Overloading A D.C. Inductive Panel Ammeter?

[MEXICOWANDERER]

I have no experience in this area.

I want to use an inductive DC PANEL AMMETER rated for 100-amps on a battery charger rated at 157 amps max.

Their 200-amp inductive gauge has a resolution of 3 numbers, obviously whole amps.

And that stinks for observing fractional amps when monitoring AGM batteries that demand fractional resolution.

The charger has an analog 200-amp meter on the front, and the digital is meant for the lid.

Supposedly after the digital inductive ammeter reaches 99.9 the over range is displayed as an "L"

I don't really want to spend another 36 dollars for a third ammeter as a user can see the "L" and know to defer to the analog gauge.

But obviously overload means overcurrent in the inductive sensor line. Do inductive DC ammeters have intrinsic circuitry to withstand 160% overloading for extended periods of time? Repeatedly? Meaning years of durability?

Mr. Wizard announced this meter on this forum. Like all inductive ammeters a button needs to be pushed to null the meter back to 0. How often? Every use?

There is a five digit voltmeter on the lid so I am not concerned with voltage resolution or accuracy.

Anyone here have hands-on experience with this 🙂 ?

Thanks in advance !

[pianotuna]

Mine do not seem to "bounce". They agreed with a Fluke meter when installed--but have not been tested since. They are NOT mission critical in my case.

[ktmrfs]

landyacht318 wrote:
What I love about the hall effect ammeter is that it can be put on the (+) battery cable. I used to have my HE sensor readng total alternator output, but once that cursiosity was satisfied, I moved it to the battery cable.

Should be noted that they provided a 2 meter 3 wire ribbon cable for my meter for between sensor and display, and I cut this in half and added some about 5 feet pf 22AWg wires to its center. This could be why mine bounces around 0.6 amps from actual, or perhaps it would do sao without this midification, I know not, Its not a big deal. Sometimes it does not bounce around that 0.3 amps +/- actual.

I just like seeing how much amperage the battery accepts a minute after starting the engine, and watching that decline as I drive. Well worth the 18$ I spent for it.

Glad to see there are so many other hall effect ammeters on the market now.

the reading bounce you see is likely not a result of the longer wires. (1) if you are moving, IMHO all bet's are off with a hall device sensor for stable readings, the earths magnetic field variations along with variations of anything nearby can cause the hall device output to change. and (2) even when stationary lower readings on hall devices have variations unless the design was very well done and well shielded from outside magnetic fields.

It is nice to see the hall device DC current meters on the market now at reasonable prices with reasonable accuracy. Not that long ago hall device DC meters were pretty spendy.

[landyacht318]

What I love about the hall effect ammeter is that it can be put on the (+) battery cable. I used to have my HE sensor readng total alternator output, but once that cursiosity was satisfied, I moved it to the battery cable.

Should be noted that they provided a 2 meter 3 wire ribbon cable for my meter for between sensor and display, and I cut this in half and added some about 5 feet pf 22AWg wires to its center. This could be why mine bounces around 0.6 amps from actual, or perhaps it would do sao without this midification, I know not, Its not a big deal. Sometimes it does not bounce around that 0.3 amps +/- actual.

I just like seeing how much amperage the battery accepts a minute after starting the engine, and watching that decline as I drive. Well worth the 18$ I spent for it.

Glad to see there are so many other hall effect ammeters on the market now.

[pianotuna]

The one that failed was a 70 amp--not a 100 amp. I use one for monitoring the alternator charging for the house bank.

Since I changed to the telecom jars it almost never charges. I thought that perhaps switching to an AGM starter battery would fix that, but there was no change.

[MEXICOWANDERER]

echo

[MEXICOWANDERER]

Well for AGM full charge usage leaving "E" at constant 14.4 and watching "I" wander a tenth for a few minutes should be good enough to assssume the half of one percent is good enough for hand grenade accuracy.

I like analog ammeters for casual glance-at ergonomics. IE "Halfway up now, so it's getting there aptitude".

