How Do You Plan To Survive (Battery) the Winter?

[wfopete]

Those of you in SoKal or those with heated garages need not apply.

For the rest of us who keep our bikes in unheated storage what are you doing to keep the battery protected from extreme cold weather?

 

[Erwin P]

Riding...

 

[Redwolf]

Riding...

Exactly, doing this daily has kept my Alta happy and healthy for 6 years now.

 

[joer]

I rent heated storage at a place near me. It wasn’t really much more expensive than non-heated. I charged my battery to about 40%. Did a full shut down (not stand by) and then disconnected the power switch (connector behind the number plate).

My concern is someone might accidentally hit the power button moving it around and not know to power it all the way down. This way they cannot.

I guess we’ll find out how well it faired in April.

 

[ksksks]

Everything above -10°C is no problem at all for storage. But it is important to fully switch it off and not use it as long as the battery temp low.
Storing in the cold is better than storing in the warm. The chemical reactions and therefore aging of the battery are slowed down. But don't use the bike when the battery is cold.
50% SOC is ideal for storage. Don't let it sit below 20% or above 80%. High and low SOCs will speed up the aging of the battery. If the SOC drops below 0%, the battery could even be damaged. Very important: Don't charge when the battery temp is low (I would not charge it when below 5°C).

So when storing over winter, charge it to about 60%, fully shut it down and put it in a place not too cold.

 

[Chadx]

Everything above -10°C is no problem at all for storage. But it is important to fully switch it off and not use it as long as the battery temp low.
Storing in the cold is better than storing in the warm. The chemical reactions and therefore aging of the battery are slowed down. But don't use the bike when the battery is cold.
50% SOC is ideal for storage. Don't let it sit below 20% or above 80%. High and low SOCs will speed up the aging of the battery. If the SOC drops below 0%, the battery could even be damaged. Very important: Don't charge when the battery temp is low (I would not charge it when below 5°C).

So when storing over winter, charge it to about 60%, fully shut it down and put it in a place not too cold.

I've always shot for 50% - 60% SOC with all of my lithium batteries that I store off season (everything from Surron batteries, eMTB, camper batteries, fishing boat trolling motor batteries, etc.). I have an uninsulated and unheated shop, though, so it gets cold. Heck, winter has barely started and it was 15F / -9C this morning. -10F / -23C is just a normal winter day and we usually get a week here and there where F and C "go to meet". Ha. (-40F/-40C is where F and C meet). I keep my little pop-up pickup camper at about 32F/0C inside and so set most of my lithium batteries in there that I'm storing for the winter. I don't charge the ones I store over the winter, but most of my larger lithium have internal heating if I needed to do so. Plus, they all have cold disconnect sensors in BMS if they were too cold, the BMS wouldn't allow charging anyway. I have some that are in the cold shop because I use them all winter, but again, they have internal heaters so the BMS directs current to internal heating elements until the cell temps are plenty warm and only then redirects the current to charge the cells.

The Varg really complicates this situation. It can't fit in my little camper, of course, and too much of a pain to remove the battery. I did buy a electric battery surround that hangs on it. Draws about 34watts so a couple bucks a month. Doesn't fit snug because of frame and skid plate, but will hopefully make a little micro climate around the battery to at least take the edge off. Most people that live in cold climates don't have an option but to leave things in the cold so we do what we can. I'd lean it against the wall in the living room if it was up to me, but so far the "there is no gas/oil/exhaust smell" argument has not swayed my wife. Ha.

I assume the Varg has a BMS that doesn't allow charging in the cold. Anyone plug in the charger below freezing and see if it pops a message?

I worry a bit about the cold, but I worry more about the heat with all my batteries. Summer time in the uninsulated shop is usually hotter than outside temps (80 - 90F and a dozen days hit 100F in there). Luckily, things cool off quickly at night here and so the shop is usually only at those temps for a few hours in the height of the afternoon heat. Overnight, it cools down into the 60s.

In the end, I'll do what I can if it's convenient, but they are pretty much either going to last or not. Not a lot more I can do, especially with the Varg since I'm not removing the battery for the winter much less during the riding season.

