Plugged In Blog

Rethinking Batteries: Six Advances that Make Batteries Your Most Reliable Portable Power Option (2022)

02.10.22

“I’ve tried battery-based power solutions before, and they didn’t work. Why would a Joule Case system be any different?”

If you’ve ever needed portable power, you’ve probably thought about using batteries. Unfortunately, previous technology wasn’t always the most reliable or efficient option. But, a lot has changed!

There is a very big difference between the battery technology that is typically used within the automotive industry and that utilized by Joule Case. Most solutions that were once impractical with standard automotive battery technology (like powering a food truck or a music festival!!!) are now entirely feasible and cost-effective with a Joule Case solution.

Here are several reasons why:

Battery Chemistry Has Evolved

The automotive industry typically uses two battery types:

  • Flooded Lead Acid (FLA) batteries contain a liquid electrolyte of sulphuric acid that comes into contact with lead plates to produce electricity. The liquid electrolyte needs to be replenished periodically and is prone to spillage. It also produces gasses that need to be vented.
  • Sealed Lead Acid (SLA) batteries, of which AGM (Absorption Glass Mat) technology is common. These also use lead and sulphuric acid to generate electricity, but the electrolyte is sealed so there is no spillage or refilling needed.

Today, however, Lithium-Ion technology is becoming more widely adopted. Lithium batteries offer greater capacity, higher power density, and longer lifespans. Joule Case utilizes Lithium Ion NCM (nickel cobalt magnesium) batteries in its products.

Usable Capacity of Batteries Has Increased

The point of a battery is to store energy. And, once that energy is stored, you need to be able to get it back out and use it. Lead-acid and AGM batteries have a very frustrating limitation—you typically can only use half of their rated capacity because draining the battery down to empty causes damage. In practical terms this means you need to purchase twice the rated capacity to get enough energy.

Lithium batteries are different. The entire rated capacity of a lithium battery can be used without damaging it.

Modern Batteries are Energy Dense (i.e. lower weight for the same capacity)

Batteries are heavy, but some batteries are heavier than others. Lithium batteries have a higher energy density than lead-acid/AGM batteries, which results in a lower weight for the same electrical capacity.

For comparison:

  • Li-NCM: 14 lb per kwh
  • AGM: 50-55 lbs per kwh (really 100-110 lbs per “usable” kwh)

In short, and given the capacity limitation discussed above, AGM batteries weigh about 9 times as much as lithium batteries do, for the same usable capacity. An AGM battery array needed to provide 6kwh of usable capacity (which is 500ah at 12V, meaning 1,000Ah of total capacity is needed) would weigh 550 lbs, vs 85 lbs for a single Joule Case Li6k battery.

Modern Batteries have Longer Lifespans

Lithium batteries are more expensive than lead-acid or AGM batteries. But, in addition to the other benefits listed here, they last much longer. Back to our example above: a Joule Case Li6k battery costs $3,995. You’d need 10 SLA or AGM batteries to provide the same usable capacity. 10 SLA batteries would cost $1,800-$2,000, and 10 AGM batteries would cost $2,800-$3,000.

A SLA battery can be expected to last 3-5 years, while an AGM battery may last 6 years. At the end of their lifecycle, these batteries effectively cannot hold a charge and must be replaced.

A Joule Case Li6k will hold up to 80% of its capacity after 1200 complete charge-discharge cycles, which under normal usage would typically be about 10 years. Even after this, the battery is still usable, it just won’t hold as much charge as it did when it was new.

In terms of cost per year of usable life, each of the options ends up costing about the same.

Lithium Ion Batteries Enable Higher Power with Inverter Support

Inverters are devices that transform stored direct current (DC) energy into the alternating current (AC) that household devices use. The output rating of an inverter determines how much power it can supply, which then determines what equipment (or how much of it) can be run.

Inverters that can operate at a higher voltage tend to be more efficient than those that operate at a lower voltage because the circuitry in them can be lighter weight. So, higher-power inverters can be made more inexpensively and efficiently for higher-voltage batteries. Since Joule Case batteries operate at 48 volts, there are a wider range of compatible, high-power inverters available for them than there are in the 12-volt space.

Modern Batteries Better Support Solar

Solar panels produce electricity, and that electricity can be used to charge batteries, no matter what the chemistry of those batteries is. A solar charge controller of some sort is required in order to match the power produced by the panels to that required by the batteries. Many of the inverters available in the 48V market, however, have integral MPPT solar charge controllers included in them. Connecting solar to those inverters is simple and does not require any additional hardware.


Joule Case is pioneering new technologies that harness these advances in batteries. Our innovative product roadmap enables batteries to power applications that were previously thought to be impossible or cost prohibitive. Naturally, new technologies have skeptics. Sometimes this skepticism comes from being unfamiliar with what batteries can do or, in this case, being too familiar with outdated technology.

Have a power need that you don’t think batteries could possibly handle? Reach out to our team ([email protected] or 800-200-5414) to discuss what our products or custom solutions can do for you.

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