[RE-wrenches] Classic 150 100 amp output breaker tripping?????

[boB at midnitesolar.com]

Allan,  No, not suggesting to get rid of E-panels or wiring centers.  
They aren't optimum though,
electrically speaking.  My suggestion was more of a technical one 
intended to illustrate a
way of wiring to reduce stress on (most) MPPT charge controllers. I 
should not have said
it was a a good practice "these days"...  That was kind of dumb for me 
to say.

With the battery electrically a few feet away from the battery buses, 
that tie the inverter
and charge controllers together (plus other components), the CCs and 
other energy sources
can be momentarily short-circuited by the inverter (various reasons)...

If that bus was right at the battery terminals, then it's not nearly as 
much stress on
things.  This is because the battery keeps a low impedance voltage point 
between
the two different systems....    This assumes that the batteries are in 
decent health.

You probably won't notice any issues wiring just the way you have been 
doing things
all these years so I would just keep doing what you are doing. With 
proper over current
protection (OCP), stress and reliability won't be an problem.

But, it doesn't hurt to  keep this concept in the back of your mind when 
thinking about
how things work.

boB


On 10/31/2015 6:12 PM, Allan Sindelar wrote:
> boB,
> I appreciate your contribution to this discussion, but it brings up a 
> couple of issues for me.
>
> - You have suggested that "A good wiring practice these days is 
> to...wire the controller's battery terminals close or right at the 
> battery terminals." This goes against all modern good practices of 
> which I'm aware. We have long accepted as standard a single pair of 
> battery cables, with all DC input and distribution handled within the 
> power center (I've heard that some people refer to these things as 
> 'E-Panels'). It's the only way to effectively run all current through 
> a shunt on the negative, and through proper overcurrent 
> protection/disconnects on the positive.
>
> I must not have understood what you meant, as it sounds like you're 
> suggesting abandoning the entire E-Panel approach. What am I missing here?
> Thanks, Allan
>
> *Allan Sindelar*
> allan at sindelarsolar.com
> NABCEP Certified PV Installation Professional
> NABCEP Certified Technical Sales Professional
> New Mexico EE98J Journeyman Electrician
> Founder (Retired), Positive Energy, Inc.
> *505 780-2738 cell*
>
> **
>
> On 10/29/2015 7:10 PM, boB at midnitesolar.com wrote:
>> On 10/29/2015 5:02 PM, Jay wrote:
>>> boB,
>>> Is the OCP still being used and does it work in both directions?
>>> JAY, Peltz power
>>
>> Hi Jay.  Yes, the OCP you refer to is still there.  This particular 
>> OCP though is a hardware
>> fast OCP intended to protect the controller against large load surges 
>> on the battery
>> side of the controller...   This usually happens when battery cables 
>> are long and
>> the inverter(s) are connected electrically close to the controller, 
>> thereby drawing
>> huge amounts of current from the Classic than from the battery when 
>> the inverter
>> is turned on, charging its input capacitors or something with huge AC 
>> loads.
>>
>> A good wiring practice these days is to, if convenient at least, wire 
>> the controller's
>> battery terminals close or right at the battery terminals. Then, when 
>> an inverter
>> is either turned on and giving a momentary short circuit to the 
>> battery lines, that
>> current will come from the battery rather than the controller's 
>> electronics.
>>
>>   Larger cables won't necessarily fix the problem due to battery 
>> cable inductance.
>>
>> The 150s and 200s rarely need the OCP circuitry.  The 250 is the one 
>> the OCP was
>> really designed for but we put it into all of the controllers.
>>
>> There is also over current protection going the other way but is not 
>> a microsecond
>> timed protection.  Plain old fast or slow ramping up surges like 
>> we're talking about is easy to
>> control, normally.
>>
>> Breaker tripping like this is extremely rare, IF it is from this kind 
>> of current spikes due to
>> generator startup.   I would suggest to be safe and bring another 
>> controller up just in case.
>>
>> Might be a bad controller but I just don't know without logging or 
>> observing it happening
>> with a scope and a current probe.  I've seen some very strange things 
>> happen.
>>
>> boB
>> Sent from my iPhone
>>>> On Oct 29, 2015, at 4:19 PM, "boB at midnitesolar.com" 
>>>> <boB at midnitesolar.com> wrote:
>>>>
>>>> Larry, because these MPPT CC's are bi-directional (for 
>>>> efficiencies' sake), they can convert a large current
>>>> at the battery side to a smaller current at the PV side if not 
>>>> adjusted right.  Normally this is just taken
>>>> care of and reduced to a bare minimum by the controller watching 
>>>> the voltages and currents carefully.
>>>> It is technically possible though for things to not work exactly 
>>>> correctly.  I am not saying that this is
>>>> for sure happening, but it is possible.   The ramping up in battery 
>>>> voltage from the chargers should
>>>> be plenty slow enough for this not to be a problem but I am wildly 
>>>> speculating that this could happen
>>>> and cannot rule it out.  There may of course be something else 
>>>> completely different happening here
>>>> though.
>>>>
>>>> If CBI breakers are being used, these are known to be extremely 
>>>> fast at tripping when overloaded.
>>>>
>>>> Also, what, if any SPDs are connected to the system ?
>>>>
>>>> boB
>

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