 

[Drjohnsen42]

I have one left.
For Sale - CHR Battery Warmer

 

[Theo]

I know that this thread is about the battery and not the inverter and motor but I still think it's relevant: don't forget to make sure that the coolant used in the bike won't freeze at the temperature at which the bike will be stored.

 

[Chadx]

I know that this thread is about the battery and not the inverter and motor but I still think it's relevant: don't forget to make sure that the coolant used in the bike won't freeze at the temperature at which the bike will be stored.

Good point. But I assume (and maybe that is a risky decision), that they are good for usual 50/50 antifreeze temps of -35F to -40F. That covers me for most, but not all, of our winter. Guess I better confirm with Stark and my dealership (or just sample it and test it myself, but I don't have a tester anymore).

 

[Theo]

Good point. But I assume (and maybe that is a risky decision), that they are good for usual 50/50 antifreeze temps of -35F to -40F. That covers me for most, but not all, of our winter. Guess I better confirm with Stark and my dealership (or just sample it and test it myself, but I don't have a tester anymore).

Well, I don't think there will be any problems if you drain the coolant and leave the cooling system empty. Just put some label on the saddle or maybe a tag on the throttle so that you'll remember to fill the bike next spring. If there is no coolant when you turn on the bike I think that you should also get a water pump error or something similar.
Asking Stark for an opinion surely wouldn't hurt either.

 

[Chadx]

Well, I don't think there will be any problems if you drain the coolant and leave the cooling system empty. Just put some label on the saddle or maybe a tag on the throttle so that you'll remember to fill the bike next spring. If there is no coolant when you turn on the bike I think that you should also get a water pump error or something similar.
Asking Stark for an opinion surely wouldn't hurt either.

Draining antifreeze is an option, but way easier to just ensure the mix is right. Draining it each winter is not something I'm willing to do. Ha. Don't do it in our vehicles, dirtbikes, ATVs, etc. and run our snowmobiles and snowbikes (dirtbikes with ski/track) all winter with no issues. Plus, I'd be concerned about corrosion/oxidation, any seals drying out, etc. if the system sat empty with air in it, but maybe that's not an issue.

Keeping the system full of 50/50 antifreeze is the easiest. Just need to confirm that is what is in it. Even if Stark confirms what is "supposed" to be in it, I'll buy a specific gravity antifreeze tester and test it myself. Then no worries. Just need to look up if Varg come with propylene glycol-based antifreeze or ethylene glycol-based antifreeze since they have different testers. I saw the type in one of the manuals or videos but don't recall. Likely ethylene but will confirm before getting a tester.

 

[Theo]

TLDR: I think that we shouldn't be worried about condensation with low temperatures, but I'd like to share my thoughts to support my statement.

A thought occurred to me today: when temperature drops, air can hold less moisture and therefore, if a space has been sealed at a certain temperature and moisture values and the temperature is now lower than the dewpoint for those tempearature and moisture values, condensation will occur.
Here is an online tool that can show you what I mean:
NOAA moisture calculator
my idea is the following: let's say for example that you disconnected and then reconnected some sealed connector when the temperature was higher than now, you try and estimate what the relative humidity was back then staying on the safe side and therefore assuming that it was a wet day, and the tool will tell you the dewpoint, which could be lower than the current winter temperature. For example, if you connected some sealed connector @30°C with 80% humidity, the dewpoint would be 26°C, but even if it was only 20% humidity, a dry day, the tool would tell you that the dewpoint would be 4.5°C, so you should expect condensation if the bike is now stored in a very cold room.
The power connector of the battery looks like an HVIL type, which should have the positive and negative tines separated well enough to prevent short circuits even if condensation forms. I guess that there could still be corrosion, though.
I don't know how much that holds true for the CAN BUS connector.
The last thing to discuss is how much moisture can be there, because if it does form but its amount is negligible, it can be acceptable. Still using that tool, you can see how in that hot wet day @30°C and 80% humidity, the absolute moisture content was 24 g/m³, which means that, if we estimate the volume of a connector to be 1 cm³, which wouldn't be little at all I think, typically it whould be way less, then the total amount of water would be 0.000024 g, which is less than 1/1000th of a raindrop. That's why I think that we shouldn't worry about condensation in sealed connectors.
As far as I've learnt, batteries manufacturers seal batteries in dry rooms, which have so little moisture in the air that even when the temperature drops a lot, that humidity still doesn't reach 100%. The Varg battery, according to their site, is sealed and has a special valve to allow pressure exchange; I guess that it also somehow prevents moisture to enter the battery.
I guess that the inverter and the VCU have been sealed in dry rooms, too.

