Does anyone know the reason a that the SCC electronics are damaged by having the PV panels connected without the battery power source connected first? You always hear that you should connect the battery first before connecting the solar panel voltage and you should always disconnect the solar panels before removing the battery power. Anyone know of any articles with schematics that explain that issue?
SCC damage from PV connection without battery
- Thread starter TomTilly
- Start date
They are not damaged.
Try it and see what happens.
Will did and guess what?
SCC were not damaged by disconnecting the battery with the panels left connected.
Connecting the battery first is so the SCC recognises the battery as 12 or 24 volts etc.
Try it and see what happens.
Will did and guess what?
SCC were not damaged by disconnecting the battery with the panels left connected.
Connecting the battery first is so the SCC recognises the battery as 12 or 24 volts etc.
gnubie
Solar Wizard
- Joined
- Sep 20, 2019
- Messages
- 3,844
I've never seen one blow up personally but there's more to think about. Some controllers react badly not having a battery connected.
My own experience with MakeSkyBlue (cue the usual suspect) V117 controller is that without battery present they go loopy. The output zig zags up and down. It doesn't seem to damage the controller but if the output voltage exceeds the ratings of any devices you have connected those loads aren't going to enjoy it. The problem seems to revolve around poor algorithms in the firmware. This is moderated a little by the fact that the controller requires at least about 10V on the battery terminals before it will even turn on so you have to try hard to get into this situation.
It's not the only one that has regulation problems without battery, there are other bottom shelf units that I can point to. Better controllers behave differently.
Renogy Rovers (made by SRNE) won't apply power to their output terminals until they can sense battery voltage when in auto-detect mode. I did see the voltage momentarily spike up with a Rover li model if the battery was disconnected once the charger had turned on. That wouldn't have made voltage sensitive loads on it's output happy either.
Once you get into the higher end products like Victron, Outback etc, they behave very well.
My own experience with MakeSkyBlue (cue the usual suspect) V117 controller is that without battery present they go loopy. The output zig zags up and down. It doesn't seem to damage the controller but if the output voltage exceeds the ratings of any devices you have connected those loads aren't going to enjoy it. The problem seems to revolve around poor algorithms in the firmware. This is moderated a little by the fact that the controller requires at least about 10V on the battery terminals before it will even turn on so you have to try hard to get into this situation.
It's not the only one that has regulation problems without battery, there are other bottom shelf units that I can point to. Better controllers behave differently.
Renogy Rovers (made by SRNE) won't apply power to their output terminals until they can sense battery voltage when in auto-detect mode. I did see the voltage momentarily spike up with a Rover li model if the battery was disconnected once the charger had turned on. That wouldn't have made voltage sensitive loads on it's output happy either.
Once you get into the higher end products like Victron, Outback etc, they behave very well.
This thread was a challenge to find a SCC. that was damaged by that.
If you know of even one SCC that was damaged please let everyone know.
Looks like it does not happen.
Trying to destory my SCC's: I can't do it!
So I took every EPEver/Victron/PWM/Renogy solar charge controller, and tried to fry it by connecting it only to solar panels, and not to a battery... guess which one survived? EVERY SINGLE ONE! I couldn't destroy any of them, and I left them connected to a high voltage array (80 volts) for 4+...
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