Met Time, Parameters Met Voltage, and Battery Charge Factor%.

Battery Capascity = C20 Battery Capascity.
End Amp 2-3% of the C20 rate

The settings that trip up most are met voltage, Met Time, and BCF%.   The
Met time for FLA, AGM, and GEL should be 45 to 60 mins. For LFP, it should
be around 30 mins.   It could be 45 to 60 minutes if you have over three
parallel strings of LFP batteries. A bit longer will allow for better
balancing between strings.

Parameters Met Voltage should be one step under the target absorb voltage.
 So, if you charge 59.2, this should be set to 58.8.

As for the Mode of the inverter, if the inverter is attempting to support
or grid sell, these modes will shorten the charging and bypass the Absrob
timers depending on how low the battery voltage dropped and for how long.
 In the old days, this used to be on only the GT-version inverters; now,
it's present in all of them. It just depends on what mode the inverter is
programmed to operate in.

[image: image.png]

For a straight off-grid system, generator mode is the correct mode, but
it's been a while, and I would have to check the OB documentation as to
what mode to operate in.

Contact me offlist or call me, and maybe I can better explain it...

I do have an optics account (Steve at surrette.com). If you invite me to view
your setup, I may be able to take a look and help find the setting(s)
causing this, but I would look first for the above-mentioned issues.

One last thing: it could be a failing battery cell or connection issue, as
this would also trigger end amps terminations early.  The problem with this
is you have a lot of installs doing the same thing, so this is a settings
issue rather than failing cells.

Hope this helps!

<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>
------------------------------
CONFIDENTIALITY: The information transmitted herein is intended only for
the addressee and may contain confidential, proprietary and/or privileged
material. Any unauthorized review, distribution or other use of or the
taking of any action in reliance upon this information is prohibited. If
you receive this email in error, please contact the sender and delete or
destroy this message and all copies.
------------------------------


On Fri, Jan 12, 2024 at 4:33 AM Mac Lewis via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> William,
>
> This is a very timely question, I have been seeing the same thing.  I also
> don't allow any Flexnet interference in charging.  I went to investigate a
> site yesterday and figured this one out.
>
> It turned out that the Flexnet was uncalibrated by about 1V on the low
> side.  This was a Lithium site and so there was not significant absorb time
> and that 1 V is very significant.  The solar controller and Radian were
> calibrated properly so it looked on Optics as though we were never getting
> full but we were.
>
> The Flexnet is a real mixed bag.  Its great to have the info but I don't
> like the difficulty of calibration (loose nuts in the casing) and that the
> Mate defaults to using its voltage meter.  We try to calibrate these as
> closely as possible.
>
> One thing I've noticed when I'm following up others work is that the
> majority have incorrectly wired/programmed Flexnet DC.  They will not have
> the appropriate shunts activated and so the system constantly reads 100%.
> A lot of these systems are installed using Outback prewired panels (Im not
> sure who builds these).
>
> If your customer is savvy, you can have them unplug the cable from the Hub
> that feeds the Flexnet.  If the voltage changes significantly, then the
> calibration could be the issue.
>
> Please keep us in the loop on what you are finding.
>
> On Thu, Jan 11, 2024 at 9:46 PM William Miller via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
>> Friends:
>>
>>
>>
>> I got a call from a client inquiring as to why his generator was starting
>> every morning, even though no one was staying at the property and there was
>> decent, albeit winter, sunshine.
>>
>>
>>
>> While looking into it I noticed that when his generator did run the
>> battery voltage did not stay at absorb level for the prescribed time period
>> as set in the battery charging settings.
>>
>>
>>
>> Outback tech support said that, lacking a better theory, it might be
>> possible the FNDC could be affecting the charge settings.  I do not allow
>> FNDCs to control generator run, so this seemed unlikely.  However I had no
>> better idea and am being not much of a fan of the FNDC, I agreed to unplug
>> it.  There was no change in the generator charging voltage profile made by
>> this.
>>
>>
>>
>> I got curiouser and started looking at other Outback sites.  All of my
>> normal Outback off-grid systems with both Radian and VFX inverters are
>> exhibiting the same problem.
>>
>>
>>
>> I know this is kind of in the weeds, but that is what we are here for,
>> right?  I made a little web page about this issue to easily share
>> information and graphics.  Here is the link
>> <https://millersolar.com/MillerSolar/case_studies/38-Radian_Charging/Outback_Charging.html>
>> .
>>
>>
>>
>> This issue has serious implications for my clients.  The charging
>> profiles seen are not good for these batteries.  Eventually the
>> deficiencies in the charging regime will shorten the life spans of very
>> expensive batteries.
>>
>>
>>
>> I am not very informed about lithium batteries, but I would be interested
>> if this profile is bad or not for lithium batteries.
>>
>>
>>
>> I am hoping this is not a design or programming defect.  I would be
>> interested in any shared experience.  Maybe some of you could glance at
>> your Optics displays and see if you are seeing the same thing.  All input
>> is very much appreciated.
>>
>>
>>
>> William Miller
>>
>>
>>
>> Miller Solar
>>
>> 17395 Oak Road, Atascadero, CA 93422
>>
>> 805-438-5600
>>
>> www.millersolar.com
>>
>> CA Lic. 773985
>>
>>
>>
>>
>> _______________________________________________
>> List sponsored by Redwood Alliance
>>
>> Pay optional member dues here: http://re-wrenches.org
>>
>> List Address: RE-wrenches at 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
>>
>>
>
> --
>
>
>
> Mac Lewis
>
> *"Yo solo sé que no sé nada." -Sócrates*
> _______________________________________________
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: RE-wrenches at 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
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20240112/9ccca3a4/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image.png
Type: image/png
Size: 66216 bytes
Desc: not available
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20240112/9ccca3a4/attachment.png>