DC Solar Trailer Replacement Lithium Iron Phosphate Battery

DC Solar is rather infamous in the renewable energy world, but they produced thousands of solar trailers before being shut down in 2018. They pop up quite often on auction sites, and can often be had for quite a good price. With typically 2650 watts of solar and 12kW of power, and often including a diesel generator, there's no doubt that a DC Solar trailer is often an inexpensive way to own a pre-built solar system.

DC Solar trailers typically feature one or two SMA Sunny Island inverters, a Midnite Classic 250 charge controller, and up to 10 235-watt solar panels. Some even have a backup diesel generator.

The downside is that these trailers may weigh up to 10,000 lb, of which 4,400 lb is in the old lead acid batteries alone. And since many of these have been sitting for nearly a decade, the batteries are nearly always dead and gone.

Renewed Power

Higher Wire has developed a line of drop-in lithium batteries to replace the existing lead acid system. Weighing only 500 - 800 lb for 15 - 25.6 kWh of power, our batteries can be swapped in as little as a few hours using the existing Anderson connectors and requiring only one additional connection for the included communication cable to the inverters. And since lead acid batteries should only be discharged to 50% for cycle life, our 500Ah battery is equivalent to two lead acid batteries, yet has a far longer life.

We use quality lithium iron phosphate (LiFePO4) cells that have undergone our strict testing and renewal process. This means that we can keep costs down while maximizing the lifespan of the cells we use, while offering a warranty and support for up to 5 years.

Our advanced battery management system (BMS) has WiFi output for remote monitoring/troubleshooting and the ability to connect to your existing network. It also sends key information such as state of charge (SOC) and battery temperature to the inverters, and will prevent system damage from over- or under-voltage at the pack and even cell level.

There's enough space in a typical DC Solar trailer to quadruple the capacity, and our advanced BMS is able to connect in parallel in a master-slave configuration to monitor the health of each battery.

Thermal management is not standard on our batteries, but can be added for an additional fee. Please contact us to go over options prior to purchase.

Please allow up to several weeks following purchase for your battery to be fully assembled. We require full payment prior to shipment.

SMA Sunny Island Setup for Lithium Ion Batteries

You may need to update the firmware on your Sunny Island inverters prior to installing the battery. This is a fairly simple process that requires you to connect the SD card from the master only to your computer, and takes about 15 minutes. Simply follow the SMA instructions found here.

The inverter firmware can be found on the SMA website here. Select 'Battery Inverters' followed by 'SIxxxx-US-10.' The model should be SI6048US-10, but you will need to verify.

Once the firmware is updated, you will need to tell the inverter that you are installing a lithium battery.

• The master inverter will display "To init system hold <ENTER>."
• In the "StartMenu," scroll down to "New Battery" and press <ENTER>.
• Press <ENTER> again when it asks "OK> Y/N"
• Under "BatTyp," select "LiIon_Ext-BMS" and press <ENTER>
• Under "BatCpyNom," press <ENTER> and then use the up arrow to set your capacity.
• Select "INIT BATTERY OK START?" and press <ENTER>.

The inverters are now set for your Higher Wire lithium iron phosphate battery.

Battery Installation

We recommend that you update firmware and set the inverters for lithium before installing your Higher Wire battery, but that is not required.

The hardest part of install is removing the original lead acid batteries. You WILL need a forklift or other heavy machinery. We've found it easiest to set a forklift alongside the trailer, then lift the battery up a few inches and drive the trailer out from under it. Repeat with the new battery.

The existing battery temperature wiring can be removed completely. The gland is the perfect entry point for the Higher Wire communication cable.

You will need to cut the charge wire at the battery, then install an M8 or 5/16" ring terminal to connect to the new battery. The wire should be 6AWG and we can help if you need hardware for the connection at the enclosure. It is essential to verify solid contact at the enclosure; we have seen this connection come loose, resulting in loss of charge and eventually battery low-voltage cutoff.

NOTE: Our 51v 500Ah pack has four battery modules weighing about 150lb apiece. It is possible to remove the battery modules and install the battery by without the use of a forklift.

Additional Solar Capacity

We've received a few questions about upgrading the panels on the trailer. The MidNite Classic 250 is good for 3200 watts. We've been able to successfully upgrade to over 4000 watts of power with new panels and charge controller. Contact us for to purchase separately if you want to add more wattage to the array.

Shipping

These will ship on a pallet via LTL freight, which is not included in the list price. Typical shipping costs are around $500, and we can typically fit two batteries on a single pallet.

Safety

Lithium batteries can be potentially dangerous! Even when properly handled, lithium batteries may ignite or explode. It is imperative that you use quality battery management and charging systems when operating lithium batteries. All users of lithium-ion batteries MUST read the warning and safety instructions on our website before using lithium-ion batteries.

Warranty

All of these packs have greater than 80% of original capacity and come with a limited warranty. If a cell or pack fails within that window, we will replace it. Note that the replacement may not have the same capacity as the original purchase, and may be lower capacity. See our warranty page for limitations.