Keep battery warm in the winter

Vitoriung

1 µW
Joined
Oct 30, 2017
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I plan to get the BBS02 set with battery that goes on the frame to cycle to work in the winter and as we get temperatures as low as -15C here in Czech Republic I am worried about battery life getting drastically decreased, so I would like to keep it warm as much as possible.

There are some covers like https://www.e-bikeshop.co.uk/fahrer-bosch-battery-cover-ebike-2013-2014 however I think that might not be freeze proof enough, so I am thinking about some active solution.

Is there any thermophore(hot water bottle) system that would wrap around the battery or some electric mini pad heater that would use the USB port on the battery?

Or any other solution that you use, ideally DIY so it's also cost effective?
 
Hell, you are a tough individual to ride in those temps. But I guess I plan to as well...so I'm interested in this. Of course you'll have the battery inside while charging, and I wonder if it's heat from charging and subsequently discharging during your commute will keep the battery sufficiently warm. But I'm new to this e bike world so I'd like to hear others' opinions as well.
 
Why not consider using some of those sew-able warming fabrics used to create warming jackets etc. Combine perhaps one of those with some kind of thermal wrapping and you may get a net gain. I haven't done this. I live in the desert southwest of Arizona and we consider anything below 40 deg. F to be silly cold. But if I lived near tundra, I might try something like this.
 
Some threads about battery warmers/etc
https://endless-sphere.com/forums/search.php?keywords=batt*+warm*&terms=all&author=&sc=1&sf=titleonly&sk=t&sd=d&sr=topics&st=0&ch=300&t=0&submit=Search
not all results are relevant, but should be obvious which are.

There's info about heated garments/etc here
https://endless-sphere.com/forums/search.php?keywords=heat*+winter*&terms=all&author=&sc=1&sf=titleonly&sk=t&sd=d&sr=topics&st=0&ch=300&t=0&submit=Search
that might help.
 
Wrap the battery in the carbon fabric, apply the required voltage and bam you got heated battery fabric.
http://www.carbonheater.us/
https://www.adafruit.com/product/1481

Cheap out and buy some vaping wire at FastTech
https://www.fasttech.com/search?nichrome
 
The battery will heat itself up as soon as you start using it. No need for any extra heating. Anything to take the wind-blast off it would help, but I think the difference wouldn't be enough to matter.
 
It depends on if you need all the capacity for your ride or not. If you use only half now, you will be using all of it in winter, when the battery is very cold.

So if you need more than that, warm the battery. That cover will work fine, and look nice. But any kind of jacket will help it keep its warm when you put that cold wind on it. Start out with the battery at room temp, even if that is kind of cold by my southern desert standards. Then on the discharge, it won't get colder from the wind, and the jacket can keep it from losing the heat it makes as it discharges. That jacket could be as simple as a cardboard box, towel, arm cut off an old coat, whatever. Just anything to keep the wind chill off the battery box will help a lot. Discarded packing foam sheets is what I used to stuff in my steel battery box in winter. ( this was a naked battery in a tool box)

As for damaging the battery, the loss of capacity from the cold is not damaging your battery. Its just kind of like, a cold battery can't let the electrons flow, has high resistance, and that resistance wastes your electrons on heating the cells. Its not permanent. You just cant run the motor with electrons that never leave the cell.

What can damage your battery, is putting it on charge when its frozen solid. So charge it warm enough, in a place above 0 c. Ideally don't let it freeze all day outside, and then hop on and ride. It may not work at all like that, ( LVC will pop) till it warms enough to hold its voltage. So if the battery does freeze, thaw it before you ride or charge.

If you choose to heat the battery, like if your parking and charging place is just too cold, look at reptile heaters. Little hot pads that heat, but gently so your snake does not cook itself basking on it. Perfect to warm a battery in extreme cold.
 
Joined the ebike world yesterday have lots to learn with the new purchase of the MXUS 350w 48v hub on 26" front wheel with a controller and 12AH 48v li=ion battery pack.

