Battery charging

[HH66]

I recently bought my first ebike - a Cube with a 500w battery. I've used it a few times for small commutes but my main usage is for long rides of 30+ miles. If I know I'm going out for less than about 20 miles I don't bother to top up the battery (unless it's really low) but, if I might be doing 40 miles or so I tend to make sure that the battery is fully charged. I'm sure I read somewhere that it's better to let the battery discharge to about 20% before recharging so will I be damaging my battery by continually topping up?

 

[Jonah]

No, all will be fine. If used regularly, top up charging is recommended, no need to discharge fully first. If leaving unused for many months it is said to be preferable to leave it at about 80% charge and top up occasionally.

 

[Andy-Mat]

I recently bought my first ebike - a Cube with a 500w battery. I've used it a few times for small commutes but my main usage is for long rides of 30+ miles. If I know I'm going out for less than about 20 miles I don't bother to top up the battery (unless it's really low) but, if I might be doing 40 miles or so I tend to make sure that the battery is fully charged. I'm sure I read somewhere that it's better to let the battery discharge to about 20% before recharging so will I be damaging my battery by continually topping up?

You have asked (correctly so!) the original $64,000 question.
You ask 10 people here and you may end up with 10 different answers, all believed to be right!
I personally prefer to have two batteries, one high capacity and one low. The low one being the "get me home" one, after the other is discharged.....
That also extends my range quite dramatically!!
I personally, as I use my bike several times a day, always charge to full from empty on my current bike. On my previous bike, I sometimes charged from not quite empty! It still had a very good life, far better than most of the stories here from some members....
There are times when you cannot start a charge from empty, but do not worry yourself unduly.
One point (that a few here still cannot believe or understand,) is that I have a modified a simple mechanical 24 timer, that I use to cut the mains to the charger, when I judge the time that battery to be full.
On my last battery it gave a 6 years plus life, still working, when I gave the bike away.....I did not count the number of charges, but I rode around 3,000 Kms per month, except in January, and February, when it was usually icy.....
But whether you follow that advice or not is entirely your choice! There are many "naysayers" here!!
There are some really expensive chargers, that basically do that automatically I am told....
Regards
Andy

 

[Eagle]

February, when it was usually icy.....
There are some really expensive chargers, that basically do that automatically I am told....
Regards
Andy

My Haibike Sduro FullSeven 3.0's charger automatically switches off after the battery is fully charged.

 

[Andy-Mat]

My Haibike Sduro FullSeven 3.0's charger automatically switches off after the battery is fully charged.

It tells you it does, the LED changes colour, but you need some simple test equipment and 2 volt meters and an ammeter (sensitive) to be 100% sure!
If you haven't made the cable and done the testing, you do not want to bet the life of your battery on that!!
I have tested several chargers, none completely "stopped", they only "reduced" the charge to a level not thought to be harmful!!
I must test my current charger one day, I was not bothered because of the timer function I use.....
......and that is far cheaper than a new battery!!
But we are all adults, we must all make our own decisions and choices in such matters!!
regards
Andy

 

[TobyAnscombe]

Cube 400w user here.

I charge a couple of times a week to keep topped off but have the charger on a timer plug so that it does *actually* shut off. You will quickly figure out what the “normal” time to charge would be..

 

[Eagle]

It tells you it does, the LED changes colour, but you need some simple test equipment and 2 volt meters and an ammeter (sensitive) to be 100% sure!
Andy

There is no power from the charger to the battery once the battery is fully charged. The charge light goes out. There is no change of colour.

 

[Andy-Mat]

Cube 400w user here.

I charge a couple of times a week to keep topped off but have the charger on a timer plug so that it does *actually* shut off. You will quickly figure out what the “normal” time to charge would be..

Perfectly put! But if your battery "needs" such topping off in such a short time, then the battery is almost finished. A fairly recent test I made showed only a 0.9 volt loss of charge in around 3 months.
Use a voltmeter to check the battery voltage....before charging.
regards
Andy

 

[Fat Rat]

Just charge it when you want
I have no rules about it just as and when
I leave the charger on to and when finished it switches itself off
You can here a relay click internally when switching it on and when it finishes (Bosch)
If you have factory charger and battery all supplied with the bike don't concern yourself with it
Get out and ride

 

[ewganhoff]

The "full discharge" thing is simply not applicable to current battery tech so you can disregard that out of date info. Everyone seems to know that it is bad to leave the battery fully discharged for any length of time, but what many don't seem to realise is that you don't want to leave it fully charged for long either as this will reduce the life of the battery. If I'm charging and I know I'm going out soon don't mind charging to 100%, but if I don't know when I'll get out next, I charge to 80%ish then top it up fully in the hours before the ride. I also work away for weeks at a time and if I know I won't be using the battery for 3+ days I make sure the the battery is around 60% as 40-60% is recommended for long term storage. 60% allows for the battery to stay within that range as it naturally discharges a small amount even without being used. Also don't charge a cold battery, give it time to get closer to room temp after a cold ride.