Can a Car Alternator Charge a LiFePO4 Battery?

I often get asked if a car alternator can charge a LiFePO4?

Then I will tell them:

Yes and No

Let me explain.

Yes, you can charge a LiFePO4 battery from a car alternator, but you need a device to regulate the current.

This device is called a DC-to-DC charger.

victron orion tr smart dc to dc battery charger

Now, why do we need a DC-to-DC charger that can limit the current?

Lithium (LiFePO4) batteries have very low internal resistance. An alternator wants to deliver as much current as possible.

With a lead-acid battery, this will be ok because the internal resistance is higher than a lithium battery.

If you charge a lithium battery with a car alternator, the alternator will start to burn out or catch fire.

Victron did a great video about this:


When you want to use an alternator to charge a lithium battery you need a controller in between. This controller is a DC to DC converter.

Curious about what kind of DC-to-DC converter I recommend? Ready my article about the best DC to DC battery chargers.


Do you need a special alternator for lithium batteries?

You don’t need a special converter to charge a lithium battery. The only component you need is a DC-to-DC charger.

Can I charge a lithium battery with a car charger?

Yes, this is the standard charger for lead-acid batteries. But you need a DC-to-DC charger in between the alternator and the battery to regulate the charging current.

Do you need an isolated or non-isolated charger?

I have written a comparison between these two. Read the article here.

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