Need help with all the settings on my Classic 150

[Vic]

Hi Lisa,

When watching the Ending Amps,   when trying to determine a good EA setting,   IMO,  would keep watching the current,   and when you finally believe that this current will never,   EVER,  go any lower.  This is the approximate proper value (at least for that DOD of the battery).

Would also suggest,  that about every two,  weeks,  or so,  that you increase the Absorb time by about 25 - 50 percent,  to try to make sure that the batteries are not being chronically under charged.   With parallel strings of AGMs,   one string can hog more charge current.   This can result in the other string getting undercharged,  chronically,  and can lead to battery damage.   During a long Absorb,   the current hogging battery gets fully charged first.   Long Absorb can allow a lagging string to get its chance at a full charge.

It is conceivable,  that one could use the Auto EQ function,  to do this periodic long Absorb.   Just a question of just how long to make the time setting on this.

The old saying,  is,  that it is better to overcharge batteries,  a bit,  than to under charge them.

On the Renogy batt monitor,  the current shown,  simply must be the battery charge/discharge current,  as the monitor has no way of knowing any other current.   In that sample pic you posted,   guess that that dash,  to the left of the displayed current,  it the Polarity of the current.  Probably has no + for charge current,   and just the dash,  for discharge current (GUESSING).

The Shunt for the batt monitor IS a 500 A unit.   SO,  their is reasonable probability that this shunt is 50 mV,   which is a very common value.   If so,  this would work with the WbJr.

There is a way to change the Scale Factor,  to use a Shunt that has a different voltage output for a given battery current.   This is a bit technical,  but is discussed in the following Thread:
http://midniteftp.com/forum/index.php?topic=1413.msg12226#msg12226

Anyway,   all FWIW  Guessing done for now,   VIc

[Lisa234]

Yes, Vic, I'll definitely experiment with lower Ending Amp settings and check the flow. I'll also ask Renogy about EQing, see what their view is. Will ask them about the Mvs on the shunt too (I don't know what happened to my paperwork on that Monitor/shunt). It sure would be great news if we can use our shunt with the WBjr.

Anyway, thanks again for all your help!!!!

[Vic]

Hi Lisa,

Just to be clear,   AGM batteries are NOT EQed in the traditional sense.   Generally,  they cannot tolerate voltages above the manufacturer's  spec  for Absorb.

But,   some AGM battery manufacturers consider an extended-time Absorb to perform an equalizing function.

The Manual for the Renogy battery monitor,   IS   on-line.  But,   it does not specify the  shunt's voltage range.   AND,  it does not seem to define just what is the apparent  clock function on the display.

FWIW,   Vic

[Lisa234]

Okay thanks Vic, good to know.

Interestingly, I set the End Amps down to 5.5 for today's cycle and the Absorb cycle came and went so fast I didn't even get to watch it happen. Must have been less than 15 min. That surprised me since yesterday's took almost an hour - though the batteries were slightly more discharged yesterday.

[ClassicCrazy]

Okay thanks Vic, good to know.

Interestingly, I set the End Amps down to 5.5 for today's cycle and the Absorb cycle came and went so fast I didn't even get to watch it happen. Must have been less than 15 min. That surprised me since yesterday's took almost an hour - though the batteries were slightly more discharged yesterday.

When your batteries aren't discharged very much and you are putting lots of amps in you will probably see it just fill up and go to float fast.
I think I would run the batteries down to at least 50% full a few times if they are new just to make sure they are working properly.
The AGM batteries are all similar - read that link on AGM's from battery university if you didn't already and also read AGM info from East Penn Deka or Rolls just to compare details.

Larry

[Lisa234]

Thanks Larry. I think my batteries are probably fine, but I don't know about my monitor. Today for instance it was showing my battery bank sinking down to 94% even though I only had a small load on the system and it's a sunny day. It also showed the amp hours down from 400 to like 386.  So I unplugged my laptop from the system, and the reading on the monitor instantly popped up to a 100% and 400ah.  I plugged the computer back into the system and the monitor still showed 100% and 400ah.

Is this normal for a battery monitor to do? 

[ClassicCrazy]

Thanks Larry. I think my batteries are probably fine, but I don't know about my monitor. Today for instance it was showing my battery bank sinking down to 94% even though I only had a small load on the system and it's a sunny day. It also showed the amp hours down from 400 to like 386.  So I unplugged my laptop from the system, and the reading on the monitor instantly popped up to a 100% and 400ah.  I plugged the computer back into the system and the monitor still showed 100% and 400ah.

Is this normal for a battery monitor to do?

Save up your pennies to get a Whizbang .  Might as well get the shunt that it will fit on too  - unless you want to figure out if that one you have will work or not . The mv rating of it should be stamped on the side of the shunt.   Then you would want to measure the two inner screws to see if the Whizbang would mount on it ( and the thread size and pitch) . If it was me I would just replace that shunt with the good Deltec shunt.

Larry

[Lisa234]

So the problem isn't with the cost of the WBjr, the problem is with our set up.  If you look at this picture you can see a copper bar at the negative post of the Inverter breaker. My partner got that bar and shaped it to fit around the breaker and the shunt is mounted to it on the other side. You can can see the red wire that goes to it.  It's a tight fit and we obviously can't see any numbers that might be on it.  Now, if we want to get the WBjr and its shunt we'd have to take everything apart and redo all of it & maybe get a different box. So that's why I'm kind of inclined right now to try and live with the monitor I've got* for awhile at least. I also don't want to go out to get new stuff during lockdown.

