Mercedes' at-home battery could have one key advantage over Tesla's Powerwall

Mercedes-Benz announced the launch of its at-home battery option in 2015, and with plans to expand outside its current market of Germany, Tesla may need to watch its back.

Tesla's Powerwall is perhaps the most notable home battery option in the US. The mountable device that comes in a several different colors holds 6.4 kWh of energy. It's also possible to stack nine Powerwalls together for almost 58 kWh worth of energy capacity.

For reference, the average person in the US uses 30 kWh each day, making the Powerwall a solid option storage-wise.

But where Mercedes could have a slight advantage over Tesla is with its design.

At under 66 pounds, the Mercedes battery is much smaller than Tesla's 200 pound Powerwall. That smaller size does mean the Mercedes battery can only store 2.5 kWh. But because it is modular, eight lightweight Mercedes' batteries can be combined for 20 kWh of storage.

From a pure energy storage standpoint, Tesla's Powerwall wins, hands down.

But one has to consider what homeowners really want: A smaller, less conspicuous battery option that still provides a good amount of energy storage may be more desirable than a 200-pound device that must be mounted.

"The modules themselves are rather lightweight at less than 30 kilograms, so you can carry it with one man compared to Tesla," Frank Spennemann, senior manager of business innovation at Mercedes' parent company Daimler, told Tech Insider. "You can put it on the ground, so you don't have to wall mount it, and it has very easy wiring."

It's actually for that reason that battery start-up Orison thinks it has a shot of taking on Tesla in the US: a mountable Orison panel holds 2.2 kWh and weighs 40 pounds, with the option to combine five panels for 13.2 kWh of storage.

The Mercedes battery is currently being rolled out in other European markets outside Germany, including the Netherlands and Switzerland, Spennemann said. He added that he sees potential to role it out in other countries.

What would really settle the debate over what is the best battery option is price. Tesla's Powerwall cost $3,000, not including the price of installation and the separate inverter that must be purchased.

Mercedes declined to provide the price of a unit, stating that pricing was handled by distributors. We've reached out to several distributors about pricing and will update this story when we hear back.

We do know that, like the Powerwall, you have to pay for the professional installation and separate inverter.

The Mercedes battery also differs slightly in function to the Tesla Powerall, but that's mostly a product of where they are sold. The Powerwall can store energy generated by solar panels and draw electricity from the utility grid when rates are low to store for later.

The Mercedes battery can't draw from the grid because net metering isn't an option that's allowed in Germany, Spennemann said. But the Mercedes at-home battery has been used to charge people's electric cars.

When it comes down to it, energy storage, size, and price are the three biggest influencers in deciding what battery option to install. Without knowing the price of a Mercedes' unit, it's hard to pick a clear winner. But there is something to be said about taking the modular approach.

Tesla did not respond to request for comment for this story.