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 <[email protected]> wrote: > Discharge and logging. > > Sent from my iPhone > > On Sep 18, 2019, at 7:12 PM, Forrest Christian (List Account) < > [email protected]> 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 <[email protected]> wrote: > >> Just graphical discharge records. >> >> Sent from my iPhone >> >> On Sep 17, 2019, at 4:33 AM, Forrest Christian (List Account) < >> [email protected]> 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 <[email protected]> wrote: >> >>> Did you ever build that battery tester characterizer thingy? >>> -- >>> AF mailing list >>> [email protected] >>> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >>> >> >> >> -- >> - Forrest >> >> -- >> AF mailing list >> [email protected] >> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >> >> -- >> AF mailing list >> [email protected] >> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >> > > > -- > - Forrest > > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > > -- > AF mailing list > [email protected] > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > -- - Forrest
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