Battery life in hot climates

[Desert Rider]

I live in the desert in southern Nevada. Summer temperatures usually range between 85 to 115 F. From mid May to mid September I frequently ride in 90+F temperature. My question is will the hot climate cause a rapid degradation of lithium batteries and/or shorten their service life?

 

[hmagoo]

I'm in the same situation here in the Coachella Valley. I've done some inquiries and a little reading. I read about how electric vehicle manufacturers ignored the existence of desert markets and ran into a lot of problems with battery longevity due to desert heat. I commute 8 miles round trip so my goal will be to keep the battery inside before riding to reduce the time outside. I will most likely not ride when it gets near 120 degrees in order to avoid excessive wear on the bike.

 

[mrgold35]

I live in Abq, NM, and temps can get into the low 20s in winter (even colder once you factor in wind chill at +20 mph ebike speeds) and between 95-105 degrees in mid-late summer. I put a Luna Cycle triangle bag to:
- protect during rain, water puddles, mud, and trail dust
- keep dark battery pack out direct sunlight (usually +10 degrees cooler in the shade in southwest)
- ability to add extra material or microwave gel packs to bag on really cold work commutes
- ability to add the same gel as cold packs in bag during really hot work commutes

I still have about a month before we see temps above 95 degrees on average. I won't do the chill packs unless we hit near/above triple digits.

 

[Desert Rider]

I bought the Trek X700+. I'm following hmagoo's advice and take the battery and trip computer inside when not riding. I've had the bike for 2 weeks. It has the Bosch motor and battery system. I also like the advice of mrgold. I'll keep the battery out of direct sunlight. The manual advices that the top operating temperature is 105 F*. I'm cool with that. I can ride my regular bike in those temps if need be.

 

[JoePah]

Have fun dude! I live in Miami and store my ebike and battery in the garage, where is it normally 80-90s.. The battery degrades about 10% a year... I think if it were stored inside the battery might have held up better.

And the usual advice also appliies, i.e. do not charge the battery more than 90%, do not discharge the battery below 20%....Do not leave the battery in direct sun..

After saying all that I always use the hell out of my batteries charge it to 100% when I can and ride ride ride it.... Battery packs are less than $500 and you should get at least 3 good years from it.

 

[Solom01]

I also live in Florida but on the Southwest coast so on top of the high heat the humidity here is insane. I'm assuming that humidity in the 80-100% range is also bad for the battery, but I've never read or seen anything about this so does anyone know if high humidity is also a problem? JoePah, I hear you. If I could count on getting a replacement battery easily I wouldn't worry about it and just enjoy the bike. Unfortunately my past experience with having to throw away an expensive bike in perfectly good shape because the battery went bad and the vendors (assuming they're even still around) could care less about supporting past customers (here's looking at you iZip) has made me realize that unless you're capable of rebuilding your own battery (I'm not) you can't count on any parts being available after you buy the bike.

 

[mrgold35]

I would be cool if battery packs had Eco, normal, and Turbo modes to factor in different charge/dis-charge levels and longivity. If they can put the tech on a charger, seems like it would be easy to place inside the battery pack or bike controller?

 

[Solom01]

They could easily do it (electric cars do which is why they can afford to have long warranties on their battery) but for once I actually see the vendor's problem here. If they rated the range of their battery based on not discharging below 20% and not charging above 90% they would get slaughtered in the market place - everyone would buy the battery with the 50 mile range instead of the one with a 20 mile range, even though the first figure is a pipe dream. What would be cool would be if the vendors (especially the ultra expensive Euro bikes) would allow you to select parameters on a smartphone app to select minimum - maximum charge/discharge. You would be able to by-pass the parameters if you wanted maximum range, but for day to day use you could maximize the life span of the battery. Of course this would be a useful feature that would actually help customers and they tend to spend their effort on things that look "cool" but which really don't make much of a difference in the real world.

 

[JoePah]

Solom if you're worried about battery replacement and can't find an OEM battery, give the guys at ElectricRider a call in texas.. They are very good at solving these kinds of problems and they've been around at least 10 years.

 

[Solom01]

Thanks JoePah, I'll keep this info for the next time around. I already ditched the iZip since the battery was in the frame and a pain to remove - at the time I bought it I was naive and was impressed by the review talking about how integrated and stealth it was. I know better now and when I buy bikes will be more concerned about the ease of component replacement and not so much about looks - it was an expensive lesson to learn not just in terms of money but in adding more stuff to the landfill. So much for being "green", it would have been more eco-friendly to have bought a moped.

