How did adding two panels kill my Renogy MPPT40 CC?

softdown

Had four panels feeding 20 amps at 28 volts under ideal conditions. I wanted/needed to add two more panels for 30 amp charging. 

Cloudy conditions with the panels 90% covered up with a car cover. Figured that would protect the CC when I hooked up the six panels. Note - usually didn't worry about this before when hooking up 2 or 4 panels. 

CC quit recognizing panel feed. LED bulb is - lights out. The wires measure 40 volts coming into the charge controller.  What may have happened?

I disconnected two of the six panels. No change with charge controller. 


So I hooked up the 24V battery charger. Unconnected to AC power - big sparks when hooking it up, Like 3-4 times the usual size. Battery charger fan comes on over time but battery is not being charged. I am - flumoxxed. Three steps backward - Zero steps forward. Eventually I got the charger to charging. How? No idea - just kept fiddlin'. 

How did adding two panels kill my Renogy MPPT40 CC?

softdown

Afternoon Solar Grade: F- 

wellbuilt

I think the regency cc just freek out and stop working .
 I would look at my system and I would be getting no power then turn every thing off and back on and it would work for a few weeks then one day it would turn off again for no reason . 

  I change to a old morning star unit . 

  My unit worked for 3 years 
 I would pop for a out back fm80 so you have a back up 
 

Photowhit

You've been here a while, might give us enough info to work on the problem...

Sounds like you had 20 amps at 28 volts going into a MPPT type charge controller to charge a 24 volt battery bank?
That would already be to low a voltage to function properly.

softdown

Something going on with the combiners boxes, then combiner box I used. Though I measured 40 volts going into the CC - the led bulb stayed dark.

Tried another CC - still didn't work. So I knew the issue was the incoming current. After eliminating the combiner box it is working fine, Me and electricity - we don't always see eye to eye.

Photowit - I don't recall incoming 28 volts - I do recall incoming 31.4 volts being changed to ~ whatever battery voltage happens to be at the time. 

Two more panels for 30 amps instead of 20 amps would solve all issues. But using my combiner boxes somehow did not work. They are four into two boxes. A six into two would be far preferable.

I had a sneaky feeling that using two 2 into 1 boxes would backfire. It was an off day. I should never do critical work on an off day. 


No idea on the giant spark when hooking up the IOTA charger either. It always sparks but yesterdays was quite unique. Working fine now- had a normal spark this morning. Must have a capacitor that gets instantly charged when hooking up,

softdown

My electrical gremlin remains consistent. Happiness upon opening the door and seeing 23 amps of charging power - best ever. Then it noticed I was staring at it and sank to 8 amps until I left. I swear.