What Is A NiCD Battery?

Jan 2, 2017

iRobot Roomba NiCD Battery vs iRobot Roomba NiMH Battery

Customers have been contacting and claiming they can find the NiCD batteries for less. The batteries they are finding on shopping networks are aftermarket iRobot Roomba NiCd batteries. Be careful, NiCD batteries look just like NiMH batteries and should be identified as NiCD on the battery label.
We would like to explain about discontinued NiCD batteries...
NiCD Batteries:
1.  NiCd batteries for iRobot have not been in production for quite some years and they are NOT carried and no longer sold in new units or as a replacement fr your iRobot. 
2. The prices customers are finding online usually do not includes shipping or tax and if outside of the country they are ordering from, there will be additional Duty, Import Fees and most likely currency exchange.
3. If people look closely, they will see a disclaimer that these are on clearance (reputable sellers usually post this except hardly found on shopping sites) and clearing out old inventory.
4. NiCd batteries are very harmful to the environment, another reason why they have been discontinued.
5. Almost all the NiCd batteries found on sale as a replacement for iRobot Roomba and other robots are under powered and start at 1800 mAh (1.8 AH) or 2000 mAh (2.0 AH). This means they will need to charge more, will burn out faster and not have a long life cycle as compared to a proper NiMH replacement starting at 3000 mAh or (3.0 AH) or higher.
6. NiCd batteries have the dreaded 'Memory Effect' and burn out faster.
7. NiCd batteries do not have the capacity that NiMH or Lithium batteries have that are also much superior to NiCd.
8. Typically the warranty period of a NiCd replacement battery is 6 months. All our iRobot replacement batteries carry a standard minimum 12 month warranty.
The Technical... What is a NiCd battery and a NiMH battery? 
NiMH refers to Nickel Metal Hydride and NiCd refers to Nickel Cadmium. The major differences between the two types of batteries are capacity, memory effect and environmental friendliness. 
NiMH batteries have high capacity, no memory effects and environmentally friendly. If you are under the illusion that rechargeable batteries are not very good then the chances are that you have been using older Alkaline rechargeable batteries (of low quality) or NiCd batteries suffering from 'Memory Effect' and you have not been aware of the effects of this dreaded Memory Effect with NiCd batteries.
What is Memory Effect?
If a NiCd battery has not been entirely drained before the next charge, the charge will not be 100% complete and will set a new lower energy capacity. Over time it will appear that the battery is no longer holding a charge. This is called the "Memory Effect". The memory effect has the consequence that the not used parts of the cell due to partially discharging are no longer in a position to receive and produce energy. Consequently their operating times become shorter and shorter and the cells have to be recharged more frequently and will burn up.
NiMH or Lithium batteries do not have Memory Effect.
What's the Difference Between NiCd and NiMH?
The main difference between an NiCd battery and a NiMH battery is that the NiMH battery (the newer technology of the two) offers higher energy density than NiCads. In other words, the capacity of a NiMH is approximately twice the capacity of its NiCad counterpart.
What Does Battery mAh Mean?
mAh stands for milli Ampere hour or milli Amp hour. It is a measure of a battery's energy storage capacity. If you think of a battery as a small fuel storage tank, which in a sense it is, mAh a measure of how much "fuel" the battery contains.
In summary, you pay for what you get. If you want a long lasting battery, it must have the correct, best cells from up to date technology which we supply our customers. We stand behind our products 110% and ensure a long lasting product worthy of your investment.