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[protomech]

I have commuted on my 2012 Zero on a handful of cold days here (cold in AL is mid 30s F) and I see some odd energy gauge behavior. When I leave in the morning (garage temp mid 50s), I see more or less expected usage of energy bars (5-6 miles per bar @ 45-55 mph). Typically two bars and a bit consumed when I park at work, 12 miles away from home. When I leave work in the evening (bike sits outside uncharged in mid 30s ambient temperature), the energy gauge will often start one or two bars lower (7-8 visible bars when switched on) and drop rapidly over several miles (typically 1 bar every 2-3 miles).

I returned home today @ 26 miles on the bike with 3 visible bars. No loss of power in the cold, but it appears to deplete energy at approximately twice the rate as in the fall (temps 50-60s) when I would return home with 7 visible bars.

I switched the bike off, plugged in, gave it a minute or so, then switched it back on. The bike then showed 6 visible bars of energy remaining .. or about what I was seeing when I commuted in 40 degree weather.

I'm guessing the bike uses a combination of cell temperature, ambient temperature, pack voltage, and coloumb counting to give a prediction for range. Perhaps voltage is dropping much more quickly than the bike expected when the temp drops below 40?

What worries me is not knowing whether the rapid fall is simply due to the cell temperature drop, and once the bike has compensated for this if the remaining bars are good for 5-6 miles apiece.. or if they will also continue to deplete at the rate of 2-3 miles per bar. Need to do some testing..

I did expect to see some range reduction in the cold - around 20-25% - but not 50% reduction in range. I think the energy gauge may be somewhat pessimistic due to the temperature delta between the morning and evening commute - I would suppose that I would see consistent range if I did a single trip leaving from the semi-heated garage, instead of allowing the bike to cold soak.

What are other people seeing? (starting a new thread specifically for the energy gauge display behavior)

[mehve]

Nothing quite as thorough, but I can concur based on this evening's ride that the gauge read lower after letting the bike sit outside for the duration of The Hobbit showing (temp dropped from 45F to 35F). I had eight bars when I parked at the theater parking lot and only six was left when I got back on it. I just saw this post an hour after i got back home and it looks like, on the interim, my 2012 Zero S ZF9 gauge has 9 bars of energy on it after being plugged into a reg 110V outlet in our attached garage.(Could 3 bars be regained in just over an hour...?)  At any rate, on other cold days (upper 30's) I usually end up one bar less than on warmer commutes which are 10.6mi round trip.

Brr... I need heated gloves.

[Electric Terry]

Cold temperatures do 2 things:

1) reduce the total energy the batteries can put out and

2) shift the discharge curve lower, meaning the batteries read lower.  But will also go lower before they are out of energy.

I've done about 1000 miles in the last 2 weeks in cold 30 degree night 45-50 degree day and range appears to be almost half at night than during the day, but then again, how many of us really want to go 100 miles when it's 10 degrees below freezing?  I'm usually looking for an excuse to pull over and start charging/warming my hands on the headlight. 

[amahoser]

Terry,
Stop by a drug store and pick up a package of heating pads. They stick on your skin and usually provide heat for 10 hours. I got caught in Vegas on a naked bike and temps dropped from a relatively balmy 50-60 degrees on my way to Vegas to 20s-30s on my way home to LA! I didn't bring enough cold weather clothing so I bought some heating pads. They dont require and power and are activated as soon as you expose them to air. I stuck them on my feet, hands thighs and anywhere else I was feeling cold. Worked like a champ and I swear it saved me from hypothermia!

Jose Soriano

[protomech]

Half range seems to be what the range indicator is predicting, extrapolating out from 26 miles @ 3 bars remaining should put a full charge commuting range (with a midday cold soak) at approximately 32-35 miles .. and I typically see 70-80 miles in non-aggressive riding during the non-winter months.

On the other hand.. a couple weeks back I rode nearly 50 miles with temps in the 30s, the last 18 of which were with the energy gauge completely empty and the fuel icon blinking (and all but the first 12 starting from a cold soak). There was definitely significant energy left in the battery in that particular ride, but does it damage the battery to discharge below 0 bars?

Perhaps a better question for Zero.

[Richard230]

I'll let you guys do the cold weather testing.  When the temperature drops below 40 degrees, I prefer to ride something that actually makes heat and I will therefore warm up one of my IC motorcycles (preferably one with grip heaters) and ride that instead of my Zero.  IC may be inefficient, but I do appreciate how it makes excess heat that can be used to warm me up while riding and warm my hands up when stopped.     Sort of reminds me of a wood-burning fireplace, instead of central heating.   

