This cell phone battery guide will help you make your battery last as long as possible.

If you’re a common mortal like me, you probably don’t want to have to learn all the chemistry involved in charging and operation just to take good care of your batteries. While I am no expert in chemistry, I have sold (and used!) a lot of electronic devices that operate on rechargeable batteries of all types, and my batteries have always lasted far longer than average because I’ve taken good care of them.

The following cell phone battery guide will give you common guidelines to make your batteries last as long as possible. Having said that however, it is important to always refer to your cell phone user’s manual first, because all types of charger operate differently.

This cell phone battery guide will cover four types of batteries:

  • Nickel Cadmium (NiCd) – They are seldom used nowadays but are still in use in older handsets.
  • Nickel Metal Hybride (NiMH) – They are considered better than NiCd batteries because they offer considerably more power for their size.
  • Lithium Ion (Li-Ion) – More powerful than NiMH and very common in handsets nowadays.
  • Lithium Polymer (Li-Po) – They are to Li-Ion what NiMH are to NiCd batteries: an upgraded, more powerful version.

Since there are a few different kinds of batteries, the first step is to identify which type of battery you have.

How to identify which type of battery you have

This cell phone battery guide will help you identify which type of battery you have. This is pretty straightforward as it should be clearly identified on a label applied directly on the battery itself. In the rare cases where it’s not, refer to the user’s manual to find out which type of battery powers your cell phone (look for a specifications table in the manual).

Once you know which type you have, there is a concept it is important to understand in cell phone battery care, especially if you have a NiCd or NiMH battery: the “memory effect”.

What is the “memory effect”?

The “memory effect” is a term I quite dislike myself, because I find it more confusing than anything and I prefer a scientific explanation. I will try to explain this effect it in this cell phone battery guide.

Only NiCd and NiMH batteries are prone to the memory effect. Li-Ion and Li-Po batteries are not affected by this. Basically, when you discharge a NiCd or NiMH battery partially and exactly to the same point many times, oxidation will occur on the internal battery plates. This oxidation will induce a drop of voltage the next time the battery reaches the point at which oxidation occurred. In effect, it means your battery appears to hold less charge, and your cell phone will complain of low battery or turn itself off prematurely.

This is called the “memory effect” because the battery seems to “remember” at which point it was last recharged and “refuses” to drain further. In order to lessen the symptoms of the memory effect, you should know how much your batteries should be discharged before attempting to charge them back to full power. Follow the following advice in this cell phone battery guide to do this.

Discharging batteries before recharging

NiMH and NiCd

Good care must be taken to prolong the life of NiCd and NiMH batteries because these are susceptible to suffer from the memory effect.

While NiCd batteries are very prone to this memory effect, NiMH batteries are less so but not completely immune. Good practice is to discharge these batteries entirely before recharging them, and to always recharge them fully when you do so.

Li-Ion and Li-Po

On the other hand, Li-Ion and Li-Po batteries do not suffer from the memory effect and can be charged at any time. It is important to note however that they should never be entirely discharged before a charge is attempted. If a lithium battery were to be completely discharged, irreversible damage could happen to the internal battery cells.

Knowing when to charge a battery is important, but we must also consider how long to charge your battery to prevent overcharging. This cell phone battery guide will give you general guidelines on how long to recharge your battery.

Prevent overcharging

NiMH and NiCd

NiCd and NiMH battery chargers are often equipped with a timer or a temperature monitor so they know when to stop charging your batteries to prevent overcharging. Cheaper chargers, however, could keep charging your battery into overcharge, which would damage it and lessen its lifetime (if not render it entirely unusable). The timer and temperature method are not very precise if the battery is not almost completely discharged however, which is another reason to discharge your NiCd or NiMH battery completely before attempting a charge.

Li-Ion and Li-Po

Typical Li-Ion and Li-Po chargers are usually “intelligent” and will not overcharge your battery because they are equipped with the equivalent of a voltage monitor. Cheaper chargers or older cell phones, however, will keep charging your battery until you disconnect them from the power outlet, which could lead to overcharging if you’re not careful. A typical full charge time for a Li-Ion battery is between 3 and 4 hours, so if you see your cell phone still charging after a long period of time your charger could be overcharging your battery and causing permanent damage to it.

Normal battery lifetime

This cell phone battery guide will give you approximate numbers on how durable each types of battery are. Rechargeable batteries do not have an unlimited number of uses, regardless of how well you take care of them. As you use them, they will wear out and appear to hold less and less power until their life runs out. This normal wear is often blamed on the “memory effect”, but it is seldom the case.


If treated well, a NiCd battery can go through 1000 charging cycles before it’s maximum power drops to half of what is originally was.


NiMH batteries can be expected to last for between 500 and 1000 cycles.

Li-Ion and Li-Po

Li-Ion and Li-Po batteries both have a normal lifetime of between 300 and 500 charging cycles, though it’s usually a bit less for Li-Po batteries as they degrade faster than Li-Ion batteries. It is also to be noted that rechargeable lithium batteries’ life start to decrease from the time of manufacturing, regardless of the number of charge cycles the batteries have had. They are expected to last between 2 and 3 years.

Storing batteries

You must often take special care when storing batteries, and this cell phone battery guide will you some advice to do so.


NiCd batteries should be stored 40% discharged in a cool place. Furthermore, fully charged NiCd batteries will lose about 10% of their power every month even when not in use.


The self-discharge rate of NiMH batteries is higher than NiCd batteries. A fully charged NiMH battery, stored at the room temperature, will typically lose between 5% and 10% of it’s power on the first day and between 0.5% and 1% per day after that. They are thus unsuitable for use in light power using devices such as remote controls, smoke detectors, etc. but this is not an issue in a cell phone as charging is to be expected every few days anyways. Newer NiMH cells have been introduced in 2005 to give NiMH batteries longer shelf lives. Manufacturers claim the newer cells preserve 70% power after one year of storage at room temperature.

Li-Ion and Li-Po

Li-Ion batteries have a self-discharge rate of about 5-10% per month, while Li-Po batteries have a self-discharge rate of 5% per month. Li-Ion and Li-Po batteries should be stored at about 40% capacity and kept in a cool place.

I hope this cell phone battery guide was useful to you. It’s important to take good care of your cell phone battery if you want to maximize its potential, and it’s also normal for a rechargeable battery to wear out after a few years of use.

If you are looking for a new battery, I suggest you buy a new one from a trusted seller. This is especially true with lithium rechargeable batteries, as their shelf time is only 2 or 3 years. For example, Amazon offers cheap Motorola RAZR batteries.