What drains your battery

[maker]

I played around with the Bosch distance tool where you can very type of ride, surface etc to estimate how far your battery will go, and guess the variations are typical of all makes (eBike range calculator for Bosch drive systems). It is interesting to see what makes a difference and my personal experience agrees. However, i wondered if people had found what makes a difference for them. To start off (15% routes on tarmac and rest mix of paths of rock, loose rock and hard rock), 50% climb and 50% downhill without assistance):
1. If I take a longer and less steep route to a point on a mountain (so mostly set a lower power mode but for longer I use about 10% less battery.
2. if a grassy route up a mountain is wet it sucks about 15% more out of a battery.
3. Going completely off path so over thick, tufted grass, bumpy terrain, heather etc sucks at least twice the power out of a battery (and on this terrain i need high power).
4. Don't find lowering pressure (28 to 24psi rear on 2.8inch tyres) makes any difference

 

[Beekeeper]

The main factor which has affected my range is my increase in mass due to over-consumption of Mr Kipling Apple pies during lockdown.

I’ve fed the data into a Spearman’s rank correlation equation in excel and there does indeed seem to be a significant negative correlation with pies eaten and range achieved on the Bosch battery.

 

[Rusty]

The main factor which has affected my range is my increase in mass due to over-consumption of Mr Kipling Apple pies during lockdown.

I’ve fed the data into a Spearman’s rank correlation equation in excel and there does indeed seem to be a significant negative correlation with pies eaten and range achieved on the Bosch battery.

^^ works for me ^^

 

[Beekeeper]

I check apple pie box each day.
when 50% pies gone I order a new box.
when 75% pies gone, I fit new box into fridge

I’ve now got a neat pie box checking tool

Never put a new pie into an old foil dish, the foil stretches over time and they just don’t mesh correctly. This can cause the pie to slip out of the dish with messy consequences

Always replace pie and dish at same time.

 

[MrBrownstone]

Riding.

 

[Nicho]

I’ve now got a neat pie box checking tool

Is that the new Park AP2 tool?

 

[maynard]

My fat ass drains it good

 

[Bigxmtb]

My fat ass drains it good

Same man, same

 

[Varaxis]

What drains my battery:

• Riding with draggy DH rear tire since I'm fed up with flatting
• Carrying a bunch of useless weight, on my body, in my bag, and on the bike
• Using assist when not necessary, out of laziness, like when I'm already riding near the cut-off speed
• Not pedaling hard as I could, when I am getting assist to raise my min speed
• Using brakes more often than I should, like not trusting my tires for corners, and needing to re-accelerate
• Inadvertently using my body as a big airbrake, since being upright is comfortable (relieves pressure on my hands and gives good vision without bending neck back), creating unnecessary drag

 

[steve_sordy]

Going uphill faster than you need to do so.

 

[PhilBaker]

agree with Varaxis, for me biggest battery drains are:-

• Going up hill aggressively in Turbo trying to get a KOM on Strava ;-)
• low cadence and/or light pedaling and letting motor do more work
• a headwind is surprisingly unhelpful and can really drain the battery
• Uneven off-road surfaces and/or non fast rolling tyres or low tyre pressures

For example from a full battery to empty:

• 51 miles in Trail Mode (100% motor support) with 3,600ft of climbing with a high degree of cadence and effort from me
• 40 miles with a mix of eMTB and Turbo mode with 3,200ft of aggressive climbing (Turbo up hills, trying to go as fast as possible)

Note: Decathlon Stilus Bosch Performance Line CX Gen 4 and 500w Powertube Battery. 100kg Weight (Bike weighs 25.66kg I weigh 75Kg)

 

[Nickolp1974]

Wind is a battery killer for me and if my ride is about range I try not to go over the 15mph restriction although there is no restriction!!

 

[Nicho]

What drains my battery:

• Riding with draggy DH rear tire since I'm fed up with flatting
• Carrying a bunch of useless weight, on my body, in my bag, and on the bike
• Using assist when not necessary, out of laziness, like when I'm already riding near the cut-off speed
• Not pedaling hard as I could, when I am getting assist to raise my min speed
• Using brakes more often than I should, like not trusting my tires for corners, and needing to re-accelerate
• Inadvertently using my body as a big airbrake, since being upright is comfortable (relieves pressure on my hands and gives good vision without bending neck back), creating unnecessary drag

Is that all you could think of?

 

[Nicho]

Wind is a battery killer for me and if my ride is about range I try not to go over the 15mph restriction although there is no restriction!!

Surely if you were to ride above the 15mph "restriction", your motor would stop assisting and therefore use less battery?

 

[Nickolp1974]

Surely if you were to ride above the 15mph "restriction", your motor would stop assisting and therefore use less battery?

It's de-restricted, better for those shorter blasts at speed!

 

[GrandPaBrogan]

Tyre high rolling resistance creates a constant drag that may override all other factors. I can’t remember where but I heard a YouTube video eMTB commentary mention that its effect on battery drain is greater than we realise.

Obviously there are various things we can change while we ride to extend our battery range, but not tyre drag. If battery management has to be the main priority, it would make sense to select a tyre width, rubber compound, and tread pattern that gives just the right amount of traction that our specific application requires. Any more would only take its toll on the battery unnecessarily.
.

 

[Rusty]

Tyre high rolling resistance creates a constant drag that may override all other factors. I can’t remember where but I heard a YouTube video eMTB commentary mention that its effect on battery drain is greater than we realise.

It is interesting that. On my first Scott I was only getting 40-41km on a Rotorua loop using mostly Eco with Trail used on a few climbs.
The bike came fitted with Schwalbe MagicMaryfront and Hans Dampf rear. Discussing this with my LBS we fitted Maxxis Rekon F & R.
The difference on the same trails with as close to the same temperatures and ground conditions was less than 500m over 2 loops with each set. I also ran Maxxis DHFII & DHRII and received similar mileage.

