Problem with amp meter

rtucker · Joined: 14 May 2016 Posts: 22 Location: Illinois

I built the Kal Kit about 6 months ago and just recently started having trouble with my amp meter. I've had a number of occasion where the meter will simply stop displaying the amperage or start displaying random lines. This evening I noticed that when I turn on the pumps alone I get no amperage reading. However, if I fired up and element I would see about 24 amps displayed and then if I fired up a pump along with the element I would see the amperage rise to 25.5 or so. This happened pretty consistently.

So, in summary it looks like no amperage displayed with only the pumps running, but it looks like I can see the pump amperage reflected in the total if I'm running the pump along with a heating element.

Any ideas as to what might be going on?

Other than the amperage display the system seems to run fine. It's a minor annoyance.

***** Follow up ****
I was playing with it a little more and saw more odd results. Still no amperage reading with just the pumps but when I turned on the heating element and the pump the amperage reading was sitting at 35+ amps. I only have a 30 amp circuit breaker so I'm pretty sure that's not right.

What do I need to replace the amp meter? The shunt? or both?

**kal** · Posted: Tue Oct 10, 2017 1:33 pm Post subject:

Hi Roger,

Sorry for the issues!

When the amp meter's not working right, what sort of voltage is it receiving from the power supply? Are you able to (carefully) measure this while it's running? Instead of measuring, you could swap the wires between the power supplies and meters just to confirm. If the problem moves to the voltmeter then you know it's a power supply issue (or a transformer issue). Now that said, it does sound like an amp meter issue (they're paired with the shunts so always sold together), but best to confirm the power supply/transformer just to be sure.

Kal

rtucker · Joined: 14 May 2016 Posts: 22 Location: Illinois

Thanks for the response. I checked the voltage on the power supply this morning. It's almost right at 5V, maybe a couple hundredths shy of that.

FWIW I tried to measure the resistance across the shunt as well as the voltage drop across the shunt. I'm guessing my meter is not accurate enough to measure those values accurately. I know those shunts are very low resistances. I got about .2 ohms and 0 volts across the shunt, but the lowest setting in my meter for AC is 200 v. If my math is right and ohm reading is right, that's only a .24 volt drop across the shunt. I'm not sure my meter is going to read that correctly.

I will try and swap out the power supplies as you suggest.

jphussey · Joined: 17 Oct 2012 Posts: 171

I had a similar problem to this; still haven't found the solution.

jphussey · Joined: 17 Oct 2012 Posts: 171

UPDATE: Today I brewed for the first time in about 4 months; my amp meter used to oscillate, seemingly randomly, between normal operations and the blanked out/error screen. Today it never worked at all. I'm thinking about buying a new one and swapping it out to see if that's the problem...I don't relish the idea of swapping it with the volt meter as that seems like a lot of rewiring...maybe not though?

When did you buy your supplies? I wonder if there were some bad components going out?

**kal** · Posted: Sat Oct 14, 2017 5:42 pm Post subject:

jphussey · Joined: 17 Oct 2012 Posts: 171

Ok, not a 60 second job given how awesomely I wired this thing, but I got the DC output wires swapped at the power supplies. I have nothing plugged in except the main power and after about 10 seconds of being turned on, the amp meter is back to acting up.

I've check all of the wires and they all seem well secured.

Thoughts? Bad amp meter perhaps?

**kal** · Posted: Sun Oct 15, 2017 1:07 pm Post subject:

Yup. I'd replace the amp meter/shunt combo just to be sure.

Kal