Need help with all the settings on my Classic 150

[Lisa234]

Hi, I just logged on here and I've got a ton of questions and not really sure where to start.
About six months ago my partner and I bought an 'Off-grid solar cabin Kit' from Home Depot that included the Midnite Classic 150, plus six 300w solar panels and a couple of wires and breakers -- and that was it! We thought we were getting an easy and simple do-it-yourself kit but of course we had to figure out a lot, and we also had buy a LOT more stuff in order to complete the system.
Anyway, we just finally finished mounting and wiring the system and now we're trying to figure out how to set all the different settings. I watched the youtube videos posted by Midnite Solar and then referred to my battery spec sheet for guidance, but that still leaves me guessing as to how everything should ideally be set. There is still a fair amount I don't "get" about this controller but we do have it running right now and we have a decent load on it and everything seems fine. But -- the Classic's fan is running pretty much non stop which has me concerned.  It is a fairly warm day today, about 75f.  Anyway should I be concerned?

Here are my 'guesstimate' settings:

I have my EQ set to 28.8v.  My absorb is also set at 28.8.   Float is at 27.6  (all 4 batts are brand new)
Absorb time 2 hrs.  EQ 1hr. 15 mins.
T-comp -5. mv (default)  (I have no idea what this is about)
I have the intermittent EQ set to once every 59 days -- for 1 hour. (have no clue what this setting should be)
Rebulk is set at 25.5v
Charge output 96amps (default).  Input 99 (default)
T-comp  min: 26.4v   max: 30     (default settings)

My system:  6 300w Renogy panels  wired 3s2p
                   Midnite Classic 150 CC
                   4 AGM Renogy 12v 200 amp batteries  wired 2s2p
                   Aims 3000w Inverter 
                   I do not have the Whiz Bang Jr. I have a Renogy battery monitor instead.

I would welcome any input from any kind person who understands this better than me, which I'm sure is most everyone here!

Lisa

[boB]

Welcome Lisa !

Yeah, sometimes that fan just likes to run when it is warm.  The Classic will tend to heat itself up a bit also and when it is warm out, it heats up more.  I would say that as long as the Fan goes off at ALL, it should be OK.  If it stays on like ALL of the time, even at night when the Classic is "Resting", then something might be making it stick on.  That can be remedied if that is the case but I expect things are actually OK there.

Your settings for Absorb and EQ are OK.  Typically EQ or Equalize isn't all that necessary even.  When those two voltage set-points are set the same, the EQ won't be any different than the Absorb cycles happening 2 hours at at time.  But it won't hurt to have it set the way you do, every 59 days.  Just playing with things like that should be good to kind of get to know the system or at least the menus in the Classic's display.  OK, so far so good...

As for the Absorb voltage and time that you chose, 28.8V or so, that sounds about right...  BUT the real settings should be specified by the battery manufacturer.   And you also chose the typical correct value of -5mV per degree Celcius temp comp.
What that means is that the Absorb voltage (and Float voltage after the Absorb has done its 2 hours) will go DOWN by 5 thousandths of a volt for every cell in the batteries when the batteries temperature goes up one degree C.   Lead Acid batteries usually are made up of 2V cells.  That -5mV is for each one of those.  You have a 24volt battery so you have 12 of those 2V cells.  5 mV times 12 is 0.060 volts per degree C total ( -60mV / degree C)  so you won't see much if any change in Absorb voltage if those batteries voltages change by just 1 degree C.  Maybe 0.1 volt ?

The reference temperature for the temperature compensation voltage is at 25 degrees C or around 77 degrees F.  Did you plug in the battery temperature sensor and stick it on one of your batteries ?  You can go to the TEMERATURE menu on the Classic remote control and see what the Classic thinks that voltage is.  So if your batteries are at 30 degrees C (5 degrees different than 25C) then the charging voltage will go down by 0.06V times 5 = 0.3 volts.

When that happens, your Classic, instead of charging the batteries at 28.8V will be trying to charge them at 28.5 volts.

The opposite happens when the batteries are colder than 25 degrees C.

OK, enough for right now.  Others will come on here as well.  Yeah there is a LOT to learn but if you keep your batteries in good shape and the panels clear and hopefully the fan(s) are just because it's warm now, you should have a great system.

You may find out eventually that you need or want more batteries or solar panels but this is a good start !  And be careful not to use too much electricity and wear down the batteries too much each day so that they have a long life.  Usually, 50% discharge is good.
If you find yourself discharging the batteries almost all the way most days, then you may need twice the battery capacity overall.

boB

[ClassicCrazy]

What are the ratings on the panels ? 
You could use the Midnite String Calculator to give you ( and us ) more info .
Just put the numbers from the back of one of your pv panels in here https://www.midnitesolar.com/sizingTool/
If you  have the PV string voltage a lot higher than the charging voltage that will tend to make the fan run more as long as it is charging.
The Whizbang is well worth the investment - you will also need a shunt with it and not to hard to install in your system. With the Whizbang you will get a very close estimate of exactly what the SOC State of Charge of your batteries are and also be able to use Ending amps to terminate the Absorb and go to Float - it is better than just using hours .  But you need to figure out the correct value for ending amps using some observation of your system at first.
But otherwise like Bob said most of your settings look okay - except check on battery temp compensation value  - some batteries are -3mv instead of -5mv .
Also if you have Android phone get the Classic Monitoring App off of Google Play .

