So the upcoming base Base 3 will have that functionality at some point (hardware is there, software not yet)... but....
There are also lots of DMM's out there which have a SD card or USB stick which you can log to. For example, see page 48 in this document https://www.eevblog.com/files/EEVblog-121GW-Manual.pdf I also have a HMC8012 on my bench (not that inexpensive), but it does both current and voltage simultaneously, and can log indefinitely to a USB stick. If you want to go the cheap route, I'd probably just grab a raspberry Pi and an appropriate ADC hat. Or an arduino using the built in ADC (if there's enough resolution) and a SD card shield. Alternatively, there are standalone dataloggers out there, for instance: https://www.dataq.com/products/lascar/el-usb/el-usb-3-data-logger.html , with varying precision, amounts of storage, voltage ranges, etc. On Thu, Sep 19, 2019 at 8:32 PM Chuck McCown <ch...@wbmfg.com> wrote: > Constant current loads are easy. Like to have a data logger that does not > need to be connected to a pc. I can download the logs, make graphs etc. > but I might want the graphs to appear on the logger. > > Sent from my iPhone > > On Sep 19, 2019, at 8:12 PM, Forrest Christian (List Account) < > li...@packetflux.com> wrote: > > If you can make a *constant current* load, then it's as simple as graphing > voltage over time, and probably adding a low-voltage cutoff at the > appropriate voltage. If you take the measurements at a regular interval, > then you can also apply math to come up with a reasonable version of power > in addition to load. Lots of voltmeters have PC based loggers. > > The advantages of all of the loads I linked to are that they're well > designed constant current loads. As to the advanced software from West > Mountain radio, that probably isn't needed. What I was referring to was > the $1K per 1000 watts of load cell once you get above 150W, but compared > to a brand new dc load at those same wattages it isn't all that pricey. > > On Thu, Sep 19, 2019 at 8:03 PM Chuck McCown <ch...@wbmfg.com> wrote: > >> I can make the loads. I like Mtn west but they want too much for the >> advanced version of the software. >> >> Sent from my iPhone >> >> On Sep 19, 2019, at 6:01 PM, Forrest Christian (List Account) < >> li...@packetflux.com> wrote: >> >> The west mountain radio CBA IV can't really be beat for price and >> functionality. >> >> For around $200, you get a little USB-attached unit which can discharge >> up to the lower of 150W or 40A, at a constant current. So you can set the >> discharge to the 20 hour rate for a battery, and an app on the PC will >> will log and graph. For newer batteries, this almost always matches >> pretty well with the datasheet voltage. I use this fairly regularly to >> verify the smaller batteries I have around. If you stick with the 20 hour >> rate @ 12V, you're good up to around 250AH (250AH at the 20hour rate = >> 12.5A/150W). >> >> If you're looking at an entire array you're probably going to need more >> power - they have add on 'amplifiers' but they aren't cheap. Another >> option is to go get a real DC load with appropriate software. See >> https://www.youtube.com/watch?v=8y7mFXD8wII for an example. The rigol >> illustrated is good up to 350W, other manufacturers have pretty much any >> size you want, if you can afford it. There are also usually a few >> floating around ebay of older types, if you can find or write suitable >> software (i.e. write a python script to pull the data out at regular >> intervals). >> >> On Thu, Sep 19, 2019 at 7:32 AM Chuck McCown <ch...@wbmfg.com> wrote: >> >>> Discharge and logging. >>> >>> Sent from my iPhone >>> >>> On Sep 18, 2019, at 7:12 PM, Forrest Christian (List Account) < >>> li...@packetflux.com> wrote: >>> >>> Are you talking about doing a discharge test on a battery and logging >>> it? (Aka West Mountain Radio CBA IV, or the output from any of several DC >>> loads w/data ports) >>> >>> Or are you looking for current in/out graphing over a long period of >>> time on a system? This is pretty common and I *do* have solutions for >>> this. >>> >>> Or battery state of charge measurement? A victron BMV-700 series, or a >>> trimetric battery monitor /w some sort of logging? >>> >>> Or...? >>> >>> Also, if this is monitoring a live system, what are you charging it with >>> and does it have a data port on it? >>> >>> On Tue, Sep 17, 2019 at 7:35 AM Chuck McCown <ch...@wbmfg.com> wrote: >>> >>>> Just graphical discharge records. >>>> >>>> Sent from my iPhone >>>> >>>> On Sep 17, 2019, at 4:33 AM, Forrest Christian (List Account) < >>>> li...@packetflux.com> wrote: >>>> >>>> Nope, never got around to it. >>>> >>>> I've recently become aware of several products which do something >>>> similar to what I had in mind. What were you looking for? >>>> >>>> >>>> >>>> On Mon, Sep 16, 2019 at 5:09 PM Chuck McCown <ch...@wbmfg.com> wrote: >>>> >>>>> Did you ever build that battery tester characterizer thingy? >>>>> -- >>>>> AF mailing list >>>>> AF@af.afmug.com >>>>> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >>>>> >>>> >>>> >>>> -- >>>> - Forrest >>>> >>>> -- >>>> AF mailing list >>>> AF@af.afmug.com >>>> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >>>> >>>> -- >>>> AF mailing list >>>> AF@af.afmug.com >>>> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >>>> >>> >>> >>> -- >>> - Forrest >>> >>> -- >>> AF mailing list >>> AF@af.afmug.com >>> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >>> >>> -- >>> AF mailing list >>> AF@af.afmug.com >>> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >>> >> >> >> -- >> - Forrest >> >> -- >> AF mailing list >> AF@af.afmug.com >> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >> >> -- >> AF mailing list >> AF@af.afmug.com >> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >> > > > -- > - Forrest > > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > -- - Forrest
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