Do not disconnect under load?..

[Oscarpop]

Just fitting our solar panels to the boat.

They have some fancy connectors which allow the panels to be removed.

The power connectors have the words " do not disconnect under load" embossed on them.

Does this mean that you shouldn't disconnect them when the panels are generating power ie during sunlight ?

Or is it something else ?


Many thanks

 

[elton]

It means do not disconnect while something is drawing current from them.

 

[VicS]

Just fitting our solar panels to the boat.

They have some fancy connectors which allow the panels to be removed.

The power connectors have the words " do not disconnect under load" embossed on them.

Does this mean that you shouldn't disconnect them when the panels are generating power ie during sunlight ?

Or is it something else ?


Many thanks

There is a Youtube video that demonstrates what happens when a solar panel is disconnected under load but it looks as tho it is some form of motrorised device ... ie an inductive load that is being disconnected .
http://www.youtube.com/watch?v=bNzK0uJzDas

Id think that disconnecting from a battery if the panel was being used for battery charging would not cause a problem provided there was not a large current involved that would cause arcing in the connector
However I maybe wrong so cover the panel and there is no risk!

 

[Oscarpop]

Many thanks for that.

 

[emandvee44]

I was wondering how to tackle this problem as we have three new batteries to install. I decided to cover the panels, which are deck mounted,with thick black bin liners, taped down, and then watch the Fox display to see if the amps come down to zero (which you would expect)
I will choose a cloudy day or I might cook the panels (it does get hot and sunny down here, sometimes)

Michael.

 

[sailorman]

I was wondering how to tackle this problem as we have three new batteries to install. I decided to cover the panels, which are deck mounted,with thick black bin liners, taped down, and then watch the Fox display to see if the amps come down to zero (which you would expect)
I will choose a cloudy day or I might cook the panels (it does get hot and sunny down here, sometimes)

Michael.

its the same with windens, stop them prior to disconnecting them

 

[VicS]

its the same with windens, stop them prior to disconnecting them

They are inductive and have diodes within, like an alternator, so for the same reasons you should not disconnect while under load.

 

[[27631]]

disconnect in the dark...at night...although the black bin liner idea sounds good...

 

[elton]

"Under load" means having something connected to them, drawing current. It doesn't mean they've got to be in the dark.

 

[dmmbruce]

"Under load" means having something connected to them, drawing current. It doesn't mean they've got to be in the dark.

Elton, I'm sure you are right that the words mean that.

However the instructions that come with the panels use that phrase but then explain that the panels should be COVERED.

The example given on the last set of installation notes that I read even suggested putting a coat over the panel before disconnecting it.

Mike

 

[elton]

Elton, I'm sure you are right that the words mean that.

However the instructions that come with the panels use that phrase but then explain that the panels should be COVERED.

The example given on the last set of installation notes that I read even suggested putting a coat over the panel before disconnecting it.

Mike

I'm answering the OP's question about the instructions that came with his panels. What do you know about the OP's panels the rest of us don't know?

 

[VicS]

"Under load" means having something connected to them, drawing current. It doesn't mean they've got to be in the dark.

But surely the way to stop what ever that's drawing current from doing so, if you cannot disconnect while it is, is to stop the panel from supplying the current ..... by covering it up. ??????

 

[elton]

But surely the way to stop what ever that's drawing current from doing so, if you cannot disconnect while it is, is to stop the panel from supplying the current ..... by covering it up. ??????

I'm just interpreting what the instructions say: If there's no load on them, they can be disconnected, with no need to cover them.

 

[William_H]

Sorry I have been fiddling with solar panels for 30 years. I can't imagine any reason to be concerned about simply disconnecting the panel if you want to in direct sun shine while it is delivering current. Current is generally quite low so no real concerns about arcing at the disconnect. Is the manufacturer of the connector or panel simply trying to avert any sort of claim against them for failure?
I dunno sounds crazy to me. olewill

 

[rogerthebodger]

I have disconnected my solar panels many times with no ill effect.

6 of my 8 panels are connect through my master battery switch so every time I leave the boat they get turned off under load, normally Durban mid day sun.

As we all should know there must be a fuse of circuit breaker between the panel and battery and if that trips will disconnect the solar panel under load.

 

[st599]

If it's driving an inductive load, how is a fuse or circuit breaker going to help?

V=L.dI/dt

So as you unplug the current drops to 0 in a fraction of a second (so dI/dt is very large) meaning the induced voltage is very large possibly arcing the connector or damaging the PV cell.

The current is reduced, so a fuse may not blow.

 

[charles_reed]

There is a Youtube video that demonstrates what happens when a solar panel is disconnected under load but it looks as tho it is some form of motrorised device ... ie an inductive load that is being disconnected .
http://www.youtube.com/watch?v=bNzK0uJzDas

Id think that disconnecting from a battery if the panel was being used for battery charging would not cause a problem provided there was not a large current involved that would cause arcing in the connector
However I maybe wrong so cover the panel and there is no risk!

From experience - you can get an arc, even when disconnecting from batteries - but I'm talking in excess of 200 watts of PV at 37N in summer.

 

[lw395]

The instructions are probably written with house installations in mind, where the panels are often connected in series.
Therefore there could be a 'dangerous' voltage when unplugging.
The inverter might also be very inductive, you might get a jolt off that side.
Even a small jolt can be fatal if you're on a roof.
It might be worth covering the panels on a bright day, not applicable today....