Solar panels

[Cowgirl]

Due to a change in work arrangements I am no longer driving 2 hours a day, more like 15 minutes.  I currently plug in a 2.4 volt solar panel during the day, my question is will it increase my 12volt Battery charge i.e from 11 to 12 during the day or does it just maintain the charge as is when I turned the engine off?

[Mjolinor]

A 2.4 volt solar panel will just flatten your Battery unless you have other components to stop it.

[Roy124]

Tut tut @Mjolinor think latterly:

https://www.wilcodirect.co.uk/product/battery-chargers/ring-12v-2-4-watt-solar-battery-maintainer-rl-rsp240/RL-RSP240

And to answer Caroline,  it depends.  Under ideal sun and lighting conditions your panel will provide up to 2.4 Watts.  That will probably be a above the residual power requirement. 

Where your conditions are less than ideal (cloudy, shade, aspect) it might just maintain the charge  state.

[Mjolinor]

Guilty as charged. 😞

To be fair though it does depend on the voltage. Is it reasonable to assume that it is 12 volt? Any more reasonable than assuming the question asked was correct?

I do think that if your Battery is 11 volts after a 15 minute drive then your Battery is on the way out.

[Derek.w]

I am using a 30 watt solar panel at the moment have tried lower wattages like a 5 watt it only drained my Battery even more than what it charged during the day.

At the moment out of 7 days I have just one with good sunshine.

I sugest you use a mains charger when you at home if its possable & your solar panel when at work at least during the summer months in the winter it just probably be a extra drain on the Battery.

[Cowgirl]

57 minutes ago, Mjolinor said:

Guilty as charged. 😞

To be fair though it does depend on the voltage. Is it reasonable to assume that it is 12 volt? Any more reasonable than assuming the question asked was correct?

I do think that if your battery is 11 volts after a 15 minute drive then your battery is on the way out.

11 volts was an example, I have not checked the voltage of my Battery.

[Cowgirl]

Currently I don’t have a problem with the Battery, I’m just trying to prevent it.

Sorry for being stupid but why would a solar charger meant for maintaining a Battery cause it to be a drain and possibly flatten it?

[jthspace]

A solar panel designed to provide a charge to a Battery will have a diode in circuit that only allows a charge to pass to the Battery and will block current flowing from the Battery to the panel - like a one-way valve. It won’t drain your battery, check the text of the advert, it should mention something like “diode protection” or similar.

[Big_D]

If you use one of these you should be fine. 

[Mjolinor]

7 hours ago, Cowgirl said:

11 volts was an example, I have not checked the voltage of my battery.

Having a background in electronics when I talk about a solar panel that is what I take it to mean. Not a device designed for charging car batteries.

A solar panel on its own with no added circuitry will discharge any Battery unless the sun is shining on it. That is why they have a diode in the lead, they are not just a solar panel.

Solar panels are also available in all sorts of different voltages, currents and power output. If you want to know what one is capable of then it is necessary to specify what it is in the question.

 

🙂

Born a pedant and at 69 years old I probably always will be, sorry.

[Derek.w]

Caroline.

Solar panel drain when not charging is usually quoted at less than 10 mA 

or it may quote self consumption <10mA. that with a blocking diode.

[Mike1394]

Just a bit late to the thread, but I have one of the pictured AA solar panels, and at the moment it's taking the Battery up to 12.6v or thereabouts at the end of the day, and certainly not discharging it overnight. It's a tad feeble in the winter with shorter days and less bright daylight generally, but it got into it's stride at the end of March and it's improving every day. The car is facing North West and doesn't get direct sunlight on the panel until late afternoon. It's reassuring knowing that the car will probably start without problems.