Battery Management

[notfub]

After every ride do you guys fully charge or charge to 70% (4 lights), then fully charge when you know you are out on a ride?

 

[Hakki]

No. But i'm riding 4-6 times in week. For long time without ride it would be good to charge up to 70%. I haven't never do that.

 

[notfub]

No. But i'm riding 4-6 times in week. For long time without ride it would be good to charge up to 70%. I haven't never do that.

Thanks Hakki. I can only get out on weekends usually due to work commitments so the battery will be left for 5 to 6 days at a time between rides.

 

[flash]

A week isn't an issue. If you're not out for a few weeks then consider leaving it between 50 and 70%.

If I have a big week ahead and can't ride till the weekend I just leave it where it was when I'm done and charge on Friday, unless I'm on the last bar. Then I charge it up and not worry about it.

Gordon

 

[MattyB]

A week isn't an issue. If you're not out for a few weeks then consider leaving it between 50 and 70%.

Sorry, I can’t agree. The “weekend warrior” pattern that many of us have to adopt is one that can easily kill a battery prematurely if it is fully charged every time. I agree leaving it at full charge only once will do little damage, but doing that week after week means it’s staying at full charge for at least 70% of the time if you charge on Sunday and ride on Sat, ~85% if you charge on Sun and ride next Sunday. Here’s a real world instance of the effect that has...

Loss in battery life - EMTB Forums

The alternative pattern you suggest is far better - check your battery after the ride, and if it is 20% or lower pop it on charge for an hour. On the night before or morning of your next ride pop it back on and charge to full. Simples!

 

[flash]

Sorry, I can’t agree. The “weekend warrior” pattern that many of us have to adopt is one that can easily kill a battery prematurely if it is fully charged every time. I agree leaving it at full charge only once will do little damage, but doing that week after week means it’s staying at full charge for at least 70% of the time if you charge on Sunday and ride on Sat, ~85% if you charge on Sun and ride next Sunday. Here’s a real world instance of the effect that has...

Loss in battery life - EMTB Forums

The alternative pattern you suggest is far better - check your battery after the ride, and if it is 20% or lower pop it on charge for an hour. On the night before or morning of your next ride pop it back on and charge to full. Simples!

It certainly could be this way. I tend to think that out batteries aren't getting 4.2V as a full charge in most cases. So they're not being charged to "100%". This is only based on what I have managed to research very basically myself, as it's hard to find real information from the manufacturers.

On my bike, Shimano quote 1000 cycles. Assuming they're not just making that figure up, it would seem they're working off somewhere between 4V and 4.1V as a full charge from the smart charger, in order to achieve the 1000 cycle figure. That should mean *in general* it's somewhat less damaging to store a bike battery *fully charged* compared to, say, a LiPo pack I use in my commercial drones. Of course it's possible that Shimano are making that figure up as few of us have been able to test that longevity claims yet.

Also our bike are almost certainly using LiFeO4 cells. That's a more stable technology which is a bit better for both safety and cell damage. Not that it can't happen. It's somewhat less likely. SO based on that I tend not to worry if I have my battery fully charged for up to a week, although it tends to be less than this. I also didn't read in the post you quoted that the issue was on a weekly storage basis. It could be that the storage time included longer storage times than 7 days on a regular basis.

I do agree that there's some mis-information out there (I'm looking at you, EMBN) and that *best* use policy is store between 50 on 70 and fully charge the night before. After all, that's when I check the rest of my bike before a ride so plugging in shouldn't be that hard. So from now on I will try to be more clear on this and recommend, as you do, the safest policy for battery care.

Gordon

 

[MattyB]

It certainly could be this way. I tend to think that out batteries aren't getting 4.2V as a full charge in most cases. So they're not being charged to "100%". This is only based on what I have managed to research very basically myself, as it's hard to find real information from the manufacturers.

On my bike, Shimano quote 1000 cycles. Assuming they're not just making that figure up, it would seem they're working off somewhere between 4V and 4.1V as a full charge from the smart charger, in order to achieve the 1000 cycle figure. That should mean *in general* it's somewhat less damaging to store a bike battery *fully charged* compared to, say, a LiPo pack I use in my commercial drones. Of course it's possible that Shimano are making that figure up as few of us have been able to test that longevity claims yet.

Also our bike are almost certainly using LiFeO4 cells. That's a more stable technology which is a bit better for both safety and cell damage. Not that it can't happen. It's somewhat less likely. SO based on that I tend not to worry if I have my battery fully charged for up to a week, although it tends to be less than this. I also didn't read in the post you quoted that the issue was on a weekly storage basis. It could be that the storage time included longer storage times than 7 days on a regular basis.

Yep, I agree with all that - to be getting 500-1000 cycles they have to be stopping shy of the 4.2V max at full charge. However, even LiFePO4 cells degrade faster when stored at over 4V/cell, so leaving them at "full" (as defined by the BMS) will still cause more damage in the long run than an indicated 60-70%.

I know this to my cost as I knackered a couple of cheap LiFe RX packs leaving them at full as I believed the hype about them being resilient to elevated SOC... Nope, they puffed up something rotten within a few weeks!

 

[Flatslide]

I've been figuring out the charge-rate on my Altitude as best as I can. I ride every day, clock 100km/wk and charge daily to 70% + or-. Today I rode around 25km with 800 metres of climbing, leaving home at 73% arriving with 23% and the app stating 16km remaining range. The 48V 5A fan cooled charger seems to be able to bang over 200W/hr into the battery over the first hour. Most days I charge for 45 mins and this is plenty for day to day commuting/bombing hills. I'm interested to see how long it all lasts ? Rocky Mountain guarantee 500 cycles to 80% and the cells are LG Chem.

 

[Cisco]

Getting on for 3000 miles on my Sommet VR. Im on my second motor and second battery. Normally I would ride 3 to 4 times a week and discharge the battery so that 1 to 2 bars are remaining. After every ride I would charge to 100%.

After a year, which was about 2000 miles the battery was obviously well past it's best, I would estimate 60-70% of it's original capacity. Seems like most people's batteries are doing better than mine but tbh I wasn't expecting it to be much better....

 

[Tuplis]

I always just plug it after each ride.

 

[pallie]

I also charge after every ride. Now at 2500 KM it seems the battery improved. The first 1000 KM I could only do 60 KM on a full battery. After the 1000 km now i'm doing 70 km, and still 1 bar left.