Smart ForTwo Electric Drive (2013) Battery
My family owns a 2013 Smart ForTwo electric drive, which in 2021 has a range of about 35 miles. We use it for short commute (~5 miles) and to get groceries; we charge it at work, since we live in a condo complex without electric charging. It’s easily been one of the best investments we made, with a ton of utility added to our lives at a very low cost. Insurance on it is super cheap since it’s an old used car that doesn’t get a ton of miles. I’ve never serviced it, which I should probably because the brakes probably need a little love.
I’ve always been amused that replacing the battery with a whole new one would cost in the realm of $13-15k, whereas the car itself only cost us ~$4000 used back in 2018. I’m also amused when I see these nice E-Bikes priced in the same range, sometimes even more.
But it is definitely aging and I started poking around YouTube because I’ve been thinking “how hard could it be to replace the individual cells in this battery pack with equivalent or even better modern ones” and “I wonder how much life it would add to my vehicle” – after all constructing batteries from small battery cells seems very simple conceptually. N in serial, M in parallel, ensure they are charged evenly and never over-drained, replace the cells that don’t output enough when they get old.
Like, why are these things built in a way that makes all of this hard? I change the batteries on many devices I own. I really wish they would make stuff like this easier.
Okay let’s say I have to do some work to replace my battery’s bad cells. How much work exactly? I found a guy doing it on youtube, brave soul.
The image is a bit hard to read, but basically it outlines the specs of the battery:
- U = 339 Volts
- E = 17600 Watt-hours
- C = 52Ah
- 178kg = 392lbs
So right off the bat, dealing with high voltage is dangerous. Dude is wearing thicc gloves. Also ~400lbs is heavy.
The next part is that the housing is riveted (…and screwed too) together. So after you break it apart, it’s not that easy to seal it back together.
Then you get inside and you see these pouches:
Each pouch is welded into the frame of the battery pack.
At this point I was just watching the video out of interest in the battery architecture, but it does seem pretty self-explanatory why replacing the battery is a total PITA today: weight, danger (high voltage), strong sealing for safety (welding, rivets).
I just can’t help but wonder if there’s a better way to build a battery, and to keep the car safe but make battery maintenence cheaper. A lot of times when a big battery like this dies it’s because a couple cells went bad (swelled up, discharge too fast, etc). Shame that we routinely throw away these 400lbs behemoths into the trash when they could in theory still be salvaged and made useful.
People are building powerwall batteries in their houses, for better or for worse. I personally don’t feel great about death by fire. But there’ve got to be folks who can figure out how to make battery construction / maintenance / reusability a lot better than it is today.
This reminds me of watching a TED talk by some Israeli dude about their grand plan to build battery swap stations for EVs all across Hawaii and Israel. So instead of waiting 45 minutes for your tesla to charge, you might be able to just swap your battery out in the same time someone uses to fill their gas tank. If we got to a world like that, servicable batteries would be a huge boon to the depots. Too bad that idea never panned out – I bet making batteries swappable is just not that easy, I mean the things weigh so damn much and need to be fireproofed quite well.
One of my least favorite tech trends in 2021 is that every device I own is basically locked into planned obsolescence by its battery. LCDs, RAM, CPUs, they all last quite long but rechargable batteries? Ecological nightmare. Give me the option to save the rest of my shit and just swap out a minimum of parts please. Everyone wants flying or even just self-driving cars but I want an electric vehicle that lets me fix and/or replace the battery with relative low cost and ease. That might be the biggest reduction to my carbon footprint because I won’t be adding nearly as much to car building demand.