Classic Lite 150 + Reverse Diversion

Started by flabroker, February 28, 2014, 08:40:36 PM

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flabroker

OK, being the typical male, I never ask for directions or instructions. But I am just plain tired of trying to figure out how to get this to work properly.

First off, I just updated to the latest firmware.

I would like to set up Aux 1 or Aux 2 to power a Solid State Relay "On" at a low battery voltage like 24.6 volts and then terminate or turn off power "Off" at a high voltage like 26 volts.

Using dump load logic, the diversion does just the opposite. With so many Aux 1 and Aux 2 options, I assume it has to be possible, but just have not been able to get it to work. I would like to use voltage specific cut-in and cut-out and not state of charge.

I have been able to get 12volts + out of aux 1, just can't get it to do it at the specific voltages I want it to.

Thanks for any help. I have not been able to find any related thread.

FlaBroker.

What I Got... 12 Renogy 300 watt panels and 2 Midnite Classic Lite controllers and 24 6 Volt Batteries @ 215 amp hours 24 volts + 2400 watt sw inverter.

dgd

Quote from: flabroker on February 28, 2014, 08:40:36 PM

I would like to set up Aux 1 or Aux 2 to power a Solid State Relay "On" at a low battery voltage like 24.6 volts and then terminate or turn off power "Off" at a high voltage like 26 volts.

Using dump load logic, the diversion does just the opposite. With so many Aux 1 and Aux 2 options, I assume it has to be possible, but just have not been able to get it to work. I would like to use voltage specific cut-in and cut-out and not state of charge.


AFAIK you can't do this. The Classic AUX outputs are only state-of-charge based.
eg if Classic is resting then auxs will never enable based on battery voltage.

dgd
Classic 250, 150,  20 140w, 6 250w PVs, 2Kw turbine, MN ac Clipper, Epanel/MNdc, Trace SW3024E (1997), Century 1050Ah 24V FLA (1999). Arduino power monitoring and web server.  Off grid since 4/2000
West Auckland, New Zealand

cybermaus

NOT TRUE.
There are a few setting that do not work classic is resting, but there are also settings that remain working during sleep. I had it running like flabroker wants for almost a year. (till the SOC% update last month)

@ flabroker

I am not near the Classic now, so do not know exact, But if you are in the Aux menu where you set diversion, one of the either the left or right button directly under the panel will say something like 'more' or 'time' or 'volts'. Press that and you can get to where you set the voltages and also delay times.


But question: What is your goal? Do you want to divert or dump power to avoid over-voltage, or just switch on users without risk of deep-discharging the battery. For me it was the last.

But allowing users based on voltages is not ideal. Especially if they are medium to high current users, you could get into a 'cycle': battery high, users on, voltage drops, users off, voltage rises ... etc.

For that reason, I had a 10 minute (600 second) delay on the on/off settings. But now they have the WBJr and SOC% which switches on battery percentage, and it is all much nicer. It may be a bit of an investment, but if your use model is the same as mine, you want to get a shunt and the WBJr. But you can do that later also if you want to try voltages first.

Do connect the relay to Aux1 though. You will want to keep Aux2 reserved for that later WBJr.




dgd

#3
Quote from: cybermaus on March 01, 2014, 02:44:24 AM
NOT TRUE.
There are a few setting that do not work classic is resting, but there are also settings that remain working during sleep. I had it running like flabroker wants for almost a year. (till the SOC% update last month)

Ok, I defer to your experience with this. I did try about 2 years ago to get an AUX1 enabled to start a genny on low voltage setting then get it to turn off when a set higher voltage was reached.
Maybe I missed something but I could never get it to work when the classic was in resting state.  In the end I used the inverter for this.
dgd
Classic 250, 150,  20 140w, 6 250w PVs, 2Kw turbine, MN ac Clipper, Epanel/MNdc, Trace SW3024E (1997), Century 1050Ah 24V FLA (1999). Arduino power monitoring and web server.  Off grid since 4/2000
West Auckland, New Zealand

flabroker

Quote from: cybermaus on March 01, 2014, 02:44:24 AM

But question: What is your goal? Do you want to divert or dump power to avoid over-voltage, or just switch on users without risk of deep-discharging the battery. For me it was the last.


My goal is to kick on an a/c charger automatically when the volts get too low and disconnect when the battery is in a safe range. I would rather pay for a little bit of grid elec than deep discharge my batteries. Right now it is configured to do this manually and I do not have to do it that often, but if I am not at home or it happens in the middle of the night, I would like for it to be automatic.

We had a few days this winter that were zero sun and lots of rain that I decided to kick over to grid because my family is still getting used to conserving. Right now they are using the word "emergency" to do a load of laundry or run the dishwasher during off peak hours.

Halfcrazy

Low bat Disconnect will be active below a set point so it should work well for this. This mode is active regardless of the state of the Classic (IE Resting bulk float etc)
Changing the way wind turbines operate one smoke filled box at a time

flabroker

Quote from: Halfcrazy on March 01, 2014, 10:37:32 AM
Low bat Disconnect will be active below a set point so it should work well for this. This mode is active regardless of the state of the Classic (IE Resting bulk float etc)

Let's use this as an exemple:

Turn on (or send 12v to switch) SSR at 24.2 battery volts and turn off SSR at 25.6 battery volts.

I want to protect the batteries from deep discharge but do not want the charger to top them off and do an absorb cycle. This is for protection only.

