Storing battery outside in winter - what insulation?

CycleEye

Finding my (electric) wheels
Aug 31, 2021
19
1
I'm looking into installing an Asgard ebike metal shed outside my home for my ebike, and running power to it (it comes with built in plates for this).

I'm aware the advice is generally to store the battery inside, but I'm looking into if there's a good way to store it outside. I'd much prefer this from a fire safety point of view.

I already have a Bat Safe fireproof box. Even with this, I'd prefer to keep it outside. I'm in the UK, so it gets cold, occasionally sub zero but rarely.

Do you think with some additional insulation for the battery inside the the Bat Safe box (maybe a neoprene cover or something), it would be ok throughout the year? Cheers.
 

cyclebuddy

Esteemed Pedelecer
Nov 2, 2016
1,640
770
Beds & Norfolk
If you're going to have electricity there, why not add a frost-guard heater? They come from 60w to usually 250w, some with thermostat so you can set them only to heat below say 5c. I've got a 150w thermostatic one in my lock-up to protect chemicals and paints from freezing.

Lithium storage batteries for camper-vans often have built-in heating elements to protect from sub-zero temperatures.

I'd be concerned more about condensation/moisture/rust - especially if you'll be putting a rained-on wet bike in a sealed metal box.
 
  • Like
Reactions: flecc

guerney

Esteemed Pedelecer
Sep 7, 2021
11,390
3,234
Do you think with some additional insulation for the battery inside the the Bat Safe box (maybe a neoprene cover or something), it would be ok throughout the year? Cheers.
How about keeping Silica Gel Dessicant Beads with the battery inside the neoprene bag? They change colour when saturated with water.

 
  • Like
Reactions: CycleEye

Wayners

Esteemed Pedelecer
Jun 5, 2023
412
89
55
Gloucester
I don't always change battery inside house and I use a timed plug to cut power after a set time just incase I forgot. Fine to store battery in the house. I must have 20+ lithium Ion batteries in our house. Phones. Ear buds. Toys. Cameras. Shavers and many more.

Li-Ion cells will become compromised if stored below 0 degrees

I'd dry bike off in house before storing outside but leave battery inside. My neighbour killed his electric mower battery storing in shed over the winter.
 

Benjahmin

Esteemed Pedelecer
Nov 10, 2014
2,590
1,746
70
West Wales
I agree, your main problem will be condensation. Unless the shed is insulated there will be dripping condensation whether it's heated or not.
I speak from experience of having a steel framed shed clad in box profile sheeting. The underside of the roof was consatantly wet in winter despite the whole shed being well ventilated - well extremly draughty actually.
Battery stored outside should not be a problem, if, however, the temperature drops below around 5 I'd charge inside.
 

CycleEye

Finding my (electric) wheels
Aug 31, 2021
19
1
If you're going to have electricity there, why not add a frost-guard heater? They come from 60w to usually 250w, some with thermostat so you can set them only to heat below say 5c. I've got a 150w thermostatic one in my lock-up to protect chemicals and paints from freezing.

Lithium storage batteries for camper-vans often have built-in heating elements to protect from sub-zero temperatures.

I'd be concerned more about condensation/moisture/rust - especially if you'll be putting a rained-on wet bike in a sealed metal box.
True. I was thinking I'd towel it down if it's wet first. The Asgards do have some ventilation to minimise condensation.

A frostguard heater is a good suggestion, thanks.
 

CycleEye

Finding my (electric) wheels
Aug 31, 2021
19
1
I agree, your main problem will be condensation. Unless the shed is insulated there will be dripping condensation whether it's heated or not.
I speak from experience of having a steel framed shed clad in box profile sheeting. The underside of the roof was consatantly wet in winter despite the whole shed being well ventilated - well extremly draughty actually.
Battery stored outside should not be a problem, if, however, the temperature drops below around 5 I'd charge inside.
Yes, I definitely need to think about condensation. I think I may add some insulation to the inside of the Asgard and have some kind of heater/insulation in the Bat Safe box as well.
 

guerney

Esteemed Pedelecer
Sep 7, 2021
11,390
3,234
Rest the box on an electric blanket, then place the probe of a temperature controlled switch inside the box, and set it to switch the blanket off when the temperature is something like 10℃? While charging the battery, a second temperature controlled switch could sound an alarm at 60℃. When not being used to store your battery, you could ferment cheeses or Natto (43℃) in the BAT box?


 
Last edited:
  • Like
Reactions: CycleEye

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,917
8,533
61
West Sx RH
For condensation one will need ventilation at opposite quarters one vent low down and another higher up but opposite it.
 
  • Like
Reactions: CycleEye

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,917
8,533
61
West Sx RH
I believe so, though they will charge to full voltage that voltage doesn't mean that full capacity has been accepted so one could expect to have less range.
 
  • Like
Reactions: CycleEye

Az.

Esteemed Pedelecer
Apr 27, 2022
2,045
903
Plymouth
These are not safe storage ways. Both items might protect your house from fire if lucky enough, but you won't be protected from toxic smoke.

Edit:

On second picture you see two people asleep while battery is on charge next to their bed. In worst case scenario if anything happens it is instant death.

On a video you can see a guy wearing a hat in his house talking about bag. There is a baby making noises, half of a dog in the background and a monitor with cables on a landing. I don't know this product to be honest, but marketing is completely lame and does not inspire confidence. Good luck to anybody who would like to bet their life on it.
 
Last edited:
  • Like
Reactions: AntonyC

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,917
8,533
61
West Sx RH
There s a lot of scare mongering that goes on regarding batteries and tbh quite a lot of dribble posted with in this forum.

Keep it simple and keeping batteries indoors is safe.

Charge only when a wake and where you can monitor /keep an eye on the charging process.
DO NOT leave to charge over night when in bed.
DO NOT charge a bttery that has a fault.
Use a timer or cease charging a short time after the charger led turns green.
Don't use an unspecified voltage rated charger and don't be tempted to fast charge the battery, for safety use the standard 2a charge rate that most chargers use.
DO NOT attempt to reverse charge bypassing the BMS .
If the battery develops a fault leave it to an expert or compitent knowledgable person to repair.
Keep the battery in a cool place and not in direct contact or neat a very hot heat source.
 

soundwave

Esteemed Pedelecer
May 23, 2015
16,895
6,507
DSC_0165_04.JPG

and dont do that at 3am pissed up, i broke the councils feed in tariff tho as needs to be reset and password locked so not my fkn problem my smart meter works now :D

and i have had my 2 batts in my room for ten years and im still not dead blown up or catch fire, yet:eek:
 

WheezyRider

Esteemed Pedelecer
Apr 20, 2020
1,690
938
Operating a Li-ion pack below 0 C is ok, but expect a significant drop in capacity. However, charging should be done above 0 C or you may have issues. So use enough heating to keep the outside shed above freezing, but it doesn't have to be much above freezing.
 

AntonyC

Esteemed Pedelecer
Apr 5, 2022
332
144
Surrey
Don't charge near an escape route, and near freezing I've read you should reduce the controller current if possible.

As said a fire needs a cause and the BMS should protect against any misuse. So in theory the culprits ought to be either storing a full battery unused for an exceptionally long time, or the BMS being affected by water getting in. But chargers have been around a lot longer than BMSs: I check the charger voltage just once but keep an eye on charging and I wouldn't keep batteries in a damp shed or leave them parked in fierce sun, I'd sooner take them indoors.
 
  • Like
Reactions: CycleEye