Anyone see a power saving difference using a neoprene sweater on their battery in winter temperatures?

[elliot friedman]

I'm seeing the bosch specific ones advertised or thinking about making my own.

 

[Telkwa]

Yes. My bike is a Haibike HardNine 1.0 with a 400Wh battery. If I'd known then what I know now I woulda asked the retailer to upgrade me to a 500.

Anyway, our usual ride is 20 miles out and back on a local rails-to-trails. In the summer I'd start out in Standard, then return in High. Back to the car with about 30% remaining on the battery. Everyone knows that ebike gauges aren't particularly accurate, right? If it says 60%, think of that as about 45%, and if it says 30%, that's more like 15%.

As winter came on and we started riding in 50 F and colder my bike was barely making it back to the car. I began using Eco more, and either staying in Standard or saving High for the last 5 miles or so.

We found a piece of midweight neoprene laying around (roughly 3mm?) and my wife sewed a tube sock out of it. I got a 10% to 15% jump in battery life.

The Yamaha battery is entirely exposed to the wind on my Haibike. The newest bikes are tucking the batteries into the frames. That's gotta change the equation.

 

[MarkF]

The only way your going to get the same range on a cold battery is to warm it up before you ride. Keep your battery in a warm part of the house. Another way to heat a battery up is to use a heating pad like the kind for your back. Use the low setting and warm the pack for at least 1 hour or more. Putting a blanket on a cold battery doesn't do much for you. Once the battery is warmed up you will get the same performance as you did in summer.

 

[Telkwa]

Oh, OK, I thought the battery would warm itself up as it discharges. All summer I'd been leaving the batteries on the bikes. Looks like I should get used to a few extra steps between rides...

 

[MarkF]

It's bad for lipos to be heated from use when there cold. You are doing more damage that way as opposed to heating them up in your house. Lipos like to be at 80+ deg F for optimum performance. The lower the temp, the lower the performance. If you warm your battery in the house before you go outside, you will get the most out of your battery. Warming your cold battery up by throwing it on the bike and riding it is a good way to shorten your cycle life,

 

[Over50]

I'm seeing the bosch specific ones advertised or thinking about making my own.

I always use mine (Fahrer covers for Bosch Powerpacks) when temps are under about 40F. I purchased the covers early-on in bike ownership so I can't recall much experience without the covers in cold temps. I can say that on my coldest commute days with them, I haven't experienced a severe range detriment vs warmer days when I don't use them. But, this may not be saying much because in those conditions I've gone from the warm house or office straight into the commute (of an hour) and the battery never has a chance to sit idle in the cold. I also recharge at work after the battery has been at room temps for a couple of hours. I think in the early days of my R&M Charger I recall parking the bike outside a coffee shop on a really cold day, for maybe an hour, and noticed my range was cut by half when I started up again. I'll have to go back and find that thread as I can't recall if I had the cover on that day.

I have been known to remove the covers mid-ride when temps are over that 40F mark and I'm pushing the bike pretty hard or have direct sunlight. On my 49 mile ride a couple of Sundays back, I started early a.m. with both batteries covered and temps of about 32F. Later in the afternoon it was around 41-42F and my bike sat in the sun whilst I ate lunch. So I removed them for the remaining 14 miles to home. I think on another day in early 2017, I had 20 mph headwinds on a moderate afternoon and I stopped to remove the cover about 8 miles into an 18 mile ride home. Perhaps overly cautious and unnecessary. Good thing with the Bosch covers is obviously made to fit perfectly and the batteries are just slightly harder to click-into place with the covers on. The inside portion of the cover is a thinner material vs the thicker neoprene outer portion. I doubt they have covers for the Powertube batteries (haven't checked recently) and perhaps the tolerances of the in-tube designs don't allow for covers.

 

[linklemming]

I did notice reduced range when I was storing my ebikes in the garage down to about 40F.

I started bringing the batteries inside(65F) a month ago and since then havnt noticed much reduced range/performance. They will warm up with use due to the internal resistance but not sure how much.

I have ridden down to 15F recently with batteries starting out at 65F and really havnt noticed anything significant, I do however like to use less assist when its colder just to stay warm. My rides tend to be less than 2 hours as my feet just get too cold after this (even with toe warmers which really only work for about an hour)

I got tired of constantly taking off the batteries so these days I bring the bikes in the house. As an added benefit I get to look at my bikes all the time (no wife to discourage this)

 

[tomjasz]

I made a simple heated insulated blanket with parts from Aliexpress. Cheap and effective.

 

[Scooteretti]

With winter now here and temperatures hitting sub zero C or below 32F there will be some benefit to using a neoprene battery sleeve. If you are out on short 20 min or less rides you probably won’t see much difference but if out fat biking for example for a few hours the sleeve will help with what feels like better torque when hill climbing and overall range.

No scientific data here but rather just feel.

So overall it’s probably a good accessory if you ride for more than 20 mins.

*note this is based on keeping your battery indoors prior to a ride.


Regards,



Will

Shop.scooteretti.com

 

[Telkwa]

Brought the batteries inside this morning. Keys need to be diligently tracked and batteries need a secure spot.

From what I'm reading here the small amount of extra effort will be worth it.

 

[Ravi Kempaiah]

No scientific data here but rather just feel.

There is scientific data.
I just wrote an article for Electric Bike Action magazine and included this diagram.
Perhaps, I will link the article when it is published.
In-depth analysis can be found here:
https://www.sciencedirect.com/science/article/pii/S1364032117306275

As you can see, there is a temperature and charge/discharge rate sweet-spot.

