Multi meter Settings

Submitted: Wednesday, Dec 19, 2018 at 13:00
ThreadID: 137573 Views:2599 Replies:11 FollowUps:17
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Like a lot of us I run a solar panel. I use it to top up my alternate battery but only when camped for 2 or more days, its only a 180 watt unit but its doing the job and I'm OK with it as it 's for the Engel fridge only. I normally check what voltage is going into the battery usually about 14.2v. The panel came with a MPPT controller rated at 15 amps attached to the panel but I have since remove it and did a bit of rewiring so that now the controller is separated from the panel and is now close to the battery which was recommended by members from this site, which did increase the voltage to the battery.
My question is, 1, what settings do I put onto my multimeter and 2. where do I test from using the probes to determine the number of amps the battery is receiving?

Cheers
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Reply By: Frank P (NSW) - Wednesday, Dec 19, 2018 at 13:19

Wednesday, Dec 19, 2018 at 13:19
1). Your multimeter is likely to have a 10 amp setting on the switch. There will also be a specific 10amp socket for the positive test probe. Set the switch to the correct position and plug the positive probe into the 10 amp socket on the multimeter.

2) Disconnect the positive lead from the regulator to the battery, either at the regulator or at the battery, doesn't matter.

If you've disconnected at the regulator, place the positive probe on the regulator's terminal and the negative on the wire that goes to the battery and read the amps.

If you've disconnected at the battery, place the positive probe on the end of the wire and the negative on the +ve battery post and read the amps.

Note: If you get the probes the wrong way around you will get a negative amp reading. That does not matter, the actual figure will be the current going into the battery.
FrankP

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Follow Up By: Member - Trouper (NSW) - Wednesday, Dec 19, 2018 at 15:32

Wednesday, Dec 19, 2018 at 15:32
Thanks Frank. That great. As soon as the sun starts shining again I will give it a go
Jeff
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Follow Up By: Erad - Thursday, Dec 20, 2018 at 12:56

Thursday, Dec 20, 2018 at 12:56
180 watts @ 14.2 volts equals 12.7 amps, which is in excess of your meter's capacity and it will probably go into overload. After a while the internal shunt int he meter will probably fail, so if the reading goes into overload, back off very quickly. The meter won;t explode or anything as drastic as that, but it may be damaged if you leave it too long.
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Reply By: DaveO*ST-R - Wednesday, Dec 19, 2018 at 14:38

Wednesday, Dec 19, 2018 at 14:38
Over time, I have bought 3 of these for different applications. They are a great and easy addition to your system to keep an eye on volts, amps, watts. amp hours etc etc.

Watt Meter

Much easier than connecting up your multimeter to measure amps.

Cheers
AnswerID: 622713

Reply By: Notso - Wednesday, Dec 19, 2018 at 15:15

Wednesday, Dec 19, 2018 at 15:15
I use a DC clamp meter. Probably not as accurate as the other way suggested but a lot easier and faster.
AnswerID: 622714

Reply By: Member - Trouper (NSW) - Wednesday, Dec 19, 2018 at 15:35

Wednesday, Dec 19, 2018 at 15:35
Thanks Frank. As soon as the sun comes out again I will give it a go

Jeff
AnswerID: 622715

Reply By: RMD - Wednesday, Dec 19, 2018 at 16:01

Wednesday, Dec 19, 2018 at 16:01
Trouper.
Only by inserting the multimeter in series with either the positive or negatib=ve line between regulator and battery will you actually see what the current flow really is.
If measuring the amp flow,, using the multimeter set on amps, inserted into the line between the panel and the MPPT regulator you will not see the amp flow into the battery, you will see less amps than what is really running from the regulator to the battery. Reason is, the MPPT holds the panel at a much higher/optimum voltage than a pulse regulator does and so the amps in the panel side may be less and the voltage measured there may be higher and the product of that energy level will cause more amps to battery than is measured in the solar line. That is exactly what an MPPT regulator is for.
So for a more accurate reading between the battery and regulator is the place to measure.
The wattmeter/ampHr meters also are a good idea as mentioned.
What you have done by placing the regulator close to the battery is advantageous because the solar lead may be still the same cable but the MPPT can utilize the higher voltage level in that line and deliver more to the battery as a result. Cables which lessen resistance between the panels and reg, or reg and battery, is always going to be of benefit for best energy capture.
AnswerID: 622716

Reply By: Genny - Wednesday, Dec 19, 2018 at 16:34

Wednesday, Dec 19, 2018 at 16:34
Generally multimeters are not suitable for measuring amps for any significant amount of time. Heed the warnings on yours!

