That product listed below shows it for use in scada operations so it must have overcome the cal and drift issues. It is claiming a tenth of an amp accuracy.
From: Forrest Christian (List Account) Sent: Wednesday, August 30, 2017 2:24 PM To: af Subject: Re: [AFMUG] Cost effective battery charging and monitoring device Most of these should work, as someone has pointed out, you should be able to use a voltage divider to get it down to the range... If you put a 204 ohm resistor across the shunt input and 10K ohms in series with the shunt that should scale 5V down to 0.1V. If you need other ranges, see http://www.ohmslawcalculator.com/voltage-divider-calculator . I'd start with 10,000 ohms in the R1 field and 0.1V on the output voltage. The other challenge is that most hall effect sensors are relatively low accuracy, say 5%. Calibration seems to help, but isn't really applicable in this case. Add the uncertainty of the divider and you may not have the accuacy you want. Remember that the shunt input is only a 10 bit ADC, which means you only have 1024 steps. So for a 100A input, each 'step' would be 0.1A. Just be aware of this. On Wed, Aug 30, 2017 at 11:42 AM, Jesse DuPont <[email protected]> wrote: Would these work on a SiteMonitor? They output 1-5V DC based on current flowing through. https://flexscada.com/product/hall-effect-current-sensor-ac-75a-dc-100a/ Jesse DuPont Network Architect email: [email protected] Celerity Networks LLC Celerity Broadband LLC Like us! facebook.com/celeritynetworksllc Like us! facebook.com/celeritybroadband On 8/30/17 11:29 AM, George Skorup wrote: Yeah, about that. I wouldn't use those on 12VDC systems. Too much current. I've burned up a couple of the 10A shunts on Traco BCMUs that were running around 200W load on battery. 200/13 = 15 amps. Ungood. One site at about 225W, first time it went to battery, the shunt went kaput after 10-15 minutes and the site went down. I'm hoping Forrest comes up with some Hall effect stuff or even plain 20+ amp shunts that can be used on the SiteMonitor's existing 100mv input. Hall effect is nice because you don't have to be "in" the circuit. But I'll take what I can get. On 8/30/2017 10:26 AM, Adam Moffett wrote: Yeah, up to 10 amp. ------ Original Message ------ From: "Chuck McCown" <[email protected]> To: [email protected] Sent: 8/30/2017 11:18:36 AM Subject: Re: [AFMUG] Cost effective battery charging and monitoring device I think Forrest has them on his site with the site monitors. From: Sam Lambie Sent: Wednesday, August 30, 2017 9:15 AM To: [email protected] Subject: Re: [AFMUG] Cost effective battery charging and monitoring device Parallel. Site Monitor! Now where can I get a shunt? On Wed, Aug 30, 2017 at 9:09 AM, Chuck McCown <[email protected]> wrote: 4 batts in series or parallel? Shunt + sitemonitor would be a better way to go and you don’t have to write code. From: Sam Lambie Sent: Wednesday, August 30, 2017 9:06 AM To: [email protected] Subject: [AFMUG] Cost effective battery charging and monitoring device Hey all, I am getting away from using APC at a couple of our sites and right now I have installed a Tripp-Lite APS750 connected to 4 Deep cycle marine batteries for a total of 404 aH system. I'd like to be able to monitor the discharge rate of the batteries when power is out remotely. What have you guys been doing to that effect? I'm thinking a Pi and a shunt and some quick scripting classes on Python to put it all together... -- -- Sam Lambie Taosnet Wireless Tech. 575-758-7598 Office www.Taosnet.com -- -- Sam Lambie Taosnet Wireless Tech. 575-758-7598 Office www.Taosnet.com -- Forrest Christian CEO, PacketFlux Technologies, Inc. Tel: 406-449-3345 | Address: 3577 Countryside Road, Helena, MT 59602 [email protected] | http://www.packetflux.com
