We come across statements and questions like-
“My shaver stops charging at certain point”
“Why is my shaver is not giving the number of shaves promised?”
“The battery status quickly falls from 60 minutes to 40 minutes”
Some rechargeable batteries, when not fully discharged between charge cycles, (or if recharged when the battery is only half drained), simply remembers the mid cycle, and the length of use per cycle is eventually reduced due to loss in the capacity to fully recharge. Low battery capacity is the most common / layman’s term used for this ‘memory effect’ / Voltage depression. otherwise known as lazy battery effect.
In most cases these issues can be corrected and it is not necessarily permanent damage in most scenarios. However, is it good to know because in most cases, incorrect charging is the issue here rather than an actual battery problem.
In order to understand maximizing a shaver’s battery life, we need to know the types of batteries used in electric shavers.
• Nickel Metal Hydride (Ni-MH): NiMH has no ‘memory effect’, lasts longer and has higher capacity to hold a charge longer.
• Lithium Ion Battery has negligible ‘memory effect’. (A recent study shows such batteries also show small amounts of ‘voltage depression’). This type of battery exhibits good energy density and shows very slow loss of charge when not in use.
• Nickel- Cadmium (Ni-CD) needs recharging very often and more charge cycle and memory effect occurs in such batteries. Very few shavers come with such battery.
Shavers like Braun 3 series 340s-4 and 390cc-4 and Panasonic ES-LT71-S Arc 3 use Ni-MH battery and will not suffer from memory effect at all. Most of the shavers have a Lithium ion battery. Lithium Ion batteries can store a great amount of energy in a relatively compact unit.
How to get the most out of your shaver’s battery
• Drain or discharge the battery as much as possible before it is charged to the maximum. Use the shaver until the battery is nearly drained or exhausted. Some shavers may not come with a battery status display. You can guess the battery status by checking the average number of shaves when fully charged. (Average number of shaves when fully charged is usually given by the manufacturer)
• Most shavers come with a quick shave charge function for emergency situations. We charge the shaver long enough just to complete one shave. Emergency recharging on rare occasions will not do much harm. Unless otherwise required, it is recommended to recharge the battery to the maximum. Likewise, discharging regularly will preserve the capacity of the battery.
• Do not overcharge. Follow the manufacturer’s recharging instructions carefully. Voltage depression or Memory effect is directly related to overcharging or exposing the battery to high temperature. Some shavers make take a longer time to recharge to the maximum but don’t leave the shaver plugged in overnight or use the shaver plugged in, if its battery is not empty.
• If your shaver is experiencing ‘memory effect’ and stops charging at a certain point get into the habit of fully discharging it every month or so. This will make a better shaving experience and add longer life to your battery and shaver.