Switching to float

[offgridQLD]

Today I watched my classic 150 via the status panel software. I wanted to see the proses  of bulk , absorb then float .

My system consists of 4kw of pv and 48v Exide 1330Ah lead acid battery's and the classic 150 . I have light base loads as I am not at the home during the week days. So I am just powering a modem and refrigerator and a couple of other small loads around 2kwh each day from the pack.  Average 80 -100w load including running my inverter.

What I found today while watching the status panel classic remote software. The classic was in bulk from sunup and hit the absorb voltage (60v) at 8:03am. The classic held that voltage as I watched the amps into the battery slowly drop from 30A down to around 20A over next 25min or so. It then hovered around 18A for around 5 min before dropping into float at the 8:33am. So exactly 30 min (minimum absorb time)

This has me confused as I have set a 10A float trigger point and a 30 min and 2hr max absorb time. Why didn't it continue to absorb until the trigger Amp set point? As apparently it needs to see a average amps lower than this set point for 90 seconds.

Kurt

[Vic]

Hi Kurt,

I use End Amps to terminate Absorb.

On my system,  for EA to be the active parameter terminating Absorb,  the Min Absorb Time needs to be set to 00:00 .

I have monitored the charge progress in the Classic's internal Log,  and  by eyes-on monitoring of the MNGP display,  and  with Min Time = 00:00,  Max Time  3-to 4:30 (Hours) the EA setting appears to always dictate Absorb termination.  If the bank was well discharged,  at some point,  the Max time would dictate end,  but  have not taken this bank down to that low level of charge.  Good Luck,  Vic

[offgridQLD]

Great thanks Vic,

I will set my absorb minimum time to 00:00 and report back tomorrow.

I only installed the classic last Sunday but I'm really happy with it. I find the ability to remotely view the classic with the provided software A key feature. Being a weekend house that's over 100km away being able to change the classics setting through the same software is very handy to.

This weekend I am going to try connecting a little wireless bridge device to the classics Ethernet socket. This way I can do away with the cat5 cable running from the classic my modem. I am hoping I can power the device (5v) from the classics USB cable?
Thanks again

Kurt.

[offgridQLD]

Ok last night I set the MIN Absorb time to 00:00 MAX at 2:00hrs . End amps at 10A

This morning it was feeding 33A into the pack in MPPT bulk and as soon as the pack hit Absorb voltage (60v) it went straight to float

So setting min to 00:00 dost work

I plan to try 1hr now. As far as I can see the (MIN absorb) time is the master parameter and not the (End amps)

edit: I actualy just tricked the charger into doing a re-bulk this morning by upping the re-bulk voltage set point. So I will see how things go with the 1hr min absorb time setting. I just want to see it switch to float at 10A.

Kurt.

[Vic]

Hi Kurt,

Sorry to hear that you are having an issue with EA.

I should have asked if you have Classic FirmWare dated 6/29/12 or later.  In earlier versions of the FW,  EA could be set,  but the EA function had not been programmed into the FW.

There is a new version of Production FW on the MidNite site,   it  is version 1070.  Look at this page for some info:
http://www.midnitesolar.com/firmware.php

And you may need some additional information on how to load the FW from the MidNite site,  if you have not loaded FW into your Classic before.

And,  yes,   if you feel that your batteries need more charge,  you can do a  ReBulk,  although,  you might need to change the Min Absorb time to something like 90 minutes or two hours.  It may take quite some time for the charge current to diminish to 10 Amps.  And,  if you have an inverter and any loads on it,  those DC currents appear as charge current.  In which case the CC will not know the difference between battery charge current and inverter loads (or any other DC loads on the battery bank).  10 DC amps is less than 1% of the stated Capacity of your  battery bank,  this is a fairly low percentage.

I hope that this makes some sense.  Good Luck,  Vic

[offgridQLD]

Thanks Vic,

I think I have mastered the settings now.

My classic is only one week old so I am running the latest FW 1070. After my forced restart of bulk charge. it quickly went into  absorb. I was able to watch the absorb Amps slowly decrease untill  flat lining at around 15-16A  I decided to then change  my end amps to 16A . I had around 3Amps load on the battery's at the time (This is a Farly consistent load) So this puts me on the 1% mark for my 1330ah 100hr rate of my battery bank. 13A + 3A load = 16A

I have set max absorb time to 3hrs and min to 1.5hrs.

Now for my next challenge setting up Vmax one step at a time..

Kurt.

[Vern Faulkner]

Hey there... I may need to update the firmware to solve a similar issue. Problem is the provided disks do NOT have an identifiable driver, so the computer won't recognise the device plugged into the USB cable. \

Where can I find just the driver, itself?

[boB]

Hey there... I may need to update the firmware to solve a similar issue. Problem is the provided disks do NOT have an identifiable driver, so the computer won't recognise the device plugged into the USB cable. \

Where can I find just the driver, itself?

The driver and .inf files are included in the FW download on the Midnite web site if you want.
I haven't looked at one of our DVDs in quite a while and so don't know if those files are in
a .exe like they are from our site or if they are unzipped or if they are even on that DVD.

I would just download the .exe...  The drivers and .inf haven't changed in quite a while now.
Just the firmware has changed.

