This is for those of us who want to go wireless (who doesnt??) without having to frequently replace batteries on our wireless devices. With the number of wireless devices I have, I realised that I was going to need to invest in rechargeable batteries and a good charger.
A few years ago, after getting a digital camera, I got some NiMH (Nickel metal hydride) batteries. Lets be more precise. I got 4 Uniross 2500Mah batteries with charger (X-Press 150) included as a set. I was a noob back then (still am
) and had no idea that there were different types of chargers with different charging currents. All I knew from the instruction manual was that the charger would take about 16 hours to fully charge the 2500Mah cells. 16 hours!!! To make matters worse, the charger did not have automatic cut off, but would keep charging the batteries at a constant low current of 160ma, till infinity, or such time as it was switched off. This type of charger is called a "dumb" charger because it does only one thing- charge batteries at a constant current, irrespective of the amount of existing charge in the battery.
(Come to think of it, the term is a deliciously ambiguous one, as it could be used to refer both to the type of charger as well as to the person who uses such things
). This type of charger is always a hit and miss thing, because unless you know the amount of charge held by the battery, it is impossible to determine the amount of charging time required. The only safe thing to do was to wait until the batteries were drained and then charge them for 16 hours to ensure optimum charge. This was rather inconvenient. The only good thing I recall about the Uniross 2500Mah was that the first full charge lasted VERY long. What I noticed however, after the first few charges, was that the battery capacity started going down. The worse thing was that the batteries had to be used immediately after being charged to get the most out of them. If I left the batteries inside the camera for a few days they would lose all their charge in the interim and not even be able to power up the camera. Not knowing of the existence of things called smart chargers, I sort of gave up on rechargeable batteries altogether and spent a fortune on Duracell alkalines. The Uniross batteries were left lying unused for a few years. I did not even bother to recharge them occasionally. They were just there. That is, until I came to know about the different types of chargers and decided to get a smart charger, without breaking the bank. Enter the ENVIE Speedster charger which claims to charge 2100Mah batteries in just 1.2 hours!!
As an aside, the first thing you should look at when purchasing chargers is not the manufacturer claims of QUICK charger or SUPER FAST charger or similar misleading adjectives. Rather, you should look at the charging current i.e. the current at which the charger charges the batteries. This is the best indicator of the actual time it would take to charge a battery.
You can get a rough idea of the length of time it will take to charge a battery by using a relatively simple formula designed around the value "C" which represents the capacity of the battery to be charged. The basic premise is that the energy you need to put into a battery for standard chargers is 1.4 x C (the capacity of the battery) and 1.2 x C for fast chargers. So this can be shown as:
Battery capacity (C) = 2200mAh
1.4 x C = 3080mA and 1.2 x C = 2640mA
This represents the energy we need to put into a battery to charge it, so if our Standard Charger has a charge current of 120mA and our fast charger has a charge current of 700mA this gives us:
Standard Charger - 3080 / 120 = 25.6 Hours
Fast Charger - 2640 / 700 = 3.77 Hours
(text in italics copy pasted from stefanv.com)
This does not necessarily mean that higher charging currents are better. Too high a charging current can shorten the life of the batteries. That means that the so-called 15 minute chargers are not such a great invention after all, since the batteries will not last beyond a few charges. The ideal charging current is one which will recharge the batteries in about 2 hours. As a general rule, 500ma seems to be an ideal charging current for 4 AA battereis. For example, the fast chargers from SONY charge 4 batteries at about 500ma, and charge 2 batteries at about 1000mah. That means they would take about 6 hours to fully charge 4 batteries of 2500Mah capacity. Quite an advance over the 16 hours required from a dumb charger.
Anyway, back to the ENVIE SPEEDSTER. The charging current is given as
1800ma for 1 AA battery
900ma for 2 AA batteries
450ma for 3-4 AA batteries
900ma for 1 AAA battery
450ma for 2 AAA batteries
225ma for 3-4 AAA batteries
(The lower current for AAA batteries does not mean that they take a longer time to charge. Remember that the capacity (Mah) of AAA batteries is considerably lesser. Rarely does it exceed 1000Mah; so charging time is quite less).
The thing I like about the ENVIE is that it enables you to charge, and monitor, each battery individually. Most dumb chargers allow you to charge only in pairs so you risk overcharging or undercharging one of the batteries if they do not hold exactly the same amount of charge at the time of charging. The charger also has a primitive LCD screen which tells you about the status of your batteries.