[protomech]

Combined heating & power systems are ideal for combustion efficiency - in cold weather, particularly when you have a heated passenger cabin, ICE (speaking generally) is as good as or better than electric powered by grid fossil fuels. Natural gas furnaces are more efficient for heating than grid fossil fuels + transmission + electric central heat. Electric heating via hydro is very clean, of course, but grid power is very very fungible.

Also mid 30s are about as low as I want to ride. I have zero desire to deal with ice.

[kcoplan]

Just got back from a 32 mile round trip on my ZF6, temperatures from 24 to 32 degrees, bike left parked outside for three hours.  Used six of eleven bars, fine bars left at end.  Really can't say I noticed any change in the range or battery level indicator.

Longer report on the "coldest ride" thread.

-Karl

[trikester]

This isn't as cold as some but here is the data from my ride yesterday.

Starting temp = 52 deg. Destination temp unknown but noticeably colder at 1000' higher and wind coming down from the higher mountains. Cold with my wind proof motorcycle jacket on.

2012 DS ZF6

Taken from my GPS:

40 miles round trip

26 mi total paved highway @ 30 -32 mph

14 mi total dirt, sand, & rock.

Elevation gain / loss 1000'

Total moving ave.= 17 mph

Ride out with 15 lbs front & rear. Return ride with lowered to 6.5 lbs front which increased rolling res for 13 mi of pavement.

7 bars showing at destination (20 mi).

4 bars showing at finish.

On charger overnight total = 4.3 KWH

Notes: With several miles of soft sandy wash road it was  little twitchy going in with 15 lbs front. At my destination I lowered the front to 6.5 lbs for the return trip, which gave me very good sand handling. Lacking an air pump I knew this would cost me some mileage on the highway going back. How much I have no idea, but I didn't have any handling trouble on the highway at my 30 to 32 mph speed. I couldn't feel any indication that the front tire was so low, even on one very tight switchback. Note: Tires Kenda K270's, 5.1" x 17 rear, 4.6" x 17 front.

Trikester

Oops - I forgot to say I let the bike sit in the bright sun for about an hour before starting my ride. It had been sitting out all night and the low just before sunup was 40.

[protomech]

Quick update.

It seems like the energy gauge will recalculate when the bike is switched off for a few minutes.

I rode in this morning, 12 miles @ 27F. 9 bars visible when I parked, 8 bars visible when I left in the evening @ 33F. Again the bars dropped off very quickly. I stopped with 3 bars visible at 18 miles total to double check my route (unexpected detour).

Switched bike off, pulled out phone, poked around for a couple of minutes. Switch bike on.. and the gauge is now showing 7 bars instead of 3.

Less than amused, but kept riding. At around 25 miles I was down to 2 flashing bars, then 1, then 0 at around 27 miles. Again, pulled over, switched bike off for a minute.

7 bars visibile now, though again they quickly fell. I arrived home @ 33 miles, 31F with 3 bars visible.

Switched bike off once again, then back on a few minutes later. 6 bars visible.

Go figure..

[BSDThw]

The effect you have is really enormous!

I have done SOC calculation for a while for Solar Systems, it is really not an easy task.

It is important to recalculate sometimes. If you only add up data you will have good results in the beginning but than all small errors add up. It will become chaotic!

It is most likely if your system is in idle mode for a time you see the battery voltage in a situation where you can estimate the SCO (temperature etc has to be in account)
Now, your SW has to decide who is right and make maybe some between.

Why act your system so extreme? Maybe the algorithm is in an environmental situation that was not tested enough. Likely you have to wait for a certain time before the values are exact and now you have the temperature falling from warm to cold at the battery, wrong timing!
It is really a hard job to make it work at all circumstances. Up to now I am happy what Zero has done but yours is too extreme.

[Electric Cowboy]

I can confirm what everyone is saying. When terry and I rode through the ice and snow up at Newcombs, my bikes gauge read empty after just 3 or 4 miles, but when stopped and power cycled the gauge would give an accurate reading.

[Electric Cowboy]

When I realised I was not actually out of power, I just rode with the gauge reading empty for the rest of the way.

[Brammofan]

When I realised I was not actually out of power, I just rode with the gauge reading empty for the rest of the way.

There must be a better way. This seems like a design flaw to me.

[Electric Cowboy]

At least I have a bike. With no real number of Blammo bikes out there nobody can find brammo flaws so they will remain perfect forever... Until they have thousands delivered and being tested by riders. Tell me more about zeros flaws when you have thouroughly tested the brammo up a mountain over a mile high in sub freezing weather. Seriously, I would love to know. Especially curious about the water cooling and transmission fluid viscosity and if the cold has any effect.