USB Cell (NiMH) (wireless technology laboratory) Battery Technology How Does It Work?
No commentsBy John C Arkin
NiMH technology is a new kind of technology used for batteries. It is an abbreviated form for Nickel Metal Hydride and this technology is largely used in industrial as well as consumer applications. One reason why this battery technology is so much in demand is because of the flexibility in design.
Reasons for popularity
There are many reasons, which make the NiMH technology so popular. It is an excellent source of energy and acts as an eco-friendly alternative to conventional power sources. The cost of this battery technology is not much, making this a suitable choice for those looking at energy within a budget. In the olden days, the typical NiMH batteries produced limited temperatures for operation. However, the modern USB technology is able to produce high degrees of power even at relatively cold temperatures such as minus 30 degrees Fahrenheit. The latest innovations performed on the nickel hydroxide and metal hydride is what has made this possible.
How it works
The method of functioning of NiMH technology is relatively simple. These batteries are essentially electrochemical cells, which are similar to cells containing to Nickel Hydrogen. By using an alloy, which absorbs hydrogen, for negative electrode, you are avoiding the usage of cadmium. Compared to conventional nickel and cadmium batteries, NiMH technology batteries have twice or thrice the capacity. Hence, such batteries last much longer and produce more power as well.
Charging methods
The voltage range for charging such USB cell technology batteries is between 1.4 to 1.6 volts. In the method of automated charging, one cannot use constant voltage values. If you intend to charge these batteries rapidly, you should use smart battery chargers in order to prevent overcharging of the battery. Overcharging such an NiMH technology battery can easily result in dangerous situations as well as damage the cells. Remember also never use NiCd charger in place of an NiMH charger.
There are many different methods of charging such NiMH batteries. These are outlined below:
- Temperature charge: Here, the voltage for charging is almost constant.
The incoming power is converted into chemical energy. Once the NiMH battery is completely charged, the charging power is converted into heat.
- Manual charge: You can also charge such NiMH batteries manually by setting the current or voltage to suitable rate of charging. You also need to set a timer for this. You will need to monitor the charging process periodically to prevent overcharging.
- Trickle charge: This is the least preferred method of charging any NiMH battery because it can result in overcharging. The ideal rate of trickle charging should be within 0.033xC to 0.05xC each hour.
Low environment impact
One reason why such NiMH batteries are in demand is because of their low impact on the environment. The absence of the poisonous substance called Cadmium makes the NiMH technology a better option compared to the conventional NiCD batteries. Industrial grades of Nickel are easily recycled and this contributes to a more eco-friendly alternative. You can easily purchase such NiMH batteries in several retail stores.
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This Article is written by John C Arkin from PrinterInkCartridges.PrintCountry.com the contributor of Printer Ink Cartridges Blogs. More information on the subject is at USB Cell (NiMH) Battery Technology How Does It Work?, and related resources can be found at NiMH Technology Batteries.
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Cisco Router With Multiple Partitions
By Roberto Garabell
We often get CCNA candidates who say they can’t upgrade their Cisco router IOS because there isn’t enough flash space available. This may be true on occasion, but we suggest you first check a few things on your Cisco router to verify this.
You can generally tell how much flash memory you need on the Cisco router by looking at the size of the IOS file you want to load. If the file size is 12 or 14MB, then you round up to the next 8MB increment of flash, which would be 16MB (ex. 8MB, 16MB, 24MB, 36MB). This is a loose rule, but pretty safe to follow most of the time.
In addition, just because you have enough flash memory to burn the IOS file into flash doesn’t mean it will be able to run successfully on your Cisco router. Why not? Let’s say your Cisco router has 4MB of DRAM and 16MB of flash. Some of the newer IOS files will require additional DRAM. Check the IOS file requirements for flash, but also make sure you meet the DRAM memory requirements.
Now you have enough DRAM and flash memory in the Cisco router to load the IOS, but it still won’t load. The error message says there isn’t enough available flash. Why, when you have two 8MB flash sticks in the router, equaling 16MB? Most likely, the flash is partitioned; you don’t have enough contiguous space to load the IOS.
How can you tell? There are one of two ways:
First, when your router boots, you may see something during the POST like below. Note the two partitions in bold:
cisco 2500 (68030) processor (revision L) with 14332K/2048K bytes of memory.
Processor board serial number 02094596
X.25 software, Version 2.0, NET2, BFE and GOSIP compliant.
Authorized for Enterprise software set. (0×0)
1 Ethernet/IEEE 802.3 interface.
2 Serial network interfaces.
32K bytes of non-volatile configuration memory.
8192K bytes of processor board System flash partition 1 (Read ONLY)
8192K bytes of processor board System flash partition 2 (Read/Write)
See how the flash is broken into two 8MB partitions instead of one 16MB contagious partition? That is the issue!
The second way is to run the “show flash” command in privileged mode. You will definitely want to be familiar with the show commands for your CCNA exam. You can see two partitions in the example below:
Router# show flash
System flash directory, partition 1:
1 3813972 c2500-y-l.111-6.1
3814036 bytes used, 4574572 available, 8388608 total
8192K bytes of processor board System flash (Read/Write)
System flash directory, partition 2:
1 3813972 c2500-y-l.111-6.1
3814036 bytes used, 4574572 available, 8388608 total
8192K bytes of processor board System flash (Read/Write)
Can you just run the “no partition flash” command and make it one big partition? No - it won’t be that easy.
If you see an IOS image in partition 2, you need to delete it before you can proceed to the “no partition flash” command; otherwise it will error out. You can erase the IOS file in partition 2 by following the example below:
Router# erase flash
Partition Size Used Free Bank-Size State Copy Mode
1 8192K 3724K 4467K 8192K Read ONLY RXBOOT-manual
2 8192K 3724K 4467K 8192K Read/Write Direct
System flash directory, partition 2:
File Length Name/status
1 3813972 c2500-y-l.111-6.1
3814036 bytes used, 4574572 available, 8388608 total
Erase flash device, partition 2? confirm
Are you sure? yes/no: y
Erasing device… eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee …erased
Router#
Enter the “show flash” command to verify that the desired Flash memory partitions have been erased:
Router# show flash
System flash directory, partition 1:
1 3813972 c2500-y-l.111-6.1
3814036 bytes used, 4574572 available, 8388608 total
8192K bytes of processor board System flash (Read/Write)
System flash directory, partition 2:
No files in System flash
0 bytes used, 8388608 available, 8388608 total
8192K bytes of processor board System flash (Read/Write)
NOW you are ready to run the “no partition flash” command. Enter the configuration mode. Create a single flash memory partition by entering the “no partition flash” command, as follows:
Router# config t
Enter configuration commands, one per line. End with cntrl/z.
Router(config)# no partition flash
Router(config)# exit
Router#copy run start
Now when you do a “show flash” you should see the following:
System flash directory:
1 3813972 c2500-y-l.111-6.1
3813972 bytes used, 12963244 available, 16777216 total
16384K bytes of processor board System flash (Read/Write)
At this point, you can start your IOS upgrade with the “copy tftp flash” command by following the article from our site. You are now on your way to understanding Cisco routers and obtaining your Cisco CCNA certification!
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