Battery Replacement — Lead acid to Lithium NMC & LiFePO4 Battery

Aegis Battery

In an increasingly electric world, many are looking to replace their old lead acid batteries with more powerful, safer and longer lasting lithium batteries. Not only do lithium batteries offer significantly better performance, faster charging, and longer 3000+ full charge/discharge cycles, but are also often 1/2 the weight.

So, can I just replace my lead acid batteries with the same volt lithium batteries? While in many cases it is that simple, one thing to consider is that good lithium batteries will have a battery management system (BMS) that is designed to protect the specific lithium battery.

While a cheaper battery supplier will often use generic off the shelf BMS with incorrect ranges, a good battery manufacturer will use BMS that is custom tailored to the specific volt and amp rated for the battery. This protects the battery from things like over-charging, over-voltage, extreme temperatures, other potential issues like accidental reversed polarity, all to ensure the battery is protected and lasts for many years.

Although the BMS provides great protection, it also means that in some applications it may either limit the performance or cut off power when the power draw exceeds the BMS protection settings. This typically happens when users try to run multiple batteries in series to achieve higher voltage or in parallel to achieve more amp hours.

For example, larger motors typically utilize 48V due to power draw requirements. Some users will try and run two 24V in series to achieve the 48V. However, for lithium batteries this will often trigger the over volt protection, as the system detects 48V draw when it is rated for 24V.

So, you might wonder, why not just have the BMS run at 24V-48V ranges? Well the problem is this negates any protection the BMS offers as it would not be able to react to over volt, over charging, and short circuit situations in time to save the battery cells from damage.

You will often see cheap resellers of LiFePO4 on Amazon or other retailers claiming they can run for an absurd 10K+ cycles and in series. Typically their BMS does not react in time to prevent damage and many resellers do not care much or lose interest in the end customer once the sale is made. This often leaves customers with no real support or ability to utilize the warranty if needed.

At Aegis Battery, we do our best to find you the right matching battery for your application. As this often means, the battery will last much longer and perform correctly for the end user application.

As talked about in the 48V example, we would recommend a single 48V battery pack with larger amp hours and BMS designed to last for a larger motor. Rather than trying to run multiple 24V batteries. Many users will find that the single 48V will still fit into the same battery area and if coming from lead acid, 1/2 the weight or more.

The one downside, is of course the cost. Lithium is a much more expensive material than lead and the batteries often have higher quality internal materials and better connectors. However, if you consider a good lithium battery should last 5–10 years (compared to 1–3 of lead acid battery), it becomes much more reasonable to compare to buying 2 or 3+ lead acid batteries.

Lithium batteries often charge 3x faster (e.g. 2 hours vs 6+ hours), are light-weight and overall provide superior performance. The initial cost is higher, but when you consider the advantages and long life, it can make replacing your lead acid batteries worthwhile.

If you are thinking about replacing or upgrading to a lithium NMC or LiFePO4 battery, Aegis Battery is happy to help you find the right battery for your application. In addition, we truly do stand behind our warranty as a US company and being our own battery manufacturer. We carry a wide variety of battery packs and if not in our stock we can custom manufacture a perfect matching battery for you.

For more details regarding our custom lithium battery either for NMC battery pack or LiFePO4 batteries, please feel free to contact us at or complete the Custom Battery form located on our website here.