Power integrating multimeter (or power meter) suggestion - Page 1
Forum section: electronics / testgear

author: diegogmx
author_rank: Contributor
timestamp: April 05, 2020, 04:19:35 pm
content: Hi, i was wondering if anyone has a recommendation for a multimeter or other device capable of integrating power usage, much in the way an electronic load does, it should sample at least at 1khzthanks

author: rvalente
author_rank: Frequent Contributor
timestamp: April 05, 2020, 04:37:15 pm
content: A power meter is what you are looking...DC or AC power?For low voltage DC you may even use those from hobby RC

author: diegogmx
author_rank: Contributor
timestamp: April 05, 2020, 04:39:45 pm
content: just dc, in average a few uA, with bursts of 300ma lasting some ms, and for some reason while searching power meters i mostly found big ac onesthe voltage is indeed low, at most 5v

author: rvalente
author_rank: Frequent Contributor
timestamp: April 05, 2020, 04:53:17 pm
content: Well, your scope could do that...A simple shunt resistor, probe voltage, probe current and do V*I in the scope...Would that work for you?

author: ogden
author_rank: Super Contributor
timestamp: April 05, 2020, 05:16:20 pm
content: Other option: Keysight power analyzer.https://www.keysight.com/en/pc-1113932/dc-power-analyzer

author: diegogmx
author_rank: Contributor
timestamp: April 05, 2020, 05:28:55 pm
content: Quote from: rvalente on April 05, 2020, 04:53:17 pmI know the scope can do that, as a matter of fact i use it to measure the bursts, i need something to measure on longer periods so as to verify how the battery of the device i'm building behaves on the long term, meaning a few days (by increasing the burst frequency to discharge in reasonable time, otherwise years)Quote from: ogden on April 05, 2020, 05:16:20 pmthat looks beautiful, i fear though i may have to sell a kidney to buy it

author: nctnico
author_rank: Super Contributor
timestamp: April 05, 2020, 05:31:28 pm
content: Recently someone pointed to a unit from GW Instek which can do AC+DC power metering. IIRC the price is around 800 euro.

author: cgroen
author_rank: Unknown
timestamp: April 05, 2020, 05:44:33 pm
content: Joulescope ?

author: diegogmx
author_rank: Contributor
timestamp: April 05, 2020, 07:33:33 pm
content: Quote from: cgroen on April 05, 2020, 05:44:33 pmi like this one

author: ogden
author_rank: Super Contributor
timestamp: April 05, 2020, 07:37:10 pm
content: Quote from: diegogmx on April 05, 2020, 05:28:55 pmWhat scope you have? Is it listed here?https://sigrok.org/wiki/Supported_hardware#OscilloscopesI ask because you possibly can capture current/voltage waveforms using some software (sigrok?).When you have .csv file - then hopefully you will know what to do, right?QuoteNext time mention "hobby" then.

author: diegogmx
author_rank: Contributor
timestamp: April 05, 2020, 08:55:37 pm
content: Quote from: ogden on April 05, 2020, 07:37:10 pmactually startup without tens of thousands in financingand i have a hacked mso5074, it's not on the list, and a typical oscilloscope doesn't have enough dynamic range nor autorange so i would have to do 2 measurements, one with a multimeter at sleep and one with an oscilloscope for the bursts and then calculate based on that, which is precisely what i'm trying to avoidand yes, of course i know what i would have to do with that csv file if it were useful

author: helius
author_rank: Super Contributor
timestamp: April 05, 2020, 08:58:01 pm
content: THS720P

author: ogden
author_rank: Super Contributor
timestamp: April 05, 2020, 09:17:52 pm
content: Quote from: diegogmx on April 05, 2020, 08:55:37 pmWhat is sleep current, active current and battery capacity? How much % of battery capacity will be drained by sleep consumption during 48h accelerated test? I bet it is below expected accuracy of total power measurement. If so, then why you need high dynamic range power measurement at all?

author: diegogmx
author_rank: Contributor
timestamp: April 08, 2020, 11:21:26 am
content: the total power usage vs the total won't be that significant, nevertheless it is nice to have, especially when we want to switch to test at varying temperatures, and if we want at some point to do an extended testing period even more

author: ogden
author_rank: Super Contributor
timestamp: April 08, 2020, 04:57:37 pm
content: Quote from: diegogmx on April 08, 2020, 11:21:26 amPut two DUT's in the environmental chamber - one for active current another for sleep current measurement. It would be much cleaner experiment anyway. Note that you can't accelerate battery tests too much due to internal heating of battery itself. I still do not see need for fancy wide dynamic range power measurement instrument, yet in case my advice is not what you want to hear - just get joulescope.

author: diegogmx
author_rank: Contributor
timestamp: April 09, 2020, 12:03:41 am
content: ok, i think you are likely right