Eco isn’t always the most battery efficient.

[Shifty]

After completing a few 40k rides now with a circa 550 metre ascent totals. If I ride in eco for full amount of ride it takes me a little longer up the hills and I have to use easier gears obviously.
Comparing this to using the second or third power level (giant 2019 5 levels on Yamaha) on the steep climbs to speed up them.
what i find is I use roughly 5% more batterypower by relying on eco and slogging up the steep inclines in granny gear 1 than I do using slightly more engine power mode and climbing more quickly in say 3rd gear (1-11).
So to summarise there is a sweet spot of time it takes, engine power, cadence and gear on steep climbs that is more efficient than staying in eco.

 

[OldGoatMTB]

Harder to measure your own energy reserves.

 

[Darren]

This counter intuitive phenomenon is true for internal combustion engines too. It's more economical to power up a hill and get it over with as soon as possible, using maximum power for a minimal time rather than the green band for longer.

 

[Eddy Current]

Battery last longer if you stay in higher cadences, so if in eco you can’t spin as fast ...

 

[Zimmerframe]

This counter intuitive phenomenon is true for internal combustion engines too. It's more economical to power up a hill and get it over with as soon as possible, using maximum power for a minimal time rather than the green band for longer.

And love making, you can get back to your beer sooner using the same system.

 

[maynard]

Hmmm.....I wonder if I wrap my hands around the headset if I’d get to the top sooner.....

Does anyone have any technical info on this phenomenon? It’s interesting to me.

Depends whos headset your wrapping your hands around .

 

[OldGoatMTB]

Battery last longer if you stay in higher cadences, so if in eco you can’t spin as fast ...

Why not? Less power means lower gear means higher cadence.

 

[wildsau2]

lower gear means often higher cadence. always good for saving battery. i‘m on shimano i‘ve tested several times with a powermeter. eco does not save battery it does not consume more. cadence, temparature, wind are the factors

 

[Shifty]

Harder to measure your own energy reserves.

Agreed, I’m never riding really hard though so my ride are so similar. Not like my running where it makes a big difference.

 

[Shifty]

And love making, you can get back to your beer sooner using the same system.

I don’t let go of my beer whilst I’m doing it... I like to multitask ???

 

[Sapientiea]

In the end, total energy needed to get your bike and you up a hill remains the same for both eco and trail. You are not putting in the same amount of energy in eco as you do in trail simple. The shimano motor has a peak watt of 500 and continuous watt output of 250. The 500 watt is used when you just start to pedal. Could be that you are just using this more because you are really dropping the cadence too low. Or maybe a little speed in trail is overcoming this and you ride smoother. Either way, 5% is not very significant

 

[Husky430]

Simple solution, just go everywhere in trail (middle of the road) mode, best of both worlds.?

 

[Eddy Current]

Why not? Less power means lower gear means higher cadence.

Because some folks stay in eco and medium gears and can’t spin fast

 

[Swissrider]

If you keep cadence to about 70rpm, which seems to be sweet spot for most motors and use a heart rate monitor or power monitor, it should be possible to monitor how much effort you are putting in. As I posted the other day, I’m going to do a big climb twice, once in trail and once in Turbo and then see how much battery I’ve used after each climb. Turbo will be quicker so I won’t use the battery for so long and trail will use less power but will take longer. I use Turbo a lot and I am not convinced there is that much difference, and it’s more fun!

 

[Pdoz]

The 2019 giant had different torque curves in eco vs the higher power modes - it would drop off assistance from about 60 cadence in eco , around 70 in the next 2 levels and around 80 in the higher settings. Or at least that's what it felt like. This produced a paradoxical effect of worse economy in eco in high load settings because it was hard to maintain high cadence and efficient human input.

From 2020 onwards, the pwx 2 motor supports higher cadence , so you can now spin around 80 cadence in eco and still get assistance- MUCH better economy in eco.

I spend way too much time thinking as I spin the cranks

 

[MB1]

As most on here have indicated, from many years experimenting on the same route, I believe cadence is the significant influence in this. If you look at the motor curves, they’re mainly most economical when cadence is high, 70-80 rpm. 90 if you can sustain it, which is common on road bikes. Regardless of mode, the battery always lasts longer if you use the gears and spin. It’s also good for you?

 

[Sidepod]

Kind of interesting this yet at the same mind numbingly boring. If we had hardware that was fit for purpose this wouldn’t even be a thing. Roll on batteries that last weeks as opposed to 75% of required ride distance.

 

[steve_sordy]

Even if you use the most efficient cadence, the faster you are going the higher the resistance from the air. That increases by the square of the speed. So if you really want max efficiency, stay in the right cadence band, and stay slow.
But I don't want to do that!

 

[B1rdie]

Out of theory, we would discuss for eternity the phisics of this, aside of wind drag there is momentum involved so if wind speed is not constant and the terrain is not level, then carrying momentum favours the faster rider. but out of experience I got convinced that keeping higher cadence improves the efficience of the rider/motor combination to the point that if you can sustain above 80 rpm cadence the difference of theremaining charge of the battery at the end of a 30km 1.000 m high ride, between using eco or trail will be minimal.

 

[B1rdie]

Just forgot a very important detail: my ebike is set to US 32km/h speed and these rides are made at average speed above 25 km/h.