Temperature Considerations

[Diverdude]

Is there a simple formula for calculating battery power reduction due to cold weather? I have some routes that (in summer) use between 75% and 80% of the battery, am I likely to get a flat battery doing the same route at around 2 degrees C?

 

[The Hodge]

No there is no formula ..
Yes your range will be affected ..by how much ?
Who knows ..but with 25% battery left in the tank ( summer use) its doubtful that you will use up an additional 25% in the winter on the same route...
There is only one way to find out ..go out and ride ..

 

[Richywalker64]

The cold does seem to effect the range as does the wet/muddy conditions
I went out in heavy snow fall around Guisborough woods a month or so back and couldn't believe how much the range was effected
I only managed around 13 miles out of a 504wh battery which I put down to the cold and the rolling resistance caused by the snow

 

[Diverdude]

Thanks for that, I guess with so many variables it would be difficult to come up with a 'one size fits all' formula for cold weather use. I'll take your advice, head off to a nice (warm) country pub and compare my stats when I get home.

 

[Stoffel]

The ground condition’s also play a big part, there’s a lot more resistance peddling through the thick mud as well as the cold effecting the battery.
I done a ride last weekend which I have done before and my battery was flashing to say it’s almost dead as I arrived at the house. I remember having at least 20% left maybe more when I done the same ride in the summer.

 

[Diverdude]

You are right, the ground conditions play a big part; near me is an old sand quarry which is great fun to plat on but it chews through the battery at an unprecedented rate. I thought, with the ground being frozen, rolling resistance would be similar to summer (when dry) and might be a good tester for temperature/range. Having given it a bit more thought it (range) is obviously far more multi factorial; I think a known ride to a nice pub may help me to figure out the query.

 

[Growmac]

Ground conditions possibly make as much if not more difference than cold, all else being equal. I reckon I only get 60-75% range in midwinter compared to the same route on a warm summers day.

One thing I have noticed though. If you stop (to go to the pub for example) and let the battery get stone cold, drain can be catastrophic afterwards. I've stopped with 40-50% left in the tank, let the bike sit in 2 degrees for a couple of hours, and had the battery not last the 3 miles home afterwards.

 

[Diverdude]

Ground conditions possibly make as much if not more difference than cold, all else being equal. I reckon I only get 60-75% range in midwinter compared to the same route on a warm summers day.

One thing I have noticed though. If you stop (to go to the pub for example) and let the battery get stone cold, drain can be catastrophic afterwards. I've stopped with 40-50% left in the tank, let the bike sit in 2 degrees for a couple of hours, and had the battery not last the 3 miles home afterwards.

Thanks for the info, I'm just about to set off so when I get to the pub I will take the battery in with me and sit by the real fire whilst I sip my half of lemonade

 

[Planemo]

I've done a fair bit of testing with the same battery tech in my unicycle - basing the best range on the hottest summer I have ridden in (around 32 degC IIRC), I noticed a drop of around 20% at around 15 degC, and 30% at around 0 degC. I haven't ridden in anything colder than that!

And the above takes away the terrain variable because I very rarely go offroad. So yes, for you mucky boys riding in slop it will be even further reduced. For sure though, temps alone make a massive difference in range.

 

[Zimmerframe]

Lithium batteries don't perform well when they're cold. So ideally start with a room/pub temperature battery.

I've always theorised that when it's really cold, it's best to just ride in Turbo. That way the current draw keep the cells warm, so the overall battery performance stays the same. This way you get to go just as far as you would in Eco, with a cooling sub performing battery, except you get to go faster .. Or maybe I'm just fishing for any excuse to use Turbo and go fast when it's cold....

 

[Diverdude]

Update. Did my ride, had my half pint of lemonade, rode home (mix of tarmac 20% and trail). No noticeable difference in battery performance, temp was around 3 degrees C compared with around 23 degrees in August. I'm not going to worry over it in future, I'll just go and ride.

 

[eMullet]

I've ridden -10 to -15 C and there is some battery capacity loss. But the trails are so flowy now that the snow has covered all the roots and rocks and frozen solid. So rolling resistance has decreased but not enough to compensate for the cold weather effect on the battery.

Yesterday I went out for 31km/550m (distance/total climb) on mostly singletrack. Eco mode all the way. Temperature average was about -5C and took nearly 50% off my 630Wh battery. The bike and battery were in warm storage before the ride.

 

[Diverdude]

I've ridden -10 to -15 C and there is some battery capacity loss. But the trails are so flowy now that the snow has covered all the roots and rocks and frozen solid. So rolling resistance has decreased but not enough to compensate for the cold weather effect on the battery.

Yesterday I went out for 31km/550m of climb on mostly singletrack. Eco mode all the way. Temperature average was about -5C and took nearly 50% off my 630Wh battery. The bike and battery were in warm storage before the ride.

View attachment 80529

That looks amazing and puts my 'slightly chilly' question in its place. I haven't seen snow like that for years enjoy.

 

[eMullet]

Comes with the territory (Finland). Its fun to ride these winter singletracks but it takes a while to form and compact for them to be ridable with regular (not fat) tyres. Nice contrast to summer.

 

[Diverdude]

That much snow in UK would paralyse the country!

 

[The Hodge]

Just in the south ..we still get a fair lick in Northumberland ..