A Forum run by Enthusiasts of MidNite Solar

Charge Controllers and Clippers => The "Classic" charge controller => Topic started by: 5 Minutes 2 Midnite on July 20, 2020, 07:40:36 PM

Title: Trying to understand why system is drawing from batteries when plenty of solar
Post by: 5 Minutes 2 Midnite on July 20, 2020, 07:40:36 PM
Finally have a full fledged system up and running, and doing some dry run tests under typical daily loads (just been plugging my freezer in up to now).

In general all is going by the numbers as I watch the Classic 150 remote display the discharge and charge cycle. Killed the circuit breakers and went on battery at 4PM yesterday. Early this morning display showed 60% remaining. By 11:30AM the system was charged to 64%:

(https://i.postimg.cc/gkLkRrRW/Charing-stats-on-Midnite-Solar-status-panel-11-30-AM.jpg)

By 11:45 the batteries show fully charged. All is well:

(https://i.postimg.cc/xT6h0Pqj/Charing-stats-on-Midnite-Solar-status-panel-11-45-AM-FULLY-CHARGED.jpg)

OK. Great. With the batteries now charged I plug in the hot water heater. NOT a diversion load. Just a load on the household circuit. There is enough power being generated to easily heat water, and not draw down the batteries.

(https://i.postimg.cc/pr2cv9Hn/Charing-stats-on-Midnite-Solar-status-panel-12-20pm.jpg)
This house power meter won't match the remote app perfectly because the freezer does not run through it. There is a 10-15 amp total power draw @110VAC.
(https://i.postimg.cc/26XLkMpF/power-meter-unplugged-car.jpg)

All is still well. System making plenty of power this time of day.

Then I push the envelope a bit further and plug in the electric car (12A load or about 1250 watts) to produce a total load of about 2500 watts. Even though there is more than enough power being produced by the panels (2628w), the system starts drawing down the batteries. That is the mystery. Why the dramatic 21A draw from the batteries (about 1100W)? There was enough power being generated for that additional 1250W load.

(https://i.postimg.cc/Bvp1ytMz/Why-is-the-system-draining-the-batteries-1.jpg)

(ignore voltage drop. Separate issue)
(https://i.postimg.cc/9MfqjVkQ/power-meter-full-load-cropped-and-sized.jpg)

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As soon as I unplugged the car the system returned to normal and the batteries charged up again.





Title: Re: Trying to understand why system is drawing from batteries when plenty of solar
Post by: Vic on July 20, 2020, 08:16:37 PM
Hello  5 Minutes..,

Just a quick few comments.

Looking at the Local App,   second and third screens;  It notes that the battery is at 100% SOC,   and yet,   there is 45.6 Amps still charging the battery on screen 2,  and down to 32.9 A on the third.   This is at least part of where some of that energy is going.   33 A at about 55 V,  is over 1800 Watts.

100% SOC may have been the result of having gone to Float from Absorb,   but your settings may not be fully charging your Li batts,  before the Classic transitions to Float.   Do not know how your BMS functions with the Classic,   etc   ...   know nothing of Li batts   ...
As you probably know,  the yellow background Alert screen on the LA,  with the small clock face in the Power meter means that the Classic clock is more than about ten minutes off from your network/computer clock.

Just a drive-by,  FWIW,   Vic
Title: Re: Trying to understand why system is drawing from batteries when plenty of solar
Post by: 5 Minutes 2 Midnite on July 20, 2020, 09:23:52 PM
Ah yes. I had noticed earlier that the batteries were still charging even though all the used up AH had been replaced. I have the controller set to go from bulk to absorb at 55.2vdc, and that voltage had not yet been reached. This could explain the mystery, and may explain why the system went from 70% to 100% in just 15 minutes.

I will be sure the batteries are fully charged tomorrow before experimenting with additional loads.

(and yes, I know about the clock icon. Time is 40 minutes off. That has been a nuisance since I first hooked up the system, and no amount of setting the time, syncing, or replacing CMOS button cells has remedied the issue. Not a big enough deal to warranty the device though. ;>
Title: Re: Trying to understand why system is drawing from batteries when plenty of solar
Post by: ClassicCrazy on July 20, 2020, 09:59:31 PM
Have  you tried the Time setting in MNGP Tweaks / More 3 / TMSync  ?  Mine is turned  On .

I have a forum question for you - how do you insert the screenshots as part of your post ? I have never been able to figure out how to do that on the forum here.
Your post was well done with all the screen shots so no one had to guess what was going on.

Larry

Title: Re: Trying to understand why system is drawing from batteries when plenty of solar
Post by: boB on July 20, 2020, 10:05:11 PM
Yes, great views of the screens without having to click on them !

So, how do you have your Absorb time set ?   Is it set to like, 1 minute maybe or some really small amount of time ?

Yeah, the TimeSync has to be "OFF" in the MNGP so that it does not try to tell the Classic what time it is.  It needs to get that time from the Local App or whatever if possible. That is, if the MNGP won't keep time.

Like this, Crazy...


(https://4.bp.blogspot.com/-uhjF2kC3tFc/U_r3myvwzHI/AAAAAAAACiw/tPQ2XOXFYKY/s1600/Circles-3.gif)




Title: Re: Trying to understand why system is drawing from batteries when plenty of solar
Post by: 5 Minutes 2 Midnite on July 20, 2020, 11:40:31 PM
Quote from: ClassicCrazy on July 20, 2020, 09:59:31 PM
Have  you tried the Time setting in MNGP Tweaks / More 3 / TMSync  ?  Mine is turned  On .

'll have to check that. Not sure.

Quote from: ClassicCrazy on July 20, 2020, 09:59:31 PM
I have a forum question for you - how do you insert the screenshots as part of your post ? I have never been able to figure out how to do that on the forum here.

I click on the Insert Image button (far left of second row). This wants an image from the web so I uploaded my images (I use postimage.com) and copy the resulting link in between the image tags that were inserted into the body when I clicked the icon. So the post looks like this before you post it:

(https://i.postimg.cc/NjGPyC52/sample.jpg)


Title: Re: Trying to understand why system is drawing from batteries when plenty of solar
Post by: 5 Minutes 2 Midnite on July 20, 2020, 11:44:03 PM
Quote from: boB on July 20, 2020, 10:05:11 PM
So, how do you have your Absorb time set ?   Is it set to like, 1 minute maybe or some really small amount of time ?

Ha ha. Well since everyone likes inline images...

(https://i.postimg.cc/xTn67pGp/Absorb-setting.jpg)

The 15 min was a guess. For LiFe am I cutting Absorb off too soon?
Title: Re: Trying to understand why system is drawing from batteries when plenty of solar
Post by: ClassicCrazy on July 21, 2020, 12:11:39 PM
Quote from: 5 Minutes 2 Midnite on July 20, 2020, 11:40:31 PM
Quote from: ClassicCrazy on July 20, 2020, 09:59:31 PM
Have  you tried the Time setting in MNGP Tweaks / More 3 / TMSync  ?  Mine is turned  On .

'll have to check that. Not sure.

Quote from: ClassicCrazy on July 20, 2020, 09:59:31 PM
I have a forum question for you - how do you insert the screenshots as part of your post ? I have never been able to figure out how to do that on the forum here.

I click on the Insert Image button (far left of second row). This wants an image from the web so I uploaded my images (I use postimage.com) and copy the resulting link in between the image tags that were inserted into the body when I clicked the icon. So the post looks like this before you post it:

(https://i.postimg.cc/NjGPyC52/sample.jpg)

Thanks for the info on how you did the image insertion .

Larry