Batteries and Battery Chargers
Battery Packs and Cells
Lithium Iron Phosphate (LiFePO4) is a fairly new battery technology, offering distinct advantages over other batteries including being lighter weight than NiMH, having a flat discharge rate, and being significantly safer than Lithium Ion. The lithium iron phosphate batteries do not burst into flame if you look at them funny or nudge them a bit. The thermal runaway in these batteries does not start until over 500 degrees C — if the battery gets that hot in the RC boats, you have far more serious problems on your hands!
The cells are sold as individual cells or as battery packs, and can be sold with tabs upon request. All cells are 3.2 volts. They are sold in the AA (14500 size) and D (32600) size form factors, and in a large flat stainless steel-encased cell. Cells in the AA and D sizes fit standard battery holders, but should not be mixed with regular household batteries as these cells are 3.2 volts instead of 1.2-1.5 volts. The flat stainless steel-encased cell is 18 mm thick, 82 mm wide, and 130 mm tall. It has two M6 threaded studs for connecting to your circuit, and is a high discharge rated to 20 C (200 amps).
The battery packs are currently shipped without a battery protection circuit PCB (the PCB and smart charger are interfering with each other), and a smart charger needs to be used to protect against overcharging. Without the PCB, you do need to be careful to not over-discharge the cells and shorten their life. The cells quickly drop off in voltage at about 85% to 95% of discharge, and should be recharged when they drop below about 2.7 volts.
Your boats and other RC projects can benefit by using these batteries and their safety and weight advantages. A 5Ah pack at 6.4 volts is just under one pound. The flat armored cell is 10 Ah at 3.2 volts and also just under a pound. A four-pack of AA cells provides 12.8 volts and is good for driving solenoid valves. The regular discharge batteries should typically be kept under a 3 C discharge rate (i.e. a 3.5 amp hour battery discharging at 10.5 amps is a 3 C rate and will discharge the battery in a little less than 20 minutes). High discharge batteries are good for 10C or more.
We have battery packs made from many sizes of cylindrical battery cells. The nomenclature for cell naming is for the first two digits to represent the diameter of the cell, while the two digits after that are the length. A 14500 cell is 14 mm in diameter and 50 mm long. We are typically building the packs with two cells side by side, but can make them end-to-end on request.
To buy, please email firstname.lastname@example.org. Shipping at the moment is too complicated for the online system.
|AA (14500)||0.5 Ah||No||0.7 oz||$2.50|
|D (32600)||3.0 Ah||Yes||4.1 oz||$17.00|
|D (32600)||3.5 Ah||No||4.4 oz||$17.00|
18mm x 82mm x 130mm
|10 Ah||Yes||15.3 oz||$45.00|
Battery Packs (two cells, side by side)
|18650||1.5 Ah||No||3.5 oz||$11.00|
|22650||1.7 Ah||Yes||5.0 oz||$20.00|
|26650||2.3 Ah||Yes||6.7 oz||$30.00|
|32900||5 Ah||No||15.5 oz||$55.00|
Battery Charger $65