Ebay "alice" 5 digit panel Digital Voltmeter - Pre-purchace confusion

[Cliff Matthews]

Alice110198 is trusted by many here, but I don't want to buy 4 x $4.52 pieces of crap. They state 3 things I'd like some clarity on:
1) measurement range of 0-33.000V over the traditional 0-20.000V header <<-- Say what? Traditional?
2) update rate: > 3s/time <<-- 3 seconds between adc conversion updates? Why so slow?
3) Precision automatic change below 4.3 V, the highest resolution of 0.1 mV, Precision automatic 4.3 V above changes, the highest resolution of 1 mV Connection is simple, just need to pick up two lines, a joint reverse protection, then do not burn <<-- I prefer not to burn anything.. I have multiple positive outputs sharing the same ground and I'll power all these by a separate LM317.

http://www.ebay.com/itm/Red-LED-5-Digit-DC-0-4-3000-33-000V-Digital-Voltmeter-Voltage-Meter-Car-Panel-/400490355805

[StillTrying]

Big thread on them here.
https://www.eevblog.com/forum/projects/$5-voltmeter-with-5-digit-(0-1mv)-resolution/

[rrinker]

 I bought one of those cheapy kind, just to try it out. Connected to my HP power supply and BM235 and it was pretty close. There's (crapper) trimt ont he back, I tweaked it slightly (tongue at the correct angle) and across the range of the power supply it's actually no more than 1 lsd  off the reading of my meter and that's usually just rounding.

 

[Cliff Matthews]

I bought one of those cheapy kind, just to try it out. Connected to my HP power supply and BM235 and it was pretty close. There's (crapper) trimt ont he back, I tweaked it slightly (tongue at the correct angle) and across the range of the power supply it's actually no more than 1 lsd  off the reading of my meter and that's usually just rounding.

I saw one close-up pic, so I looked-up the 20-pin STM part.. Only 10-bit ADC's, but it's good to hear somebody had a positive result.
Was that within the last 6 months? I ask because when the demand goes up, the quality goes down (missing bypass caps etc..).

[StillTrying]

According to the other thread there's a MCP3421 18 bit ADC on it, which would make more sense than a 10bit.
http://www.microchip.com/wwwproducts/en/en520011

Possible schem. http://eddy-em.livejournal.com/73375.html

[Cliff Matthews]

According to the other thread there's a MCP3421 18 bit ADC on it, which would make more sense than a 10bit.
http://www.microchip.com/wwwproducts/en/en520011

Possible schem. http://eddy-em.livejournal.com/73375.html

Right you are! In a quick skim-over, my eyes completely passed-over a 6-pin diminutive I2C as an opamp or tvs.. 
Mouser wants $2usd each on a 3k reel, so China must be price dumping these meters. How can they make a profit?