PbA, RAM, NiCad, NiMH, NiZn, NiFe, Li-Ion, LiFePO4

[kineticautomotive]

PbA, RAM, NiCad, NiMH, NiZn, NiFe, Li-Ion, LiFePO4 are the 8 major rechargeable storage devices to choose from, to date. There are other technologies in the works but here is a brief of these 8 in an effort to assist those DIY'ers and EV builders;

PbA (Lead Acid) - This is what the 12v system in a standard automobile uses.
- Energy Density is ~30Wh per Kg, these cells are extremely heavy for the power they store
- Cycle Life is long if not deeply discharging, otherwise you can kill a lead acid battery very quickly
- Charge Rate is relatively long, if you charge a lead acid too fast, you can boil the water and destroy the cell
- Discharge Rate is moderate, lead acids can push a bit of power but watch for over discharging
- Cost per watt is very low, this is the cheapest solution for stored energy

RAM
- Energy Density is ~75Wh per Kg, these cells have good weight to power ratios
- Cycle Life is relatively short regardless of power management, and gets shorter if abused
- Charge Rate is relatively long but less than lead acid but these take special care when charging
- Discharge Rate is pretty good but like lead acids, they prefer shallow discharging
- Cost per watt is very low, this is also a cheap solution for stored energy

NiCad (Nickel Cadmium)
- Energy Density is ~50Wh per Kg, these cells have pretty good weight to power ratios
- Cycle Life is very long, these cells will last but require you to completely discharge before recharging, each time
- Charge Rate is very long, you must not charge NiCad packs too quickly or their life will be shortened drastically
- Discharge Rate is high, they can discharge very rapidly without damage to the cells but watch the temperature
- Cost per watt is about the middle of the road, this is a practical solution for stored energy if you are dis/recharging overnight, but NiMH are a better alternative

NiMH (Nickel Metal Hydride)
- Energy Density is ~70Wh per Kg, these cells have a good weight to power ratio
- Cycle Life is very long, these cells will last and do not require you to completely discharge before recharging but these cells have high self discharge rates
- Charge Rate is a bit shorter than the previous options but again, as with most rechargable cells, watch the heat
- Discharge Rate is pretty good, they can discharge rapidly without damage to the cells but watch the temperature or poof, your investment is lost
- Cost per watt is a little high, this is a good alternative to NiCad's and Li-Ion / LiFePO4 cells due to lower cost

NiZn (Nickel-Zinc)
- Energy Density is ~170Wh per Kg, these cells have a huge power to weight ratio
- Cycle Life is average, these cells will last but do still suffer from technology issues
- Charge Rate very fast, you can charge these cells as fast as you can discharge them but as always, watch the heat
- Discharge Rate is pretty good, they can discharge rapidly without damage to the cells
- Cost per watt is a equivelent to NiCad but this technology still remains questionable long term

NiFe (Nickel Iron)
- Energy Density is ~200Wh per Kg, these cells also have a huge power to weight ratio, better than any of the other technologies
- Cycle Life is extremely long, these cells will last up to 80 years if you do not abuse them
- Charge Rate is extremely slow, plan on charging for days, not overnight
- Discharge Rate is pretty good, they can discharge rapidly without damage to the cells
- Cost per watt is low, these cells are inexpensive but the major drawback is they do not charge fast at all

Li-Ion (Lithium Ion)
- Energy Density is ~100Wh per Kg, these cells also have great power to weight ratio
- Cycle Life is about middle of the road, these cells will last about 7 years if not abused
- Charge Rate is rapid, these cells will charge about as fast as NiMH
- Discharge Rate is great, they can discharge rapidly without damage to the cells but watch the heat
- Cost per watt is very high, these cells are expensive

LiFePO4 (Lithium Iron Phosphate)
- Energy Density is also ~120Wh per Kg, these cells also have great power to weight ratio
- Cycle Life is about middle of the road, these cells will also last about 7 years if not abused
- Charge Rate is rapid, these cells will charge about as fast as NiMH
- Discharge Rate is very high, they can discharge rapidly without damage to the cells but again, watch the heat
- Cost per watt is very high, these cells are expensive