Isolating my solar panels x 2

[albertramsbot]

The lead from my solar has fallen out of my Victron MTTP controller but I dont want to touch it putting it back in as its sparking a lot. My only thoughts are that I could cover the panels up with boards or something

Or is it next to nothing in amps and volts to worry about

Thanks

 

[Richard n Ann]

It's only about 19v. It will probably spark as you shove it in the connector but it's harmless. (unless you've got a gas leak )

 

[Stealaway]

Cover it with a carpet or mat.
Install one of these for future use while you are at it

Pardon our interruption...

 

[Jimbohorlicks]

As it's loose ,put an inline fuse holder in place with a 20 amp fuse.easy to unplug then for any future maintenance.

 

[ontheroadagain]

Fix it at night.

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[Badknee]

Fix it at night.

Brilliant idea, but an in-line fuse would have been a better one but that would have spoilt a good gag.

 

[albertramsbot]

I think it is more than 19V, it was 38V the other and it was raining

 

[albertramsbot]

I wonder what isolator I need? I have two panels that are about 5 feet long and 3 feet wide. I have a 24 V system so would imagine that the panels are wired in series. Pretty sure they are, however the previous owner has used red wires for everything

 

[autorouter]

The voltage of the panel is determined by the number of cells wired in series. Count the cells. Popular layouts are 9 x 4, 10 x 6 and 12 x 6. Then call it 0.5V per cell, so that's 18V, 30V and 36V. Obviously that's just an estimate, depending on the brightness of the sunlight, but it'll give you a ballpark figure.

Once you know the panel voltage, if you measure the voltage at the controller, you should be able to tell if the panels are wired in series or parallel. For series, the voltages add, for parallel, the voltage is the same as one panel.

The voltage will need to be about 32V at least, to charge a 24V battery.

 

[albertramsbot]

Thanks, I will have a look tomorrow. My Victron app seems to have the ability to switch from 24v to 12v. And I have to say I am confused by that. I assume that this should just be left on 24v. If the system is in series - thanks

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[Tombola]

And the isolator switches mentioned above are really only ygood for up to about 40v

 

[autorouter]

My Victron app seems to have the ability to switch from 24v to 12v. And I have to say I am confused by that. I assume that this should just be left on 24v. If the system is in series - thanks

The Victron solar controller is supposed to automatically recognise if the battery is 12V or 24V. But you have to connect it in the right sequence for this to happen. Disconnect both battery and panels. Connect the battery, then connect the panels.

 

[albertramsbot]

The voltage of the panel is determined by the number of cells wired in series. Count the cells. Popular layouts are 9 x 4, 10 x 6 and 12 x 6. Then call it 0.5V per cell, so that's 18V, 30V and 36V. Obviously that's just an estimate, depending on the brightness of the sunlight, but it'll give you a ballpark figure.

Once you know the panel voltage, if you measure the voltage at the controller, you should be able to tell if the panels are wired in series or parallel. For series, the voltages add, for parallel, the voltage is the same as one panel.

The voltage will need to be about 32V at least, to charge a 24V battery.

I have two 12 x 6 panels, so 36v each in series to produce 72V?? The max from the app is around 70V today its 38v but they need cleaning badly

 

[autorouter]

I have two 12 x 6 panels, so 36v each in series to produce 72V?? The max from the app is around 70V today its 38v but they need cleaning badly

Yes, if you get 70V from the panels then they must be in series. These 12 x 6 panels are sometimes called '24V' panels because one panel can charge a 24V battery through a simple PWM controller. They are normally wired in parallel on a motorhome, but that's mainly because of the shading problem - a bit of shade on one panel can reduce the power from both panels to a surprising extent. In parallel it only affects one panel. If you are aware of that you can work round it.

 

[Guigsy]

At this time of year, wait until it's cloudy or work at any time other than 11am to 1pm. Or just put anything, even a placemat, on the solar panel. That way, there'll only be a few watts max anyway.

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[albertramsbot]

And the isolator switches mentioned above are really only ygood for up to about 40v

Can you tell me why only 40V as I thought that the amperage would be the important aspect of isolation. Can you point me in the right direction as my solar can produce 70V. I would also like some hefty ones to isolate the 100amp 24V batteries and 240V hookup - cheers for your help