The charger is made in the PRC (China) and is marketed by IMS Mercantiles Pvt. Ltd., Rohini, Delhi (with 1 year warranty). This charger makes some great claims which are difficult to verify without sophisticated equipment. It claims to automatically cut-off fast charging and switch to trickle charging (think of trickle charging as a minimum maintenance charge) once the batteries are fully charged. True, the LCD turns itself off once the three bars are full but does it really switch to trickle?? No real way to find out except by deliberately leaving batteries in the charger for about 24 hours AFTER full charge is indicated. If the claim of auto-cut off is correct then nothing would happen. but if it does not switch to trickle, then chances are that you will be celebrating an advance New Year with the explosion. But I would give the benefit of the doubt to the company claims, since I have noticed that the batteries and charger start to cool down once the LCD indicator goes off even if the charger is left on.
One thing that the charger could have done with is a refresh mode. The refresh mode basically drains the batteries completely and then automatically recharges to full. This supposedly ensures longevity and maintains the capacity of the battery. It should be done only periodically depending on usage patterns. Think of it as a regular servicing of a vehicle. Some will argue that LSD (low self discharge) batteries like Sanyo eneloop do not require refreshing, but to each his own. No use bickering over whether it is actually beneficial or not. In any case, you do not need a charger to refresh a battery. Simply place the batteries in a high-drain device like a digital camera, and use until they can no longer power on the camera; and then let the charger do its work.
About the actual performance of this charger... I placed my Uniross batteries which had been lying unused for the better part of 3 years. The charger topped them up without a fuss. However, the charger indicated full charge before the estimated calculated time. Im putting that down to the reduced capacity of the batteries. After full charge was indicated, I put them in the camera and they worked. I took a number of photos just to see whether they would lose charge quickly. Surprisingly they held up. I left them in the camera overnight and the next day I turned on the camera. After taking a few shots they died on me, which was no surprise. These batteries discharge at a furious pace, but again Im putting that down to their age and the fact that they were unused, without periodical maintenance, for almost 3 years. But still, they self-discharged rather too quickly even when new. But the positive side is that I wont have to wait 16 hours to get a few hours performance out of them thanks to the ENVIE Speedster.
I also recently found an old pair of Eveready rechargeable Ni-Cd batteries... they had been lying unused in the bundled charger, for nearly 4 years. I checked the capacity and it was printed 700Mah. I charged them and am using them in my wireless mouse. Sure, what with the lower capacity and other factors, they can only power the mouse for an average of 2 days. But that's not really a problem since the charger enables me to fully charge them within 15 minutes!!:lol:
I recently got a pair of sanyo eneloops which I believe are authentic. Ill try and post something on them after some time, since its pretty pointless, not to mention premature, to post a review of rechargeable batteries based on first impressions. All Ill say for now is that sanyo, and experts, claim that they have a very slow self-discharge rate, with the ability to retain upto 75% charge even after 3 years of storage.
A few years ago, after getting a digital camera, I got some NiMH (Nickel metal hydride) batteries. Lets be more precise. I got 4 Uniross 2500Mah batteries with charger (X-Press 150) included as a set. I was a noob back then (still am
) and had no idea that there were different types of chargers with different charging currents. All I knew from the instruction manual was that the charger would take about 16 hours to fully charge the 2500Mah cells. 16 hours!!! To make matters worse, the charger did not have automatic cut off, but would keep charging the batteries at a constant low current of 160ma, till infinity, or such time as it was switched off. This type of charger is called a "dumb" charger because it does only one thing- charge batteries at a constant current, irrespective of the amount of existing charge in the battery.(Come to think of it, the term is a deliciously ambiguous one, as it could be used to refer both to the type of charger as well as to the person who uses such things
). This type of charger is always a hit and miss thing, because unless you know the amount of charge held by the battery, it is impossible to determine the amount of charging time required. The only safe thing to do was to wait until the batteries were drained and then charge them for 16 hours to ensure optimum charge. This was rather inconvenient. The only good thing I recall about the Uniross 2500Mah was that the first full charge lasted VERY long. What I noticed however, after the first few charges, was that the battery capacity started going down. The worse thing was that the batteries had to be used immediately after being charged to get the most out of them. If I left the batteries inside the camera for a few days they would lose all their charge in the interim and not even be able to power up the camera. Not knowing of the existence of things called smart chargers, I sort of gave up on rechargeable batteries altogether and spent a fortune on Duracell alkalines. The Uniross batteries were left lying unused for a few years. I did not even bother to recharge them occasionally. They were just there. That is, until I came to know about the different types of chargers and decided to get a smart charger, without breaking the bank. Enter the ENVIE Speedster charger which claims to charge 2100Mah batteries in just 1.2 hours!! As an aside, the first thing you should look at when purchasing chargers is not the manufacturer claims of QUICK charger or SUPER FAST charger or similar misleading adjectives. Rather, you should look at the charging current i.e. the current at which the charger charges the batteries. This is the best indicator of the actual time it would take to charge a battery.
