1 voltage meter for both solar panel and battery

[deannos]

I have bought one of these (ebay item-251214397202) 0.56" Digital Voltmeter Green LED Panel 3/2-Wires DC 0-100V 4-30V Power Monitor. I want to read the voltage of a battery and a solar panel fitted to my caravan. What switch do i need and how would i wire this circuit please.

[Clive S]

I have bought one of these (ebay item-251214397202) 0.56" Digital Voltmeter Green LED Panel 3/2-Wires DC 0-100V 4-30V Power Monitor. I want to read the voltage of a battery and a solar panel fitted to my caravan. What switch do i need and how would i wire this circuit please.Not sure what you mean by "what switch" but these little meters are quite good for the price. Just connect the red and yellow wire to a + 12volt and the black to the -ve and it will read the voltage of the battery. If you want to read above about 30V then you have to connect the red wire to a source below 30V and the yellow wire to what you want to measure up to 100V. The -ve has to be to be the same for both the supply and the higher voltage you want to measure.
It would of course be prudent to put a fuse in line to protect the cables ..Clive

[deannos]

Not sure what you mean by "what switch" but these little meters are quite good for the price. Just connect the red and yellow wire to a + 12volt and the black to the -ve and it will read the voltage of the battery. If you want to read above about 30V then you have to connect the red wire to a source below 30V and the yellow wire to what you want to measure up to 100V. The -ve has to be to be the same for both the supply and the higher voltage you want to measure.
It would of course be prudent to put a fuse in line to protect the cables ..Clive

I wish to read either the battery voltage or the solar panel voltage separately, so i thought i would a switch of some sort

[Clive S]

Well in that case you just need a change over switch. Connect the yellow wire to the common and the battery +ve to one of the other contacts and the solar to the other contact. See thishttps://learn.sparkfun.com/tutorials/switch-basics/poles-and-throws-open-and-closed you can get a small switch for Maplin ..Clive

[deannos]

Well in that case you just need a change over switch. Connect the yellow wire to the common and the battery +ve to one of the other contacts and the solar to the other contact. See thishttps://learn.sparkfun.com/tutorials/switch-basics/poles-and-throws-open-and-closed you can get a small switch for Maplin ..Clive

Ok, thanks for your help. So i need a SPDT and switch the common, is that correct

[Clive S]

Yes in this case the common goes to the meter (yellow wire) but the red wire will have to be energised from the battery because the solar panel may not be providing enough Voltage to drive the meter. The -ve on the solar panel will have to be connected to the battery -ve hope this helps you could of course put 2 meters on the system ..Clive

[deannos]

Yes in this case the common goes to the meter (yellow wire) but the red wire will have to be energised from the battery because the solar panel may not be providing enough Voltage to drive the meter. The -ve on the solar panel will have to be connected to the battery -ve hope this helps you could of course put 2 meters on the system ..Clive

I did buy 2, be silly not to at that price

[Clive S]

I used 4 on my control box all different colours vey pretty :excitement: ..Clive