Hall effect amp-hour counter

In terms of convenience, I don't see a lot of difference:

CleanPowerAuto really wants you to insert their specially sized copper bar in the circuit so the Inductive Coil will precisely wrap around it.

Inserting a resistive shunt seems about the same amount of trouble.

I guess the engineer in me trumps other considerations. Compare that exposed and vulnerable circuit board to...



Blue Sea Systems 8255 Digital Meter Shunt (500A/50mV)
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I simply do not trust the longevity nor durability of inductive DC AMPERE collectors. The silicon steel lamination's oxidize over time, the amplifier board is permanent. It is subjected to cruel transient voltage spikes from the DC system. Every one I tried degraded to uselessness over a five year period. The circuit components in the board drift as they decompose. With a six gigawatt electric car error does not mean much. With AGM batteries and monitoring fine resolution for determining final 5% charge status you could not GIVE ME an inductive pickup meter setup.

The Manganin shunt pictured is ultra precise. What IS SENSITIVE about shunt ammeters is the integrity of the two small meter wires. They MUST MUST MUST MUST MUST be soldered to the #6 ring terminals. I solder my meter leads DIRECTLY to the brass blocks. I use silicone grease allover the major power wire termination connections.

Gigantic Manganin shunts are IMPRACTICAL for EV cars. I spray heavy duty silicone spray over the metal of the shunt for oxidation resistance.

To each his own. No criticism intended. But good meters do not come cheap. I suggest a meter brand and model popular in alternative energy 12 volt homes circuit.

pianotuna wrote:
Hi Mex,

Are you saying this one won't work? http://minibms.mybigcommerce.com/products/EV-Display.html

After reading about Mex's concerns on power draw I queried dimitri at cleanpower. He says:

cleanpower wrote:
Its 30mA draw on 12V battery when LCD is backlit, drops to about 20mA when backlight goes off.

Forgot to ask about accuracy or precision though.
Dimitri responds very quickly if you ask though.

Hi Mex,

Are you saying this one won't work? http://minibms.mybigcommerce.com/products/EV-Display.html

Get ready to spend $2,000+ US Dollars, the inductive shunt MUST be sized correctly for the wire, it is not CLAMP on, rather pass through, 50mv. it uses 10-times the Milli amps than a shunt type amp hour meter uses and it is around 90 times more inaccurate than a proper MANGANIN shunt at levels of around 800 Milli-amps or less. A lot of the power of a clamp type meter powers the circuit that senses the magnetic flux and translates it to an analog signal.

Hi Larry,

I can already measure amps of demand and amps going back in. If I upgrade it will need to be a 'counter' of some kind.

fluke makes a clamp-on, will that work? ac-dc amps Maybe you could calculate amp/hours from that?

http://minibms.mybigcommerce.com/products/EV-Display.html

But they recommend putting the supplied copper bar in the circuit for the best Hall Effect results.

Found 1 but it is a build kit and can not meet PT's capacity:

http://www.mtmscientific.com/ampkit.html

Personal preference.