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Power, where you need it.

Especially out here.

Joule Case

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Without the noise or fumes.

Power where you need it.

Enjoy nature, in comfort.

Technology that blends into the background. So your experiences can take center stage.

Joule Case, power where you need it.

Joule Case is a portable power supply when and where you need it. Use it as a battery backup for off-grid use, a battery for solar power systems, and a backup power supply during power outages. It is the best back up power supply that is easily rechargeable from renewable energy resources, solar power, wind power—a quiet alternative to noisy gas generators.


Learn more about the different Joule Case modules below. If you have additional questions please see the FAQ or send us an email [email protected]

Additional Details

    • 12 vdc accessory connection
    • Built-in smart charger
    • 2.1 amp dual USB power
    • LCD screen reports usage
    • LED displays realtime DC voltage

Additional Details

    • Stack and Snap
    • Maintenance-free
    • No wiring required
    • Hundreds of cycles
    • Parallel-capable

Additional Details

    • Built-in MPPT solar controller
    • Simple easy to connect
    • Panels tuck away for storage
    • Multiple configurations for setup

Questions about the operation or function? Check below for some frequently asked questions.

Charge Times

The built-in smart charger in the P1000 and P2000 control modules will charge [1] depleted battery module in 3.5-4 hours. Each additional 500wh battery module will add the same recharge times to the system. Example [4] depleted 500wh battery modules will require 14-16 hours using the integrated smart charger.

Options are available to charge larger battery systems in short periods. Contact us directly if you need a high-power charging system.

Charging Indicator Lights

On the back of the control module located to the right of the power switch is the charger indicator light port. The built-in smart charger LED light will display the status of the charger, and indicate the charging process.

Green Light:

  • Flashes roughly every 1/4 second, battery is less than 50% charged
  • Flashes roughly every 1/2 second, battery is between 50% and 80% charged
  • Flashes roughly once per second, battery is more than 80%
  • Green light on following charging cycle, indicates the charge cycle is complete

Red Light:

The red light indicates the unit is on but is not charging, this can occur in the following conditions:

  • False start, the grid power (from the wall or other source) was not sufficient to begin charging should be disconnected by unplugging the Joule Case from the wall outlet, the control module should be disconnected from the battery module to allow the unit to reset.
  • The charger has recently completed a charging cycle and is turning off.

Charger Operation

The built-in smart charger can accept a wide variety of input voltages 100-220 VAC. Erratic or otherwise unstable grid power supply may cause the charger to fault (red light) and turn off.

A 3 stage charging cycle protects the battery modules and extends life. An indicator light located to the right of the On/Off switch displays the current charging operation.

When the charge cycle is complete it is best to unplug the Joule Case. Once the charger is disconnected and the power is “off” it is safe to store the Joule Case. The battery will maintain its energy for several months.

If you plan to leave your Joule Case stored it is best to leave it partially charged until you are ready to use it, and charging it before use.

The charger is intended for battery charging only. When charging, leave the Joule Case “off”. Do not attempt to use the P1000 or P2000 as an Uninterruptible Power Supply (UPS). The charger will eventually fail.

Modified or Pure Sine Wave

Joule Case uses a Pure Sine Wave output for AC. This is wave form is the same smooth AC power you expect from the grid. Why is that important? Your AC devices were made expecting to have Pure Sine AC, and some will not perform correctly or can even be damaged.

“Hey I found a cheap ‘inverter’ from my local hardware store and it doesn’t say what the wave form is…”

  • That is more than likely going to be a modified sine wave device. It can potentially harm your devices, especially if there is an electric motor that requires pure sine to operate, like a fan or a compressor.

“Why is Pure Sine more expensive?”

  • There are more components required to drive DC into the smooth curve of AC power. That just means more copper, silicon etc.

Big-box hardware or discount tool supply stores are going to try and deliver the most power or “Watts” for your dollar. That might not be the best solution for you. If the device doesn’t clearly say “Pure Sine” and the deal seems too good to be true, it might be.

