High self-discharge NiMH batteries can be inconvenient to use, because: The self-discharge rate is too high. NiMH retains 50-80% @ 12 months : Alkaline retains 80% @ 10 years . For 2400 mAh batteries, 20% to 30% of stored energy discharges in just the first month.

Let me explain in greater detail the concept of battery self discharge. Continuous charging at low rates is not very efficient, therefore, pulse charging is recommended. This presents a significant challenge to battery charger designers. Self Discharge Rate : NiMH retains 50-80% @ 12 months Lithium retains >90% @ 15 years . Furthermore, the self-discharge increases with use and age, of which crystalline formation (memory) is a contributing factor.

instantaneous charge current 180 A Performances Cycle Life > 8 000 cycles (@ 80% DoD) Capacity Efficiency > 95% Mechanical Battery pack 40 cells (1.2V each) Modularity Up to 6 battery pack in one … Environmental Issues : Recycling options available for NiMH and lithium . They could be out of power within a couple of months of just sitting on the shelf. Good news: if you have a rechargeable battery all you need to do is recharge your battery! However it is very intolerant of overcharging, suffering a reduced capacity if this occurs. That said, I see no practical reason to cycle NiMH packs except to test them, and when I test them I cycle them at a load which approximates the load they will be subjected to during use. In general, NiMH batteries can’t handle the high rate of charges or discharges that NiCd batteries can. The rate will depend on why you want to cycle them, what kind of NiMH cells they are (standard or low self discharge), and how you will use them. NiMH cells have no memory effect. a 600mAh cell loses about 6mAh each day). NiMH self discharge cause. continuous charge current 100 A Max. I charge my small NiMh receiver and transmitter packs (1200mAh capacity) at somewhere around 1/10C overnight. I use 6volt nimh batteries and was wondering what charge, and discharge rate should I use. It should be fairly clear from the data that 3 of the cells are experiencing very high self-discharge rates. There is a great deal of uncertainty amongst NiMH users about just what effect temporary bouts of cell voltage reversal have on cell performance. Many intelligent chargers for NiCds sense a small but distinct \"bump\" in the output voltage when a NiCad is fully charged. You may … The purpose of trickle charging is to replace the charge that is continually draining off. High-performance NiCd has a higher self-discharge than the standard versions. Best AA NiMH My favorite NiMH AA is the Imedion by Powerex. 3.9 NiMH Battery Storage Overview . When fast-charging, it is advisable to charge the NiMH cells with a smart battery charger to avoid overcharging, which can damage cells. These can broadly be described as an oxygen cycle that occurs at high states of charge, and then ion movement that contributes to the self-discharge over longer periods of time.

All batteries will self discharge over a period of time naturally whether the battery is used or not. A standard maintenance charge at a C/128 rate is designed to counter this self-discharge.

Charging voltage is in the range of 1.4–1.6 V per cell. Some NiMH chemistries are able to handle maintenance charge rates up to a C/64 rate.

There are several factors that contribute to the self-discharge of an NiMH cell dependent upon the state of charge. instantaneous discharge current 300 A Self-discharge rate at 25°C < 15% for 30 days (initial SoC: 65%) Max. The only downside to the Imedions are that they're slightly larger than regular AA's, so they might not fit in your device. Max. NiMH batteries also tend to have a higher capacity than NiCd batteries of the same size, but NiMH batteries do discharge nearly twice as quickly as NiCd batteries, sometimes in just one week. In operation the NiMH cell has many similar characteristics to the more familiar NiCd. NiCds and NiMH cells, like all batteries, self-discharge. self discharge rate. It's a good balance of capacity (2400 mAh), charge cycles (500), and low self-discharge rate (retains 85% after one year). After about a week, it would be at 93%; after a month, 73%; after three months, 40%. No problem for many. LSD NiMh (Low-Self Discharge Nickel Metal Hydide) batteries, are the latest generation in NiMh battery chemistry.In standard NiMh rechargeable, the discharge rate is high. NiMH better than alkaline : Battery Weight . Trickle charging is similar to standard charging (i.e. They simply recharge them and off they go! A good NiMH battery had a self discharge rate of about 1% per day. It follows a very similar discharge curve to that of the NiCad allowing for the extra charge it can take. Higher capacity batteries discharge even faster. NiMh doesn't have a memory effect, so cycling is not required so often, but I believe an occasional cycle can help keep the cells in balance. NiCds and NiMH actually have a relatively high self-discharge rate of about 1% per day at room temperature (i.e. Low Temperature Performance : Lithium better than NiMH . continuous discharge current 240 A Max.