When the battery pack is discharging its making heat , for winter riding my plan is to carry the battery inside a daypack wrapped in something warm.
As a plus the battery will travel easily indoors for easy charging and storage in a temperate climate.
In the summer will likely attach the battery to the frame so a daypack will not always be required.

So imo at -15 stuff the battery in a daypack and wrap it tight !
 
Shouldn't be much of a problem in Vancouver. Isnt a -5 C day kind of rare there?

You will notice a lack of perk below 10C or so, but nothing extreme. the pack itself should be plenty to keep in the warm above freezing.
 
dogman dan said:
Shouldn't be much of a problem in Vancouver. Isnt a -5 C day kind of rare there?

Says he lives on Vancouver Island. The northern tip of the Island is almost 300 miles north of the city of Vancouver (which isn't on said island), and it's mostly mountains. It can get pretty gnarly up there in winter.

As for Vancouver, we had a 2 week+ stint of -10C and below last year. Not a common thing to happen but not unheard of. Incidentally during this time my ebike was the only vehicle I owned that could make it all the way up my driveway to the house, so I was using it as a shuttle or sorts from my work van to the house. (Studded ice tires, and a great deal of confidence in myself)

So I'd ride down the hill, lock the bike to the gate post, put the battery in the van and take it with me while I worked. When I got back, unlock the bike, put the battery back on and ride it back up the hill

As long as the battery doesn't sit out in sub zero temps for more than an hour or so it doesn't seem to have much effect on performance. If I'm going to be at my destination for more than an hour, I bring the battery indoors with me.
 
When Vancouver hits -5C there is an "Extreme Cold Advisory" warning and the [strike]province[/strike] city sets up additional measures.

Today in Alberta, it was a mild -11C with a wind chill of about -18C, which I rode in with an average toque, meaty gloves, a medium thickness hoody and a walmart $40 winter jacket, wearing regular jeans and regular shoes. Now the jeans were frozen solid but I rode around in e-grin joy!
 
One would think we Vancouver islander dont see much cold weather but it really just starts later and leaves sooner. The cold winter weather normally starts at the end of December and ends in March , well from mid island and below.

This last week has been extra cold with -5 -4 and -2 nights.

Right now its -3 see the attachment

Screenshot-2017-11-6 Port Alberni, BC - 7 Day Forecast - Environment Canada.png
 
The other problem we have in Vancouver is that the air is usually so damp that any subzero weather leaves our roads covered in black ice, with plenty of hills to slide down. I can stand outside in -10 Calgary weather wearing a T-Shirt, until frostbite sets in at least. Dry air doesn't absorb as much heat, standing outside here in -10 will turn you blue pretty fast.

Alberni gets some pretty special weather of it's own, being at the end of a long inlet the other end of which is open to the Pacific. Extra wet air. I've never been there in winter but I can imagine it's not too pleasant at times.
 
Its dampish here but not by anymore or much more then Victoria as they are right on the ocean , on it. We are 20 miles away from it in the middle / center of the island. It does alright Ive been here for 12 yrs or so and used to walk my Dog twice a day and 9 x out of 10 I would could do it without getting wet.. Most our rainy days are really just days with on/off showers.

The weather forecast here always makes it sound like it will be a bad day but they are wrong 90% of time it seems.

As Alberni is tucked away at the end of inlet in a Valley we get the hottest weather on the island often all of B.C by few degrees in July and August. The inlet has two winds , in the morning it blows out to sea in the evening it reverses and blows in from the Ocean. Its a constant and makes for good sailing weather.

Problem with Alberni is the wood industry is dead and most people have left for greener pastures / Jobs.
 
To wade in here, certainly the black ice in Vancouver and surrounding regions is a dealbreaker. Every Winter for weeks or months on end, I'm greeted in the morning to perfectly formed invisible black ice that is far more slippery than the best polished skating rinks. I don't know many serious riders who haven't wiped out on an unexpected patch of black ice (me included), and I know a few who have been seriously hurt. Studded tires don't really help against the thin veneer of ice since the asphalt wears them down quickly. Ironically, I was able to ride year round in Ontario with snow most of the winter. Here, it doesn't snow most winters, but due to proximity with ocean, we can get these epic dumpings of heavy wet snow. In addition to black ice, the roads are not cleared of snow/salted effectively, and the heavy wet snow is immediately compacted into sheer ice that can linger for weeks until temps rise enough to melt it.

