After getting the solar panels on the roof and connected to our existing batteries in Phase 1 it was time to upgrade the system with a bigger better battery. We opted to install a Tesla Battery Module in our RV.
We did lots of looking into different battery options trying to figure out what would give us the best performance and bang for the buck.
Most RV batteries are deep-cycle 12 V lead acid batteries that, honestly, are a pain to maintain.
We finally settled on lithium ion batteries, but new they can be crazy expensive. That’s when we started to think about getting a used electric car battery.
Reusing Electric Vehicle Batteries
After doing some research, we found that electric cars that have been wrecked are a great place to get big inexpensive lithium ion batteries. Once we decided on using a used battery it then came down to picking which one.
The options at this time we could use were Chevy Volt, Nissan Leaf or Tesla Model S batteries. There are other out there but these are the easiest to get our hands on.
After some careful consideration we decided to use a Tesla Model S battery module. You can learn all about the battery we chose in this video we put together about it:
So after we had purchased the battery it was time to figure out how to use it and a few big hurdles stood in our way.
Our RV (and most RVs) primarily operated on 12V DC but this battery is a 24V battery.
We went with a 24V battery for many reasons the first of which was that we got an awesome deal on our Victron Multiplus 24/3000 Inverter that is a 24V unit.
Also, after getting the inverter we installed a Victron MPPT 100/50 Solar Charge Controller that is limited to 12 or 24V battery systems (although it can handle over 100V from the RV solar panels).
Ideally, I would have gone with a 48V system but 24 is still better than 12 when you are talking big power usage. This is primarily because you can use much smaller wires and the inverters tend to be more efficient.
This is the schematic of what we ended up installing. See the link below for a full resolution PDF.
!! IMPORTANT !!
Before reading further, the design in this article does not meet new requirements I have learned of about the BP220, During design of this 2 years ago, there was no information about reverse charging with the BP. We got away with it for a long time but this could be a fire hazard, read more here.
While Tesla batteries are a very high quality and safe when handled and run within operating characteristics, if something goes wrong they can be quite dangerous. It is your responsibility to fully understand and make sure the system is safely programmed and installed if you choose to install a Tesla battery in RV.
Furthermore, this build is not endorsed or supported by any manufacturers of the components used in this build, and they may not provide support on an install like this if you run into trouble. I am not able to provide individual support on these builds. You might be able to find community support over in the Second-Life Batteries Facebook Group.
*This design has been updated – check out the update here.
After we got it all figured out, we went ahead and installed it!
This video walks you through the installation of this battery and integration with our existing 12V system.
Be sure to check our our Phase 3 post where we install the Victron Multiplus hybrid inverter and power up our 120V AC system.
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