I like the bandage and waste heat concepts. How about a neoprene insulator that is designed to transfer motor heat to the downtube?
Are battery packs and charger system like good and bad neighbors (cells) randomly huddled together in cold weather around a fire (charger) ?
- Thread starter BikeMike
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I like the bandage and waste heat concepts. How about a neoprene insulator that is designed to transfer motor heat to the downtube?
I read that changing a battery in cold weather is a no-no. However, a Bosch Dual Battery allows both batteries to be inserted in a warm garage. The question is: are the operating characteristics amenable to cold weather? I posed this question to the head of Bosch eBike of NA. Someone from Germany will call me.
Big Tom
Member
You have a situation that IMHO requires building your own bike. Personally I would get a nice fat wheel bike, maybe used, and a 48V 750 W rear wheel kit from a quality manufacturer, I like a small company called Bison Moters but there are others. Get a triangle bag for batteries and controller and insulate the crap out of it on the outside. Leave room for a good sized heating bag if you can. The bag I have actually has a side pouch that would work.
Because the bag hangs from the frame it won't get the cold transfer from the frame and I bet you could keep the batteries above 60 F for a 20 - 30 minute ride in 25 F or less.
I am all for the idea. My dexterity is undeveloped. I try to do as much of my maintenance as my mechanical ability allows.
Why 48V? What difference does that make in cold weather? More cold crank amps?
I noticed a 48V bike on the showroom floor. I believe it was an izip E3 Dash.
https://izipelectric.com/e3-dash-step-over
What is your opinion on the Dash?
Big Tom
Member
In a
In a perfect world you would take the heat from the motor and route it along the wires coming into the hub and transfer to the frame. In the summer it would cool the motor and in the winter would warm the frame. Don't know if it can be done
I have a direct line to Bosch in Stuttgart, Germany. I can certainly ask them. They would enjoy the information, or may have already something planned.
What gauge wire and tpye?
Big Tom
Member
I'm not familiar with the bike and hesitate to make any comments. Sorry.
The 48V will support a 750 watt motor. On a big tire bike, possibly in snow, you need the horsepower. Mid drive or a geared rear hub, no direct drive motors. There's more then cold you have to consider..
Would a fuel gauge in the BMS be of any practical value?
http://www.ti.com/download/aap/pdf/batt_mgmt_3q00.pdf
Big Tom
Member
I'm not an engineer, that would be their job. I would ask that they do NOT patent the idea or at the very least make the patent available to other manufacturers. It would be in the best interest of the industry.
Being an engineer might be more of a disadvantage than advantage to solve some types of problems. No offense to engineering. I am an iPhone developer, so some overlap in the realm of computer science and math. I had to take a lot of engineering classes.
I simply avoid snow or melting snow. The sun is so intense and humidity so low in Denver that snow or rain never lasts for long. The elevation is my area is almost 6,000 feet.
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I think for the additional money that need to spend on the 2019 Trek Powerfly 5 to "winterize" it, I would be better off with this bike. The big problem is service. The sole R&M dealer location is too inconvenient for me. I sold my car. Perhaps, I can use something like BeeLine to do the service at my home. This would mean R&M or the dealer contracting with BeeLine.
Please note the Dual Battery system. I think BigTom's idea of heating the batteries might be achieved by putting a small battery inside the frame triangle, attached to bosses. Enclose the batteries with a frame cover, which might simply be a small electric blanket. The battery chemistry that powers the heating strips must obviously have very low temperature properties.
(Link Removed - No Longer Exists)
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Service is much more important to me than design. I have gotten stuck in the middle of nowhere before. I have roadside assistance with Veloinsurance. I need the support to fix a broken bike. R&M has just one dealer for the entire state of CO, which is pathetic.
R&M needs to contract with a mobile repair service, like Beeline.
I think aluminum could get super chilled if slush or cold water sprayed on the battery or frame. I wonder if that is all it takes for a voltage drop that cause the BMS to turn off power?
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The crux of the matter is discussed on this page:
"Environmental conditions, not cycling alone, govern the longevity of lithium-ion batteries. The worst situation is keeping a fully charged battery at elevated temperatures. Battery packs do not die suddenly, but the runtime gradually shortens as the capacity fades."
https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
Table 2: Cycle life as a function of
depth of discharge.* A partial discharge reduces stress and prolongs battery life, so does a partial charge. Elevated temperature and high currents also affect cycle life.
Table 3: Estimated recoverable capacity when storing Li-ion for one year at various temperatures. Elevated temperature hastens permanent capacity loss. Not all Li-ion systems behave the same.
Figure 6: Capacity loss as a function of charge and discharge bandwidth.*
Charging and discharging Li-ion only partially prolongs battery life but reduces utilization.
Figure 7: Predictive modeling of battery life by extrapolation.
Li-ion batteries are charged to three different SoC levels and the cycle life modelled. Limiting the charge range prolongs battery life but decreases energy delivered. This reflects in increased weight and higher initial cost.
"Environmental conditions, not cycling alone, govern the longevity of lithium-ion batteries. The worst situation is keeping a fully charged battery at elevated temperatures. Battery packs do not die suddenly, but the runtime gradually shortens as the capacity fades."
https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
Table 2: Cycle life as a function of
depth of discharge.* A partial discharge reduces stress and prolongs battery life, so does a partial charge. Elevated temperature and high currents also affect cycle life.
Table 3: Estimated recoverable capacity when storing Li-ion for one year at various temperatures. Elevated temperature hastens permanent capacity loss. Not all Li-ion systems behave the same.
Figure 6: Capacity loss as a function of charge and discharge bandwidth.*
Charging and discharging Li-ion only partially prolongs battery life but reduces utilization.
Figure 7: Predictive modeling of battery life by extrapolation.
Li-ion batteries are charged to three different SoC levels and the cycle life modelled. Limiting the charge range prolongs battery life but decreases energy delivered. This reflects in increased weight and higher initial cost.
I am personally most interested in the Battery Management System Information, as opposed to the Motor Controller information. I am interested in a reliable battery system for cold weather. An eBike is an investment in batteries to me. Batteries are the neglected, ugly ducklings. The motor holds all the sex appeal.
The Bosch Nyon display is a perfect device to communicate critical information in a pleasing and easily understood manner. I believe Bosch can gain a huge strategic advantage over competitors by providing useful BMS information to the USA market.
The Bosch Nyon display is a perfect device to communicate critical information in a pleasing and easily understood manner. I believe Bosch can gain a huge strategic advantage over competitors by providing useful BMS information to the USA market.
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https://www.instructables.com/id/DIY-carbon-heated-blanket/
The battery chemistry that powers the heating strips must obviously have very low temperature properties, unlike the ebike battery .
The battery chemistry that powers the heating strips must obviously have very low temperature properties, unlike the ebike battery .
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