 

[stephane]

I have an interesting situation/opportunity related to cold temperature and stark varg. I live in Minnesota where it gets really cold (-15cel to -30 at times). I am hoping to take my bike to an indoor track an hour away from my house. I usually transport my bike on a bike hauler (exposed to the element). I wonder what it will do to the bike/battery to be on the road/cold for an hour and then be brought inside and ridden on a small track.
Anybody here with that kind of experience?

 

[joer]

I have an interesting situation/opportunity related to cold temperature and stark varg. I live in Minnesota where it gets really cold (-15cel to -30 at times). I am hoping to take my bike to an indoor track an hour away from my house. I usually transport my bike on a bike hauler (exposed to the element). I wonder what it will do to the bike/battery to be on the road/cold for an hour and then be brought inside and ridden on a small track.
Anybody here with that kind of experience?

I'll be interested to hear how this goes for you.

Generally, Lithium ion batteries can safely discharge at a much lower temp than they can charge at. So assuming you get there with a full battery, I think it'll be fine. I'd guess that by the time you want to charge it back up after doing some riding, it should be fine.

Again, very generally, you don't want to charge Lithium batteries when they're below 0C. I believe that's more true for Lithium Iron Phosphate batteries. In our bikes, we've got Nickel Manganese Cobalt. I think they're more tolerant of cold temps than LiFePo4. And even then, if you slow charge when cold, it's not as bad. Something I've learned with my EV. It will slow charge (level 2) no matter how cold it is. But hooked up to a fast charger, it will throttle the charge rate until the battery can get warmed up.

Here's a link to the data sheet for the actual cells (Molicel P45b) in the bike. Looks like you can discharge down to -40C (F and C scales overlap at -42. )

Have fun riding inside! What a treat. I'm just stuck watching YouTube videos till the local track opens.

 

[Chadx]

(F and C scales overlap at -42. )

They overlap at -40; not -42. But what's a couple degrees amongst friends! Ha.

As for discharging, if it's below freezing temp, it would be good to take it easy on the bike before he rips a hot lop at WOT. Between a bit of time indoors while getting suited up and an easy-going practice/warm up lap or two, that will let the cells warm up. Added points if one could use some type of electric warming pad around the battery, plugged into the truck, as you drive and then once he arrives while in the pits getting ready.

Like others have said, the battery will warm up with use so once you are in need of recharging after riding for a while, you'll be good to charge.

I haven't ridden below freezing, but my last few rides of the year were bike in the back of pickup and just over an hour drive to OHV riding area at right about freezing. It warmed up to almost 40F by the time I unloaded and changed into riding gear. I took it easy for the first mile or two of the trails before going WOT. The displayed battery percentage dropped fast for the first 5 or 10 minutes of riding and then slowed to normal discharge rate from what I could tell. It was about the same 40F temp all day and overall range that day was only slightly below what I'd expect in warmer weather.

@stephane Curious what the temps are in the indoor track area during the cold months? I assume its ventilated if ICE bikes are there and so about the same temp as outside? Arena simply keeps snow off the track vs. it being an climate controlled environment? Just curious. And do you have access to 120v AC, 240v AC or generator or battery power station that you'll be charging during the day?

 

[Theo]

In the manual they have written not to charge the battery below 4°C, i.e. 40°F.
They've also written that the recommended temperature range for use and storage starts at 0°C, i. e. 32°F and that the maximum recommended humidity level is 60%, which is harder to achieve at colder temperatures.