How to measure DC current?

[Paulfrench35]

Hello,
What device can I use to measure the current and voltage at the output of solar panels and deduce the power?

 

[Mattb4]

In order to calculate wattage you need both voltage and amperage. Typically you do not hook directly to an inverter unless grid tie. Instead your panels connect to a SCC. often that SCC will give readouts of incoming PV voltage and either incoming amps or charging amps with battery voltage. Some give incoming watts.

You can get amperage with a DC clamp on meter or a shunt. Voltage can be measured with a volt meter and some shunts have a meter that calculate watts from reading both amps and volts. W=VA

 

[Tomthumb62]

A clamp meter like this one. You need the place the clamp around either the positive or negative wire, but not both at once.

Digital Clamp Meter, Multimeter Voltage Tester Auto-ranging, Measures Current Voltage Temperature Capacitance Resistance Diodes Continuity (AC/DC Curr https://www.amazon.com/dp/B08MTY51R4/ref=cm_sw_r_cp_apip_XABrSwNyun2uL

I just bought this one, on the recommendation of someone on this forum. They said they tested it against their much more expensive Klein meters and it’s quite close in similar readings. Most of the budget ones cost $60-90, so at $32 it’sa good deal. Price has gone up about $5 since I bought it in July.

 

[fpgt72]

My system is first and foremost something for me to learn with. Then it is a great big expensive toy.

Because it is a toy and analog is cool:

 

[Vigo]

an inverter that includes a solar controller would have a screen item showing incoming solar watts. you may have to click around through the various things that can display and it may or may not let you set that as a default item for the screen.

 

[efficientPV]

There are plenty of meters like this which give you watts at the moment, voltage, total watts and amp hours. This one even gives you how long even a minor amount of current was present. I use the external temperature probe to measure hot water tank temp or it could be helpful to know how hot a charge controller or inverter get. full scale current ranges are from a0A to 100A.

 

[Paulfrench35]

Where did you buy it?

 

[RV10flyer]

My system is first and foremost something for me to learn with. Then it is a great big expensive toy.

Because it is a toy and analog is cool:

View attachment 167195

Analog is cool. It’s 12:47 PM and my batteries are all charged up so the current is low. If anyone is looking for a clamp on amp meter, this is a good one from Amazon.

 

[Hedges]

Here's the ammeter I bought. Harbor Freight Ames 1000A.

Advantage of this one is 0.01A resolution, so better for comparing PV strings than one with 0.1A resolution.
It also has inrush, good to test motor loads.

check all panels are connected and working on fronius 27kw

we have a Fronius 27kw inverter connected to the grid with 90 x 375w jinco panels. The installer is no where to be contacted anymore. All this time, the inverter was not connected to the internet as there was no internet close to that building. Now I have connected the inverter to the internet...

diysolarforum.com

 

[efficientPV]

The KEWEISI meter I bought on AliExpress for $10 shipped. It only takes about 12 days to get here from China. Lots of vendors with this and similar items. Prices keep changing so shop around and carefully watch shipping costs and times. Fast shipping over $5 and with some cheap things shipping costs take an instant jump at $5 in stuff. I've become like an old lady watching QVC on Ali buying stuff every week!

 

[jeffkhlam]

A clamp meter like this one. You need the place the clamp around either the positive or negative wire, but not both at once.

Digital Clamp Meter, Multimeter Voltage Tester Auto-ranging, Measures Current Voltage Temperature Capacitance Resistance Diodes Continuity (AC/DC Curr https://www.amazon.com/dp/B08MTY51R4/ref=cm_sw_r_cp_apip_XABrSwNyun2uL

I just bought this one, on the recommendation of someone on this forum. They said they tested it against their much more expensive Klein meters and it’s quite close in similar readings. Most of the budget ones cost $60-90, so at $32 it’sa good deal. Price has gone up about $5 since I bought it in July.

Sorry to bring this old thread up but I can’t find the answer online: is it true that the clamp can NOT measure dc voltage, only dc amp? I tried multiple clamp meters but none are able to measure my solar dc voltage.

If not, then what’s the proper way to measure dc voltage? I know I can use the probes but everytime I use it, it gives me some spark so I’m wondering if there is a better method out there.

 

[Glock24]

Sorry to bring this old thread up but I can’t find the answer online: is it true that the clamp can NOT measure dc voltage, only dc amp? I tried multiple clamp meters but none are able to measure my solar dc voltage.

If not, then what’s the proper way to measure dc voltage? I know I can use the probes but everytime I use it, it gives me some spark so I’m wondering if there is a better method out there.

The clamp will only measure current, you need to use the leads on the cable ends to measure voltage.

 

[Mattb4]

You should not be getting sparks when you measure voltage. Make sure you use the probes in the com (-) volt (+), set your meter to the correct voltage position (DC in your usage) and never to amps.

 

[MattMan119]

Amp meter is good for what is going on .. What has happened is another question .. I used a cheap shunt (would have loved to use a victron smart shunt .. but cant use the good stuff for everything you will go broke) ..

I used it to measure from my DC battery to a bus with all battery usage other then inverter.. I dont see any reason it would not work to measure PV power ... (this the victron or inverter tell me now, but cant see waist this way) ..

Link to it on amazon: https://a.co/d/86t4XI8