Now back to topic, temps lower than -10C are somewhat rare in Vancouver and surrounding regions, but they happen occasionally. If it is a dry cold and the roads are rideable, my favourite is to place the battery in a pannier well wrapped in a towel and let internal heat do the rest. Less than -10C, and I don't worry so much. I was thinking of sewing an insulated cloth cover to slip over top but I never got around to it.
 
Its reported Lithium batteries don't perform well in +10*c temperatures.

About all winter for many of us

G2-EN.jpg
 
The cost of the rosenberger magnetic disconnects was too high once I factored in shipping and a 30% exchange rate so its on the back burner for a few months. So I can use the battery in the pack sooner just picked up a set of Anderson connectors and a pair of pig tailed 10AWG XT90 connectors to test and will choose one

$5 for the Anderson set

s-l1600.jpg


$10 for the pigtail 10 awg XT90 set
s-l1600.jpg
 
Those SB50 andersons work really well (I use them on all my battery and other high-current connections)--but you need a really good crimper for the contacts, and you need to get teh right contacts for the gauge of wire you are going to use in them.

I don't recommend soldering because you have to then support the wires so vibration/etc won't eventually crack the wire at the end of the soldered area. For a very thick wire it won't matter as much (10g, 8g, bigger) but thinner ones break quicker. But with Andersons, the wire and contact *must* float in teh connector shell, to allow the springs to keep the contacts aligned for low-resistance. If you support/brace the wries, self-alignment no longer works, and connections are not optimal, and heating at the contacts can occur and eventually fail.

FWIW, those caps wont' actually do anything to keep stuff out of the connector, unless they are panel-mounted and sealed into the panel, because they're still open at the back.

If you need to waterproof connectors, filling them with dielectric grease (like that in the little packets for car battery terminals) will prevent water from getting in, and onto the contacts themselves. Just make sure you also get it on the contact/wire interface, so it doesn't get wicked into the wire and crimp.


BTW, given their source, those SB50s are unlikely to be genuine andersons, so the quality of the contacts and especially of teh housings and springs may be questionable. In most cases this won't cause any problems, but if the springs are not strong enough, they won't hold the contacts together tightly, and resistance will be higher. If it's high enough, then it causes heating at the contacts, and then the housing (which could be made of less-heat-tolerant plastic than genuine ones) may deform, and cause further connection issues, increasing heating, etc.

Since I've seen this happen with PP45 types, though so far not with any of the SB50 types, genuine or clones, I figure a heads up is a good idea.
 
Thanks for the tips , Im thinking will keep the controller in a mini tank bag that fits near the head tube / front hub motor.
As I do not have a crimper just solder join the main power wires and hall sensor wires to the motor and using wore stripper crimps crimp bullet connectors on the switches and throttle for removal.

I bought the Anderson connects with contacts for 10 to 12g wire. Will be using 10g for the increased Amp flow.

A floating connector sounds good for vibrations , I will likely choose the set that pull a part the easiest / least resistance from all angles. The connector leads will get a dummy lead to go taunt to pull the connectors apart in the event of a bail.
(so far) plan is to JB weld a section of shifter cable to the under seat connector and attached the wire to the day pack itself.

otherwise the solder or crimped joints would take the strain

I'll look and if I can find a strong crimper for $20 will buy it otherwise I'll be soldering but a crimper would be nice to have
 
Just noticed DrkAngel posted a link in the one liner !

I like the heat pads and temp controller , these expensive packs are worth keeping warm.

This chart has better resolution

lithium-battery-temperature-vs-capacity.jpg


Looks like the sweet spot for storage is 25*c / 77*f

You don't want to wrap them up too tight or capacity drops as well

main-qimg-23f0c17f4fafb119da528d4a8bbed24c
 
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