If you only used 50% of a lead Acid battery, using 80% of a Lithium battery of the same capacity
(Ah) should provide at least
60% more range
(0.8/0.5x100=160%) but I suspect that you may well be using more than 50% of the Lead Acid battery's capacity.
A lithium battery
of the same capacity would also weigh a lot less compared to the Lead acid battery.
Lithium batteries are a lot more efficient and have less voltage sag under higher discharge rates compared to Lead Acid batteries, therefore you should get even more mileage at the same current draw from a lithium battery compared to a Lead Acid battery of the same rated Ah capacity.
The slightly higher nominal voltage of the LiFePO
4 battery
(12.8V instead of 12V) combined with the reduced voltage sag results in more power for the same amount of current being drawn, therefore you will require less current to maintain the same speed, which should also extend the available range.
Lead Acid Batteries Lose Capacity At High Discharge Rates
Peukert’s Law describes how lead acid battery capacity is affected by the rate at which the battery is discharged. As the discharge rate increases, the battery’s usable capacity decreases.
A typical battery’s capacity is measured by the current that is required to fully discharge in 20 hours. If your application’s discharge current exceeds the manufacturer’s 20-hour rate, Peukert’s Law explains why your battery capacity becomes significantly reduced.
However, this law does not hold true for lithium-ion batteries due to the technology’s high level of efficiency. Lithium-ion battery capacity remains satisfactory for years after installation, regardless of your discharge rate.
Lithium-Ion Batteries Have A Higher Usable Capacity
In many applications, lead acid batteries are sized to a 50 percent depth of discharge in order to extend battery life. This means you are taking up twice the amount of space and adding extra cost, neither of which are efficient options.
Rechargeable lithium-ion batteries are 99 percent efficient and offer a much higher usable capacity at the same Amp-Hour (AH) rating. Lithium-ion technology commonly provides 20-50 percent more usable capacity and operational time depending on the discharge current.
This allows you to substitute your lead acid battery with a much smaller, lower capacity lithium-ion battery to achieve similar results and run time. Additionally, lithium-ion battery life far exceeds the life span of lead acid batteries.
Basically, you will get more miles per Ah from a Lithium battery than you get from a Lead Acid battery. So if you changed from a 160Ah Lead Acid battery to a 320 Ah Lithium battery you would get a lot more than double the range if you used the full 100% capacity of both batteries.
Alan