 

[Chris Hammond]

@Ravi Kempaiah
Thanks for the chart and link.
I could only read the abstract of the article you linked. So I have a few questions.
I only charge my battery after it has reached room temperature, which as far as I can tell is optimal for lifecycle??? I have the Juiced 52V 21Ah battery pack, is there an easy way for me to calculate what a 1C charging rate would be in Amps per hour? Is there any data to suggest charging at a rate slower than 1C will provide even more lifecycle benefit?
As far as discharging the battery goes while riding, what should I do to maximize battery life? I have already made a neoprene sleeve for my bike, which has a small benefit for range while winter commuting. Should I look at making some sort of heater to warm the pack? I am a little concerned with creating "hot spots" doing this. I have enough range on the pack for my 30 mile commute even at temps of -10C which is about my limit for acceptable riding conditions. Performance clearly suffers at these temps but is accpetable. Any insight is appreciated, Thanks.

 

[Ravi Kempaiah]

I have the Juiced 52V 21Ah battery pack, is there an easy way for me to calculate what a 1C charging rate would be in Amps per hour? Is there any data to suggest charging at a rate slower than 1C will provide even more lifecycle benefit?

Chris, you are fine. 1C means you can charge or discharge in 1 hour.
So, from 0% to 100% in 1 hour. That would mean 21A rate for your battery. Even the cycle satiator max limit is 8A, which is already ~ 0.4C.
For your battery you can safely charge at 8A (0.4C) or even better 4A (0.2C) without any repercussion with one single caveat, (of course!!), the BMS in your battery is designed for such high current charging.
EV (cars) have far more sophisticated BMS and can accept 70A+ charge rates. We don't see that kind of BMS on E-bikes.

If you have 20Ah battery, 6 or 8A charging is perfectly fine. If your battery is <12Ah, then switching to 4A charger makes sense.

More than the fast charging rate, time spent at high voltage has far more deleterious effect. So, I would not worry too much about it.

 

[tomjasz]

My solution, some examples. Sadly my battery is mounted and in place for the winter. I will make an instruction sheet in the spring when I can disassemble and take pictures. One customer used a 3 piece made for clothing as it had a temp and timing control.

 

[MarkF]

I use an electric ice chest. These also have a heating function and can heat your battery to 40 deg above ambient. They work off of a 12 volt power supply or a cigarette lighter in your car. Some of my customers use a heating pad for your back as this works faster than the ice chest. It's also bad to leave your lipos in an environment that's freezing or below. The electrolyte can crack at freezing temps.

 

[MarkF]

Ravi

Your article is on EV car batteries and as you know, you can't take your car pack out and bring it in the house. For that reason, car manufacturers have made provisions to protect the battery from extreme heat and cold. You can't compare how they use a battery to how a bike uses one. There data is going to be a little different than ebike data.

 

[Ravi Kempaiah]

For that reason, car manufacturers have made provisions to protect the battery from extreme heat and cold.

Mark,
Not all car batteries have thermal control of the battery pack. Nissan Leaf is the world's largest sold electric car and even the 2019 version don't have thermal cooling technology.

Did you know Nissan lost a $24 million lawsuit? because of the lack of battery thermal control?
Many owners in Nevada and Arizona started this lawsuit.

Here is a link: https://www.autoblog.com/2015/07/20/2011-2012-nissan-leaf-class-action-lawsuit-settled/



Even their recent 30Kwhr packs have lots of problems:
https://insideevs.com/nissan-issues-statement-on-leaf-30-kwh-battery-degradation/

The same is true with some other electric cars.

You can't compare how they use a battery to how a bike uses one.

If expensive cars suffer this fate because of poor engineering and lack of understanding then It makes it even more imperative that E-bike batteries should be treated with diligence.

There are people who would like their E-bike batteries to last 4-5 years of good usage and obtain 25,000 miles of ride time. For those, thermal control of the pack can make a difference.

Whether it is Tesla Model S or Jaguar i-pace or BMW i3, many of them run 18650 cells or prismatic cells. The fundamental electrochemistry is the same. They are all cut from the same cloth.

 

[MarkF]

Preaching to the choir. I've been selling lipos for 7 years now. My main customer base is racers, and I'm one of them too. We do more damage faster than most. I'm the USA distributor for the brand I sell. https://www.dinogylipos.com/
I deal directly with the factory that makes my brand and have asked many lipo question along the way, so i can inform my customers and for my own knowledge. Unfortunately they don't make 18650 cells so no bike packs.

 

[Ravi Kempaiah]

Preaching to the choir. I've been selling lipos for 7 years now. My main customer base is racers, and I'm one of them too. We do more damage faster than most. I'm the USA distributor for the brand I sell. https://www.dinogylipos.com/
I deal directly with the factory that makes my brand and have asked many lipo question along the way, so i can inform my customers and for my own knowledge. Unfortunately they don't make 18650 cells so no bike packs.

It's nice to have knowledgeable vendors like you. The industry needs well-informed vendors.
I hope the tariffs don't affect your business. Hope you are having a great time this holiday.

 

[tomjasz]

Preaching to the choir. I've been selling lipos for 7 years now. My main customer base is racers, and I'm one of them too. We do more damage faster than most. I'm the USA distributor for the brand I sell. https://www.dinogylipos.com/
I deal directly with the factory that makes my brand and have asked many lipo question along the way, so i can inform my customers and for my own knowledge. Unfortunately they don't make 18650 cells so no bike packs.

PM coming need 3s 6000mAh 65c, Graphene is what many are using.