To be 100% clear.... The negative sides (-) are common
The positive sides (+) are independent.So we should be able to put different (+) voltages on PWR1 and PWR2, and we should not expect them to back feed each other.
The behavior we were seeing was voltage from PWR2 was back-feeding through PWR1 and providing power to equipment that was on PWR1, even though the breaker to PWR1 was turned off.
bp
<part15sbs{at}gmail{dot}com>
On 5/10/2017 4:27 PM, Forrest Christian (List Account) wrote:
On the base unit, the - side of both DC inputs are tied together. It is designed that way, since it was designed to be powered from two positive sources.If you are connecting two -48VDC busses to the base unit by connecting 'common or return' to the + input on each, and the -48VDC bus to the - input on each, the base unit will internally connect both of those buses. As I described, this is by design because the unit was designed for + voltages, not negative ones.The next iteration of the base unit will handle this much more gracefully. I am not yet sure about whether the device will simply just support either +48VDC or -48VDC, or if you'll have to select it in some way (at ordering, with a jumper, etc....)On May 10, 2017 7:34 AM, "Sorin Esanu" <[email protected] <mailto:[email protected]>> wrote:Yes, neg48 plant. I’ll send the requested info. Thank you!On 10 May 2017, at 16:32, Forrest Christian (List Account) <[email protected] <mailto:[email protected]>> wrote: If we're still selling the same version of a product, we warranty it. We regularly replace things which are far older. I like to see the in field failures so I can roll the lessons learned into the next generation of products. Just send an email info [email protected] <mailto:[email protected]> with the serial (mac address) andyour address we'll send a ups label to ship it back to us. Please include a note as to what is wrong so I can remember whenI look at it. Oh, one thing I just noticed. .. is this a positive ground plant by chance? (I.E. -48) On May 10, 2017 7:16 AM, "Sorin Esanu" <[email protected] <mailto:[email protected]>> wrote: We’re monitoring A and B of our DC power plant. It is wired directly into the GMT fuses panel, A and B sides. This particular unit was installed over 1 year ago, close to 2 years. If your offer is still valid, let me know the procedure. Thanks!On 10 May 2017, at 10:32, Forrest Christian (List Account) <[email protected] <mailto:[email protected]>> wrote: Can you let me know more about your setup? Is this the unit you bought in November? (In case this is something which has gone weird with a batch, and somehow not caught by our test procedures). If you've got a defective one, we'll swap it, paying shipping both ways. On Tue, May 9, 2017 at 9:49 PM, Sorin Esanu <[email protected] <mailto:[email protected]>> wrote: We’ve experienced this exact same behaviour last week. It seems like PWR1 and PWR2 are acting like one now. We are in process of replacing all the SiteMonitor II devices with Tycon TPDIN-Monitor-WEB2, which can monitor more things and it’s a lot smarter. > On 10 May 2017, at 01:31, Bill Prince <[email protected] <mailto:[email protected]>> wrote: > > I think I have a SiteMonitor II with a problem, as I always thought that the two power sensors (PWR1 and PWR2) were independent of each other, and should have a pretty high impedance between then. > > We set up a new solar site, and put our load on PWR1 and the batteries on PWR2. As soon as we hook up either one of the sense wires, the breaker to the batteries (30 amp) pops, and all the lights go out. > > We can monitor one voltage on PWR1, or the same or different voltage on PWR2. However, if both are connected we blow the 30 amp breaker to the batteries. > > We've checked the polarity (both voltages are negative ground), and they are both "about" the same voltage (although we have monitored radically different voltage in the past (like 12V on one and 48V on the other). This is a 48VDC system, so we are seeing ~~ 56V on both right now, > > BTW, when we hook up just one of the sensors and leave the other open, we see ~~ 43 volts between PWR1 and PWR2. I haven't checked other SiteMonitors, but this doesn't seem right to me. > > > -- > -- > bp > part15sbs{at}gmail{dot}com-- *Forrest Christian* /CEO//, PacketFlux Technologies, Inc./Tel: 406-449-3345 | Address: 3577 Countryside Road, Helena, MT 59602 [email protected] <mailto:[email protected]> | http://www.packetflux.com <http://www.packetflux.com/> <http://www.linkedin.com/in/fwchristian> <http://facebook.com/packetflux> <http://twitter.com/@packetflux>
