Charging a Lithium Phosphate Motorcycle Battery

Shorai Charger

Lithium Iron Phosphate batteries (LiFePO4) commonly referred to as “Lithium Iron” batteries are an alternative battery type for common lead-acid batteries for motorcycles.

Lithium Iron batteries, while often more expensive than lead-acid batteries, offer some advantages over lead-acid batteries.

Charging the Shorai LFX Batteries

In our example we use a Shorai LFX Lithium Iron battery. Shorai claims to be one of the most affordable Lithium Iron batteries. It has proven to be a lightweight, affordable solution for SLI (starting, lighting, ignition) of motorcycles.

To charge any of the Shorai LFX batteries, you may need to first remove the battery from the motorcycle. Plan to store the battery in a dry cool area such as a garage. Avoid direct sunlight. Place the battery on an insulator surface such as piece of polystyrene foam, wood or cardboard that has low thermal conductivity. Avoid sitting/storing battery on metal as it has high thermal conductivity. Highly conductive surfaces that experience dramatic temperature change may increase the discharge rate of batteries. If you are an engineer you might enjoy reading this chart which shows thermal conductivity of common materials

For the Shorai LFX Battery the Shorai BMS01 battery management system is the ideal charger/battery management system. The advantage this type of battery management system has is if you plan to not ride motorcycle for several weeks or even months, you can use the “store” function of the Shorai charger. What this function essentially does is increase your battery life by monitoring the percentage of charge your battery has and maintaining a maximum charge rate of 80% and a minimum discharge rate of 60% capacity. In general Lithium Iron batteries will last longer if they are stored at a lower charge percentage. A fully charged Lithium Iron battery will have a higher internal temperature which is above recommended storage temperature and could affect the lifespan of the battery.

When motorcycle season starts, you simply click the “charge” mode on the Shorai battery management system and within an hour, your battery should be fully charged and ready for you to hit the road.

Does the Shorai LFX Lithium Iron Battery have to be fully charged for it to start my motorcycle?

Shorai, asserts that their Shorai LFX batteries crank motorcycles strongly even if the capacity is well below the 60% charge state. So if you want to take a quick spin, have no fear your battery should easily start your motorcycle. Just disconnect the battery from the charger and install the battery in your bike, start and go!

I just installed my battery after storing it and tried to start my engine and it wouldn’t crank. What’s going on?

Occasionally this could and probably will happen. Lithium Iron batteries are really a paradigm shift from Lead-Acid batteries. When a lead-acid battery has been discharged below the necessary cold cranking amps required to start your motorcycle engine, you will experience the engine turning over a little bit the first time you attempt to start it, then on sequential attempts to start the engine it will crank less and less until there is a dreadful buzzing or clicking response and then nothing at all. Technically speaking, the lead-acid battery experiences an increase in internal resistance as more attempts are made to start the engine.

With Lithium Iron batteries, it is actually the complete opposite. On the first attempt to crank the engine you may experience nothing at all. This process has now actually started to warm the battery and it will get stronger on each additional attempts. The best method for starting your motorcycle when it is cold or hasn’t been driven for a few days or weeks is to turn the key to the “ON” position and turn your headlight on for 30 seconds without starting the engine. This will get the current flowing in the battery. In extreme cold weather you may need to wait 4 to 5 minutes with the headlight on. Once the battery warms up, you should have no problem starting your engine. Sequential engine starts shouldn’t be a problem since the battery will be warmed up. In lieu of headlight, you can turn on any accessory such as radio, etc. that will get the current flowing in the battery.


Lithium Iron motorcycle batteries are a good investment for Motorcycle enthusiasts. While upfront costs are higher, the total cost of ownership decreases since average battery life is higher than Conventional Lead-Acid and Sealed Lead-Acid motorcycle batteries. An additional investment in a Lithium Iron battery management system/charger will provide further enhancement to battery performance and lifespan.

Charging a Shorai LFX (LiFePO4) battery with the Battery Tender

Video Transcript:

In this video we demonstrate how to charge a Shorai Lithium Iron Phosphate motorcycle battery with a Battery Tender Charger. You can use this particular charger because it does not have an automatic desulfation mode and it will not overcharge the battery.

Do not use a charger that has auto-desulfation since it will hurt Lithium Phosphate batteries. Overcharging is also an enemy to batteries. Your charger should have a float mode which prevents the battery from being overcharged.

The reason people like the Battery Tender charger, is because of its simplicity. It’s really a plug and play charger. Here we show you just how simple it is.

First connect the positive cable to the positive terminal on the battery. Then connect the negative cable to the negative terminal on the battery. Then plug the charger in. The Battery Tender Plus Charger, immediately recognizes the voltage of the battery and starts charging which will be indicated by a red led light on this Battery Tender charger.

When the battery is fully charged, the Battery Tender automatically switches to a “storage” or float mode which is indicated by a green led light on this particular charger.

There is also a quick connect pigtail that comes with this charger. We recommend using the quick connect instead of the alligator clips so you can quickly connect the charger without any inconvenience such as removing your motorcycle seat.

That’s all there is to it! It really is simple. Be sure to read all the precautions provided by the manufacturer of the battery and the charger before attempting this.

You can purchase this Shorai battery and the Battery Tender Plus Charger at

Shorai Battery Installed on Harley Davidson Motorcycle w/ Battery Tender Quick Connect

Video Transcript:

In this video Arcenio with Batterytown of Valencia shows you a Shorai battery installed on his Harley Davidson Motorcycle.

Alright, so we have a Shorai Battery in a 2005 Road King Harley Davidson. It’s the LFX36L3 model. It’s basic wiring connection. I actually have it connected here to a Battery Tender disconnect, ah quick disconnect, that I can just throw in and put it on a Battery Tender just to maintain the battery if need be. Connects very simple just positive and negative.

There’s actually padding on the bottom that elevates the battery to give it the feel of the actual battery and you can actually put padding here so the battery doesn’t vibrate uh while you’re riding.