[Nut-upsdev] "Battery constant" value for APC UPS

Russell Odom russ at gloomytrousers.co.uk
Thu Jun 1 11:12:31 UTC 2006

Hi all,

Thought I'd forward this on, as the apcsmart driver doesn't appear to
have any support for this (admittedly obscure) setting and it doesn't
seem to be listed at http://www.networkupstools.org/protocols/apcsmart.html.

Hope someone finds it useful.



Russell Odom

Fast, cheap, good: pick two.

-------- Original Message --------
Subject: Runtime estimate is very low; new batteries made no difference
[Incident: xxxxxx-xxxxxx]
Date: Thu, 1 Jun 2006 10:27:29 +0100 (IST)
From: American Power Conversion <esupport.emeaen at apc.com>
Reply-To: American Power Conversion <esupport.emeaen at apc.com>

Recently you requested personal assistance from the APC Customer
Solutions Team through our on-line support center. Below is a summary
of your request and our response.


Runtime estimate is very low; new batteries made no difference

Discussion Thread
Response (Radha Patturajan) - 06/01/2006 10:27 AM
Dear Russell,

Thank you for confirming the model number. The battery constant for
DL3000RMI3U is 8C.

Please go through the following procedure in the event that the
batteries on a Smart-UPS have been changed and fully charged and when a
self test has been performed, the runtime is incorrectly displayed or
when the battery capacity LEDs blink. You may also get a message such
as “UPS battery is discharged” from the management software.

Reference: In order to successfully reset the battery constant, all
accompanying devices (SmartSlot Accessories such as Interface Expander,
Web/SNMP Management Card) must be removed from the SmartSlot or from the
Comport of the UPS.

In order to fit into or remove devices from the SmartSlot of the UPS,
please shut off all connected load, switch off the UPS, pull the power
plug of the UPS and switch off the UPS once again till you hear a click.

Turn on the UPS again and connect a computer with Windows 95/98/ME,
Windows NT 4.0 or Win 2000, which runs on Hyperterminal.
** You MUST have the cable with part number 940-0024B, 940-0024C or 940
1524C **

1.	Close Powerchute plus-Server. With Windows NT/2000, the UPS service
must be stopped. If you are using PowerChute Business Edition, stop the
Agent – service.

2.	Select Start | Program | Accessories | Hyperterminal | HyperTerminal.

3.	You will be requested to enter a name and a symbol. Enter a favorite
name and click on OK. When a message that a modem must be installed
appears, you can ignore this message.

4.	Select the serial port to which black serial cable is connected to.

5.	The correct settings for the COM-connection are 2400 Baud, 8 data
bits, 1 Stop bit, no parity, protocol Xon/Xoff. In this window, click on
Advanced and make sure that the option FIFO activated is unchecked.
Click twice on OK.

6.	An empty window is opened. With the shift-key depressed, press the
Y-key. You should get the response message SM. When you get the response
message SM, Powerchute Plus can communicate with this connection.

Warning: Do not enter any other characters via Hyperterminal other than
that described in these instructions because this can cause irreparable
damage to the UPS!!

7.	Enter “1” twice with a gap of two seconds.

8.	The response message “PROG” appears in the Hyperterminal window.

9.	Enter a “0” and the UPS reports the present value of the battery
constant. In case this value does not correspond to the default value
mentioned below, it must be changed.

Battery constant = 8C

10.	After you have entered “0” and the battery constant is displayed,
enter a “+” as long as the correct battery constant appears as the most
recent value (in the standard settings mentioned in the document)  in
the Hyperterminal window. (you can go back with “-“).

11.	Enter “<Shift> R”, the UPS reports “BYE” and you have exit the PROG

12.	Enter “<Shift> Y”,  the UPS reports again with “SM”.

13.	Enter “0” once again and check if the UPS reports back the standard
setting that has been set.

14.	Hence the problem is solved. Close the Hyperterminal, start the UPS
again and check the UPS runtime in the management software.

Explanation: The battery constants give the battery status via their
life expectancy. If the battery ages and is “exhausted”, the constant is
overwritten. The management software calculates the runtime of the UPS
with these constants. If the battery is now replaced, a self test must
be done with the new batteries. Through it, the red battery replace
indicator goes out and the battery constants should be reset to the
standard settings. This does not occur in some cases. Therefore, the
constants must be reset manually.