 

[Robie]

I'm in Texas, and any time it gets in the 90's I change my charging routine. 1st let battery cool down off bike. Use a fan on battery and charger when beginning charging. And unplug charger, right before fully charged , on my Stromer that's when the light flashes green. I was concerned about how it would handle the heat , but 2yrs, running takes it better than I do.

 

[Ravi Kempaiah]

I live in the desert in southern Nevada. Summer temperatures usually range between 85 to 115 F. From mid May to mid September I frequently ride in 90+F temperature. My question is will the hot climate cause a rapid degradation of lithium batteries and/or shorten their service life?

Extremely high temperatures are the prime reason for battery degradation. But eBike batteries are very different from EV batteries. Cars like Volt and Tesla have their own internal cooling system to keep the batteries in optimal temperature.
But eBike batteries never get exposed to extremely current draw that you see in EV acceleration. If you don't leave the batteries outside when it's super hot, nothing to worry. Also charging batteries when it's cold is not a good idea.
Bosch batteries can be safely operated upto ~105F and above that, it may have -ve effect ...

 

[Desert Rider]

I see some mention about not letting a battery charge fall below 20% and not fully charging it. I get not running a battery until it's dead, but what is the concern about fully charging the battery? I have a Bosch system. Does this advice pertain to all batteries or just some brands?

 

[Solom01]

As far as I have been able to determine (and not from eBike vendors who have an interest in claiming the longest possible range) fully charging a lithium battery is hard on it and will substantially reduce it's longevity. Many laptops have settings to stop charging when the battery reaches 90% capacity or so. The physical characteristics of lithium batteries are the same for all brands, but whether it pertains to your system would depend on whether it's BMS stops charging at under full capacity or not. Grin technologies sells an expensive charger that, among other things, allows you to monitor things like this. You can also just kind of keep an eye on an estimate of how long it takes to charge your battery and unplug it at the appropriate time, but boy would this all be easier if vendors took this into account and gave realistic information. It's kind of like the gushing over high amp chargers - yes, they're quicker, but the faster you charge the battery the more harm one does to it. I'm hardly an expert so this is just based on what I've been able to gather from disinterested sources, so hopefully if someone has better information on this they'll jump in. There's a long interview with the founder of Grin technologies here where it talks about battery characteristics. I don't know how unbiased it is, but the guy seems to have a lot of knowledge on battery characteristics.

 

[Larry Ganz]

Well, I'm trusting Bosche to know just how fast to charge the battery, and how to not overcharge when it's done, and also to not let the cells run down too low before the bike shuts off.

 

[Desert Rider]

As far as I have been able to determine (and not from eBike vendors who have an interest in claiming the longest possible range) fully charging a lithium battery is hard on it and will substantially reduce it's longevity. Many laptops have settings to stop charging when the battery reaches 90% capacity or so. The physical characteristics of lithium batteries are the same for all brands, but whether it pertains to your system would depend on whether it's BMS stops charging at under full capacity or not. Grin technologies sells an expensive charger that, among other things, allows you to monitor things like this. You can also just kind of keep an eye on an estimate of how long it takes to charge your battery and unplug it at the appropriate time, but boy would this all be easier if vendors took this into account and gave realistic information. It's kind of like the gushing over high amp chargers - yes, they're quicker, but the faster you charge the battery the more harm one does to it. I'm hardly an expert so this is just based on what I've been able to gather from disinterested sources, so hopefully if someone has better information on this they'll jump in. There's a long interview with the founder of Grin technologies here where it talks about battery characteristics. I don't know how unbiased it is, but the guy seems to have a lot of knowledge on battery characteristics.

Thanks for the good info. I hover over my battery when charging and unplug it as soon as it is fully charged. I don't allow it to "bake" on the charger. I think I will vary the levels of discharge and charging too so the battery doesn't gain "memory", if there is such a thing. I'll check out Grin Technologies for more background on battery characteristics.
Happy Riding!

 

[Ravi Kempaiah]

I see some mention about not letting a battery charge fall below 20% and not fully charging it. I get not running a battery until it's dead, but what is the concern about fully charging the battery? I have a Bosch system. Does this advice pertain to all batteries or just some brands?

There is HVC (high voltage cutoff) on most premium brands like Bosch, Brose, Shimano or Yamaha. Their charger shuts off charging once the cells reach certain voltage but some generic 2A chargers don't have that capability.

