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Rivian's TM-B electric bike

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190 points hasheddan | 2 comments | 22 Oct 25 18:00 UTC | HN request time: 0.001s | source
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jakedata ◴[22 Oct 25 20:21 UTC] No.45674654[source]▶
$4500 is ten or more of my homebrew 750 watt electric mountain bike originally built in 2004. I just repowered with LiFePO4 after 10 years in storage and the new batteries really pull. It has a front hub motor with a throttle control limited to 20 mph. My commute is 10 miles, 6 on a dedicated bike path. Life is good.
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wigglewoggle ◴[22 Oct 25 20:54 UTC] No.45675021[source]▶
What kind of capacity from your LFP battery? Is it diy built? I did one in the spring 16S with 25Ah cells and it's been amazing since. Only problem is it's a bit too big to fit anywhere I'd like it to. I have to mount it on a rear rack
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jakedata ◴[22 Oct 25 21:04 UTC] No.45675123[source]▶
I am using 3x 12v 185wh batteries in series. Realistically I can count on around 500wh. They are only 3 lbs each and fit neatly within the frame of the mtb. I don't like having them up on the rear rack, they tend to make the tail of the bike wag a bit compared to low and centered.

https://old.reddit.com/r/ebikes/comments/1o0qthk/dynagirl_ri...

I just 3d printed protective covers for them last week when marketing turned their back on the new Bambu printer.

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1. wigglewoggle ◴[22 Oct 25 21:27 UTC] No.45675374[source]▶
Nice

I have a big commute and in the (Canadian) winter my old 750Wh was sometimes not up to the task. So I went wildly over the top and built a huge cap battery. I never need to worry now

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2. jakedata ◴[22 Oct 25 22:44 UTC] No.45676104[source]▶
I don't plan to bike commute in the winter, it is too dark AM and PM. Have you tested your LiFePO4 batteries in low temperatures?