Inexpensive data-logging DMM - Page 1
Forum section: electronics / testgear

author: danb35
author_rank: Contributor
timestamp: August 15, 2015, 07:18:13 pm
content: I'm looking for a DMM to use for some battery capacity testing--measuring voltage over time with a known load attached. Requirements are pretty straightforward:Minimum 2000 count resolutionHave a USB cable, or work with a USB/serial converterWork with QtDMM, or have Mac-compatible software available (though I do have a Windows VM I could use, I'd prefer not to add that layer of complexity to this application)Only function really necessary is DC VoltsAvailable in the United StatesAs inexpensive as possible given 1-5I already have a TekPower TP4000ZC, but I've lost the data cable, and don't have a practical means of fabricating another one at this time. I'm leaning toward buying another one ($37 from Amazon, free Prime shipping, understand they now come with a USB cable rather than DB9 serial), but open to other options. I know the TekPower works with QtDMM because I've used it before.I also have a Brymen BM257. I understand a data cable is available for it, but I don't have that cable now. I don't see that it's on the supported list for QtDMM, though.What other options should I consider? No "buy a Fluke", please. I already have a Fluke (two, actually--an 87V and a 27), so I'm covered as far as rugged, reliable DMMs, but neither of them will talk to my computer.

author: linux-works
author_rank: Super Contributor
timestamp: August 15, 2015, 08:03:58 pm
content: I hacked a vichy vc99 to work with serial TTL and qtdmm.you do have to hack it and its not a high end meter, but it does have serial ttl output and qtdmm does parse it.

author: Macbeth
author_rank: Super Contributor
timestamp: August 15, 2015, 09:06:00 pm
content: linux-works, IR LED and USB UART isso last yeardude! The cool kids are rocking Bluetooth HC-06 modules on their VC99's. Cheaper too!(Mine is in surgery at the moment as I am modifying it to use a serial detect to power up/down the bluetooth and also a 14500 battery and TP4056 with protection module to replace the AAA's)All the meter snobs can diss the VC99, but you would be insane to do this kind of fun butchery to a Fluke! Who cares with a $20 DMM?

author: linux-works
author_rank: Super Contributor
timestamp: August 15, 2015, 09:17:59 pm
content: I think those photos came from at least 4 yrs ago, or around then. does that excuse me? lolthe point is, once you have ttl serial, you could wrap it in any transport you want.

author: danb35
author_rank: Contributor
timestamp: August 15, 2015, 09:18:46 pm
content: I'm not a DMM snob (I have a TekPower, and I'm considering buying another one), but the VC99s I'm seeing on eBay are $30+. For that I might as well get the TekPower, and get the cable with it. Bluetooth would make it interesting, though...

author: retiredcaps
author_rank: Super Contributor
timestamp: August 15, 2015, 10:05:08 pm
content: Quote from: danb35 on August 15, 2015, 07:18:13 pmFranky, a member here, might have spares to sell since he sells the Tekpower as well.http://www.ebay.com/itm/200912705694You can ping him on his ebay account or eevblog account name "iloveelectronics"https://www.eevblog.com/forum/profile/?u=26834

author: Deathwish
author_rank: Unknown
timestamp: August 15, 2015, 10:10:06 pm
content: I have a uni-t 61D , i like it.

author: ElectricGuy
author_rank: Regular Contributor
timestamp: August 15, 2015, 10:51:33 pm
content: Quote from: Deathwish on August 15, 2015, 10:10:06 pmx2

author: Macbeth
author_rank: Super Contributor
timestamp: August 16, 2015, 12:28:57 am
content: Quote from: ElectricGuy on August 15, 2015, 10:51:33 pmI've got a UNI-T 71D (actually the better Tenma 72-7732A with proper HRC fuses and input protection) and it has 9,999 data memory points as well as the USB data lead to read it all off later.I like it!- Oh, please don't confuse these with Daves rant on the UNI-T 71E...actually, why not - it's funny and well worth the watch!I've also got an unused Tenma 72-7730A (UNI-T 71B) same EU law protection and 100 point memory as well as USB data lead, probes, clips, thermocouple, software, case, etc. I got them both from toploser with trivial faults I fixed instantly and it's just sitting thereMy brother wants it but is being slow with the readies

author: danb35
author_rank: Contributor
timestamp: August 16, 2015, 08:05:14 pm
content: The UT-61* is on my short list, if it will work with QtDMM or some other Mac-compatible software--will it? The -71* is just right out of the budget. Internal data logging would be nice, but not $100+ nice for me at this time.

author: Unknown
author_rank: Unknown
timestamp: August 20, 2015, 06:28:49 pm
content: Quote from: danb35 on August 15, 2015, 07:18:13 pmIf that's the main thing you want, there are plenty of battery discharge testers for sale on eBay, many cheap:http://www.ebay.com/itm/Capacity-Tester-Indicator-for-0V-30V-Lithium-LiPo-LiIon-Battery-LCD-Display-/111296152208?hash=item19e9c48290http://www.ebay.com/itm/Digital-Lithium-Li-ion-NIMH-Battery-Capacity-Tester-Voltage-Detector-Discharger-/181719010510?hash=item2a4f4c0ccehttp://www.ebay.com/itm/DC-5V-USB-Battery-Capacity-Tester-Battery-Life-Internal-Resistance-Analyzer-/181743302391?hash=item2a50beb6f7The last one is less than $13, shipped.Search on "battery discharge tester" and "battery capacity tester".

author: danb35
author_rank: Contributor
timestamp: August 20, 2015, 09:55:53 pm
content: Quote from: danb35 on August 15, 2015, 07:18:13 pmI went ahead and ordered the TekPower, and it was delivered yesterday. As I bolded above, some reviews have suggested that the meter ships with a USB cable; mine did not--it came with the DB9 RS232 cable, just like my old one did. That isn't really a problem, just means I need to dig up a USB-serial adapter, but figured I should correct that.