Larry

[Lisa234]

Hi boB and Larry,  I really appreciate your help on this!

Firstly, no, the Classic's fan isn't on all the time, just maybe about 60 percent of the time when there's a load on it, and at night (when I don't have a load on the system) its totally quiet. With everything being new to me I'm sort of nervous about everything right now.  There was also a sort of sulfur, electronic smell about the Classic on the first two days but I think that's dissipating now. The inverter makes a bit of a hissing sound when we first turn it on, so all these little things have our (hyper) attention and have been giving me a nervous stomach.

So as to the temp...  My partner did hook up the blue temp sensor (long blue wire from the Classic to the battery bank) but he has it hanging between two of the batteries -- I think we read (somewhere) it's not necessary to adhere it to the battery.  Should we stick it to the side of one of the batteries?  And that said, I can't find where the temperature menu is!  You said it's on the Classic "remote" control?  Not sure what you're referring to.  I looked for it in the Classic's main menu where everything else is, and couldn't find it.  I probably should mention I don't have the Classic hooked up to my internet. I don't have a cell phone so I'm assuming I wouldn't be able to hook the system to my computer since it requires an APP. ??

"As for the Absorb voltage and time that you chose, 28.8V or so, that sounds about right...  BUT the real settings should be specified by the battery manufacturer."

I'll attach my battery spec sheet and maybe that will clarify whether I've got this at a good setting or not. I could email Renogy but last time I did they took nearly a month to answer.

Larry, I'll go up on the roof tomorrow and get that number off one of the panels and take it to that link you gave.  I think we're okay regarding the fans but I'll check on that anyway.

As to the Whiz Bang, unfortunately the Whiz Bang was one of the things not included in the kit. Gosh darn it. I didn't hear of the Whizbang till after I'd bought a Renogy batt monitor, which is a good quality monitor and cost about a hundred.  It's hooked up and giving me very good readings but now I've learned that I can't calibrate the Endamps unless I have the Whiz?  So, is this pretty important to be able to do?  Actually at this point I have no idea what the Endamp function is.  I read about it but it it was a little too technical for me to follow.   
Anyway, fortunately so far we've been able to mount and wire up everything, plug stuff into it, and so far nothing ruined!  As to the batteries, we'll probably never discharge them much at all.  This is just a back up system for us that we wanted to have for when our PG&E shuts down -- which it's been doing a lot lately. We're just going to use it mostly during daylight hours to power a few things that I run during the day. Batts may never need to drop below 80%.  But that raises the question of breaking the batteries in.  I'm thinking perhaps I should make a point to drain them at least to 80% for about fifty times, so that they're broken in ??  Or perhaps more??  Wow, is this complicated or what???!!

Anyway, thanks again guys!  I really appreciate your help soooooo much!

Lisa

[ClassicCrazy]

Most AGM batteries have the same voltage setpoints . You don't want to equalize  - in the most common sense of the term which is a controlled overcharge.  But since you have the equalize voltage the same as the absorb you are okay - though I would just just disable equalize for an AGM battery .
If your battery supplier won't give you good info just look up AGM batteries for another battery supplier and you will learn the general characteristics and care of them.
Not sure if you wired the batteries or if they came prewired but with the parallel connection you want to take special care so the wiring is correct otherwise the charge discharge may favor one string over the other.
Look at this for more info
http://www.smartgauge.co.uk/batt_con.html
I am not familiar with the Renogy battery monitor.  Do you know if there is a shunt in the system that it connects to ? The shunt would be the first thing that the battery negative terminal connects to if it was there - and all the other negative connections would be on the other side of it. 
You should consider getting a router which wouldn't even need to be connected to the internet - any old router should work - to plug the Classic into. That way you could program and monitor using apps on computer or android phone or tablet.  Makes life easier for sure.
Yes to all the fan sounds and noises controllers and inverters can make.  Mine are not where I can hear them all the time so I don't take too much notice most of the time. It sounds like the fan on your Classic is working normally.
Yes there is usually a break in for new batteries to get them to their full capacity .  Again look up AGM batteries on East Penn Deka or Rolls or some other battery company if you can't find the info from Renogy . Or here https://batteryuniversity.com/learn/article/absorbent_glass_mat_agm
I have to run but can answer more questions later.

Larry

[Vic]

Hi Lisa..,

If your Renogy PVs are Polycrystalline,   then this is probably the spec for them:
file:///C:/Users/OMX/Documents/Renogy%20300-W%20Poly%20PV%20Spec.pdf

Couple of things.   In an ideal world,   if the above PVs are the ones in your system,   the best PV string configuration would probably be three strings of two PVs.  This will reduce the input voltage into the Classic. And,  depending on the coldest temperatures at your location,  on cold mornings/days,  the input voltage might be so high that the Classic will shutoff,   protecting itself.   Restringing PVs can be a bit of a pain,   AND,   when there are PV strings of three or more,   an added electrical box with circuit breakers needs to be added,   for safety and debugging convenience.   This would change the PV wiring,  a tit. (not to rain on the Parade,  too much).