You can get a rough idea of the length of time it will take to charge a battery by using a relatively simple formula designed around the value "C" which represents the capacity of the battery to be charged. The basic premise is that the energy you need to put into a battery for standard chargers is 1.4 x C (the capacity of the battery) and 1.2 x C for fast chargers. So this can be shown as:
Battery capacity (C) = 2200mAh
1.4 x C = 3080mA and 1.2 x C = 2640mA
This represents the energy we need to put into a battery to charge it, so if our Standard Charger has a charge current of 120mA and our fast charger has a charge current of 700mA this gives us:
Standard Charger - 3080 / 120 = 25.6 Hours
Fast Charger - 2640 / 700 = 3.77 Hours
(text in italics copy pasted from stefanv.com)
This does not necessarily mean that higher charging currents are better. Too high a charging current can shorten the life of the batteries. That means that the so-called 15 minute chargers are not such a great invention after all, since the batteries will not last beyond a few charges. The ideal charging current is one which will recharge the batteries in about 2 hours. As a general rule, 500ma seems to be an ideal charging current for 4 AA battereis. For example, the fast chargers from SONY charge 4 batteries at about 500ma, and charge 2 batteries at about 1000mah. That means they would take about 6 hours to fully charge 4 batteries of 2500Mah capacity. Quite an advance over the 16 hours required from a dumb charger.
Anyway, back to the ENVIE SPEEDSTER. The charging current is given as
1800ma for 1 AA battery
900ma for 2 AA batteries
450ma for 3-4 AA batteries
900ma for 1 AAA battery
450ma for 2 AAA batteries
225ma for 3-4 AAA batteries
(The lower current for AAA batteries does not mean that they take a longer time to charge. Remember that the capacity (Mah) of AAA batteries is considerably lesser. Rarely does it exceed 1000Mah; so charging time is quite less).
The thing I like about the ENVIE is that it enables you to charge, and monitor, each battery individually. Most dumb chargers allow you to charge only in pairs so you risk overcharging or undercharging one of the batteries if they do not hold exactly the same amount of charge at the time of charging. The charger also has a primitive LCD screen which tells you about the status of your batteries.
The charger is made in the PRC (China) and is marketed by IMS Mercantiles Pvt. Ltd., Rohini, Delhi (with 1 year warranty). This charger makes some great claims which are difficult to verify without sophisticated equipment. It claims to automatically cut-off fast charging and switch to trickle charging (think of trickle charging as a minimum maintenance charge) once the batteries are fully charged. True, the LCD turns itself off once the three bars are full but does it really switch to trickle?? No real way to find out except by deliberately leaving batteries in the charger for about 24 hours AFTER full charge is indicated. If the claim of auto-cut off is correct then nothing would happen. but if it does not switch to trickle, then chances are that you will be celebrating an advance New Year with the explosion. But I would give the benefit of the doubt to the company claims, since I have noticed that the batteries and charger start to cool down once the LCD indicator goes off even if the charger is left on.
One thing that the charger could have done with is a refresh mode. The refresh mode basically drains the batteries completely and then automatically recharges to full. This supposedly ensures longevity and maintains the capacity of the battery. It should be done only periodically depending on usage patterns. Think of it as a regular servicing of a vehicle. Some will argue that LSD (low self discharge) batteries like Sanyo eneloop do not require refreshing, but to each his own. No use bickering over whether it is actually beneficial or not. In any case, you do not need a charger to refresh a battery. Simply place the batteries in a high-drain device like a digital camera, and use until they can no longer power on the camera; and then let the charger do its work.
About the actual performance of this charger... I placed my Uniross batteries which had been lying unused for the better part of 3 years. The charger topped them up without a fuss. However, the charger indicated full charge before the estimated calculated time. Im putting that down to the reduced capacity of the batteries. After full charge was indicated, I put them in the camera and they worked. I took a number of photos just to see whether they would lose charge quickly. Surprisingly they held up. I left them in the camera overnight and the next day I turned on the camera. After taking a few shots they died on me, which was no surprise. These batteries discharge at a furious pace, but again Im putting that down to their age and the fact that they were unused, without periodical maintenance, for almost 3 years. But still, they self-discharged rather too quickly even when new. But the positive side is that I wont have to wait 16 hours to get a few hours performance out of them thanks to the ENVIE Speedster.
I also recently found an old pair of Eveready rechargeable Ni-Cd batteries... they had been lying unused in the bundled charger, for nearly 4 years. I checked the capacity and it was printed 700Mah. I charged them and am using them in my wireless mouse. Sure, what with the lower capacity and other factors, they can only power the mouse for an average of 2 days. But that's not really a problem since the charger enables me to fully charge them within 15 minutes!!:lol:
I recently got a pair of sanyo eneloops which I believe are authentic. Ill try and post something on them after some time, since its pretty pointless, not to mention premature, to post a review of rechargeable batteries based on first impressions. All Ill say for now is that sanyo, and experts, claim that they have a very slow self-discharge rate, with the ability to retain upto 75% charge even after 3 years of storage.
