[This review is for the EBL 5000mAh C sized batteries, not the EBL charger. Unfortunately Amazon often lumps reviews of related products together. I paid for this product, my review is unsolicited.]Update 1 (3/29/2016):I have not used any of the four batteries since initial testing but instead set them aside for long term self discharge testing. After three months I tested two batteries I had previously analyzed and charged using an Opus BT-C2400. I found they had both were ~81% charged (discharged ~19%). Considering how much self discharge has occurred in just three months, it's very unlikely these will hold 75% of their charge for three years as advertised. I will charge these up and test them again in the future, as well as the other two that are still sitting to get a couple of more data points on self discharge.Original Review:The EBL "C" rechargeable batteries arrived quickly and were well packaged. They came as two pairs, each pair in a plastic storage case. The measured size was within the standard for C (LR14) batteries and there shouldn't be an issue with them physically fitting into most devices. The batteries appear to be well constructed.With rechargeable batteries the key information is capacity, self discharge rate, and number of cycles. Capacity is how much power (in milliamp-hours) the battery can hold, self discharge rate is how much power is lost in an unused charged battery after some period, typically 1 year. Cycles is the number of times the battery can be discharged down to a certain amount then recharged. With the right equipment, capacity can be easily measured. Self discharge rate can't be measured on a new battery as time has to pass before measurements can be done. Cycles is hard to measure without special equipment.The EBL C batteries are advertised as having a 5000mAh capacity, a 25% self discharge rate after 3 years, and 1200 recharge cycles. Most "C" alkalines will maintain a capacity >7000 mAh during the first few years after manufacture. Don't expect any NiMh battery to perform the same as an alkaline, inherent differences in the chemistry just don't make this possible.I can't test the 3 year self discharge rate now, nor the number of cycles, but I did test the initial charge and capacity. NiMh batteries need to be "conditioned" when new and periodically to achieve maximum capacity. My measurements and conditioning utilized an Opus BT-C2400. I performed three deep cycles to condition.Initial charge as received: 4086, 3012, 3001, 2788 mAh (when new, a less than full charge is normal)Capacity after conditioning: 4247, 4275, 4284, 4321 mAh (this should be >5000)Unfortunately in my analysis, the stated capacity, or even 90% of it wasn't met. Further conditioning might give slight gains, but are unlikely to achieve even 4500mAh. I would have preferred to see them spec these at 4000mAh and over deliver instead of under delivering.I plan to set aside two of these for at least three months then measure how much charge is left. That won't provide the 3 year self discharge rate, but it will give some idea of the self discharge characteristics. I'm particularly interested in these compared to regular NiMh batteries which can lose 30% or more in 3 months and eneloops which loose less than 10%.Regardless of brand or size, getting the most out of rechargeable NiMh batteries is highly dependent on the person using them. Over discharging your batteries and using low quality "dumb" chargers is a sure way to a very short battery life.Please click Yes if this review was helpful. I'll also try to respond to any questions.