Hi All, when it comes to charging a battery up, do i run it into the ground first then charge up from empty or charge up after every ride out.

Which is the best method?

Cheers for your input.

Andy.

Best possible is to charge it up fully just before each ride, but that can be awkward/unpredictable.

 

As long as you ride at least several times a week charge it up after each ride, or when it shows 1/2 full. The thing there is to try to avoid charging it up fully and leaving it that way unused for any significant length of time.

 

The worst possible thing is to get it to what the BMS says is empty and leave it there for any length of time. It might drop below what the BMS finds acceptable and be difficult/impossible to revive.

 

(BMS is battery management system, usually integral to the battery.)

Best possible is to charge it up fully just before each ride, but that can be awkward/unpredictable.

 

As long as you ride at least several times a week charge it up after each ride, or when it shows 1/2 full. The thing there is to try to avoid charging it up fully and leaving it that way unused for any significant length of time.

 

The worst possible thing is to get it to what the BMS says is empty and leave it there for any length of time. It might drop below what the BMS finds acceptable and be difficult/impossible to revive.

 

(BMS is battery management system, usually integral to the battery.)

Thank you sjpt.

[mention=19726]sjpt[/mention] - Hi ,

 

What say if a person doesnt want to be out riding their bike so much , say once per wk only

 

then what with regards charging battery and how often should they charge it ?

[mention=19726]sjpt[/mention] - Hi ,

 

What say if a person doesnt want to be out riding their bike so much , say once per wk only

 

then what with regards charging battery and how often should they charge it ?

If the once a week is predictable, then charge the day before the ride.

If it's not predictable then maybe after it drops to half.

 

Try to work out a pattern suitable to you allowing for

- you don't want to be stranded on a ride

- you want your battery to last as long as possible

- don't leave it nearly empty over a long period (especially very long period such as winter)

- don't leave it fully charged over a long period

 

 

I'm not really sure whether leaving it full for a week really matters or not. I think it may even depend on the particular battery. There are a lot of people here who know much more about it than me; most of what I'm saying here is second hand knowledge partly from them and partly from other web sites.

If the once a week is predictable, then charge the day before the ride.

If it's not predictable then maybe after it drops to half.

 

Try to work out a pattern suitable to you allowing for

- you don't want to be stranded on a ride

- you want your battery to last as long as possible

- don't leave it nearly empty over a long period (especially very long period such as winter)

- don't leave it fully charged over a long period

 

 

I'm not really sure whether leaving it full for a week really matters or not. I think it may even depend on the particular battery. There are a lot of people here who know much more about it than me; most of what I'm saying here is second hand knowledge partly from them and partly from other web sites.

 

Cheers Sjpt appreciated ^

Charge the battery a few hours before use (24 hrs is fine before), ride the bike. Back at home leave the battery in the discharged state though d make sure it is at or above nom voltage, so 25v for 24v, 36v for 36v & 46.8v for 48v.

A battery at full voltage won't damaged if left for a week but try not to do so on a regular basis.

Charge the battery a few hours before use (24 hrs is fine before), ride the bike. Back at home leave the battery in the discharged state though d make sure it is at or above nom voltage, so 25v for 24v, 36v for 36v & 46.8v for 48v.

A battery at full voltage won't damaged if left for a week but try not to do so on a regular basis.

 

Hi Neal ,

 

What about say in all of Winter time if you dont want ride the bike out ?

Store the battery at storage voltage which is anything between the nominal voltage and 3.85v per cell. Probably the best thing is leave it at nominal voltage in a cool unheated (not freezing) place like a garage, check the voltage every 3 or 4 weeks and if need be give it a 10 min charge.

 

Cold /cool (not freezing) is good for unused storage,

It doesn't need to be fully charged unless you need the range, is my understanding. Charging to 80-85% extends battery life a bit. As mentioned, do not allow to fall below the level at which the BMS treats the battery as 'empty', which basically means make sure it is partly charged (say 40%-50%) for storage. Do not charge when very cold.

 

This is a 10 year old article so may not be the latest thinking but it seems consistent with the advice I see generally.

 

https://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

It doesn't need to be fully charged unless you need the range, is my understanding. Charging to 80-85% extends battery life a bit.

 

https://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

That's not good advice. OP should aim to always charge his battery until he gets the green light. It's Ok to do short charges (not to full) occasionally, so it's nothing to get worried about, but it mustn't be done as a matter of course.

 

That Battery University article is about cell management, but batteries like Andy's already have a management system in them that manages charge control and balancing. It might not be the best, but you have to work with it. Balancing only happens at the top of the charge cycle, so if you were to charge it to 80%, it would never balance, and it's life and capacity would be drastically reduced. Their article is about making a good management system, not about what you do in your charging procedures for your ebike battery. You're stuck with whatever the manufacturer puts in the battery, not what Battery University says you should have, though, if you're technically competent, you can change it and fit your own management system, which could allow a different balancing procedure.

