DIY heated battery cover for charging and storage in cold conditions.

gunshot72

Well-known member
Jan 13, 2019
51
50
Rushden, UK
If you have a detachable battery that you can take indoors during the winter to keep warm and charge, then lucky you. For the rest of us with internal batteries that are not allowed to keep our bikes in the house I’ve just done this hack. We all know lithium ion batteries do not perform well when either charged or used in very cold conditions.

It’s a 44x30cm heated pad from Amazon that fits my Focus Jam2 downtube perfectly. The heat that the pad puts out is not so high that it could damage paint etc, but is enough to keep the worst of the chill away from the battery while I charge it. Furthermore it’s made from a very soft fleece and is machine washable.

I have mine set on level 2 of 3 heat settings and on a timer so that it switches on for 15 minutes and then off for 15 minutes continuously.

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nicklej

Active member
Patreon
Oct 11, 2018
156
122
Camberley
That's pretty neat...and so is your bike. That thing is shop floor immaculate! Will try this out myself next year when I have to leave my bike outside. Cheers
 

gunshot72

Well-known member
Jan 13, 2019
51
50
Rushden, UK
How cold is cold?
I charged and rode mine at zero degrees and saw zero impact on performance.

When it drops below 2c in my opinion. Although the Focus manual recommends storage of the battery and therefore the bike at 18c plus. I’m lucky enough to have a garage I guess because bikes in the house is a big NO for the missus!
 

MattyB

E*POWAH Elite World Champion
Jul 11, 2018
1,274
1,301
Herts, UK
I went in the bike shed this morning to go for a ride and found both water bottles full of ice. I made a mental note that ebikes with internal batteries like the Focus are not an option...
 
Last edited:

highpeakrider

E*POWAH Master
Aug 10, 2018
692
566
Peak District
Your not going to store a bike at 18plus in the UK

The Shimano website should be the point of reference.

Operating temperature range: During discharge
-10 – 50 ̊C
Battery type
Lithium ion battery
Operating temperature range: During charging
0 – 40 ̊C
Nominal capacity
Refer to the user's manual for the battery "UM- 70F0A". For the latest information on manuals, see the website (http:// si.shimano.com).
Storage temperature
-20 – 70 ̊C
Rated voltage
36 V DC
Storage temperature (Battery)
-20 – 60 ̊C
Drive unit type
Midship
Charging voltage
100 – 240 V AC
Motor type
Brush-less DC
Charging time
Refer to the user's manual for the battery "UM-70F0A". For the latest information on manuals, see the website (Manuals & Technical Documents).
Rated drive unit power
250 W
 

OldBean

E*POWAH Elite
Patreon
Apr 28, 2018
602
528
East anglia
Like that electric blanket ...I can use it on my feet after a winter ride.....and might delay a divorce due to “bike in house” causes:rolleyes:
 

WheelsandBoards

New Member
Dec 13, 2018
36
31
Cirencester
I know it's tempting to keep a bike clean but if you ride a lot in the winter, a lot of washing will stuff all the bearings. Mud will not ruin the paint......
 

R120

Moderator
Subscriber
Apr 13, 2018
7,819
9,190
Surrey
What have you sleeved the seat tube collar with - I do something similar, is it an old inner tube?
 

gunshot72

Well-known member
Jan 13, 2019
51
50
Rushden, UK
What have you sleeved the seat tube collar with - I do something similar, is it an old inner tube?

Yes. An inner tube from a 700x42 tyre. Rather than disengage the dropper take the saddle off put some talc on the inside of the inner tube piece and slide it down. Takes a bit if pulling but you need it tight of course.
 

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