A new battery type has appeared:
- 1000+ (dis)charge deep-cycles.
- Low self-discharge; 5% / month at 25 deg. celcius
- Very electrically robust
- Very mechanically robust - can literally be nailed without explosion danger.
- -30...60 deg. celcius operating
- a123systems ANR26650M1 3.3V 2.3Ah can be charged in 15 minutes.
- a123systems ANR26650M1 3.3V 2.3Ah cells are laserwelded instead of crimping, which lower water losses and therefore extends celllife.
Test by Sandia National Laboratories:
- September 2008: lifebatt.com: Sandia report, ( http://www.lifebatt.com/ , http://www.lifebatt.eu/ ).
- Pdf-file: http://www.rc-netbutik.dk/getdoc.asp?id=100&md5hash=9810C237586CF6B4325753101E37DAE1 Quote: "...Curent test projecting excellent calendar life: 17% impedance growth and 23% capacity loss in 15 [fifteen!] years at 100% SOC, 60 deg. C..."
- Quote: "...according to our tesing, for 2.3AH high rate LiFe cell, the self-discharge rate is 4% of rated capacity per 28days...Jason's information is pretty close. We rate the cells at 5% cpacity loss per month...."
- DeWalt 36V Technology (A123 Systems):
- Quote: "...The M1 cells behave differently from other Lithium technologies. The specified end of charge voltage is 3.6 volts rather than 4.2 volts....The M1 cell, on the other hand, accepts very little additional energy above 3.6V....So how do the M1 cells compare? Tests so far show that over the course of a couple of weeks, the loss of capacity is close to zero. That's a good thing!..."
- http://www.sunhigh-battery.com/sdp/426453/4/pd-2390692/4068629-1538920.html Quote: "...The chemical structure of LiFePO4 used in SUNHIGH battery is very stable. The cycle life is extraordinary. The performance of the SUNHIGH's Fe- Battery is excellent for cycling at high temperature as well as for overcharge and over discharge..."
- Info AA Portable Power Corp:
- Polymer Li-Fe-PO4 Cell: 8790160L 3.2V 10 Ah, 2 C Drain Rate (LFP-8790160L):
- Quote: "...
- New Generation Polymer Li-Fe-PO4 Battery: High discharging rate, non explosive, lighter weight and much safe
- Energy density: 124 wh/kg
- Dimensions (HxWxL) 8.9mmx92.5mmx163.0 mm
- Weight 258 grams
- Detail Data Sheet: http://www.batteryspace.com/prod-specs/3.2V_10Ah_LiFePo4_poly.pdf
- Ask for a suitable flat-pack:
- AA Portable Power Corp: http://www.aaportablepower.com/
Traditional (Li-ion (polymer)) lithium-accumulator only handles 300-500 (dis)charge deep-cycles
How to prolong lithium-based batteries: http://www.batteryuniversity.com/parttwo-34.htm Quote: "... A lithium-ion battery provides 300-500 discharge/charge cycles. The battery prefers a partial rather than a full discharge. Frequent full discharges should be avoided when possible...Increasing internal resistance with cycle life and age is typical for cobalt-based lithium-ion, a system that is used for cell phones, cameras and laptops because of high energy density. The lower energy dense manganese-based lithium-ion, also known as spinel, maintains the internal resistance through its life but loses capacity due to chemical decompositions..."