 

And don't think that you can charge to 80% most of the time and just do an occasional full charge to balance it. The balancing system is based on the little and often principle. The balancing current is very small and is not switched on for very long.

And don't think that you can charge to 80% most of the time and just do an occasional full charge to balance it. The balancing system is based on the little and often principle. The balancing current is very small and is not switched on for very long.

I knew a lot of what you said above (mainly from reading posts on this forum), but I had not realized that last part (quoted). I'd been doing it right out of laziness, but it's good to know it was right as well as lazy.

That's not good advice...

 

That Battery University article is about cell management, but batteries like Andy's already have a management system in them that manages charge control and balancing.

 

Point taken, thank you. I shall make sure it gets fully charged when convenient, assuming this applies to the Bosch system.

 

It's a little bit annoying that the manufacturers provide page after page on "safety" and stating the obvious (connect the mains cable and the charger cable, plug in the charger etc.) but never give any information about the charger design - at what voltage it closes down and stops discharge, and also stops charging for that matter - I suspect that there is a trade off between final charge voltage and battery life, with some if not all already stopping short of the absolute maximum energy that can be stored.

 

Neither for that matter is either of the Bosch charger manual or the battery manual that I have explicit about the necessity to charge the battery fully. They just say "the charger will switch off when charging is complete" or words to that effect.

 

Do all the system chargers use top balancing do you know?

Point taken, thank you. I shall make sure it gets fully charged when convenient, assuming this applies to the Bosch system.

 

It's a little bit annoying that the manufacturers provide page after page on "safety" and stating the obvious (connect the mains cable and the charger cable, plug in the charger etc.) but never give any information about the charger design - at what voltage it closes down and stops discharge, and also stops charging for that matter - I suspect that there is a trade off between final charge voltage and battery life, with some if not all already stopping short of the absolute maximum energy that can be stored.

 

Neither for that matter is either of the Bosch charger manual or the battery manual that I have explicit about the necessity to charge the battery fully. They just say "the charger will switch off when charging is complete" or words to that effect.

 

Do all the system chargers use top balancing do you know?

The problem is that this misinformation is on electric bike forums all over the internet. It's not your fault. How would you know? It all seems very plausible. I'm not sure how a Bosch battery works. They have the same cells as some Chinese ones, but do seem to last well, which could be down to a good management system. In principle, it works the same as any Chinese batteries, but software is probably very different. If I had one, I'd charge it to 100% because that's what's implied in their instruction.

The problem is that this misinformation is on electric bike forums all over the internet. It's not your fault. How would you know? It all seems very plausible. I'm not sure how a Bosch battery works. They have the same cells as some Chinese ones, but do seem to last well, which could be down to a good management system. In principle, it works the same as any Chinese batteries, but software is probably very different. If I had one, I'd charge it to 100% because that's what's implied in their instruction.

One difference between charging our Bosch battery and our 'standard' (Woosh kit) battery is that when 'done' the Bosch turns off all lights (on the battery), but with the Woosh the charger light goes from red to green. That may or may not mean that the Bosch charger has disconnected itself completely from the battery when it considers it has finished its job, but the Woosh one goes on providing a connection, voltage and small current.

 

I haven't made any measurements to verify, and clearly the lights can be made to behave in any way independently from what is really happening.

I follow the mantra of not storing a fully charged battery for an extended period, and generally start charging in the small hours in preparation for a 09h00 ride....but.....

Can anyone cite original scientific research that supports this approach?

Here's a standard for an 18650. Point 11 details storage. I don't think you need to study test data and standards. Whenever you buy a battery or cell, it comes to you at about 3,6 to 3.7v per cell, which is the voltage the manufacturers and the suppliers store them at. That's good enough for me, as there must be some reason why they all do the same .

https://www.ineltro.ch/media/downloads/SAAItem/45/45958/36e3e7f3-2049-4adb-a2a7-79c654d92915.pdf

One difference between charging our Bosch battery and our 'standard' (Woosh kit) battery is that when 'done' the Bosch turns off all lights (on the battery), but with the Woosh the charger light goes from red to green. That may or may not mean that the Bosch charger has disconnected itself completely from the battery when it considers it has finished its job,

 

FWIW, the Bosch charger manual says

 

"If the charger is not disconnected from the battery after

charging, after a few hours the charger will switch itself back

on, check the state of charge of the battery and begin the

charging procedure again if necessary."

 

My actual approach to battery care is to be aware of what helps and doesn't help, but primarily to just use it - I didn't buy it for the purpose of preserving it forever. There's a good chance it will last longer than I will.

quote "https://www.ineltro.ch/media/downloads/SAAItem/45/45958/36e3e7f3-2049-4adb-a2a7-79c654d92915.pdf "

 

Thanks vfr400 a very informative document, though I hope it was proof-read and corrected before issue as there are some howlers!