Why are lithium batteries better than lead acid batteries?
The key factors are energy density and cycle life. Here are some numbers to explain the difference...
A LiFePO4 battery, for example the CALB 100AHA, has an energy density of 45.4 watt-hours per pound and 2.6 watt-hours per cubic inch.
A lead acid battery, for example the Deka Group 27, has an energy density of 16.4 watt-hours per pound and 1.22 watt-hour per cubic inch.
A LiFePO4 battery can store 2.75 times more energy by weight and 2.1 times more energy by volume.
LiFePO4 batteries can be cycled (charged and discharged) 2000-5000 times while lead acid batteries only have a life of 400-600 cycles.
Lithium batteries have 4-5 times the cycle life of lead acid batteries.
The bad news is the cost. LiFePO4 batteries cost about 2.3 times more per watt-hour of storage than lead acid batteries.
68 CALB 100 Ah LiFePO4 batteries
Using my battery pack calculator
, I designed a new lithium battery pack that would fit into my existing lead acid battery boxes with minimal modifications.
The batteries were ordered directly from the China Aviation Lithium Battery company office in California. After about 8 weeks all 68 batteries arrived in three crates and a box. The order also included 68 copper bars and 68 pairs of stainless steel bolts and washers.
A local sheet metal company made some 16 gauge mild steel U-channel to my specifications.
The U-channel was then cut, drilled primed and painted as needed.
The batteries were then grouped together and stapped tight with stainless steel threaded rods.
The Largest of the Battery Groupings
The largest battery grouping goes in the area where the spare tire used to go. This unit was 2 rows of 10 batteries and weighs about 140 lbs. The 20 batteries were first layed out on a table and strapped together with U-channel and threaded rod -- then an engine crane was used to carefully lower the group into the car.
Connecting the Batteries
After each grouping was installed, the batteries were connected in series using the copper bars provided by CALB.
Under the Hood
5 different groupings of batteries under the hood in the front.