My inverter will do this but, it doesn't kick on until 22 volts and then stays charging until 29.2 my batteries rarely go below 24.8 and I would not want the charger to kick on until 24.2 but also wouldn't want it to stay on past 25.6 (This will protect the batteries but save on grid power.)

flabroker

Low Battery Disconnect will not allow to set the Off volts higher than the On volts.

TomW

Quote from: flabroker on March 01, 2014, 11:18:36 AM
Low Battery Disconnect will not allow to set the Off volts higher than the On volts.

I checked this and it is true. Wonder if you could invert the switching state somehow?

A DPDT relay might work if wired correctly. On when not energized, Off when it is energized? No connection to the contacts that are active when off, power to the other set?

Just a thought. Downside may be it being mechanical but if not cycled much should be fine.

Tom
Do NOT mistake me for any kind of "expert".

( ͡° ͜ʖ ͡°)


24 Trina 310 watt modules, SMA SunnyBoy 7.7 KW Grid Tie inverter.

I thought that they were angels, but much to my surprise, We climbed aboard their starship and headed for the skies

TomW

I think I got something wrong in there? Haven't reached my caffeine target level yet.  :o

Inverting the output state should let you set numbers it can use properly? Maybe a better option for AUX1 altogether?

Still mulling it over.

Tom
Do NOT mistake me for any kind of "expert".

( ͡° ͜ʖ ͡°)


24 Trina 310 watt modules, SMA SunnyBoy 7.7 KW Grid Tie inverter.

I thought that they were angels, but much to my surprise, We climbed aboard their starship and headed for the skies

cybermaus

I used diversion in the past, but I wanted to switch exactly the other way around.
I'd have to play with it to see if there is one that switches your way. But I am away from the solar again.


But taking a slight step back? Are you sure this 'extra charge' on low battery voltages is smart?

Not only is there still the risk of a feedback loop in the voltages, causing the relay and charger to turn on and off rapidly.

But also you are using (expensive?) grid power, and feeding it through a charger (80% efficiency) a battery (90%) and an inverter (80% ) causing overall 58% efficiency and wearing your battery out one extra cycle.
I simply switch the mains (230 for me, maybe 120 for you) on and thus the inverter off and let the solar power charge the battery at leisure.

It may take the solar a longer time to do so, but energy wise, it is better to use the grid at 100% efficiency direct, then trough the battery chemistry at 42% loss.



flabroker

cybermaus,

I understand your reasoning for using Grid power direct instead of charging the batteries, but as I said this is just a rare occurrence and for protection only. When I am here at the house, I can do many things differently. My concern is when I am not at home monitoring the system on a winter day or rainy couple days that the system gets drawn down further than I like to see it. I would rather have the charger kick on and protect the batteries than have them cycle too far below where I like to see them. I am still training the family to be aware of our available power and uses. If I simply invested in another dozen batteries or so, I guess I wouldn't have a problem. The 12 panels I have easily generate enough kwH's for three days for us on an average charging day.

There are other devices on the internet that will control the SSR and do what I want, but I was hoping to use the Classic as I monitor the App from my office at work and could see if it is engaged or not.

cybermaus

#12
Ok then. It was just an consideration

Quote from: flabroker on March 01, 2014, 11:18:36 AM
Low Battery Disconnect will not allow to set the Off volts higher than the On volts.

As to low bat disconnect:

Quote from: manual page 39Low bat disc
This mode will turn Aux 1 off when it reaches a set point based on battery voltage (V High) and turn it on
at another set point based on battery voltage (V Low). It also allows you to set a delay time in seconds the
Classic will wait before turning Aux 1 off after reaching the V High set point. It also allows you to set a
hold time in seconds the Classic will wait before turning Aux 1 on after reaching the V Low set point. This
can be used with a NC relay when the battery gets to the set point the Classic will send 12vdc to the relay
holding it open and disconnecting the load.

Its for use with an NC (normally closed) relay, and you have (as almost all SSR) an NO (normally open) relay.
My guess is MS did this because they do not want to have a coil-activation current active on an already low-bat. Over days/weeks of unattended operation, even a 100mA of a light non-SSR relay could kill the battery.

So as mentioned in one of the posts above you would need an inversion of the signal. The simplest is to add a cheap and simple NC relay to your setup. A very small one will already do as it only needs to power the driving gate of the SSR.


Alternatively, you could still go the SOC%/WBjr route. It not yet in the manual, but they were nice enough to add both high and low logic to the SOC% switching.

Halfcrazy

Wait low battery disconnect should do everything you want?

It is supposed to go down to a low voltage and then provide power (12v) after the delay time is satisfied
Then it should wait till it gets to a higher voltage and remove the 12v signal after a hold time is reached

So you are saying the voltages are backwards and it does not work? If so I can get that fixed as it is supposed to work

Ryan
Changing the way wind turbines operate one smoke filled box at a time

Halfcrazy

Quote from: flabroker on March 01, 2014, 11:01:53 AM
Quote from: Halfcrazy on March 01, 2014, 10:37:32 AM
Low bat Disconnect will be active below a set point so it should work well for this. This mode is active regardless of the state of the Classic (IE Resting bulk float etc)

Let's use this as an exemple:

Turn on (or send 12v to switch) SSR at 24.2 battery volts and turn off SSR at 25.6 battery volts.


Thats exactly how it should work.

So batteries fall to 24.2 after the adjustable delay time is met the Aux sends out 12vdc to turn on the SSR and connect the grid
When the batteries reach 25.6 and the adjustable hold time is met the Aux removes the 12v to the SSR disconnecting the grid
Changing the way wind turbines operate one smoke filled box at a time