The challenge with higher current shunts is how much power is dissipated by the shunt. A 20A shunt at maximum will dissipate (waste) around 2 watts. I know this doesn't sound like a lot, but when you're talking a tiny device on a circuit board, it is.
I've recently redesigned the shunts and currently have a couple under test. The new shunt has a connector suitable for over 10A (the old was rated for 12), and am hopeful that I can get 20A to work, but the first try didn't go so well, unless you like melted mounting hardware. (The good news is the shunt electronics survived just fine). I've changed resistive elements and plan on using them for 10A and 20A models but am waiting for everything to come in to test in the next day or two. If you've got a 10A shunt order on backorder with us this is why. The other thing I continue to mention is that shunts above 10A are relatively easy to come by or as Chuck points out, make. (Google 20A 100mV as an example of buy). I know they're not on a din track - and I'm aware of the form factor desire to have them on the DIN rail On Wed, Aug 30, 2017 at 11:29 AM, George Skorup <[email protected]> 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 <%28575%29%20758-7598> Office >> www.Taosnet.com <http://www.newmex.com> >> > > > > -- > -- > *Sam Lambie* > Taosnet Wireless Tech. > 575-758-7598 <(575)%20758-7598> Office > www.Taosnet.com <http://www.newmex.com> > > > -- *Forrest Christian* *CEO**, PacketFlux Technologies, Inc.* Tel: 406-449-3345 | Address: 3577 Countryside Road, Helena, MT 59602 [email protected] | http://www.packetflux.com <http://www.linkedin.com/in/fwchristian> <http://facebook.com/packetflux> <http://twitter.com/@packetflux>
