Should solar controller come on with just power from panels?

[RogerFoxTerrier]

My Epever solar controller is getting about 16.5v from the panel, but there's no sign of life until I also connect the battery. When I do so it tells me it's not charging...

Any idea what I'm doing wrong? Chat GTP said the incoming voltage has to be more than 5v greater that the battery (12.7v) so that might explain the lack of charge, but I'm confused about the lack of display.

Ta

 

[Boater Sam]

The battery should always be connected when the panels are producing current, you risk wrecking the controller otherwise.

 

[RogerFoxTerrier]

The battery should always be connected when the panels are producing current, you risk wrecking the controller otherwise.

Ah, maybe I've killed it then - it's been connected loads to the panels with the battery on and off.

 

[KevinV]

The battery should always be connected when the panels are producing current, you risk wrecking the controller otherwise.

This. Connect controller to battery, then panels to controller. If you're lucky your controller may have built in protection, if you're unlucky you've fried it.

 

[RogerFoxTerrier]

Well what a muppet. After sourcing a replacement controller, I had the same problem. Testing the polarity on the inputs from the panel I found they were simply the wrong way round, so old one back in, wires swapped over and hey presto - all good again!

Doh.

 

[DangerousPirate]

Well what a muppet. After sourcing a replacement controller, I had the same problem. Testing the polarity on the inputs from the panel I found they were simply the wrong way round, so old one back in, wires swapped over and hey presto - all good again!

Doh.

Are you still running them without connecting to the battery then? Well, congratulations. You have what we boaters call a "spare". Now that you've accquired the taste for it, you'll realise the weight of your boat will double because now you'll get one for every item you have on board. I even have spare whisky.

 

[RogerFoxTerrier]

Are you still running them without connecting to the battery then? Well, congratulations. You have what we boaters call a "spare". Now that you've accquired the taste for it, you'll realise the weight of your boat will double because now you'll get one for every item you have on board. I even have spare whisky.

LOL - no it's connected to the battery and I'm careful with that now, even though it evidently didn't do any harm.

I'm probably going to use it in the shed to charge the eBike - but at about 12p per charge it's going to be a long payback!

 

[DangerousPirate]

LOL - no it's connected to the battery and I'm careful with that now, even though it evidently didn't do any harm.

I'm probably going to use it in the shed to charge the eBike - but at about 12p per charge it's going to be a long payback!

Well, if you use the bike enough, you'll live longer. Soo ..... possible?

 

[Refueler]

RTM ... Manuals say - Connect controller to battery first before connecting panel. I have heard reported that once the 'initial' connection has been made - that battery or panel first after is possible. But its better to not test that ...

Battery first.

 

[Sea Change]

I killed an Epever MPPT by accidentally disconnecting the battery whilst the panels were in full sun. Expensive mistake.
I've since learned that Victron MPPTs have protection against this... another reason to go blue...

 

[alahol2]

As a corollary to this question does anything untoward happen if an unconnected solar panel is exposed to full sun?

 

[vas]

when I was setting up the system on the boat, I did all panel/bat connection tests at night better safe than sorry!
OK, you have to wait to see the results but rather do that than having to fork out for another controller

 

[Sea Change]

As a corollary to this question does anything untoward happen if an unconnected solar panel is exposed to full sun?

Nope, as far as I'm aware it's fine.

 

[LiftyK]

Nope, as far as I'm aware it's fine.

Ok for mine too. My portable panels have to be unfolded and exposed to some sunlight in order to reach the connector. So far so good.

 

[PaulRainbow]

No problem having solar panels exposed to the Sun when not connected.

FYI, Victron MPPT controllers can be connected to the panels first, without harming them.

 

[Refueler]

As a corollary to this question does anything untoward happen if an unconnected solar panel is exposed to full sun?

Its similar to the old matter of the alternator blowing if switched off when engine running. But you can start and run an engine with alternator switched off fine.

The panels in the sun when not connected to anything are basically open circuit and nothing happens. But once you connect a controller or battery - you then close circuit and current flows.

As long as you connect battery to controller before panels - even in full sun - its fine ...

 

[PaulRainbow]

Its similar to the old matter of the alternator blowing if switched off when engine running. But you can start and run an engine with alternator switched off fine.

The panels in the sun when not connected to anything are basically open circuit and nothing happens. But once you connect a controller or battery - you then close circuit and current flows.

As long as you connect battery to controller before panels - even in full sun - its fine ...

This is not correct. How do you get a panel out of its packing box and connect it without it seeing any Sun ?

It's OK to have a panel in full Sunlight without it being connected to anything. If you disconnect it from the controller whilst the Sun is shining, nothing bad can happen.

 

[Refueler]

This is not correct. How do you get a panel out of its packing box and connect it without it seeing any Sun ?

It's OK to have a panel in full Sunlight without it being connected to anything. If you disconnect it from the controller whilst the Sun is shining, nothing bad can happen.

Paul ... read my post again ...

My post totally agrees with yours ..... if panel is not connected to anything - nothing happens .... go read it again.

 

[PaulRainbow]

Paul ... read my post again ...

My post totally agrees with yours ..... if panel is not connected to anything - nothing happens .... go read it again.

I was referring to "Its similar to the old matter of the alternator blowing if switched off when engine running." and "As long as you connect battery to controller before panels - even in full sun - its fine ..."

Unlike an alternator, nothing will happen to the panel if it's disconnected from the controller, it just becomes open circuit again.

Of course, as mentioned, some controllers might not like it.....

 

[Refueler]

I was referring to "Its similar to the old matter of the alternator blowing if switched off when engine running." and "As long as you connect battery to controller before panels - even in full sun - its fine ..."

Unlike an alternator, nothing will happen to the panel if it's disconnected from the controller, it just becomes open circuit again.

Of course, as mentioned, some controllers might not like it.....

Blimey Paul ... I was trying to illustrate a similar event .... that an alternator is fine if not connected (as with panel) while engine is running (full sun) ....

Doesn't take much to understand ..