how many batteries are in/on your bike?
 

inspired by a recent conversation in another thread about batteries, e-bikes, etc.

for your most-commonly ridden bike, or the one you put the most miles on, count all the separate batteries in your bike, or onyour bike for the majority of your rides? if you always ride with a computer/head unit, that's one. if you use a phone instead, it still counts as one. power meter might have one, might have two. SRAM wireless 2x setup has four, i think? shimano 12 speed "wired-less" has three, GRX di2 maybe only one? if you almost always ride with a varia, tail-light, etc, count that if it has it's own battery. for an ebike, the main battery just counts as one but often there are others in the displays or control units.

for my most-ridden bike:

iphone 12 mini
left brifter
right brifter
di2 derailleur battery
left 4iiii PM
right 4iiii PM
garmin varia

ooops. forgot HRM.

1, computer.

does a dead battery count? If so, 1... me!

I'm way more "minimalist" now, but back when I had a SRAM eTap equipped bike, there were NINE batteries in total! Ridiculous... 😮

(four in groupset, two for power pedals, front light, rear light, Garmin headunit)

I counted my HRM, too, so that put me at 5 (others are PM, computer, headlight/camera, radar/tail light).
Edit: ****, 6! I forgot about the speed sensor.
​​​

****, i forgot that.

None on either bike. Four on me: Fitbit, iPhone tucked in a sports belt and wireless earbuds.

Otto

uh-oh, cue the earbud naysayers.

3 for me, 5 when running lights.

I mean it depends on the bike, my e-bike has 2 Bosch batteries and my Di2 road bike has one and my other bikes don't really have any though some do have usb charged lights but two of the bikes have Dynamos so they generate their own power.

5 if by night. 2 if by day.

5 on the bike.

2 on me.

Four at a time: Expendable button battery on the old "computer". Rechargeables on horn, fore and aft lights (plus one spare head light).

Front flasher
rear flasher/radar
cadence
wheel speed
garmin head unit
HRM

0 in my bike

One in the bike (Di2, in seat post).
Four on the bike (Garmin, head light, tail light, radar)
One on my wrist.
One more on the bike if I mount a movie camera.

So, to answer the actual question asked: One

GPS head unit, watch broadcasting HR, front and rear lights, Duotrap S, phone for Strava Beacon (when it works).

the question was actually “in or on your bike,” should have specified also on your body!

"On" my bike? Two, front and rear lights. On my body, three, Garmin watch, iPhone and Aftershokz headphones.

I replaced all my batteries with one fuel cell.

All my bikes have a rear flasher and most are two AAAs. And I just remembered I carry my cell phone but that's in my pocket. At night, two more flashers on my reflecting vest and a handlebar headlight. Every blue moon or so, I ride with a computer but just about never on my fix gears and those are 2/3s of my riding. Sometimes a heart monitor so two more batteries but usually not on the fix gear as it is simply too much information, most of which is useless.

The question posed in the title says "in" but not "on."

Anticipating your actual intended question, I gave a full accounting.

sorry, i assumed people would read the post text. good point!

to some extent, that’s what i’m wondering. would it be better (lighter, more reliable, less environmental impact) if bikes had a low voltage network with a smallish central battery that could power everything… lots of issues with getting power to the devices, of course.

Garmin
Fly12
Quarq
blinkie

Oops voted 1 but really 4:
Assioma Uno Power Pedals
Garmin 830
Wahoo HRM
Red flashy light...don't often use it

Di2 system
Flare headlight
Garmin 1030+
Garmin extended battery pack
GoPro camera (front facing)
HRM
Left side power meter
Flare tail light on helmet
Varia 715 radar/light/camera
Cellphone (don't actually use it for the bike, but just in case)

So, that makes 10. The new Varia, with one battery, replaces 4 - Varia (radar only), Flare tail light, GoPro camera (rear facing), Anker power supply for GoPro.