ebike charging question

[numbnuts]

I use my battery until there is about 5 miles left in it and charge it up until the red light turns to green on the charger, after 4 years, so far so good

 

[Mike_P]

Thinking of rigging up some appropriate voltage lights to run the battery down as and when.

 

[gzoom]

Varies by battery / make, the one on my Giant ebike apparently should be fully discharged after 15 charges or ever 3 months to increase in lifespan.

If it's a lithium ion cell there is no need to do this. The BMS may 'forget' the true capacity of the cells if you don't do full on 100-0% drains but you will not loss that capacity to degredation.

The worst culprits for causing early degredation in lithium ion cells are:

1. Extreme energy transfers - so during extreme fast charging for EVs, doesn't really apply for bikes.
2. Letting the battery sit at 0% for ages.
3. Letting the battery sit at 100% for ages.

Everything else you do should be fine. Most lithium ion cells should still hold over 80% charge way beyond 500+ cycles. Am getting about 50 miles per charge at present, which means 25,000 miles before any degredation becomes noticeable.

 

[confusedcyclist]

I ride the same milage day in day out, so I have a good idea how much I need in the battery, and I aim to keep the capacity between 20% at lowest and 80%. Using the battery beyond these extremes increases the wear rate. Happily I use roughly 60% in any given day, so I charge up to 80%, and when I return home it will be down to 20%. If I'm storing the bike for the weekend, I'll store it at 60% and top it off to 80% just before the next ride. If I know I need it the next day I might just charge to 80% when I get back. This is easy to do with a smart plug socket and remotely from the garage using an app and build in schedules and timers. I worked out that it takes roughly 2.1 minutes to charge 1% of the battery up to 80%, then it starts to slow down. I'm able to get get a ball park time to desired capacity with a quick calculation, however, because my computer has bluetooth I can remotely check the battery percentage in my bosch app and if it's too low, I can top it up with a quick swipe of a button. Wonders of modern tech!

If I didn't have consistent miles, and never know how much I needed in the battery, I would probably just charge to 100% just in time for my ride, being sure to charge only to 60% for periods of storage.

 

[rogerzilla]

Main thing with Li-ion batteries is to keep them cool, so try to avoid storage in a hot shed, and park it in the shade.

 

[Zanelad]

I charge mine when it dtops to 15 to 20%. In the summer i use about 10% of the battety on each leg of my 11 mile each way commute. (more in the colder months) I reckon i might squeeze 5 round trips from it, especially if there's a decent tail wind on one or two days. During lockdown when I've been furloughed and only riding for exercise I'll charge it at around 30%. Giant say it should take 1000 charges before dropping down to 80% output. I've had the bike a little over a year and charged it 25 times. Sad sack that I am, I've kept a record. I reckon the battery will see me out.

 

[RichardB]

I recently had an issue with my battery refusing to take a charge. Turns out it was a blown charging fuse, so no drama apart from the fuse being an odd size I had to order off the internet. In conversation with the dealer I bought it from, he asked me how I was charging the battery. I told him I was using the bike almost daily to approx 50% capacity, and topping up fully overnight, every time it was used. "Your battery will love you for it" were his words. It's still holding a good charge 6 years later.

 

[ebikeerwidnes]

The problem with all of this is that different people, including manufacturers seem to offer different advise

some say leave it (as long as not too low ) and charge it just before you ride it. But this is a bit difficult when it takes several hours to charge.
This assumes that your usage is very predictable (like commuting) but a lot of people use them for pleasure and just decide to go out in 20 minutes - therefore not enough to recharge it.

Some other people say it should be charged up to 50% - but don't provide any reasonable way to do this. If this is important then you need to be able to adjust the charger/BMS so that it monitors the charge level and stops at 50%. I know that some people can measure the voltage (or current?) and work out that it is at 50% - but my system is a Bosch one and I don;t want to start messing around with measuring it in case it gets confused and bricks itself.


My bike gets used most days (not yesterday or today as it is raining) so it gets charged about 2-3 times a week - normally overnight so I am depending on the BMS to not allow the cells to get over charged - then it gets used the next day up to about 60-70% (15-20 miles ish)

However my wife's bike only gets used once a month or so (normally when I feel sorry for it). I normally try to charge it for a few hours after I get it down to low charge so it is about 50% - but I have no real way of knowing where it really is. It is a Carrera witrh a Bafang hub motor and the display of the charge is only on the bike and is unreliable as it tends to vary depending on what I am doing. I can be going up a hill and it will show 1 light on the charge - then I get to the top of the hill and it happily lights up 3 leds.
So I have little real idea of where the charge is really up to until the motor starts cutting out when I am pedalling!