For those that know Rotorua - The Trails:

Tahi
Creek
Piglet/Pig
Mad if You Don't
Puarenga (right side)
Yellow Brick Road
Cross country past Roller Coaster entrance on Reservoir Road and Ring Road to Sandy Skid Road
Pondy New
Roller Coaster
Moonshine
Chinese Menu (Choy Suey, Spring Roll, Sweet & Sour)
Bunny Jugs 1 & 2
Old Chevy
Puarenga (left side)
Larch Road
End of Be Rude Not To
Lion
Turkish Delight
Arepa
Challenge Roadside
The Dipper
End of Tahi
Rosebank

 

[Tony.OK]

Am sighing in disgust at everyones milage.....19 Trance e+1, I ride in lowered level 3 200%, yesterday I rode 24km/15m and 818m/2600ft and had 10% batt left.....
Have Assegai exo's front and rear, before I had dhf/dhr2 combo with slightly better batt range ?

 

[Rusty]

Am sighing in disgust at everyones milage.....19 Trance e+1, I ride in lowered level 3 200%, yesterday I rode 24km/15m and 818m/2600ft and had 10% batt left.....
Have Assegai exo's front and rear, before I had dhf/dhr2 combo with slightly better batt range ?

More than I get - 41km and completely flat = around 25.5 miles.

 

[Tony.OK]

More than I get - 41km and completely flat = around 25.5 miles.

Mines nearly flat at 24km ☹

 

[Bigxmtb]

Mines nearly flat at 24km ☹

wow, thats not alot at all. I done a 27km ride last on weds and still had 2lights so assuming that means estimated 40% battery left granted was only 1200ft climbing. Thats on my 2020 trance e+2 and I was kinda happy with that as I feel bad the bike has to carry my heavy ass up those hills.

 

[GrandPaBrogan]

It is interesting that. On my first Scott I was only getting 40-41km on a Rotorua loop using mostly Eco with Trail used on a few climbs.
The bike came fitted with Schwalbe MagicMaryfront and Hans Dampf rear. Discussing this with my LBS we fitted Maxxis Rekon F & R.
The difference on the same trails with as close to the same temperatures and ground conditions was less than 500m over 2 loops with each set. I also ran Maxxis DHFII & DHRII and received similar mileage.

One possibility for close results could be that the bike was set on eco - minimal assistance. Perhaps your fitness and strength is what carried the battery drain over and made the discharge rates closer that they might’ve been, if say the bike was set on a higher assist mode - where the motor would be taxed more. But that’s just speculation.

Your test results on the other hand are absolutely valid and certainly challenges the assumptions about tyre drag... ??

Edit in addition:
Your testing actually just reminded me of a MTB magazine article I read (can’t remember the last time I bought a magazine - that’s how long ago it was, haha) where they did a 26”wheel shoot out between 1.75” MTB tyres vs 2.2” MTB tyres. The prevailing belief at the time was that the narrow XC tyre would be faster, but by how much? Contrary to expectations the 2.2” tyre turned out to be faster rolling over rougher uneven ground conditions! But on pavement the 1.75” was faster. So yeah, eco mode or not - seeing as our bikes are eebs meant for the trails... your data proves that tyre drag, is not a big factor. ??

 

[GrandPaBrogan]

wow, thats not alot at all. I done a 27km ride last on weds and still had 2lights so assuming that means estimated 40% battery left granted was only 1200ft climbing. Thats on my 2020 trance e+2 and I was kinda happy with that as I feel bad the bike has to carry my heavy ass up those hills.

I get 22 kms with about 60% battery left but that’s over mostly level gravel over hard pack with some moderate climbs. Bike is Giant Trance e+3 and I weigh just shy of 80 kg currently on Maxxis 2.5 High Rollers.

I’m really not able to make definite measurements because I don’t have devices that display that kind of data accurately. Seat of my pants guess tho, is that my Continental 2.4 Mountain Kings coasts and accelerates faster but the front washes out when leaned and pushed harder.

 

[PhilBaker]

Here’s an interesting video. Net net 30kg weight difference between the test riders and only 2.4k further distance for the lighter rider...

 

[GrandPaBrogan]

^ Only 2.4 km? ?

I’ve always visually roughly estimated 1km to be from where I stand to the near horizon. Two and a half that distance to walk with a flat battery pushing a 50 lbs bike isn’t that small when I look at it that way. ?

 

[Rusty]

When @duk916 and I did the Waikato River Trail I had the 700Wh fitted to the Levo and until we got to the hilly stuff south of Aratiatia I was running at close to 1km = 1% of battery. Once I started needing Trail a lot more and then usage ramped up, but at the end it was 74.5km with 12% remaining.

 

[steve_sordy]

Ref tyre pressure impact upon range. If the trail is smooth, then high pressure will have lower rolling resistance. But if the trail is rough, then lower pressure has reduced rolling resistance. The high pressure tyre will be bouncing off the rocks and roots, impeding flow. The lower pressure tyre conforms and the bike rolls on.

 

[maker]

Ref tyre pressure impact upon range. If the trail is smooth, then high pressure will have lower rolling resistance. But if the trail is rough, then lower pressure has reduced rolling resistance. The high pressure tyre will be bouncing off the rocks and roots, impeding flow. The lower pressure tyre conforms and the bike rolls on.

Saw a report from a German lab confirming that.

 

[B1rdie]

Wind is a battery killer for me and if my ride is about range I try not to go over the 15mph restriction although there is no restriction!!

Riding unrestricted against the wind is ?.