How to kill your Kid !

[tecnodave]

I post this so you don't do the same thing!  Please don't try it.

I was refurbishing some batteries that were surplus from a local cell phone provider. I had just finished charging three 12 volt 105 amp hour CD Technologies AGM batteries in series. They were in float for a short while, but fully charged. I set mode to off. Batteries were at 43 volts and I had three Sharp NE-165 panels in series for 105 volt DC in from array. I reached for the breakers, MNPV's mounted in a big baby box to shut off the solar input but I fumble fingered and tripped the battery breaker instead.
There was a small flash of light around the input fuse area of the Kid and a puff of smoke came out around the fuse. I quick shut off the battery breaker, but too late, the damage had been done!

I am not sure just what happened but with large capacitors and huge inductor in the input section I assume that power dumped into something that could not handle it.

boB has said that it is important to shut off the solar input first then the battery breaker.  I have done that in the past but this time things did not go right.

After  reviewing block diagrams and schematics for solar controllers and buck converters I am pretty sure that is what happened.

After thinking about this for a while I am now doing a modified shutdown routine for my solar controllers which includes an extra step or two. Ihave noticed that when shutting off solar input when mode is  ON , that solar input voltage remains high even though the controller goes to resting! By pressing the enter button and forcing a sweep the voltage will drop quickly to approx 1/2 battery voltage.

So now my shutdown routine is :

Shut off solar input breaker,
Force a sweep,  ( mode must be on),
verify input volts drops down ,
Set mode off,
Shut off battery breaker.

I'm not sure that this modified procedure will help but it does drain away the high input voltage.
It sure can't hurt anything

Don't cook your Kid controller, be sure input power is off!

David

[ClassicCrazy]

Are you going to send it in for warranty repair ?
Doesn't seem like it should die from what you described  if the voltage of the PV is within design limits which sounds like it was.

Larry

[CDN-VT]

@ tecnodave

I had the same thing on one of my kids .
Warranty repair & a cap was changed when the smoke & oil  was set free !!!!

VT

[tecnodave]

VT & Larry,

It's all boxed up and will ship in the morning. It's one of the first beta's released for testing. I did it back in October but with many things going on I did not ship it.  I was operating well within limits si I was really surprised that it happened. The crew at midnite said I am still in warranty. I was the first to post when the beta program was started. This is its third visit back to Arlington, first time the original blue screen failed then that repair failed on the first day due to a faulty inductor that was installed when the unit was rebuilt. O well.....that's beta testing.....no regrets

David

[TomW]

Didn't those beta units have a full lifetime "dummy proof" warranty?

I also agree that as long as you were within voltage specs it should not let out the special smoke and oil!

Tom

[tecnodave]

TomW,

Yes those had a full lifetime dummy proof waranty, it was shipped this morning. I did not follow boB's advice fully by my error and am willing to take the consequences of that but I have been assured that this will be a warranty repair.

Does anybody have any opinion as to my modified shut down procedure. Basically by shutting off the solar input then forcing a sweep I am looking to discharge the stored energy of the inductor and capacitor , there by further protecting the controller?

David

[TomW]

TomW,

Yes those had a full lifetime dummy proof waranty, it was shipped this morning. I did not follow boB's advice fully by my error and am willing to take the consequences of that but I have been assured that this will be a warranty repair.

Does anybody have any opinion as to my modified shut down procedure. Basically by shutting off the solar input then forcing a sweep I am looking to discharge the stored energy of the inductor and capacitor , there by further protecting the controller?

David

My first thought was a high value bleeder resistor across the input like on the old time electrolytics sometimes had to ensure it wouldn't bite you after sitting unpowered for 6 months but that probably is not a good solution for this situation?

Old time tube solutions don't always apply to modern solid state gear. I cut my teeth on electronics with heaters driving electrons.

Just a thought

Tom

[ClassicCrazy]

I have a feeling that the only thing that is same on your Kid when it returns is the case.

Larry

[onanparts]

Old time tube solutions don't always apply to modern solid state gear. I cut my teeth on electronics with heaters driving electrons.

Just a thought

Tom

Hey! What he said. Them thar heater thing's mingling with electrons and stuff.

[RossW]

Not identical, but quite similar:


It's quite a while ago, but I think that one was the modulator.

..... while this one generated the 2KW carrier wave

[grgdgreek]

Nice!

[CDN-VT]

TomW,

Yes those had a full lifetime dummy proof waranty, it was shipped this morning. I did not follow boB's advice fully by my error and am willing to take the consequences of that but I have been assured that this will be a warranty repair.

Does anybody have any opinion as to my modified shut down procedure. Basically by shutting off the solar input then forcing a sweep I am looking to discharge the stored energy of the inductor and capacitor , there by further protecting the controller?

David

I shut off one of my kids when we get a week or two of RAIN , I can be wet for a few & no need to have the golf cart outside . So I bring it into a car garage & pull the solar & then the battery fuse. Last over winter ,the cart maybe saw  4 days out in 4 months . On reinstall of fuses , Battery & then solar & now drive it out into a sunny day I hope.

VT

[tecnodave]

Just got my fist kid back from MidNite, haven't hooked him up yet but I will before the weekend. He has been resting since October last year and I need to rewire my panels for the Kid,  I've been using a very old Trace C-40 with all panels in parallel but need to change config to 2 series 2 parallel for enough voltage for th Kid to work.

David

[CDN-VT]

Photo out the watch band & i'd swear Scotty  from the Enterprise was holding the Fluxcore

[Vic]

Now,  with handles!