 

[RichardB]

the display of the charge is only on the bike and is unreliable as it tends to vary depending on what I am doing. I can be going up a hill and it will show 1 light on the charge - then I get to the top of the hill and it happily lights up 3 leds.

Mine does this. The reading without any load is the true reading, I think. At a full charge, I have one red LED and three green. After about 10 miles, if I go up a steep hill the green lights disappear, but they come straight back when I am on the level again. I suspect it is just the voltage dropping under load. Nothing to worry about.

 

[ebikeerwidnes]

Mine does this. The reading without any load is the true reading, I think. At a full charge, I have one red LED and three green. After about 10 miles, if I go up a steep hill the green lights disappear, but they come straight back when I am on the level again. I suspect it is just the voltage dropping under load. Nothing to worry about.

Yes - I agree

 

[Andy_R]

I charge mine when there is 1 bar left. I never let it run down to nothing.

...or 14.7psi....

 

[CXRAndy]

The problem with all of this is that different people, including manufacturers seem to offer different advise

some say leave it (as long as not too low ) and charge it just before you ride it. But this is a bit difficult when it takes several hours to charge.
This assumes that your usage is very predictable (like commuting) but a lot of people use them for pleasure and just decide to go out in 20 minutes - therefore not enough to recharge it.

Some other people say it should be charged up to 50% - but don't provide any reasonable way to do this. If this is important then you need to be able to adjust the charger/BMS so that it monitors the charge level and stops at 50%. I know that some people can measure the voltage (or current?) and work out that it is at 50% - but my system is a Bosch one and I don;t want to start messing around with measuring it in case it gets confused and bricks itself.


My bike gets used most days (not yesterday or today as it is raining) so it gets charged about 2-3 times a week - normally overnight so I am depending on the BMS to not allow the cells to get over charged - then it gets used the next day up to about 60-70% (15-20 miles ish)

However my wife's bike only gets used once a month or so (normally when I feel sorry for it). I normally try to charge it for a few hours after I get it down to low charge so it is about 50% - but I have no real way of knowing where it really is. It is a Carrera witrh a Bafang hub motor and the display of the charge is only on the bike and is unreliable as it tends to vary depending on what I am doing. I can be going up a hill and it will show 1 light on the charge - then I get to the top of the hill and it happily lights up 3 leds.
So I have little real idea of where the charge is really up to until the motor starts cutting out when I am pedalling!

If you know how long it takes to charge to full, use a mains timer socket to switch on and finish just before you use it.

Sitting at 100% for a period is the issue

A battery that is dipping two lights whilst climbing indicates it just about to drop out.

I have two chargers, one that will go to max 100%(58.6V) and another which will shut off 85/90/95%. This is the one I use for my wife's bike.

My wife's bike has a voltage display, we have now learnt 48V is critical and any excessive demand (hills, sudden acceleration) will shut the motor down.

On big rides 70+ miles I would use the max charger

 

[ebikeerwidnes]

Interesting

now on my 4th ebike and I have never seen a charger that shuts off at a charge level

Is this normal - how does it work??

 

[CXRAndy]

Interesting

now on my 4th ebike and I have never seen a charger that shuts off at a charge level

Is this normal - how does it work??

Interesting

now on my 4th ebike and I have never seen a charger that shuts off at a charge level

Is this normal - how does it work??

If you have an Ebike that comes from one of the big manufacturers, Bosch, Yamaha, etc. they tend to have a plug connector which might be difficult to source.

The chargers are available from ebike supplies where aftermarket kits are sold, ebay or Amazon.

They work by holding a certain voltage below maximum

Here is a 36V version
https://www.eco-ebike.com/products/36v-advanced-300w-eco-charger-2-to-6a-80-90-100

There are others for 48V, 52V and above

 

[aldus]

So a tad more detail — as I said, I run mine down to "one bar left" then hook up the battery when I get back in. I charge it until it shows "full bars", unplug and put the battery back on the bike (it's easier for me to charge it off the bike). I usually wind up riding within about 36 hours of that, so it's not sitting fully charged for long.

I don't ride all that far, most of my trips are under 5k, so that charge could last several weeks. The pandemic has had a definite stifling effect on my riding...