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AnswerID: 622718

Reply By: Allan B (Sunshine Coast) - Wednesday, Dec 19, 2018 at 16:36

Wednesday, Dec 19, 2018 at 16:36
.
Trouper,

A word of warning when using your multimeter to measure current (Amps) as described above by Frank and RMD.

When the meter lead is placed into the "10 Amp socket on the meter" be very careful to NOT CONNECT your multimeter across the battery or wiring as you would when measuring voltage. If you were to do this a very large current will flow through the meter and blow the internal fuse (and maybe worse!).

It is wise to remove the test lead from the meter's 10A socket as soon as you have completed making the current measurement. If I had always done so then I would not have needed to replace my meter's internal fuse as many times as I have! LOL
Cheers
Allan

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AnswerID: 622719

Follow Up By: RMD - Wednesday, Dec 19, 2018 at 20:33

Wednesday, Dec 19, 2018 at 20:33
Allan
On amp setting, I found 24v across the probes as you touch it fairly quickly arcs the brass pointed end off the test probe, then the fuse blows. We have all done that at some time. I instantly became more aware.
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Follow Up By: Allan B (Sunshine Coast) - Wednesday, Dec 19, 2018 at 22:45

Wednesday, Dec 19, 2018 at 22:45
.
I too became "more aware"...... several times I became more aware!
Cheers
Allan

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Follow Up By: Member - David M (SA) - Thursday, Dec 20, 2018 at 10:30

Thursday, Dec 20, 2018 at 10:30
I never even became " aware", let alone "more aware" because I never made that mistake. :)
Dave.
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Follow Up By: Allan B (Sunshine Coast) - Thursday, Dec 20, 2018 at 11:39

Thursday, Dec 20, 2018 at 11:39
.
Ahh David, that gratification then awaits you! lol
Cheers
Allan

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Follow Up By: RMD - Thursday, Dec 20, 2018 at 17:23

Thursday, Dec 20, 2018 at 17:23
Mistakes are an educational tool and provide a means of learning. No mistakes then less learning.
I discovered a LED connected to a high voltage instantly becomes a NED. Noise Emitting Diode. It fairly blows the top off them.
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Follow Up By: Allan B (Sunshine Coast) - Thursday, Dec 20, 2018 at 17:47

Thursday, Dec 20, 2018 at 17:47
.
If mistakes "provide a means of learning" then I must have learned a helluva lot in my lifetime! lol

I always thought it became "DED"........ Deceased Emitting Diode.

Or was it "BED".... Buggered Emitting Diode?

The technician said a "NED" was a Non-emitting Diode.
And the apprentice said it was a "FED" but I never learned what the 'F' stood for. lol


Cheers
Allan

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Follow Up By: qldcamper - Saturday, Dec 22, 2018 at 07:42

Saturday, Dec 22, 2018 at 07:42
Before investing in a clamp i always ran an external inline fuseholder in a lead 5 amps smaller than the internal after the first few times.
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FollowupID: 895780

Follow Up By: Member - David M (SA) - Saturday, Dec 22, 2018 at 10:34

Saturday, Dec 22, 2018 at 10:34
My first educational mistake Alan was a failure to disconnect the battery on a brand new vehicle when fitting some serious accessories. Failure to do so resulted in the Loom integrity disappearing in a cloud of smoke. A costly mistake as explained to me by the service manager.
Dave.
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Reply By: Member - Trouper (NSW) - Thursday, Dec 20, 2018 at 14:14

Thursday, Dec 20, 2018 at 14:14
Thankyou all for your informative replys. With a bit of luck I wont blow the meter.

