$60 amp-hour meter, any good?

[random]

At first glance this looks like it might do that job.  But it has a max amperage of 100a, and a built-in shunt with "14 gage, stranded, high flex, high temperature silicone rubber insulated wires".  I'm getting "too wimpy" vibes here, but I am out of my depth.  Opinions?

http://www.rc-electronics-usa.com/ammeters/rv-battery-monitor.html

[henjulfox]

Random,

I have a couple wind turbines, each one feeding through one of those meters. Love 'em!

At any time I can check current amps, cumulative amps, or peak amps. Geat way to tell how the turbines compare to each other. For example, I have a commercial Windseeker 500 next to a homemade mill with Jerry blades. The Windseeker will hit higher peak amps but the homemade one will have higher cumulative amps due to the lower cut in.

They are only rated for 60 volts. If you were dumb enough to un-hook the battery for a miniute without throwing the kill switch and let the turbine run over 60 volts it WILL let the magic smoke out...

I got mine under the name "Watts up" meter for around $50 delivered on ebay. If your mill will stay below the rated specs I reccomend it.

-Henry

[Ungrounded Lightning Rod]

The page doesn't give a rating for max continuous amps.

14. ga is a bit wimpy for the 100A "peak" rating if it's average draw.  It's rated for 15 when used for house wiring and buried in an insulated wall.  Might survive 100A inside the meter minus the covering and insulation - though I wouldn't trust it.
    
100. A at 12V is 1200 W into your inverter - maybe 8A out of it at 120 after converter efficiency is taken into account.  10 100W lightbulbs and you're off-scale as well as risking a fire.
     
     

It's obviously intended for use with the small-load, house-battery-conserving 12V appliances in a vehicle - like an RV or boat, not for a homepower system.

I'd look for something purpose built - and with an external shunt.  Or if I was going to work on the cheap I'd get one, tear it open, and replace the dinky internal shunt with a sturdy external one (made of wire rated for the current and scaling down the signal delivered to the meter).

Shunts are easy to build and moderately easy to calibrate if you have a decent meter for a reference.  Should be easy to make a 10:1 scaled shunt for that one so the amp, watt, and KW hr ratings read the right digits with the decimal shifted.

[dinges]

Have noticed them before.

However, I'm contemplating building this one:

http://www.rcgroups.com/forums/showthread.php?t=203159

http://www.rcgroups.com/forums/showatt.php?attachmentid=187169

Basically, it's just a PIC with LCD display, and a current sensor.

[RP]

I wonder if you could add an external shunt and put a label on the device that says "X10"

[henjulfox]

Ungrounded is of course correct about the wimpy 14 gauge wire. I've only gotten over 12 amps @ 24 volts a few times and have had no problems.

-Henry

[ElSenator]

Man, I LOVE these things!

[commanda]

Seems to me, if you opened it up, removed the internal shunt, and used an external shunt, the two black wires would only be carrying at most the 7 mA to run the meter.

http://www.jaycar.com.au/productView.asp?ID=QP5414&CATID=&keywords=qp5414&SPECIAL=&f
orm=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax
&SUBCATID

Amanda

[random]

"Or if I was going to work on the cheap I'd get one, tear it open, and replace the dinky internal shunt with a sturdy external one (made of wire rated for the current and scaling down the signal delivered to the meter)."

That's what I woke up thinking this morning.

"Shunts are easy to build and moderately easy to calibrate if you have a decent meter for a reference.  Should be easy to make a 10:1 scaled shunt for that one so the amp, watt, and KW hr ratings read the right digits with the decimal shifted."

Seems like I've seen 10:1 shunts on the web for under $50.  One of these meters and a heavier shunt might do the job for a sizeable battery bank for $100+ less than what the premium meters cost.

I wonder if DanB would be interested in selling upgraded meters like this to folks like me who have very few electrical clues.