I have one shunt with two WBjr's connected to two Midnite Solar Classic 250's. My Midnite Solar web page shows different values for the WBjr current. Is the difference because the time the web page polled the data is a few minutes different? The Classics should be showing the same WBjr current, correct?
Thanks,
Jeff
There may be variations on how you have the two controllers wired up ?
That would probably make a difference on what they read. To be even every wire would have to be exact same resistance in it's path to the shunt and beyond , and maybe internal variations in each controller components and or how they are programmed.
How far off are the values from each other ?
Larry
Larry,
Thanks for your response!
One was reading 4-5 amps and the other 25 amps.
I figured out the Classic with the low reading had the WBjr wire disconnected. Oops. Reconnected and they are reading nearly the same. Any difference i see can easily be due to the times when each was read, sometimes they are a minute or two different.
Jeff
oh wow - that was a big difference !
Always nice to find an easy fix
Larry
Larry,
Looking at the My Midnite monitoring, I see aprox 17 amps on my second Classic, with the WBjr wire disconnected and the aux configured to something other than WBjr, and off. Classic number one shows aprox 22 amps, with aux configured for WBjr and on. I think the 22 amps is correct. I don't have a clue where My Midnite Monitoring picks up the 17 amps on Classic 2.
I have noticed in Graham's Android App, that if I have the WBjr connected to my Classic 2, Classic 2 aux configured to WBjr and off, Grahams app will read Classic 2 WBjr. If I configure Classic 2 aux to something other than WBjr, it won't read the fake amps from the Classic 2 WBjr.
I think I have seen a Classic showing 4-5 volts PV in at night or sometime when it I don't think it should show amps. I don't know if this is the same sort of thing as the WBjr showing amps when there isn't a WBjr connected.
Any clues why my Classic 2 WBjr is showing amps on My Midnite monitoring with Classic 2 aux set to something other than WBjr and WBjr wire disconnected?
Thanks,
Jeff
Quote from: JohnsIsland on April 01, 2025, 03:44:00 PMLarry,
... I think I have seen a Classic showing 4-5 volts PV in at night or sometime when it I don't think it should show amps. I don't know if this is the same sort of thing as the WBjr showing amps when there isn't a WBjr connected.
Any clues why my Classic 2 WBjr is showing amps on My Midnite monitoring with Classic 2 aux set to something other than WBjr and WBjr wire disconnected?
Thanks,
Jeff
Hi Jeff,
The PV input voltage readings, at night, is due to the Power FET switch leakage current inside the Classic -- that PV input is floating, and the other side of the FETs is connected to the battery +.
Would guess that the Classic 2 readings are probably just a bit of noise. Full-scale voltage for 500 Amps is only 0.05 volts, so even a small amount of noise could cause some reading ... IMO.
Vic
Vic,
Thanks for the information. FET leakage and noise makes sense and is helps me understand the system a bit more.
It's interesting how the Classics work. Midnite Solar provides fantastic support for there hardware. The Classics seem to be built like tanks. I wish Midnite had a smaller 12 volt inverter, built like a tank, for us with itty bitty systems. Or perhaps I wish my retirement budget was a bit bigger!
What started me chasing the WBjr information is Graham's Android app is designed so that WBjr's are specific to a battery bank (if I understand it correctly.) I have e-mailed Graham asking him if he would modify his app so I can have two WBjr's for one battery bank and not include the second WBjr in the Consumption calculation. I hope it is as simple as including an option to ignore all but the first WBjr and the noise won't affect the Consumption calculation.
Thanks again for your info and reply,
Jeff
Do you have your two Classics connected and in Follow Me mode ?
That is the best way for two Classics to charge one battery.
Larry
ClassicCrazy,
Sorry for the late response...
I have the Classics connected and configured for Follow Me mode.
I have two shunts because the system could produce more than C10 of my batteries. It's nice to have the extra panels in winter for charging and to have extra power for running daytime loads especially in summer.
This will be my first summer with this system, I am looking forward to seeing how many amps the system will produce during the summer. I haven't figured out how to tell what the system is capable of producing, when its not in bulk. I might try connecting extra loads to figure out what the system is capable of.
Jeff
Jeff
Yes you would have to turn on lots of loads until you see the power start to go negative on the shunts .
You can use the Aux contacts to turn on loads if you want to try to use all your power.
I just got used to having lots of extra power available since I can't use all the power.
But if you have enough water to heat that is a good load .
I made a video about how I used Classic Aux2 contact to pwm extra AC power via inverter to hot water heater coil. But that was more useful when I was using lead acid batteries. With lithium there isn't extra power to try and siphon off while charging - it is just easier to turn load on all the way. I was using an igbt for turning higher voltage pv direct to heater coil. But now I use a rated DC contactor to do that.
Here is video of my hybrid hot water heater where I used direct pv and power from inverter . I have another video where I bypassed power around controller to a resistance load using a contactor.
What I have now is some bypass breakers that will switch pv power either direct to water heater or to controller - but only one at a time . And this is manual. With some contactors I could automate it .
https://youtu.be/s7trVpHLts4
https://youtu.be/1Vjfv_GMH94
Larry