TheBug - APC CP12036LI

Introduction

The CP12036LI from APC is a simple to operate battery backup solution, designed for use with small electronic devices, e.g. routers, cameras etc. This UPS ensures uninterrupted power during a mains 230V outage, providing emergency support to compatible devices that normally rely on an AC/DC adapter. A single output version is available in 12VDC, the UPS can deliver 36Watts (3 Amps)

The CP12036LI has an 80cm long Output lead terminating in a 5.5/2.5mm jack, and an Input socket (5.5/2.5mm) for connection to an appropriately rated AC/DC power supply.

Four LEDs are used to indicate status of the batteries and the UPS operation is controlled and indicated by a LED illuminated Power ON/OFF button.

The UPS is supplied with a four adaptor jacks to allow it to connect to 5.5-1.7/2.5mm , 5.5-2.5/1.7, 5.5-2.1/2.5, 5.5-2.5/2.1 devices.

Key Points

Supplier Specification schneider-electric.com Guide

Quoted prices Feb2024 £72, from Amazon UK.

Can Supply up to 36Watts e.g. 3Amps@12VDC

Emergency Runtime for a typical Router (6-8Watts) is between 3hours40" and 2hours45"

Battery recharge power allowance 5Watts.

Recharge time from empty ~12Hours

Manual On/Off through soft button.

No Audio warning of power or battery status

A Power LED is used to both indicate whether the UPS is switched ON and whether there is an external source of power connected to the Input.

LED Off: UPS is Off
LED Solid Green: UPS is On and there is power connected to the Input jack
LED Flashing Green: UPS is On and there is no power connected to the Input jack.
LED Flashing Red: Battery Fault, contact supplier

Four LEDs indicate the discharging status of the batteries, when the Power LED is Flashing Green i.e. UPS is providing backup power.

Four Solid Green: Battery charge remaining 75 to100%.,
Three Solid Green: Battery charge remaining 50 to 75%
Two Solid Green: Battery charge remaining 30 to50%
One Solid Green: Battery charge remaining 15 to 30%
One Flashing Green: Battery charge remaining 0 to15%

Four LEDs indicate the recharging status of the batteries, when the Power LED is Solid Green i.e. UPS is connected to an input power source.

One Flashing Green: Battery status 0 to30%
One Solid Green, Second Flashing Green: Battery status 30 -50%
Two Solid Green, Third Flashing Green: Battery status 50-75%
Three Solid Green, Fourth Flashing Green: Battery status =75-100%
Four Solid Green: Battery status =100%.,

The UPS is turned On by pressing and holding the Power Button/LED for 3 seconds

The UPS is turned Off by pressing and holding the Power Button/LED for 5 seconds

The CP12036LI contains 3 off 2500mAh lithium-ion cells, arranged in a 3S form, with a nominal total capacity of 27.75Wh.

The CP12036LI does not provide an audible warning when a mains input power cut occurs, the only indication of a power cut is that the Power LED switches starts flashing. In the event of an extended power cut, the UPS can be turned off by pressing the Power Button/Led. This action will preserve the battery charge remaining.

Connection

Designed for ease of use, the CP12036LI is simply connected** between the electronic device and an associated AC/DC adapter. This setup introduces a useful battery backup function with minimal effort. The UPS is activated by a soft press ON/OFF power switch which includes an LED.

**When intending to use it with a device's existing AC/DC adapter, a crucial assumption comes into play: the device’s adapter must meet both the electronic device's peak power needs and provide the extra power required for UPS battery recharging after a power cut. Testing indicates that the CP12036LI needs a maximum 4-5 Watts (or 0.33-0.42Amps at 12V) for recharging, with a typical maximum recharge time of 12 hours. It is essential to carefully consider this additional power requirement when integrating the CP12036LI into an existing setup, and appropriately manage the AC/DC adapter's power budget. In cases of doubt, opting for an uprated AC/DC supply is strongly recommended to minimize the potential risks of failure and fire.

In the event of uncertainty, a simple mains power monitor can be used to help determine the peak and average power used. Note the AC input power measured will be slightly different to the DC figures but can be used as a good indication of power demand in a particular situation.

Testing and Performance

Performance testing on a unit found that the usable capacity, when supplying 6 Watts at 12VDC, was 23Wh compared to a theoretical maximum of 27.75Wh, or 83% usable capacity. The UPS requires ~34Wh to fully recharge the batteries. It should be noted that the Fourth Battery Status LED remains flashing green for 2-3hours before the battery state reaches a nominal 100% charge, this is because the recharge power rate reduces to around 1.2Watts as the cells near capacity. When fully charged and connected to an operational device, the UPS uses ~3Watt for its normal function, so has low overhead running costs. The low recharge power level ensures that negligible heating of the cells occurs because of recharging; during testing a difference of 4Deg C was found between the upper sections of the case and ambient temperature.

It was observed that when supplying the maximum rated 3Amps (nominal 36Watts) the UPS casing warmed to ~50DegC. It should be noted that the device has an over temperature safety cut off feature, if a higher temperature occurs the device will shutdown the output and indicate the problem by LED's 1 & 2 Flashing Red.

Using the CP12036LI with a B4RN supplied Zyxel VMG8825 Router.

The Zyxel VMG8825, used for testing, was supplied with a 36Watt AC/DC adapter. Analysis of the VMG8825 power usage showed that when operating Wi-Fi and a single ethernet port, the average demand was approximately 6.5 Watts. This means the supplied AC/DC adapter was capable of powering both the router at 6.5Watts and the UPS max recharge power of 5 Watts. If the Zyxel AC/DC adapter is retained then it is essential that the total power demand from the router and any attached devices does not exceed 30 Watts, note the UPS is not the limiting factor as it is capable of delivering 36Watts.

When powering a Zyxel VMG8825 from the CP12036LI in battery mode, the router ran for 2Hours 55Minutes. The router had two ethernet link in use along with Wi-Fi active and low power USB device plugged in. No Telephone ports were being operated. The router average power demand over the test cycle was 7.6Watts