Range vs Temperature

363 Views 14 Replies 5 Participants Last post by Adventures on Zero, 23 d ago

Nwfg

Discussion Starter · 27 d ago (Edited)

My knowledge of the LWs Range vs Temp is purely a product of observation. What I have found is that when riding on back roads (35-55mph, 56-88kph) in warmer weather with the RESS (high voltage battery) temp in the high 80s°F and above (27+°C and above) I can easily maintain a range ratio of about 1mi / 1% (1.6km / 1%), and usually a better than 1mi to 1% ratio.
But when riding on the same back roads in cooler weather with the RESS temp below the high 80s°F (27+°C), I find it’s a struggle (need to ride much slower, baa) to maintain a ratio of 1mi to 1% (1.6km / 1%).

If I start a ride In 95°F (35°C) weather, and ride 30mi (48km) west to Hwy-1, along the Pacific Coast, it’s usually much cooler there and the LWs range drops off noticeably. This wouldn’t be a big deal, but there are exactly ZERO DC/CCS chargers on the way to and along Hwy-1, going N. or S.
I usually hit the coast about 60mi (97km) N. of the capital of wokeland (San Francisco, not sure if it’s the capital, but the infestation is so severe that it’s beyond recovery) and there isn’t one DC/CCS (one Tesla Super Charger station in Fort Bragg, not open to non Tesla) charger on Hwy-1, from Mill Valley all the way to One Log House. That’s a DC/CCS charger desert, 224mi (360km) long. The wokenese use this route regularly, so you would think there would be at least one DC/CCS Charger along a scenic rather isolated 224mi route. But I digress.

I’m riding in a relatively mild climate, so I would like to know what others have noticed when they compare riding in warm / hot weather vs riding in cooler / cold weather.

In my ignorance, I thought the LWs coolant circulated through the RESS, but I was wrong, the coolant circulates through the OBC, motor and motor controller. The battery is air cooled and seems to have ample cooling ability. When riding in 100°F (38°C) weather I haven’t noticed the RESS temp above 102°F (39°C), it may have actually hit higher temps, when I wasn’t checking.

What I’m getting at is, when riding in cooler weather the range could be increased by taking the waste heat from the OBC, motor and motor controller and transferring this heat into the RESS by circulating the coolant through the RESS only when it’s temp is below optimal.

I realize this is standard technology on caged EVs where the need to save weight and volume are not nearly as critical. This would have added weight, volume, complexity and $$$ to the LW.
But with the LWs limited range (I believe if you do a “range anxiety” search there’s just a photo of a LW, don’t get me wrong I really enjoy the LW, I make it work, and I have a blast doing it) it seems like a waste not to take advantage of what would be essentially free range, and everybody knows free range is the best range.

See less See more

Reactions: 1

1 - 15 of 15 Posts

colton111391

· #2 · 26 d ago

I’ve noticed similar results to your observations though I found a temperature as low as 60F can bring about the desired range. Where I live in the upper Midwest, a range of 110 miles is all I need but in very few circumstances. When it’s cold in the late fall through early spring, I have a hard time getting the battery temp above the ambient air temp even when I DCFC. That certainly hampers range but it’s too cold to go further than I need to anyway.

Reactions: 2

Nwfg

Discussion Starter · #3 · 26 d ago (Edited)

I ride for pleasure 95% of the time. Some will call me a wimp, but I do not own the proper riding gear (heated gear) nor do I find much pleasure in riding when it’s below 55°F (13°C). But when there’s a 30°F drop in temp on the same day of riding, the decreased range is a bummer.

I don’t think there is much we can do about it, short of coming up with a super insulated blanket for the RESS, or a cowling like those used around an aircrafts engine, with vents that open and close to regulate the temp. Both would not be an impractical solution for our existing bikes.

Reactions: 1

Phaedrus

· #4 · 26 d ago

I don't see much change in range due to temp, from mid 40s to mid 60s F. Looking back at my notes and charge data, I get virtually the same range for my 99 mi loop over 2 low mtn ranges with speeds from 35 to 65 mph.

My range has varied by less than 2 mi - but that could just as easily been due to riding style as due to temp.

colton111391

· #5 · 26 d ago

Riding style, elevation changes and wind are definitely bigger factors than battery temperature in my opinion.

Reactions: 2

Nwfg

Discussion Starter · #6 · 26 d ago (Edited)

Let me clarify, I never meant to imply that temperature has more effect on range than: speed, elevation changes or wind, nor did I state that it does. Temperature is just one more factor, that effects range, and honestly it took me by surprise.
All I meant, or should have said is: that after riding the ELW for a few thousand miles in warm to hot weather, and then riding it in cooler weather, I was surprised that after riding for only a few miles, and by just watching the miles traveled compared to the % of battery used, I was able to noticed a drop in range. With the RESS fully charged, I believe that a 30°F drop in temperature can decrease my range by roughly 17mi (27km). If you’re 17mi (27km) from the nearest charger, that’s about a 4+ hour walk, add more time if pushing your bike.

Then again maybe it’s just my RESS (battery).
Notice the “Serial #: 0001” (third line down)

Font Material property Label Auto part Electric blue

See less See more

Reactions: 1

colton111391

· #7 · 26 d ago

Appreciate your insight. Love being able to compare notes with other riders!

Reactions: 1

Phaedrus

· #8 · 25 d ago

colton111391 said:
Appreciate your insight. Love being able to compare notes with other riders!

Definitely appreciate the insight!

I've just not noticed more than 2 mi difference in range under varying temps, over the same 99 mile ride - with other variances being how hard I hit the climbs and whether traffic slows me at times.

I've not ridden under 40F yet though.

