Difference between revisions of "Rechargeable"

'''Recommended batteries:''' There are a number of sources of batteries and quality varies widely. Some are outright frauds with brand name labels pasted over recycled cells or worse (one battery was hollow and contained a small Li-po battery inside). eBay is a notoriously bad place to buy lithium ion batteries, with fake brand name batteries and false claims regarding capacity and battery protection. Panasonic NCR18650, NCR18650A, and NCR18650B cells of 2900, 3100, and 3400 mAh capacity are high quality cells available from a variety of dealers. Cells by LG, Samsung, Sony, and Sanyo are also good. Then retailers will put labels on those batteries and sell them. Just make sure you find a reputable dealer with satisfied customers on the forums and stick with batteries that use new cells from reputable companies.

New LiFePO₄ batteries have about 20% lower energy density than Li-ion, but also have much longer life (typically about 10 years, as opposed to 2-3 years for Li-ion) and can endure almost double the number of charge/discharge cycles of Li-ion. They also have lower self-discharge rate, are able to deliver higher current, and are more resistant to thermal runaway. However, as they are not as popular as Li-ion, they are still somewhat more expensive. Because they can not be charged to 4.2V, they require a charger with a LiFePo setting or hobby charger that can be set to 3.6V max. Walmart sells 3.2V AA-sized LiFePO4 cells by Westinghouse for solar lighting (so no charger included). The working voltage is below what most LED's need in direct drive and if a driver has low voltage protection for ICR cells, it could trigger too early with LiFePo cells.

Similar to IMR cells above, and sometimes called INR, these cells typically are not rated for as high a draw as IMR cells, but are still safe without protection, and often have higher capacity than IMR cells. Realistically there may not be that much difference between IMR and INR batteries since different manufacturers will tweak the recipe with traces of elements to get the best performance. Panasonic makes 2250mAh cells that have the product number CGR18650CH and Samsung makes two highly regarded models called 25R and 30Q, with the 30Q offering a little more capacity. Often the manufacturers will rates cells for some number of amps (10 amps, 15 amps) but beware false claims from retailers.