WHY THEY LEAK OR EXPLODE?
1. Never drain an alkaline rechargeable! If the calculator gives you a warning that the batteries are low then you have gone too far. When drained, the alkaline will leak and when charged in this condition, can give off a gas that makes it "blow up". That is the main thing people do wrong with these newer type of battery.
2. The second cause could be the charger. Ni-Cad chargers charge constantly and never shut off. Alkaline charges contain a charging circuit to shut the charging down when they are full. If you put an alkaline battery into a Ni-Cad charger, it never shuts off. It will fry the batteries. Use only alkaline chargers for alkaline batteries.
WHEN TO CHARGE
When you bought your Schoolcells you were given a "Charging Schedule" that goes on the calculator door. Follow this the best you can for best value and to keep your warranty in effect. If you do not have a Schedule, you may purchase them for 20 cents each.
HISTORY OF THE ALKALINE RECHARGEABLE AND THE CANADIAN CONNECTION
Battery Technologies, in Toronto has the patent for the Alkaline Rechargeable technology. It licensed it to Pure Energy Visions in Canada and Rayovac in the USA. Rayovac has not upgraded the original formula for the rechargeables and has ceased making them. Pure Energy Visions, who makes the Schoolcell for CCS, uses only latest formulation. In 2005, the Schoolcell XL was introduced just in time for the higher drain TI-84+ with the USB port. CCS is the exclusive North American distributor of Schoolcell.
Compared to the one use battery. eg Duracells
Money: One use batteries initially cost slightly less than the rechargeables to buy. The rechargeables will give you a minimum of 25 charges. This is a huge savings per calculator. You are paying approximately 19 times more for one use. See our calculations below.
Environmental: By using Alkaline Rechargeables, you are reducing your landfill by 25 fold. It takes approximately 25 one use sets for each Alkaline set.
Typical Misconception: The big complaint about the Alkaline rechargeables is the pain of charging, keeping track of when to charge and leakage. With the Calculator Charging Station, Charging Schedule, and performance warranty, that's no longer an issue.
Compared to the Nickel Cadmium (NiCad) battery.
Alkaline do not have any environmentally harmful chemicals & can be thrown in the garbage
Alkaline are for low drain use like in a calculator while NiCad are for high drain use such as for toys, tools etc.
Alkaline do not drain while stored where as NiCads drain even while sitting around.
Alkaline come fully charged and ready to use, while NiCads need to be charged before use.
Alkaline have no 'memory' and can be charged when partially empty while NiCads have a 'memory' and need to be fully drained before charging.
Compared to the Nickel Metal Hydride (NMH) battery.
Alkaline can be thrown in the garbage while NMH have Nickel & other heavy metals and require special disposal.
Alkaline are for low drain use like in a calculator while NMH are for high drain use such as toys, tools etc.
Alkaline do not drain while stored where as NMH drain even while sitting around.
Alkaline come fully charged and ready to use, while NMH need to be charged before use. While NiCad have Nickel and Cadmium so they require special disposal.
Here are our calculations comparing cost of using one use Duracells to rechargeable Schoolcells:
Prices for Duracell vary, but recently in a local Walmart, the best price I could find, they were over $6.17 for a set of 4. Schoolcell sells for $7.46 for a single set. Remember you get conservatively at least 25, usually you get over 30, charges from a set of Schoolcells. For 25 sets of Duracells you pay 6.17 X 25 = $154.25 dollars.
For the approximately* the same amount of power, for Schoolcell alkaline, you pay only $7.46. That's a saving of $146.79 per calculator for a 21 : 1 ratio. If you have 3 class sets of 30 calculators, thats 90 X $142.54 = $13,211 dollars saving. Could you find use for that money in your budget?
( * approximate because with rechargeables, you get less power for each successive charge )
Cost for Duracells for 90 calculators: $13882.50
Cost for Schoocells for 90 calculators: $671.40
Don't forget you are reducing solid waste by at least 25 times too!