Inverter Troubleshooting Alarm/Buzzer

Battery low alarm: 2 short consecutive “beep beep” sounds are audible.

  • Check the DC voltage displayed on the USB outlet. If the voltage is approaching or under 10v the Joule Case will need to be recharged.
  • If the battery stack has been recharged but the alarm continues, turn off the Joule Case, disconnect the control module from the battery stack, and cycle the on/off switch. Reconnect the control module (in the off position) and restart.

Battery too low/fault: 1 “beep” with long pause break

  • The battery voltage is too low to power the inverter. Recharge the Joule Case. Check DC voltage display to confirm.

Over Temperature alarm: 1 short consecutive “beep” sound will be audible.

  • The fans are running, both screens on, but no power and periodic single “beep” indicates the Joule Case is too hot to run. Make sure the control module fans and vents are not blocked, reduce the load, place in the shade if in direct sunlight.

Excessive Load alarm: 3 short consecutive “beep” sounds will be audible.

  • The Joule Case can provide short term peak or starting power that exceeds the rated total power for a short period of time.
  • If this alarm is present during startup then the starting load of the device exceeds the output of the Joule Case peak power. This could also indicate that the available remaining battery cannot support the peak load.
  • Reduce the load on the Joule Case and restart.

Battery Care and Maintenance

There is a lot of information out there about how to handle and care for batteries. And all too often conflicting resources can be found. Below is a general guidance for battery care.

How to care for your sealed lead acid battery modules?

  • For optimal life, store in a cool dry environment at 50-60% state of charge (capacity). Charge to 80% and discharge to 50-60% once per month.
  • Rarely discharge past 25%
  • Do not store at 100% SOC for over 6 months

The above is guidance for best care of your SLA battery modules. That being said if it is possible to observe these you will have hundreds of outings at optimal performance.

Battery Runtimes

How long will it run my “__________”. Is one question we hear quite often. Each SLA 500 module has about 500wh of potential energy. Watt hours can be a little tricky to understand right away and with a coulombic discharge fade as well for high discharge applications the answer is usually “it depends”. Here are a few ways to think about your SLA500 battery modules.

If you think of your Joule Case as a sports car or heavy duty truck and the tank of gas as the battery stack that should help. You can get plenty of power from your Joule Case (sports car) but if you are mashing the pedal for power you will quickly run out of fuel.

For best performance try to have enough battery for 4+ hours of runtime, here is how to calculate that from 500 watt hour modules:

Say you are going tailgating, you have a 60w LED TV and a 40w satellite receiver.

  • You can find the rated capacity on the bottom or back of most devices, you can also check the power consumption on the front of your Joule Case. See the “Display Operation” tab in the FAQ for more details.

These devices will draw 100w per hour from your 500 watt hour module. By dividing your power draw (W) into your total fuel (WH) you will be left with time (the watts cancel each other out) Watt Hours/Watts = Hours in this case 500wh/100w= 5 hours.

Now if you have 5 of these TVs and 5 receivers that total 500 watts the basic equation suggests that 500wh/500w = 1 hour. But high discharge (draining in under 4 hours) will decrease the available capacity. If you are running 500 watts of constant output the ideal performance will be more than 4 battery modules which is 2,000 watt hours. The equation then gets back to this 2000wh/500w = 4 hours.

In reverse, if you want your devices to run for a specified amount of time you can figure out the power (w) and multiply times the number of hours (30 min = .5 hours).

  • 200 watts of power for 4 hours = 800 watt hours
  • 200w x 4h = 800wh

A Joule Case with [2] 500wh battery modules will give you 1,000wh of energy. So you will have 200wh to spare!

Display Details

The Joule Case provides details about AC power output and stores runtime and runtime + total power out.

New display provides in-depth visuals on power usage.

Ready to order your Joule Case system?

Individuals can contact [email protected]
Commercial customers and distributors please contact [email protected]