My N.I.S.T. certified meters went the way of the auction block 27 years ago. I even had a 3 foot square gray panel with 10 pole decade switches and a full scale 3.0 4" round meter that was glycerin filled. WWII sub battery monitor? You got me.

ktmrfs
Chargerl' housing is plastic and it's a Meanwell 1500 watt RSP unit (aluminum) -- so good luck there 🙂

The analog amps will be dialed-in with 11 Bourns 3K 19 turn cermets.

And thanks for some intelligent info about the meter Landy. Why ignorant people respond to concise questions on eBay is beyond me. "Yeah. I own six. Dah meter shows "L" when out of range" (especially after smoking a quarter pounder?)

[ktmrfs]

as mentioned, for DC current either a resistive shunt or hall effect device is used.

If it is a shunt, then overload conditions can lead to quick failure. Depends on how much and how long, it's basically a resistive element.

Hall devices are much more tolerant of overload. First, what is the overload limit for the hall device itself. It could be WAY more than the max range of the meter itself. Hall devices do present a load to the circuit, nothing comes for "free", but the load is milli or mico ohms. But hall devices can heat up.

So, it's hard to answer your question on overload without knowing the spec's on the hall sensor, that's the key. But I'm going to say, it can likely withstand sigificant overload for maybe even hours, days, or forever.

The inexpensive meters I've seen use a common meter and then hall sensors for max range with the hall sensor output set to match meter max range at the spec'd meter range.

Now for the "zeroing" question. Hall devices are a magnetic field sensor. So..... anything that changes the magnetic field will change the reading. Location, anything in the proximity, time of day.

And finally I'll echo landyahts comments. When at a small fraction of max reading unless it is extremely well designed, a hall sensor is very likely to show (a) lot's of reading bounce and (b) significant error due to field variations and poor zeroing function.

In a previous life I was involved with inductive and hall device current measuring devices with high precision, traceable to NBS, etc. The hall design is NOT trivial, and the cost involved in having a linear stable reading is involved. While we had significant patents around the technology, the real key was our in house "trade secrets", that were well protected. That was more important than anything. And we did not buy our hall devices, we could not find sources that gave us the quality we needed. Our hall devices were fab'd in house, again with lots of "magic sauce" and "trade secrets".

[BFL13]

Not me! Mr Wiz just gets away with his 100a because of a smaller microwave ISTR

I have a 500a shunt with Trimetric.

[pianotuna]

Hi Mex,

I think that Mr Wizard or BFL13 had an inductive meter that gave up the ghost possibly from overage. Mine is rated for 70 amps. I've never been close to that.

[landyacht318]

'Bayite DC 5-120V 100A Mini Digital Current Voltage Amp Meter Ammeter Gauge with Hall Effect Sensor Transformer'

I have the above unit.

It has a resolution to only 0.2 amps, and will bounce around with my engine running about 0.6 to 0.8 amps around the actual figure. Where my shunted ammeter does not.
Basically it is useless for determining end amps with any precision. Close enough, sure.
Perhaps it needs better shielding in my rig, but that 0.2 amp resolution is not getting any better.

[DrewE]

It's not technically an inductive pickup for a DC ammeter, but that's neither here nor there. (I think they generally use a hall effect sensor, which detects a magnetic field; an inductive pickup only can sense a change in the magnetic field, which makes it ideal for AC use but not very handy for DC.)

I would not expect any problems at all. With a (digital) shunt meter, the main concern I think would be destroying the shunt through excess power dissipation; the higher input voltage to the meter, within reason, should not cause any damage in most cases. An analog meter movement may be a completely different story, though they're still often relatively robust.

[time2roll]

Inductive I would worry less than if it had a shunt.
Since it includes an "L" display I doubt 200% over current will hurt it.
Probably some specifications around somewhere.

[landyacht318]

My 100 amp meter sees well over 100 amps every time I start my engine.

Of course that is brief. But repetitive and been ok for a few years now.