*junk?

[Lisa234]

I was able to catch my system's Absorb time today:  35 seconds total.

I had my Ending Amps set at 6.  All loads were off, inverter off.  Amps were already around 2 when the MC flipped into Absorb. 


So I'm assuming this is all good and my batteries are super charged ??

[Lisa234]

I just got this email from Renogy regarding my shunt:

Hi Lisa,
Thank you for contacting Renogy support.
Yes our battery monitor has a 500amp / 50mv shunt.
--------
So this is good news! We're going to go ahead and order the WBjr and since we can use the shunt we have, we can keep our set up as is.   The Renogy monitor has been totally malfunctioning so I'll be really happy to replace it! 

So hopefully with the WBjr I'll be able to figure out how much available power there is in my PV array at any given time of day..?

Also, I think Vic asked me which firmware I have.  I have no idea. How would I find that out?  And, is it essential for me to update?

[Vic]

Hi Lisa,

Great news,   that your existing shunt will be compatible with the WbJr.

Using the MNGP Display panel on the Classic,   from the main status page,  press the small round button on the left about 6 - 7 times.  This should bring you to the page that gives the Classic,  MNGP and Network Firmware version numbers.

If you were able to run the Local App on your Windoze computer,   the Firmware versions are listed there,   as well.

Thanks for the update,  Vic

[ClassicCrazy]

You should deep cycle those batteries a few times and make sure they are working properly.
It won't hurt them.
There should be a date code stamped in the case on your AGM batteries. It wouldn't hurt to see how old they are.
If you are using any appreciable amount of power at night they should be in Absorb for longer than 35 seconds .

Larry

[Lisa234]

Hi Larry thanks for that (and thanks also to Vic for his post 2 days ago).  Yeah I was figuring on giving the bank an extra long charge about once every 10 days.  I'm hardly discharging my batteries at all. I have about 450 watts of appliances in my load and we have those things on two-pole toggle switches that give us the ability to manually (and seamlessly) switch them over from our city grid to the PVs when the sun is out, and flip them back off when the sun starts going down.  That's sort of an unusual set up I know but this is, as I'd said earlier, really just a back up system for us in the event of a Zombie Apocalypse. Anyway, I turn the inverter off at night and don't turn it back on till the sun is on the PVs. So, my batteries remain very charged and that's why there's almost no absorb time even though my Ending Amps are now set at 4.  But I'm thinking I'll give it a 20-30 minute absorb charge by way of the 'time set' option every 10 days. Do you think that sounds reasonable? Or do you think I should go for an hour?

FWIW, I did ask a person at Renogy if I should discharge my batteries down, say 20 or 25% (ie down to 75% full) occasionally just to keep them healthy and he said no. With my AGM batteries he said the less use, the better.

Anyway, I will be getting my WBjr on Monday (yeay!!) and we'll get that hooked up right away.  I sure hope it gives really accurate moment to moment readings on batt discharge because the Renogy monitor does not!

[ClassicCrazy]

There is some truth to the fact that the less  deep that you discharge your batteries the longer they will last.
But the other thing that is very true is that if it isn't tested you don't know if it works.  So  you should run your loads off your batteries down to 50 % once just to make sure they work and hold their voltage.  You could have a bad battery and never even know it if you don't test it . Plus I still think that it is good to break in new batteries with some deep discharges in the beginning - to test their capacity and some batteries won't get their full capacity until you do.
I worked maintenance and we tested things like the generators, transfer switches, fire pumps, etc once a month - to make sure they all work .  Sometimes you find problems and the best time to find the problem is when you don't need it as a real backup.

The thing with AGM batteries - some of them anyway - is they can get out of balance when they are always in float . At least that is what happened to some of the ones that were backup for our fire alarm systems. We replaced a lot of AGM batteries after only one year of use and they were in float all the time - of course there may have been other contributing factors such as charging systems, age of batteries and care prior to installation, etc.  Did you ever look at the date code on your batteries and see how far from manufacture they were before you got them ?

Good to hear your Whizbang is on the way. Keep in mind that it is designed with screws and holes that fit in a standard Deltec shunt - and if your shunt has different dimension between holes or different pitch on screws then you will have to connect it not on the shunt but make some wires that go to it .

Larry

[Lisa234]

Larry, there's no date stamp on the batteries. I emailed Renogy after I got them and they said the batteries were new judging by the charge they held (which I found with my multimeter) ranged from 12.88 to 12.92v. Yeah, it seemed sort of questionable that there was no date.

Anyway, I did take the batteries down to 80% full last week and everything seemed okay. But given your experience with batteries i'll take the bank down 50%, and see what happens. I've been testing the voltage on the batts with my meter every morning after their overnight rest and this morning they were all within .01v of each other. I do notice they all like to drift from their float level which is 27.4 to pretty much exactly the level they were at when I first got them which is a volt and a half lower.

Yes, my partner is going to use wires to make our shunt work with the WBjr. He worked as a maintenance mechanic for a grain mill many years ago, so he knows how to wire stuff but he doesn't know much about these types of batteries.  He's leaving this part of it up to me    I'd love to be able to avoid ruining them prematurely!