BTW, new firmware coming up in the next few days or possibly on Monday or so.
This will include our "Follow Me" networking features that enable multiple Classics to
follow each others' charge stages, BTS and ground fault.

We will have another look on the EA and make sure it's all working as planned and
try to fix it if not.

boB

[dgd]

I am hoping I can power the device (5v) from the classics USB cable?
Thanks again

Kurt.

The small USB client type connector on the Classic does not provide 5v power.  A dc to dc converter seems the way to go, I use a small Datel device 5v out 8-72v input
Dgd

[offgridQLD]

The small USB client type connector on the Classic does not provide 5v power.  A dc to dc converter seems the way to go, I use a small Datel device 5v out 8-72v input
Dgd

Thanks for that info. I have a 240v wall outlet close to the classic I will just use a small USB power outlet that plugs into that.

Kurt

[boB]

The Classic is not a USB host....  Just a USB client, so it will not talk with another USB client.

What are you trying to connect the Classic to ??  An Android phone with USB host mode but
no power maybe

boB

[offgridQLD]

What are you trying to connect the Classic to ??  An Android phone with USB host mode but
no power maybe

boB

No,
     I am just connecting a wireless bridge device to the classic. So I don't need to run a cat5 cable from my classic to the modem inside the house. this Wireless bridge device will eliminates the need for a hard wired cable .  The device  it needs 5V power in the form of a USB plug to run.  So I was just just asking is the mini USB port on the classic had power or not .

No big deal I will use a simple external usb power adapter to power it

Kurt

[Resthome]

Saw similar switching to Float issue here today.

I have the Classic set for End Amps of 15 amps. Absorb Min 1:59 and Max 2:00. Today we have a solid overcast morning with the Classic staying in Bulk MPPT a lot longer than usual. When the Classic reached the Absorb Voltage of 14.6 V it went to absorb and within a few minutes went to float.

Prior to this End Amps had been working fine on very clear sunny days and staying in Absorb for about 30 min on a very lightly loaded system with the above settings.

Unfortunately I did not have the local application running today so I am taking the information from the Classic MNGP Logs. The absorb charge timer also seems to reset themselves to the Min 1:59 after reaching End Amps with no way that I am aware of to determine how long it was in absorb from the MNGP other than trying to read the logs. It would be nice to be able to tell how long it remained in absorb.

I'm running the 8/13 – 1070 firmware. Any idea what would cause this? Would a passing cloud that dropped the absorb amps below 15 amps for a couple minutes cause this?

[boB]

Saw similar switching to Float issue here today.

I have the Classic set for End Amps of 15 amps. Absorb Min 1:59 and Max 2:00. Today we have a solid overcast morning with the Classic staying in Bulk MPPT a lot longer than usual. When the Classic reached the Absorb Voltage of 14.6 V it went to absorb and within a few minutes went to float.

Prior to this End Amps had been working fine on very clear sunny days and staying in Absorb for about 30 min on a very lightly loaded system with the above settings.

Unfortunately I did not have the local application running today so I am taking the information from the Classic MNGP Logs. The absorb charge timer also seems to reset themselves to the Min 1:59 after reaching End Amps with no way that I am aware of to determine how long it was in absorb from the MNGP other than trying to read the logs. It would be nice to be able to tell how long it remained in absorb.

I'm running the 8/13 – 1070 firmware. Any idea what would cause this? Would a passing cloud that dropped the absorb amps below 15 amps for a couple minutes cause this?

A passing cloud could bring the output amps down below Ending Amps setting ~BUT~  the battery voltage must stay at or above the Absorb
setting (temperature compensated) before the Ending Amps will change the Classic to Float.  At that time, it will reset its time to your
minimum time (1:59).  You should be able to use the Recent History logs to see what happened on a 10 minute interval.  The battery voltage
and output power and charge stage at those times should give you an indication of what happened.  I like to use the graph and cursor
rather than the text output for this.

One thing that CAN make the Ending Amps stop the Absorb cycle early is if you have multiple battery charging sources.
If the batteries are at the absorb voltage and a cloud comes by or the sun goes down or something that brings the battery
current below that Ending Amps setting on that Classic AND some other source is keeping the batteries at the Absorb voltage setting,
the Classic can not tell that it is not the one keeping the battery at Absorb voltage.  If that happens, then the Ending
Amps could end the Absorb cycle early.

I just now added an Ending Amps setting of 0.0 amps to be a DISABLE value for Ending Amps.

Of course, a global current amperage with the networking or even better yet, a real battery monitor reporting
the Ending Amps value would also be a way of fixing this multiple source issue.

boB

[Resthome]

No multiple charging sources here Bob just 5 strings of 2 – 140W PV with the Classic 150 connected to a set of 6 Solar One 850AH- 2V cells.  I have gone back and looked at the logs for 11/8/2012 and here is what I see. Absorb is set for 14.5V

11:21AM  14.3V  241W  Bulk M  -- 16.85A
11:31AM  14.6V  227W  Absorb --- 15.54A
11:40AM  13.7V  109W  Float    ----  7.95A

Somewhere in the last 9 minutes the current must have dropped below my 15A EA for longer than 90 seconds. So maybe I should be setting EA lower. Hoping the battery monitor is around the corner. Would love to see it under the Christmas tree this year.