I am a doctoral researcher working on batteries, from my understanding the reason you don't want to keep your battery fully charged for a long time is ...... [analogy] it's like cooking on HIGH-setting, some dishes cook better at low setting. Similarly, a fully charged battery is like HIGH setting on your stove. The Li-ions are raring to go to the other electrode and release energy but since there is no load (your ebike is turned off), they can't move anywhere and this promotes the electrolyte oxidation and degradation. Recently, there was a lot of news about Prof. Goodnenough and his solid electrolyte batteries. The reason people are working on it is because, solid electrolyte won't attack the electrode like the liquid ones.
Anyway, the point is, keeping your batteries at high voltages is not a good idea... it's like arousing a boy intentionally and not let him release his pent up tension. LOL

If you charge it to 90%, for sure it's better but Bosch systems have puny batteries at 400Whr and if you only use it between 20% to 80%, you have roughly 300Whrs usable capacity and that seems very small.
Ideally, you would want a 700Whr battery and then you have lot of room to play with it.

To be honest, charging to only 90% may enhance the battery life but in 2 years the bike itself will be outdated and it seems too much cognitive work for a minor improvement. FYI, Bosch dropped the price in 400 powerpacks once they released the 500 powerpacks and if you don't leave your batteries plugged in all the time, a Bosch battery will last you ~500-600 cycles.

 

[Desert Rider]

Well, I'm trusting Bosche to know just how fast to charge the battery, and how to not overcharge when it's done, and also to not let the cells run down too low before the bike shuts off.

The parameters recommended by Bosch may be base line based on average temperatures and use. I live in the Mohave Desert where high summer temperatures (June-September) can degrade battery logetivity. I'm trying to figure out how to off set the effects of heat on battery life. Maybe. I'm overly concerned.
Thanks

 

[Desert Rider]

There is HVC (high voltage cutoff) on most premium brands like Bosch, Brose, Shimano or Yamaha. Their charger shuts off charging once the cells reach certain voltage but some generic 2A chargers don't have that capability.

I am a doctoral researcher working on batteries, from my understanding the reason you don't want to keep your battery fully charged for a long time is ...... [analogy] it's like cooking on HIGH-setting, some dishes cook better at low setting. Similarly, a fully charged battery is like HIGH setting on your stove. The Li-ions are raring to go to the other electrode and release energy but since there is no load (your ebike is turned off), they can't move anywhere and this promotes the electrolyte oxidation and degradation. Recently, there was a lot of news about Prof. Goodnenough and his solid electrolyte batteries. The reason people are working on it is because, solid electrolyte won't attack the electrode like the liquid ones.
Anyway, the point is, keeping your batteries at high voltages is not a good idea... it's like arousing a boy intentionally and not let him release his pent up tension. LOL

If you charge it to 90%, for sure it's better but Bosch systems have puny batteries at 400Whr and if you only use it between 20% to 80%, you have roughly 300Whrs usable capacity and that seems very small.
Ideally, you would want a 700Whr battery and then you have lot of room to play with it.

To be honest, charging to only 90% may enhance the battery life but in 2 years the bike itself will be outdated and it seems too much cognitive work for a minor improvement. FYI, Bosch dropped the price in 400 powerpacks once they released the 500 powerpacks and if you don't leave your batteries plugged in all the time, a Bosch battery will last you ~500-600 cycles.

Thanks for you explanation. It's not encouraging to hear that my bike will be obselete in a couple of years. Especially given the expense. I'm not certain that a 700 Whr battery is available. It would be good if it is. As I understand a "cycle" is theoretically charging from 0 to100% percent. Am I wrong?

 

[Ravi Kempaiah]

It's not encouraging to hear that my bike will be obselete in a couple of years.

That's the nature of the technology itself. We are all early adopters and we are paying heavy premium. You should peek into Nissan leaf and Chevy Volt forums. Some Nissan leaf owners paid $25,000 for a brand new car in 2013 and now the range has gone down like crazy.
On the flip side, if you use your eBike regularly, it will pay for itself many fold. It really brings so much positivity to your life. I assume you purchased an expensive bike with one of the premium drive systems. I am sure it will last long time, you may need to replace the batteries but that cost is nothing compared to paying hospitals.
Let's use Bosch for example, people who bought the Bosch performance line system in 2014 can still use their bike but may need to replace their batteries. It's always a trade-off. You could go DIY route with fancy Grin satiator charger etc but you don't get a good torque sensing system.