Battery care question

[Brian park]

Hi Folks

I have just bought a new Bosch powered bike with battery in downtime. Having lost both keys though (doh!) I'm no longer able to remove the battery and the bike is kept in sub zero celsius conditions in the bike shed. It's dry but it's cold. I cycle it into work where it's then stored and charged indoors at room temp 18c. I then ride it home to charge it outside and put it away in the shed where its kept overnight in the cold.

Question is - Is this damaging the battery?

 

[Nealh]

Cold generally doesn't damage batteries but charging in freezing cold means capacity isn't fully being accomplished dispite reaching max voltage.

If the bike is new and you have the paperwork one would have thought key numbers should be available to get replacements, after all it is drummed down forum users throats at times that they are supposedly a superior bike brand.
Superior though usually means I have spent more then you on your bike so it must be better.

 

[cyclebuddy]

Question is - Is this damaging the battery?

From what I've read, charging in sub-zero temperatures isn't good. As Neal says, get some new keys and keep/store/charge your battery in the warm, especially given that the cost of a replacement Bosch battery would be absurdly expensive.

 

[jimriley]

Lithium batteries can be used and drained when below 0c, but mustn't be charged, it knackers them, immsmr it causes a crystal growth on one of the poles. I bring my battery in to charge when it's cold. I've just bought a lipofe battery for my caravan, I'm researching a small heat pad and thermostat to stop it dropping below 5c or so, so I can charge it when towing in winter.

 

[WheezyRider]

According to this paper, you should be ok discharging down to -20 C, but charging should always be done above 0 C. The colder it gets, the less capacity you will have available, so you will need to charge more frequently.

Radware Bot Manager Captcha

 

[Brian park]

According to this paper, you should be ok discharging down to -20 C, but charging should always be done above 0 C. The colder it gets, the less capacity you will have available, so you will need to charge more frequently.

Radware Bot Manager Captcha

Thanks folks -This is really useful - concensus seems to suggest Bosch/lithium ion batteries can handle sub zero storage with no ill effects. As long as they are not charged whilst below freezing. I do charge the bike after riding in below freezing conditions but I guess that's fine to do as the batteries will be warmed up after 40 minutes of use?

 

[WheezyRider]

Thanks folks -This is really useful - concensus seems to suggest Bosch/lithium ion batteries can handle sub zero storage with no ill effects. As long as they are not charged whilst below freezing. I do charge the bike after riding in below freezing conditions but I guess that's fine to do as the batteries will be warmed up after 40 minutes of use?

I would not be so sure a battery on a bike in cold weather will warm up in use. The wind chill factor is significant and can quickly take heat away. You could even end up with a pack where the end cells are below freezing and those near the centre are warm.Unless you can measure the temperature inside the pack, and at several point in the pack, I would always let the pack warm up before charging if used in subzero temps.

 

[Brian park]

Ah - so that advice goes against the information in the article you linked to which suggests sub zero charging is fine albeit at a slower rate than the optimal temp range of 20c. No I'm confused again!

 

[flecc]

Lithium batteries can be used and drained when below 0c, but mustn't be charged, it knackers them, immsmr it causes a crystal growth on one of the poles. I bring my battery in to charge when it's cold. I've just bought a lipofe battery for my caravan, I'm researching a small heat pad and thermostat to stop it dropping below 5c or so, so I can charge it when towing in winter.

According to this paper, you should be ok discharging down to -20 C, but charging should always be done above 0 C. The colder it gets, the less capacity you will have available, so you will need to charge more frequently.

Radware Bot Manager Captcha

This is the conventional wisdom, but it is is questionable.

From the beginning 12 years ago Norway, which encompasses the arctic circle, has led the entry into lithium battery e-cars. Since all ic car sales are to be banned there from 2025, for several years now over 50% of all new registrations have been e-cars of several makes with Tesla and Nissan leading the numbers.

They have to charge in the cold, often well below zero degrees and some of these e-cars, like my Nissan, don't have battery heaters. In any case even where battery heaters are fitted they usually don't cut in until far below zero degrees.

Norway isn't experiencing any problem with lithium battery life in e-cars or e-bikes. We have members there and two of them beyond the arctic circle in the far north, even above Murmansk in Russia. Member Boreios there has sent some of his photos of him wrapped up like a Michelin man in deep snow with his Wisper 905.

See this link

The only concession I make in charging in the cold as I did earlier this week, most of it below zero degrees overnight, is to use my slow charger which charges at 2 kW/h rate average instead of the normal 6.5 kW/h.

My car is almost five years old now and has no easily measurable loss of capacity, albeit capacity temporarily dropping by nearly a third at zero degrees.
.

 

[flecc]

Ah - so that advice goes against the information in the article you linked to which suggests sub zero charging is fine albeit at a slower rate than the optimal temp range of 20c. No I'm confused again!

Yes, see my post paragraph five just above.
.

 

[Bikes4two]

@Brian park - I have a friend who bought a used Bosch motor driven bike but no battery keys. Finding a blank key was easy but not the key code used for cutting it.

Later in his ownership he took it in for a Bosch dealer for service and there on the service printout was the key code - maybe you have some old paperwork hanging around?

 

[WheezyRider]

Ah - so that advice goes against the information in the article you linked to which suggests sub zero charging is fine albeit at a slower rate than the optimal temp range of 20c. No I'm confused again!

The problem is conventional chargers for e-bikes will not take into account the battery's temperature when charging and will only charge at their maximum set current until CV conditions take over towards the end of the charging cycle. Therefore, I think it's best not to take the risk.

Also, this is what the paper says for NCA and NMC cells:

 

[Brian park]

The problem is conventional chargers for e-bikes will not take into account the battery's temperature when charging and will only charge at their maximum set current until CV conditions take over towards the end of the charging cycle. Therefore, I think it's best not to take the risk.

Also, this is what the paper says for NCA and NMC cells:

View attachment 49747

 

[Brian park]

So does the Bosch bike battery comprise either an NMC or a NCA group of cells?

 

[Nealh]

So does the Bosch bike battery comprise either an NMC or a NCA group of cells?

Yes they basically encompass all can cell types in use today, Cobalt or manganese being a main part of the cathode or annode. It matters not whether ICR, IMR, NMC or NCA they all in general amount t to the same. Using differing acronyms is just splitting the hairs.

 

[Nealh]

Just keep things simple charge indoors some where above freezing.

 

[WheezyRider]

Just keep things simple charge indoors some where above freezing.

But not overnight, unattended when you are sleeping

 

[Bikes4two]

But not overnight, unattended when you are sleeping

I always charge via a countdown timer just in case I forget to unplug the charger. Product below is from Amazon.

 

[guerney]

I use a mechanical timer to charge my ebike battery, but doing so has instilled a false sense of securty... leading to my forgetting that it's charging, which means it has on at least two occasions started another charge cycle 24 hours later. I'm now thinking of swapping that timer with a digital one, which can have days of the week specified, as well as hours.

 

[Bikes4two]

@guerney - the timer I showed in the pic above is a 'one shot' countdown timer - you press a button to increment the ON time from 15min to 9hr and once it has' counted down' the switch goes OFF and stays that way (although it does have an optional repeat function via another buton which of course I don't use to avoid the situation you describe).

I use all sorts of Smart switches for the home but this countdown timer was simple and fitted my purpose entirely.