Did you know that the factory 12V battery in your Telsa Model 3 is a heavy, inferior AGM battery? Somewhat silly that a car with up to 75kWh worth of lithium batteries has a heavy, old technology like AGM as the low voltage battery! But this is understandable since the added cost just didn’t make sense for Tesla with the Model 3. Our lightweight lithium battery shaves 24 pounds from the front of the chassis. At MPP we’re hyper-focused on weight reduction, so to be able to get 24 lbs out in quick 30 minute bolt in part is massive.
We’ve been quietly testing our lithium 12V battery for the last six months, installing it almost directly after receiving our car. We knew that we needed to perform heaps of real-world testing before offering our battery kit – as we needed to ensure the vehicle’s normal behavior continued – such as regularly falling into deep-sleep, performing OTA software updates normally, waking up quickly for mobile access, and having no issue in the extreme cold.
Of course, we also performed a significant amount of safety and suitability testing with our battery kit – ensuring the Model 3’s DCDC always charged at an acceptable current and voltage for this battery’s chemistry. We’re happy to report that this battery is a perfect match for the Model 3’s DCDC charge logic. We are happy to discuss details with those of you that are concerned about this.
One thing that was extremely important to us when selecting a battery was to use one that has a built-in BMS (battery management system) that is capable of disconnecting the battery from the vehicle in the event of a fault. We selected the EarthX ETX900 because has both under and over-voltage protection, as well as cell management. This means in the event that the battery is drained below a safe voltage, the BMS will disconnect the battery from the vehicle so that the voltage does not continue to fall to a level that would otherwise damage the battery. The built-in BMS also balances the voltages of the individual cells connected in series, so that the battery never has a single cell that goes above a dangerously high voltage – something that most other aftermarket lithium-ion batteries do NOT have, making them potentially dangerous for long term operation.
The EarthX ETX900 is designed and manufactured in the USA, and is normally used to power small aircraft! So you can take comfort in knowing that if it is safe enough for flight it’s safe and reliable enough for your Model 3. The battery can deliver a massive 840 cranking amps (not that our Tesla’s will need that!)
Of course, we wanted to make an extremely light, easy to install and elegant battery bracket to go along with the battery. That was no easy task considering the smaller size of our battery and the strange stamped bracket on the Model 3. There was no way we were going to make a bracket that weighed almost as much as the battery, so a lot of design went into a CNC machined, 6061 aluminum bracket that bolts into the OEM battery carrier with no drilling or cutting required. We also decided to use a strap rather than an aluminum bracket to further reduce weight, and we include all stainless steel hardware so that rust and corrosion will never be an issue!