Some research needs to be done to check the proper battery charge temperature compensation value.   AGM batteries often use between about  -3-4 mV per cell.   Your setting of  -5mV,  is fine for now.  Will try to confirm the exact desire of your batteries.

Do you know the coldest temperature for the location of your cabin? This would help to determine the maximum input voltage for your system,  in cold WX.

Using the string calculator has been mentioned in this Thread,   we could run that calculator for you,  if you could confirm the PM model number,   the coldest and warmest temperatures.

Welcome here,  Lisa.  Thanks for added info, Vic

[Lisa234]

Hi Vic, thanks so much for your answer.  Really appreciate everyone's help.

We actually have the monocrystalline panels.  We can't get the info from the backs of the panels, they're bolted to the roof. But I did get the specs from the Home Depot site and I'll attach them to this post. We tried to fill in that string calculator but were not able to figure out which numbers went where, as terms are different.  Maybe someone can help with this...

[Vic]

Hi Lisa,

The Renogy 300W Mono PVs that you are using (60 Cells,  vs 72 cells for the Poly PVs),   have a lower operating voltage.

Forget what I had said about high operating voltage going into the Classic.   You should never see any issue with high input voltages,  even on the coldest day.

Strings of three PVs should be fine.

Will try to confirm the charge temperature compensation for your AGM batteries.

Later,  thanks,  Vic

[Lisa234]

Great Vic, that would be great to know.

Lisa

[Lisa234]

Hi Larry, here's a link to the battery monitor:  https://www.renogy.com/500a-battery-monitor/
Yes it came with a shunt and that's attached on the neg side of the battery.  The monitor is working and also has a temp sensor but I can't get a read out on temp from that either.  Weird!  I've got two battery temp sensors and my system doesn't want to tell me what the temp is!   

Anyway, I'm still sort of trying to understand why I have to get a Whizbang. It's going to be a hassle to fit it into our arrangement, so before I get it I want to know why I gotta have it.  What if I reset the "absorb" time from two hours to one hour?  Would that be a bad idea?   As I said we're not going to be using the batteries much so if not having a Whizbang means they'll last a few days less I could live with that. Btw, the batteries are all wired properly and in fact all wired with 4/O cable.

I don't know what a router is.  Will it let me see the temperature of my batteries??? 

More stuff....  I guess that's fine as long as the end result is, my life becomes simpler 


p.s.  Sorry for all the crying!

[boB]

Lisa, you do not "need" the Whizbang Junior.  It is nice to have but you should be fine with what you have.

Maybe some time in the future you can add one because they are pretty inexpensive but no absolute need now.

The main thing is to make sure your batteries are getting charged.  That's the object with all of this.

Sounds like you are well on your way to being energy independent

[Lisa234]

Bob, glad to hear you say that. We'd have to redo some of our set-up to fit the Whizbang in and we just don't feel like doing that at this point. We are ready for the fun part now (kicking back and letting the sun do all the work).  There will be a fun part to this, yes??

Btw, it was cooler today in the Bay Area and the MC fan seemed to be kicking on less than yesterday, so I think we're good there.

Yessss!

[Lisa234]

Hi again Vic, you had asked: "Do you know the coldest temperature for the location of your cabin? This would help to determine the maximum input voltage for your system,  in cold WX."

Actually, our system is set up to be a back-up system for our house. We live in the S.F bay area and the climate is pretty mild here.  The battery bank is inside our house in a box in the laundry room.  Our laundry room gets maybe down to 45 degrees F on the coldest day of the year.  It's usually above 50 in there though, even during the winter. The room is probably in the 58 to 75 degree range 90 percent of the time. We'll get a few days (like maybe 5) in the summer where the room may get into the 80s.

Were you able to find out if I need my t-comp setting at -3 mv rather than -5 ?

Lisa

[ClassicCrazy]

Do you have internet where your Classic is ?
The internet in your house is usually plugged into a wireless router . The router has ports in the back of it - you plug a cat5 internet cable from Classic into the router. Then you can use the Midnite Local Status app or Grahams Classic Monitoring app .

Larry

[Lisa234]

Larry, I do have a new modem that I think can also serve as a wireless network bridge. It has several Cat5 sockets in the back. This will require a long cable because the modem is two rooms over from where the Classic is.
So my partner said he'll be willing to run the wire under the house and we'll probably do that. Will one of these APPs provide the means for me to get ALL the Classic's info onto my Mac?  (Or if not my Mac, my partner's PC?)

EDIT:  I finally found the Battery Temp readout in the Classic's display menu. I just wasn't scrolling down the line far enough to find it. Wow I'm dumb! but this is a bit confusing. Temp was 20.6, btw.

Thanks again for the help,
Lisa