Quick Electronics help please

[Dave100456]

Help please:
I'm looking for the right diode to stop a small solar panel draining the battery at night as I'm not using a regulator.

I'm no electronics expert but understand a Schottky diode is best but which one???? PV panel specs are max peak voltage is 22v and max peak current is 0.65A Any one know a suitable diode, and will an over spec diode ie 30v and 10 amp reduce my voltage more than a 30v 5 amp variant would?

Thanks

Dave

 

[trbt]

will an over spec diode ie 30v and 10 amp reduce my voltage more than a 30v 5 amp variant would?

The other way round. But really you should look at the datasheets for forward voltage vs current graphs to find the one that has the least voltage for your target current.

 

[William_H]

You can find a schotky diode of suitable rating in an old computer power supply or similar switch mode power supply. They are usually a square black plastic box about 1cm square or rectangle attached with a screw to an ali heat sink. May have 2 leads or 3 leads. Often built in a pair. Usually have a pair of diode symbols on the face.
However as said any schotky diode of ratings greater than the panel current will be OK.
Indeed an ordinary silicon diode will drop more voltage but in practice will not make much difference to overall amp hours in to battery. The difference will only at lowest light levels. You mightalso like to check the panel with a digital multimeter on amps scale to check for actual current flow backwards in darkness. Every time I have checked I can't measure any loss. Maybe a diode in the panel or it doesn't really matter. ol'will

 

[duncan99210]

Don’t most panels incorporate a diode into the panel wiring?

 

[Dave100456]

Don’t most panels incorporate a diode into the panel wiring?

Most do but the one I have doesn't.

 

[wully1]

Go on flea bay and buy a cheap as chips regulator and save all the worry?

 

[GHA]

Go on flea bay and buy a cheap as chips regulator and save all the worry?

? Takes less power than many think to push up the voltage of a fully charged battery.

 

[Dave100456]

Thanks for the suggestions

 

[Yellow Ballad]

If your panel had mc4 connectors then you could put one of these inline.

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine

 

[Skylark]

Help please:
I'm looking for the right diode to stop a small solar panel draining the battery at night as I'm not using a regulator.

I'm no electronics expert but understand a Schottky diode is best but which one???? PV panel specs are max peak voltage is 22v and max peak current is 0.65A Any one know a suitable diode, and will an over spec diode ie 30v and 10 amp reduce my voltage more than a 30v 5 amp variant would?

Thanks

Dave

Diode 1N34A is commonly used by the RF fraternity. It has a forward voltage of less than 0.3v, a reverse breakdown voltage of greater than 40v and is readily available, for example:-

https://www.ebay.co.uk/sch/i.html?_...MIptqA-P247QIViJ7tCh09_wDfEAAYASAAEgLiaPD_BwE

 

[Dave100456]

Sylark, Yellow Ballad

Thanks, just what I wanted.

 

[trbt]

Diode 1N34A is

Only if 50 mA average current limit is sufficient...

 

[VicS]

Diode 1N34A is commonly used by the RF fraternity. It has a forward voltage of less than 0.3v, a reverse breakdown voltage of greater than 40v and is readily available, for example:-

1N34A is a germanium diode. It's completely unsuitable

I'd be looking at 1N4001 (PIV 50V, IF 1A )
or 1N5400 (PIV 50V, IF 3A )

 

[coopec]

Diode 1N34A is commonly used by the RF fraternity. It has a forward voltage of less than 0.3v, a reverse breakdown voltage of greater than 40v and is readily available, for example:-

https://www.ebay.co.uk/sch/i.html?_nkw=1n34a Diode&norover=1&mkevt=1&mkrid=710-154051-335098-4&mkcid=2&keyword=1n34a diode&crlp=435275215655_&MT_ID=584526&geo_id=32251&rlsatarget=kwd-296661366633&adpos=&device=c&mktype=&loc=9046455&poi=&abcId=1140016&cmpgn=1537721926&sitelnk=&adgroupid=60349740204&network=g&matchtype=e&gclid=EAIaIQobChMIptqA-P247QIViJ7tCh09_wDfEAAYASAAEgLiaPD_BwE

I've just spent about half an hour typing in that http thing and it doesn't work. (I've checked my typing twice) Can you tell me what I'm doing wrong?

 

[VicS]

I've just spent about half an hour typing in that http thing and it doesn't work. (I've checked my typing twice) Can you tell me what I'm doing wrong?

You could simply click on it .... ( its a link to an ebay page of suppliers )
BUT DONT BOTHER its not a suitable diode!

 

[Skylark]

1N34A is a germanium diode. It's completely unsuitable

I'd be looking at 1N4001 (PIV 50V, IF 1A )
or 1N5400 (PIV 50V, IF 3A )

Oops, thanks for pointing that out VicS, happy to say sorry ? By coincidence, I bought a packet of 1N34A just this week for a little project to measure RF voltage.

 

[prv]

I've just spent about half an hour typing in that http thing and it doesn't work. (I've checked my typing twice) Can you tell me what I'm doing wrong?

Typing in huge long links by hand instead of simply clicking on them, or at least copying and pasting?

Why on earth would you do that?

Pete

 

[coopec]

Typing in huge long links by hand instead of simply clicking on them, or at least copying and pasting?

Why on earth would you do that?

Pete

Sorry Pete I was joking but I was intrigued as to why the link wasn't automatically truncated.

 

[Dave100456]

I'd be looking at 1N4001 (PIV 50V, IF 1A )
or 1N5400 (PIV 50V, IF 3A )

Thanks VicS