Battery Usage Tip, Industry News

Why can’t a lead-acid battery charger be used for a lithium battery?

Ebike Battery and Charger

Why can’t a lead-acid battery charger be used for a lithium battery? Many people have this question, why are all 48V electric vehicle batteries, chargers can not be universal. Actually, it doesn’t. Lithium battery chargers can be used for emergency use with lead-acid batteries of the same specifications, but even those with lead-acid batteries of the same specifications can not be used for lithium batteries. Let’s talk about what the difference is and why it doesn’t work?

Why can’t the Charger of lead-acid battery be used for lithium battery?

Electric Vehicle Lithium Battery Charger

1.Lead acid battery material is different from lithium battery

1) The unit voltage of a lead-acid battery is 2V (so batteries are commonly available in the range of 6V, 12V, 24V, etc.). The unit voltage of a fully charged lead-acid battery is 2.4V.

2)The unit voltage of the NCM lithium battery is 3.6 to 3.7V, lithium iron phosphate battery is 3.2 V. The fully charged NCM battery voltage is 4.2 V and that of the lithium iron phosphate battery is 3.65V at full charge state.

2.The chargers are programmed and manufactured differently

1)Lead-acid battery chargers are generally charged at a higher voltage than lithium-ion batteries, as in the case of 36V lithium battery chargers. The lowest charging voltage for a lead-acid battery charger is 41.4 V-44. XV, lithium battery charger’s highest voltage is generally within 42.5V, usually even allows the battery to stop charging around 41.8 V in most cases.

2)The charging mode is different. The charging mode of the lead-acid battery charger is pulse constant current charge, and the charging mode of the lead-acid battery charger is two or three stages, that is to say, the charger will continue to recharge the lead-acid battery in a low current mode after the turn lamp is light up. So many times the longer the lead-acid battery charge feel more durable.

The lithium battery charger is using CC/CV constant current to charge the lithium battery at a constant voltage, use constant current to charge the lithium battery at the beginning to about 90% and then the charger to the constant voltage mode to recharge the battery, and when the charger determines that the lithium battery is fully charged, in addition to the power indicator lamp display, the charger will not have the current to continue to recharge the battery. Because lithium batteries are not allowed to overcharge. Overcharging can not only damage lithium-ion batteries, it can also bring more serious risks.

3.What is the impact of the mixed use of chargers on the batteries?

1)Lead-acid battery charger for an electric vehicle lithium battery will lead to overcharge lithium battery, the protective board will enter the state of protection.

2)Lithium battery chargers charging lead acid batteries is okay in an emergency situation with the same specifications, but because the lithium battery is charged at a lower voltage and there is no small current to recharge it, it will not be fully charged.

Ebike Battery and Charger

4.The reason why the lithium battery charger can not charge the lead-acid battery

This is generally not recommended, although the theory that a charger without a pulse function can charge a lead-acid battery can still cause battery damage.

1)Lead-acid batteries last less than one charge and have a memory, so we usually give them longer charge times to make sure they’re fully charged. If you use a scooter lithium battery charger to charge a lead-acid battery, the actual charge may sacrifice the lead-acid battery more than 1 cycle life.

Summary: In theory, DC current relative to charging is no problem. But the battery performance data is different. So you need to be careful when you use it. Basically, the lithium charger charges the lead-acid battery will lead to undercharging. lead-acid battery charger charges lithium battery will lead to overcharge. So lithium battery pack and lead-acid battery pack must use their specific chargers separately for safety and longer circle life.

SmartPropel Original Writer: Nancy Liu