[RE-wrenches] Over voltage error message
bob at midnitesolar.com
bob at midnitesolar.com
Fri Jul 21 12:55:59 PDT 2017
The Classic is pretty good at catching spikes but it's a compromise in
design as to how high above the present
battery voltage a controller can quickly respond to a real rising
battery voltage and how often it will catch an
extremely fast noise spike and become a nuisance.
Another good test is, while a charge controller is running hard, turn
off the battery breaker to the charge
controller itself and watch the CC terminal voltage to see how high it
rises during that instance. Before the
CC turns itself off that is... That would be a worse case scenario
because the battery will not be holding the
voltage down at all. This method was used in the design of the Classic
but I haven't tried that in a while
but should be pretty good.
Regarding the "whip" effect (or the French version of the word), the
battery impedance should help
to slow down the battery voltage rise time after the grid or inverter
goes away but that time will vary.
The Classic won't log a high voltage unless it stays for more than like,
2 seconds or so but should catch
a high voltage within a second. Even if it does well, a battery that
rises fast to an overvoltage will
probably stay high because of the whip effect. Capacitors do this very
will too of course.
You could, I suppose, excess battery charge voltage back into the PV
array but we try NOT to do
this for various reasons. Either way, a short but not too high of
voltage spike (even 65V for 48V system)
should not hurt anything.
boB
On 7/21/2017 6:48 AM, Drake wrote:
> Hello boB and Steve,
>
> I haven't been able to make it to the site yet, but so far, no more
> reports of spikes. I plan to try boB's suggestion of shutting off the
> grid input while it is selling, to see what happens.
>
> The spike did only last one second, so I don't think it is a chemical
> whip effect. If the spike only lasted a fraction of a second, wouldn't
> the Mate 3 still show the event lasting a second, since that is its
> lowest level of granularity?
>
> The array size is 2240 W and the Concorde battery bank is 305 AH at 48
> V for a C/6.5 charge rate. The battery bank should have been fully
> charged. If the grid went down and the Radian quit selling during a
> heavy selling period, could that not cause a 1 second voltage spike,
> or should the Classic catch it instantaneously?
>
> Thanks,
>
> Drake
>
> At 11:49 PM 7/18/2017, bob at midnitesolar.com wrote:
>
>
>> The Classic can overshoot but not very much, normally.
>>
>> I would try this...
>>
>> Sell to grid while watching the battery voltage and then turn the
>> inverter breaker off
>>
>> and see what the battery voltage does. If the battery voltage rises
>> to the mid 60V range
>>
>> from a low sell voltage of around 52 or 53V, then something is really
>> amiss.
>>
>> If the system has been in service for some time, you might also check
>> the capacity of
>>
>> the batteries. They should not easily allow 65-ish volts. I don't
>> think that the
>>
>> FM's communication can respond to keep spikes from happening any better
>>
>> than it could without communications. Data packets just don't come
>> all that
>>
>> often.
>>
>> boB
>>
>> On 7/18/2017 5:25 PM, Jerry Shafer wrote:
>>> Wrenches
>>> The Outback system with grid connection would be programmed for grid
>>> connection all the way from the inverter to the Outback FM CC, using
>>> a midnite CC this option may not be possible resulting to a CC push
>>> if the grid disconnects resulting in a spike. the disconnect might
>>> be from settings to tight or as it was said utility spikes. You
>>> might thing that the battery bank should take it up but internal
>>> resistance in the battery or to it may prevent it. The other thing I
>>> would look at is connections, if there is any resistance in a
>>> connection this could happen.
>>>
>>> On Mon, Jul 17, 2017 at 2:36 AM, Drake
>>> <drake.chamberlin at redwoodalliance.org
>>> <mailto:drake.chamberlin at redwoodalliance.org>> wrote:
>>>
>>> Hello Wrenches,
>>>
>>> My client reported seeing an overvoltage error message on her
>>> Mate 3 on a Radian system. The Radian is selling to the grid and
>>> is being fed by a Midnite Classic 200. It has shown two spikes
>>> so far, the last one going to 67 volts and lasting 1 second. The
>>> batteries are Concorde AGM, 305 AH.
>>>
>>> Does this momentary spike seem like a problem or a warning of
>>> problems to come?
>>>
>>> Thanks,
>>>
>>> Drake
>>>
>>> _______________________________________________
>>> List sponsored by Redwood Alliance
>>>
>>> List Address: RE-wrenches at lists.re-wrenches.org
>>> <mailto:RE-wrenches at lists.re-wrenches.org>
>>>
>>> Change listserver email address & settings:
>>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>>
>>>
>>> List-Archive:
>>> http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html
>>>
>>>
>>> List rules & etiquette:
>>> www.re-wrenches.org/etiquette.htm
>>> <http://www.re-wrenches.org/etiquette.htm>
>>>
>>> Check out or update participant bios:
>>> www.members.re-wrenches.org <http://www.members.re-wrenches.org>
>>>
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> List sponsored by Redwood Alliance
>>>
>>> List Address:
>>> RE-wrenches at lists.re-wrenches.org
>>> <mailto:RE-wrenches at lists.re-wrenches.org>
>>>
>>> Change listserver email address & settings:
>>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>>
>>> List-Archive:
>>> http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html
>>>
>>> List rules & etiquette:
>>> www.re-wrenches.org/etiquette.htm
>>> <http://www.re-wrenches.org/etiquette.htm>
>>>
>>> Check out or update participant bios:
>>> www.members.re-wrenches.org <http://www.members.re-wrenches.org>
>>>
>>
>> _______________________________________________
>> List sponsored by Redwood Alliance
>>
>> 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
>>
>> List-Archive:
>> http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html
>>
>>
>> List rules & etiquette:
>> www.re-wrenches.org/etiquette.htm
>> <http://www.re-wrenches.org/etiquette.htm>
>>
>> Check out or update participant bios:
>> www.members.re-wrenches.org <http://www.members.re-wrenches.org/>
>
>
> _______________________________________________
> List sponsored by Redwood Alliance
>
> 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
>
> List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html
>
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
>
> Check out or update participant bios:
> 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/20170721/1590d49c/attachment-0003.html>
More information about the RE-wrenches
mailing list