Puzzled about DC Clamp meter reading

Thread Starter

bhvm

Joined Jul 16, 2009
53
Dear friends,
I brought myself a Highend AC & DC "hall effect" Clamp meter that claims to measure Amps, Duty cycle and HZ via Clamp.

My main reason for the investment is my New off grid solar setup. The solar setup has 4 batteries in PARALLEL for a total of 400AH storage at 12v. I wanted to know How many amps is my solar unit generating and how much is it being distributed to each battery. I also would like to know how many each battery "contributes" during a discharge use.

I can put the Clamp meter into DC Amps and see some amps on the display. sometimes I see amps Marked with a "-" Sign as well.

I am confused if the amps I see are charging amps or discharging amps. I can get a positive or negative reading depending on the orientation of the meter itself which aggravates the confusion!
 

alfacliff

Joined Dec 13, 2013
2,458
the + and _ are determined by the direction of current flow, if you turn the clamp over, it will change. if you mark the clamp on one side, and always have that side toward the load, it shouldnt change except with charge and discharge.
 

bwilliams60

Joined Nov 18, 2012
1,442
Amp clamps are typically marked with an arrow on the inductive pickup which indicates the direction of current flow. If you are still unsure, clamp it on the large cable coming off the B+ post on your car and get a positive reading when it is running. The direction will be from alternator to battery.
 

gerty

Joined Aug 30, 2007
1,305
Dear friends,
I brought myself a Highend AC & DC "hall effect" Clamp meter that claims to measure Amps, Duty cycle and HZ via Clamp.

My main reason for the investment is my New off grid solar setup. The solar setup has 4 batteries in PARALLEL for a total of 400AH storage at 12v. I wanted to know How many amps is my solar unit generating and how much is it being distributed to each battery. I also would like to know how many each battery "contributes" during a discharge use.

I can put the Clamp meter into DC Amps and see some amps on the display. sometimes I see amps Marked with a "-" Sign as well.

I am confused if the amps I see are charging amps or discharging amps. I can get a positive or negative reading depending on the orientation of the meter itself which aggravates the confusion!
The only way to tell the amp capacity is to check it with a load on it. Increasing the load will tell you what the max available current is.
 

Thread Starter

bhvm

Joined Jul 16, 2009
53
the + and _ are determined by the direction of current flow, if you turn the clamp over, it will change. if you mark the clamp on one side, and always have that side toward the load, it shouldnt change except with charge and discharge.
Thats the major comfusion I see. Even if I am holding the meter with display facing to me, sometimes the wires are routed up to down or Down to up. This causes mess!
Amp clamps are typically marked with an arrow on the inductive pickup which indicates the direction of current flow. If you are still unsure, clamp it on the large cable coming off the B+ post on your car and get a positive reading when it is running. The direction will be from alternator to battery.
Yes! My Clamp meter has a "+" sign on top (the side with display).
I loved your car idea. I will try it soon.

The only way to tell the amp capacity is to check it with a load on it. Increasing the load will tell you what the max available current is.
I am wanting to understand the - and + amps.

Please me explain me below-
1)Which post shall i take reading? I've heard I should measure the Negative terminal as electrons flow out out negative end, right?
2) What do '-' amps as a reading on meter mean? (At negative terminal)
What do + amps mean?
3) Any tips to increase the accuracy of my readings?
 

bwilliams60

Joined Nov 18, 2012
1,442
I am wanting to understand the - and + amps.

Please me explain me below-
1)Which post shall i take reading? I've heard I should measure the Negative terminal as electrons flow out out negative end, right?
2) What do '-' amps as a reading on meter mean? (At negative terminal)
What do + amps mean?
3) Any tips to increase the accuracy of my readings?
1) You can take your readings from either post as long as you know what you are reading. If you go from the positive post, using the conventional theory, most meters will want you to place the arrow toward the positive post when you are taking your reading. On the negative post, it would point away from the negative post. You can tell because the reading will be a positive reading.
2) If you are reading (-) amps, it simply means you have the pickup hooked up in the wrong orientation. It is the meter reading positive or negative, not electrons running backwards. Voltmeters and ammeters are polarity sensitive because they have current running through them. Ohmmeters are not because you are working with a dead circuit.
3) In order to increase the accuracy of your readings, you can:
a) Buy a more expensive and accurate meter
b) Buy an accurate ammeter that you actually hook into the circuit. It must be placed in series with the circuit so that it can measure the full circuit current value.
 

Thread Starter

bhvm

Joined Jul 16, 2009
53
Here is how the meter looks.
There is + mark on the display side.
Would someone be kind enough to draw up a rough visual how the wire should pass and which way the battery should be?

Thanks all for your time.
 

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