Nwfg

Discussion Starter · #9 · 25 d ago

Maybe I’m hallucinating, and that is a real possibility. The numbers I’m seeing and relating here, are all “seat of the pants stuff”.

For your 99mi ride comparison, You did not specify the high temp compared to the low temp.

But if you do a 99mi ride in 95°F temperature, and then do the same ride under the same conditions, except with the temperature at 55°F, and you only see a 2% change in range, well, good on ya, and don’t sell that battery.

If the above is accurate, I definitely need a new battery.

Phaedrus

· #10 · 25 d ago

Nwfg said:
Maybe I’m hallucinating, and that is a real possibility. The numbers I’m seeing and relating here, are all “seat of the pants stuff”.

For your 99mi ride comparison, You did not specify the high temp compared to the low temp.

But if you do a 99mi ride in 95°F temperature, and then do the same ride under the same conditions, except with the temperature at 55°F, and you only see a 2% change in range, well, good on ya, and don’t sell that battery.

If the above is accurate, I definitely need a new battery.

I've done the same ride multple times in 40-45 deg temps and in 65-75 deg temps. The temp range for the rides is because I go over passes where the temp falls. I start fully charged and end up with 0-2% battery at the end. (While I've hit 0% charge a couple times, I've yet to go into limp mode at the end. ) I stay under 65 mph, and mostly under 60 mph, wih some 25-35 mph cruising, passing through small towns. The climbs to the passes are "spirited." But, I've yet to ride that ride on hot days.

Reactions: 1

xophere

· #11 · 25 d ago

I think it very hard to get accurate numbers with out lots of details about how the pack % is measured and if the % curve is really linear. As I have said I feel like there is a hole in the 30-15% range that goes much quicker. Temp is interesting. I wish we could get ideal specs for charging and discharging. So we would at least know. I remember someone question if the air temp effect the drag on the bike. Got very mixed results from google but the low could point to the tires and the air accounting for a bit. Certainly if we are talking a few %. Given how much heat the tires do generate even on cold days the effects of the rubber being stiffer and flexing increasing the drag could be significant.

alohonyai.blogspot.com

Effects of Winter on Fuel Economy

If you're pinching pennies, or maybe just nerdy about your fuel consumption, perhaps you've noted that your fuel efficiency gets a fair bit...

alohonyai.blogspot.com

Reactions: 1

Nwfg

Discussion Starter · #12 · 25 d ago

You are correct, there are a multitude of factors that affect range. And with out a strictly controlled test, one can not tout definitive numbers (myself included, so I will no long state numbers) and that’s not what I intended to do. But once I noticed the temperature effect, I really started to pay attention, and I was wondering if others had noticed a change in range vs temperature. Like I stated before riding the same route under similar conditions, except riding one at 95°F and one at 55°F makes a noticeable difference in range.
I should also note the battery temperature doesn’t change instantly (there is quite a bit of mass sitting in that case) when it exposed to temperature change. So if you start with a hot battery the range won’t be effected until the battery cools off. Charging heats the battery some what. When I know I’m going to ride on a cool day, I try to time the charging so that I’m unplugging the charger as I ride off, just before I reach the end of the cord, ha, ha.

I time the charging (this is probably low tech compared to other technology that is available) by using a “SwitchBot, Mini Plug” which can be controlled via Wi-Fi with an app on your smartphone.
It is capable of scheduling timed on and off cycles.

Xophete, mentioned: “someone question if the air temp effect the drag on the bike”. I was wondering the same thing, cold, dry air is denser (denser air = denser oxygen) than hot air, and ICE make more power with cold dry air. But our E-MCs don’t use oxygen to produce power (as far as I know). So this is just a guess, but if the dense air isn’t enhancing the power, it seems the dense air would create more drag, and therefore degrade the range. But I would again guess the degradation would be minimal.
Just thinking out loud.

See less See more

xophere

· #13 · 24 d ago

Good points @Nwfg we should probably talk about air and battery temp separately. I did notice it was very slow to catch up or cool down as the charging riding cycle changed even with 15 degree changes in temp at 70mph. And of course use seems to heat the battery as well not just charging.

Reactions: 1

Nwfg

Discussion Starter · #14 · 24 d ago (Edited)

So many variables to the range equation.

Xophere, I believe you are correct, it’s not only during charging the battery that produces heat, discharging the battery also creates heat (propulsion).

But when I’m going for range by trying to keep the orange arc as short as possible, not much heat is produced within the RESS.

We know the LW comes with a heat exchanger (radiator), pump and all the plumbing required to circulate the coolant through the heat exchanger, it’s not an option. Its unlikely that the bean counters at H-D would have allowed this feature if it wasn’t necessary. So obviously the heat produced by the OBC (during charging), motor and motor controller (during propulsion) needs to be removed.

This heat is removed and transferred to the air. It took energy to create that heat and that energy in the form of heat could be used to keep the RESS at an optimal temperature, which would conserve at least some energy.

I know at this point I’m beating a dead horse, when it comes to our existing LWs, but hopefully future generations will incorporate this technology.

I must admit I don’t know, if during propulsion whether the motor and motor controller create enough heat to substantially raise the RESS’s temperature. But if the heat has to be removed from the OBC, motor and motor controller, why not transfer it to the RESS when the RESS’s temperature is below optimum, like many of the caged EVs do that are on the market today.

See less See more

Adventures on Zero

· #15 · 23 d ago

The external factors that affect range, increase as temperature lowers and speed increases. Temp also affects the chemistry exchange both at the high and low ends. Riding behavior and speed is the best way to counter the external factors that affect range. A windscreen can help as well to reduce some drag.

Reactions: 1

1 - 15 of 15 Posts