Problem: Article: Both NiMh and NiCd batteries can be recharged over time, but you might want to think about investing in NiMh batteries over NiCd. NiMh batteries use newer technology to store more charge and can also be fast, slow, or trickle charged. Check the product in which you plan on using your batteries before purchasing your batteries. Certain equipment may require either NiMh or NiCd to operate best. These are one of the least expensive varieties of battery chargers available on the consumer market. A pre-set shutoff timer will charge all batteries in the charger for a period of time and shut off once that time has elapsed. These chargers are less precise than smart chargers, which can lead to under- and over-charging. Take this into account when buying a timer charger; over-charged batteries can be ruined and cost you more money. Smart chargers can be more expensive initially, but these are equipped with sensors that detect missing voltage in your batteries. This way, your charger will continue to charge your battery until it has reached full charge, saving you the cost of batteries ruined from over-charging. The rechargeable batteries you bought earlier will also help you to decide which charger you invest in. Some chargers are intended for only NiMh or NiCd batteries, though some universal chargers are available. Most AA and AAA battery chargers can be used for both NiMh and NiCd batteries, though you should always consult your manual to be certain. You should never attempt to charge a battery that isn't intended to be rechargeable. This can cause a dangerous explosion from hydrogen gas buildup and may ruin your battery or charger as well. Check the manual that came with your charger to know the recommended safety procedure for your charger, but generally you should:  Keep your charger and batteries away from fire or intense heat. Do not charge your batteries around or on top of flammable materials, including flammable gases, like gasoline vapor. Insert your batteries into your charger firmly before plugging in your charger. Prevent your charger from being exposed to rain, snow, water, and oil. These kind of batteries experience what is called the "memory effect." This means that if you charge your battery before it is completely dead, your battery will remember the smaller capacity as its full potential, which will hurt your battery life. Some batteries may have a specific amperage for best results. This may include charge times for "fast" or "standard" charge speeds. Always follow manufacturer recommendations for best results and safest use. As an example, you may see that your battery might have "Std. CHARGE: 60mA 14 - 16 hrs" written on it. This battery would charge best at 60 milliamps for a minimum of 14 hours. Some chargers come with an interface or a timer that you might need to set. You may be able to set the rate of charge (fast, quick, normal, slow, trickle) as a function of capacity. This is represented by a fraction of the capacity, represented by the format "C/#".  You should also set your timer with respect to your charge rate (C-rate).  For example, charging your battery at C/10 will charge 10% of your batteries full capacity per hour, charging your battery fully in a little over 10 hours, depending on efficiency of your charger. Many manufacturers recommend slower rates of charging. Faster charging will result in less efficient charging. This should be done before you plug your charger into an electrical outlet, unless otherwise indicated by your charger manual. Once you feel the batteries click into place, you can plug in your charger and begin charging. Once your timer is up or the display on your charger indicates that all batteries are fully charged, as is usually the case with smart chargers, unplug your charger and remove the batteries. If you find that your batteries are difficult to remove, use a gentle tapping motion until one is jarred free.
Summary: Learn the differences in battery chemistry to prolong battery life. Evaluate time controlled chargers. Optimize with smart chargers. Purchase an appropriate charger. Follow safe usage guidelines. Wait until the battery is completely drained for NiCds. Check for noted charge rates. Set your charger, if necessary. Insert your batteries. Remove all charged cells.

In one sentence, describe what the following article is about: The Frequently Asked Questions page hosts users' most commonly requested topics. You can use this section of the site to find answers to many questions you might have. Just go to https://www.groupon.com/faq. The FAQs are divided up into the following categories: Managing Your Account, Using a Groupon, Returns, Shipping and Tracking, Purchasing a Groupon, and Editing or Cancelling an Order. Fortunately, there's no need to browse through every FAQ help topic. You can search for your issue using the search bar in the middle of the page. For example, if you're having an issue closing your account, you might type "How do I close my Groupon account?" Then, click the magnifying glass button to the left of the search bar or press enter to submit your question. These appear below the search bar. Keep in mind that you may not see a direct copy of your own question. If you don't see a perfectly matching result, try to look for similar concerns from other users. While you may not see your specific question listed here, you'll likely see one that comes close. Look for similar keywords in other questions to help you find the answers you need.
Summary:
Open the Groupon FAQ page. Click the "Search help topics, keywords, or phrases" bar. Type in your question then click the magnifying glass. Review the search results. Click the title of a question that matches yours.