Please let me know if the problem is resolved. Should you ever require
further assistance or if your UPS problem is not resolved, please do not
hesitate to contact me again by responding to this incident. I would be
glad to assist you.

With kind regards,
APC Tech Support

Customer (Russell Odom) - 06/01/2006 09:50 AM
Hi Radha,

Thanks for the response. The model number is DL3000RMI3U.


Response (Radha Patturajan) - 06/01/2006 06:40 AM
Dear Russell,

Thank you for contacting APC technical Support.  Sometimes after
replacing the old batteries in the UPS, the device needs to be told that
there are new batteries present and even after replacement the UPS still
assumes the characteristics of the old battery. This might be the cause
of the UPS problem. To avoid this, we need to reset the battery
constant. I would be glad to assist you in this procedure. But before
proceeding with this procedure, we need to know the exact model number
of the UPS. Every UPS has a specific battery constant value. Entering a
wrong value may damage the UPS. So please send me the exact model number
of the UPS. You can find out these details on the white barcode sticker
at the rear of your unit. For more information on identification of
these numbers, please
visit the following link:


Is the UPS SU3000RMINET or SU3000RMI3U?

Once I receive the model number, I would be glad to assist you further
with the resetting of battery constant.

With kind regards,
APC Tech Support

Customer (Russell Odom) - 05/31/2006 04:13 PM

We have a Smart-UPS 3000 RM that is seemingly calculating the battery
runtime incorrectly.

The calculated runtime at 45% load and 100% battery charge stays
somewhere between 0 and 120 secs, but according to
the runtime should be about 13 minutes at half load.

Since the estimated runtime is not more that 2 mins, the UPS is
permanently in a 'Low Battery' state (with the front-panel LEDs
flashing), and the monitoring software therefore forces an immediate
shutdown any time there is a wobble in our mains supply and the UPS goes
onto battery, even if it's only for a few seconds.

The replace battery light came on a couple of weeks ago, although it
went off again a few days later; I have just replaced the batteries
(which were a little over a year old) with brand new ones, but it has
made no difference. I tried a self-test and and completely powered the
unit off and disconnected from the mains to try to force it to
recalculate the runtime, but without any luck.

I am using Network UPS Tools (NUT) with the "apcsmart" driver to monitor
the UPS; status info as follows (all values agree with the front-panel
LEDs where applicable):
battery.alarm.threshold: 0
battery.charge: 100.0
battery.charge.restart: 00
battery.date: 02/15/01
battery.packs: 000
battery.runtime: 120
battery.runtime.low: 120
battery.voltage: 54.55
battery.voltage.nominal: 048
driver.name: apcsmart
driver.version: 2.0.1
driver.version.internal: 1.99.6
input.frequency: 50.00
input.quality: FF
input.sensitivity: H
input.transfer.high: 253
input.transfer.low: 196
input.transfer.reason: T
input.voltage: 243.1
input.voltage.maximum: 244.4
input.voltage.minimum: 241.8
output.voltage: 243.1
output.voltage.target.battery: 230
ups.delay.shutdown: 180
ups.delay.start: 000
ups.firmware: 92.11.I
ups.id: UPS_IDEN
ups.load: 045.2
ups.mfr: APC
ups.mfr.date: 02/15/01
ups.model: SMART-UPS 3000 RM
ups.serial: [deleted]
ups.status: OL LB
ups.temperature: 057.6
ups.test.interval: 1209600
ups.test.result: NO

Having run some tests by powering off the mains and looking at the rate
of battery discharge, I would guess that the real runtime would be
perhaps 4-5 mins, which is higher than its estimate but less than the 13
mins your web site says I should expect.

My other thought was that one of the batteries might not be properly
connected, but all seems fine as far as I can tell.

I'm not sure if this is a fault with the UPS or if there's something
else I need to do to force it to recalculate the runtime. Can you advise?



Question Reference #xxxxxx-xxxxxx
    Product Level 1: Smart-UPS
    Product Level 2: SU3000RMI
   Category Level 1: Troubleshooting
       Date Created: 05/31/2006 04:13 PM
       Last Updated: 06/01/2006 10:27 AM
             Status: Waiting
             Serial: [deleted]
Management Software:
   Operating System: Linux (RHEL4)


Radha Patturajan

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