Blown up Kid ?

[mat]

Hi,

After my first post few days ago for a breaker problem, i now have a much worst problem...

So,i'll try to explain everything without omissions.

I thought my popping breaker was a problem linked with my firmware update.
After changing wires from Kid to batteries (via said breaker), no tripping for two days...

The thing is : while i was changing wires, i also installed load wires, with a plan in mind. I have to explain here that i have 2 kids, result of bad planning : i was hoping at first to have one for solar and one for hydro, but after seeing that our creek doesn't have enought water in summer, when we need the most power, we decided to go completely solar. So i had this second Kid still in his box, a spare 12v battery, and after seeing that some folks here were successful with that, i planned to use pwm divert on my first Kid (48v system) to go to second Kid and at last be able to store/use some of this wasted power during absorb/float...
I installed that yesterday, and it seemed to work ok.
I limited load ouput at 2amps/48v, and 8amps input on the 12v Kid.
As 48v system was in float, everything was ok. When some clouds or loads (fridge) came, it started to go quicly from float (so charging 12v battery) to floatMppt, stopping to charge as not enought amps in.
Another thread from Brian (http://kb1uas.com/mnsforum/index.php?topic=2168.0) mentionned that his system had problem with his load (a water heater) as pwn was switching on and off too fast. He gave the setting that Midnite told him.
This morning, after seeing that breaker hasn't tripped, i entered the same settings for pwm divert (quote :'I used PWM Divert using an offset of -.8 and a width of .5.  This keeps the PWM load on while protecting the batteries for my system.")...

About 2 hours later, while i believe the 48v system was still in bulk (2 fridges and washing machine running), i went to check : dead screen, no breaker tripped, no fuse blown, no way to put my Kid back on...

So my question is : did i kill my Kid or is it the breaker not tripping/firmware problem that did it ?

I'm 2 months out of xarranty, so i suspect any repairs if possible will be on me, but still i'd like to know (and understand) if i did something stupid or if it's a firmware/breaker problem and if my second Kid is also at risk ?

Thanks anyone for inputs, but i'm really waiting for an answer from Midnite.

Mat

Edit : i changed the title as apparently nothing to do with the new firmware...

[TomW]

I would say, in general, using a battery as a source voltage for any MPPT controller is a Bad Thing [TM].

A battery is just too stiff for such use.

Added to the fact you were going from 48 V. to 12 V. probably was not ideal, either.

You should contact Ryan at Midnite ryan@midnitesolar.com He can help sort it out pretty quick.

I will point this out to him and see if he can respond here.

I think you may have let the magic smoke out of The Kid and it may need to go back to the factory to get it replaced. Luckily, even some user errors may be covered  under the warranty. Never known these guys to split hairs on warranty issues but it is not my call.

I will poke Ryan on this.

Tom

[mat]

Thanks Tom,

I tried to fill the form to contact Midnite, but not having a US address i couldn't send that request...

I have to say that i probably would never had the idea myself, but seeing that at least 2 forum members were successful with this... I thought i would give it a try... With all the breakers and fuses i never imagine something that Baaad would happen !

I'll wait for Ryan input...

Thanks again

Mat

[TomW]

Thanks Tom,

I tried to fill the form to contact Midnite, but not having a US address i couldn't send that request...

With all the breakers and fuses i never imagine something that Baaad would happen !

I'll wait for Ryan input...

Thanks again

Mat

Mat;

One thing most folks do not understand is that breakers / fuses protect wiring not devices! By the time a breaker reacts electronic devices will already have been damaged.

As far as others having done it, some folks like to push limits.

Best of luck with it.

Tom

[mat]

Well, explained like that... I have to admit you're totally right...

[Halfcrazy]

That is spot on Tom, fuses and breakers only keep us from burning the place down AFTER we blow up the devices

[mat]

Still, i'd like to understand if it's from the unusual/stupid (your choice) setup, the changes in settings (was working ok the day before, and as i said i think it was still in bulk so no pwm charging this morning), or a problem with my breaker (i read your comment about small number of trippings before loosing accuracy/ability. I've never heard that before. Anybody knows ? Still, my other Kid could be at risk then), or last and not very pleasant to imagine, i nasty bug in 1811 firmware (also with risks for other Kid)

I just had an answerfrom Ryan, he apparently thinks also about the "bad" load...

Will let you know...

Thanks

Stupid Mat...

[mike90045]

AFIK, MPPT mode can be used with batteries or other "stiff" voltage sources.   rough, but possible

But PWM cannot, as there is no internal component to limit current, other than the MOSFET, which costs much more than fuses or breakers.

[mat]

Some times ago, when i was still considering hydro for my second Kid, i read that :

"Note the position of the green 30 amp
Load fuse. When in the CLIPPER
position it will divert the incoming voltage
to the diversion load. When in the LOAD
position it will divert the battery voltage
to the diversion load."


My Kid doesn't have this Clipper fuse posts, so does it means it is 2 different versions (when i bought them, it was stated that wind/hydro modes would be available later with just a firmware update. No talk about different versions then, if i recall correctly (i'm quite doubting everything today...)).
Would have it made a difference if load current be taken from surplus input rather than batteries ?

Mat

[mat]

Hi,
Just a last update with this story...

So yes, Kid was blown up by me...
Others are lucky to use one to charge a 12v battery with a 24/48v bank, even if it's supposed to be Bad Idea... I wasn't lucky...

So as Midnite folks gave me a reasonnable price to repair it, it went to US and back.
Plugged it on 12v, and it said low voltage as it was apparently trying to find a 24v bank. So i did a factory reset. Once done, gzzz, it just fried dead !
I was a bit puzzled and contacted Ryan, again... Explained the story...

His answer came fast : probably something missed by repair tech guy, we'll send you a brand new one !

I had last year so much troubles with a warranty claim with a Taiwan brand, who refused to repair my inverter UNDER warranty, that all i can say is Thanks, Midnite guys ! Your support is great !

Have fun !

Mat