Shorai LFX Deep Cycle Applications
Shorai LFX batteries are primarily used as a high performance cranking battery. Simply put, cranking batteries are designed to provide very high currents for short periods of time. This is mainly for applications such as starting (or turning over) an engine. Starting batteries (cranking battery) are not designed to be discharged or provide current for long period of times, for example, running lights, accessories or even operating electric vehicles.
Shorai’ ability to produce an exceptionally small battery with approximately 1/8th the weight of conventional lead acid batteries is often seen as a possible solution for deep cycle applications. This is particularly important when there are size and weight restrictions such as running golf trundlers, golf carts, electric scooters and bikes.
It is very important to understand the current demands of your application, as discharging Shorai (or any Lithium based battery) too far is guaranteed to cause failure, even if it is only done a few times. Shorai LFX batteries are designed from ground up to provide unparalleled cranking power and not to be pushed into a too deeper state of discharge (although in some cases this is possible).
If you are planning on using a Shorai LFX battery in a deep cycle application, there are basic formulae to keep in mind to ensure you do not damage and void your Shorai warranty.
Calculating Shorai Usable Deep Cycle Capacity
Shorai LFX batteries optimum deep state of charge is approximately 35%. Discharging past this point will place huge stress on the Shorai cells, reducing the overall lifespan and increasing the probability of failure.
The basic formulae to determine usable deep cycle capacity for Shorai batteries can be calculated by this equation:
(Shorai AHR rating / 3) * 0.65 = Usable AHR in Deep Cycle Applications
For example if we using a Shorai LFX18:
18/3 * 0.65 = 3.9ahr
Determining Safe Run Time
The first step is to determine the current draw on whatever application you are planning to use your Shorai LFX battery for. Using an inline ammeter is the easiest way to get this information.
Once you have the current draw, divide it by the usable AHR of your Shorai Battery, as explained in the above equation.
For example, if your current draw is 3.9a and you are using a Shorai LFX 18 battery, your total run time would be 1 hour before the battery is being over discharged. If your current draw is 7.8a, the run time is 0.5 hours or 30min.
This is a rough equation and any application will have peak and average current draw. As always it pays to leave a bit of head room.