Jeff
AnswerID: 622727

Follow Up By: Tomdej - Thursday, Dec 20, 2018 at 18:54

Thursday, Dec 20, 2018 at 18:54
One more thing that may be worth considering. Solar regulators work best when connected close to the battery, which I note you have done, and also when connected to the battery prior to connecting the solar panel.
When you disconnect the regulator/controller to introduce the multimeter to measure amps the panel is now connected to the regulator/controller first.
Could this cause a problem or inefficiency?
Buy an inline amp/volt meter from ebay or better still install a good battery monitoring system.
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FollowupID: 895772

Reply By: patsproule - Friday, Dec 21, 2018 at 05:38

Friday, Dec 21, 2018 at 05:38
Go and get yourself a DC clamp meter like this one.. I carry one camping and it allows you to check all sorts of things including solar output, load consumption, alternator output, parasitic drain etc. Also has a basic multimeter function. I find it incredibly handy when inevitably I get asked to diagnose someones dual battery / solar install.

Pat
AnswerID: 622731

Follow Up By: Member - Boobook - Friday, Dec 21, 2018 at 07:14

Friday, Dec 21, 2018 at 07:14
Yes, awsome meter. Made by Uni-T.

Makes current testing a breeze.
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FollowupID: 895774

Follow Up By: Member - Trouper (NSW) - Friday, Dec 21, 2018 at 18:00

Friday, Dec 21, 2018 at 18:00
Pat, Do the instructions for the clamp meter explain how to do all those things you mentioned. Otherwise I'll be back on here asking similar questions. :)

Jeff

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FollowupID: 895776

Follow Up By: Member - johnat - Saturday, Dec 22, 2018 at 21:54

Saturday, Dec 22, 2018 at 21:54
Jeff,
Is that a problem? Answers here are free (and sometimes free of facts ... but ;) ) and the only stupid question is the one that you don't ask!
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FollowupID: 895807

Follow Up By: patsproule - Saturday, Dec 22, 2018 at 22:02

Saturday, Dec 22, 2018 at 22:02
Not a whole lot to learn. For current you set the dial to Amps, blue button to set DC, then you put the clamp around either the negative or the positive wire on the circuit you want to test (but never both at once). Eg, if you want to see what your solar panel is outputting put the clamp around one of the output wires of the panel. Want to see what the fridge is sucking down, clamp it around one of the wires (+ or -), want to see the total current drain on your aux battery, again clamp around the output wire. Also comes with some probes for checking voltage (as the clamp only does current).
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FollowupID: 895808

Follow Up By: Nomadic Navara - Sunday, Dec 23, 2018 at 15:23

Sunday, Dec 23, 2018 at 15:23
Something to watch - some clamp meters are only accurate with the DC current flowing through them in one direction. There will be an arrow in the loop somewhere to show which way the current in the wire through the loop should be flowing.
PeterD
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Reply By: Nomadic Navara - Friday, Dec 21, 2018 at 07:26

Friday, Dec 21, 2018 at 07:26
One thing I have not noticed above is that generally a solar controller should not be disconnected from the battery whilst the panels are connected. When working on a solar system the panels should be disconnected first. Then you insert the meter between the controller and the battery. When the meter is in place then reconnect the panel(s.)
PeterD
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AnswerID: 622736

Follow Up By: RMD - Friday, Dec 21, 2018 at 08:29

Friday, Dec 21, 2018 at 08:29
A good point.
I would perhaps say it is more than general info to do exactly that. An MPPT controller I connected a few days ago specifically mentions the order of the connections.
Always battery to controller first when connecting and solar connection last.
Always Solar disconnected first and battery to regulator connection last.
When testing it is no different.

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FollowupID: 895775

Reply By: DiggZ - Friday, Dec 21, 2018 at 08:25

Friday, Dec 21, 2018 at 08:25
A watt meter can be a very handy tool also.

This is just one brand that I knew of off the top of my head.

https://www.australiandirect.com.au/Battery-Systems/Electronics-Appliances/KAMeter1

Current (Amps/A) at the present moment
Voltage (Volts/V) at the present moment
Power (Watts/W) at the present moment
Total Amps (Amp hours/Ah) since device initialised
Total Power (Kilo Watt hours/KWh) since device initialised
Highest Voltage Maximum (Vm) since device initialised
Highest Power Peak (Watt Peak/Wp) since device initialised
Highest Current Peak (Amp Peak/Ap) since device initialised
AnswerID: 622738

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