Please help Solar System problems

[tod24]

Firstly i'd like to say hi to everyone.

I have been scratching my head for months I do not understand why I cannot run my laptop on my boat?

I have 3x 120 amp hour Leisure batteries that cost me a fortune and I have 2x 20w solar panels to keep them topped up.

All I am running is a 12 car radio LED lights at night time for 1 or 2 hours at the most but never have them on all at same time.

I have turned off everything, apart from the 12v socket outlet that I plug the 12v to 19v laptop inverter for a car
I have a 12v socket

the light is on but when i press the on button on the laptop the volt meter beside the 10A solar controller drops down to zero my laptop makes a squeak and click sound and turns off?
I even bought a new laptop and it does the same. But when I put the inverter into the cigarette lighter of my mums little car with a tiny little battery it works?

Do i need more solar panels?

But if so why can I run it on a small car battery without the engine running?
I'm very confused and would appreciate any help please.

Many thanks
Tod

 

[Kelpie]

Welcome to the forum.
Sorry to hear about your troubles. Do other 12v appliances work OK from the same socket?

 

[RichardS]

Firstly i'd like to say hi to everyone.

I have been scratching my head for months I do not understand why I cannot run my laptop on my boat?

I have 3x 120 amp hour Leisure batteries that cost me a fortune and I have 2x 20w solar panels to keep them topped up.

All I am running is a 12 car radio LED lights at night time for 1 or 2 hours at the most but never have them on all at same time.

I have turned off everything, apart from the 12v socket outlet that I plug the 12v to 19v laptop inverter for a car
I have a 12v socket

the light is on but when i press the on button on the laptop the volt meter beside the 10A solar controller drops down to zero my laptop makes a squeak and click sound and turns off?
I even bought a new laptop and it does the same. But when I put the inverter into the cigarette lighter of my mums little car with a tiny little battery it works?

Do i need more solar panels?

But if so why can I run it on a small car battery without the engine running?
I'm very confused and would appreciate any help please.

Many thanks
Tod

It sounds as if you are trying to run the laptop from the solar panels using an inverter. This won't work as 40W of solar panel plus the inverter losses will never deliver enough current. If the inverter is connected directly to the charged battery, as in the car, it will work.

Try connecting the inverter to the boat battery with a jump lead. If it works there is something wrong with the wiring of your 12V boat socket.

Richard

 

[lpdsn]

Hi Tod,

Do you have a multi-meter? It's not expensive to get an adequate one.

You can then check the voltage at the battery terminals themselves. If they're running a 12V car radio and LEDs (I think that's what you mean) then they should be OK - that doesn't imply they're necessarily in good condition nor does it imply they're not.

What does the voltmeter that drops to zero actually measure? Is that the solar panel input to the batteries?

My laptop says 19V DC 3.9A - assuming yours is the same you'll probably be trying to take something in the order of 6-7 Amps out of the batteries at 12V. Again, it should be do-able.

I assume your solar panels do charge into the batteries and you're not using them to drive the laptop directly. You probably won't be getting much out of 2 X 20W panels (for a start they measure the power at the voltage the panels output, not at 12V, plus they're only that efficient in ideal conditions - assuming you're somewhere around the UK you'd be pretty lucky if you're getting 1A at peak times. I'll make a rough guess of 0.5A for 8 hours, so 4Ah per day. Might be a little more, but not much.

I presume you have some other way of charging your batteries (engine/shorepower). You will need it.

The other thing to look at is the wiring to the 12V socket - if there's a faulty connection somewhere there, then the voltage it supplies will drop when you try to draw current through it.

 

[macd]

As said, if the 12v socket is fed solely by the direct output on the solar panel controller, it won't have enough clout to power a laptop (and if the OP can turn "everything off" other than the 12V socket, it rather sounds as though it might be wired that way.
If that's not the case, is the polarity of the 12V socket correct?

tod24: can I suggest that you refrain from using headings with expressions like "Solar System Problems". They could make six billion or so people quite worried

 

[Tony Cross]

Agree with all the above, but for the future you'd probably get more responses posting questions like this in the Practical Boat Owner's Reader To Reader forum, though lots of us read both of course.

You might even want to post it in there now (as well in in here).

 

[V1701]

In answer to the question of whether you need more solar panels, the answer is almost certainly yes - 40w isn't enough in the UK winter to keep up with that size battery bank. I have a 330AH bank & use the batteries for LED TV & lights & charging netbook , phone, etc. In the winter 160w of solar just about keeps up...