Symptoms of a failing battery

[allen-uk]

I'm a petrol-head at heart. Not by inclination, just by 40+ years.

So when I came to ebikes, I admit that I expected the battery to behave a bit like a fuel tank - fill it, use it, refill it, and so on.

I wasn't expecting a 1/4 full battery to behave any differently from a FULL battery, just to have fewer miles left in it.

Ok, I have learnt (a little) since last year.

But what I would like guidance on is this: eventually, I know, my battery will stop functioning altogether. But what are the symptoms of battery decline? Will it always be as zippy when first full? Will it just do less miles between charges? Does the '2 year' rule of thumb for battery life hold water, or can you shorten the life by frequent charging, or by (say) heavy throttle use, and by a heavy rider?

I ask as after 900 miles/9 months my Wisper SEEMS to be a little less willing than it was. I have a series of bench-mark hills which I use to assess the general fitness of me/battery, and even though the weather is no longer a factor (reasonable temperatures), they feel harder... or maybe it's just my perceptions changing. Not 100% sure.

(Like all Wisper owners I do have a standing invitation to take my bike back to my dealer; it's just that I can't really face stripping it down so that I can cram it into my smallish car, ploughing through 50 miles of London traffic (each way, and possibly on two successive days), so I'm taking the lazy route first and asking my fellow ebikers!)


Allen, Wisper 905.

 

[NRG]

Typically a reduced range. If a cell is failing before the others you may get cut outs when the motor is under load followed by a recovery when on the flat. Because our E-bikes use the available battery capacity to the full they are placed under some stress so at the two year mark it's not unreasonable to find a marked drop in range. Many batteries will continue longer than this depending on the quality and amount of stress they have been subjected to. Frequent charging should not hurt the battery but keeping it plugged into the charger can, so when its charged best to remove it from the charger.

Although the weather has improved a bit (not today!) try the bike again when the temps are nearer 20c, I think you'll be surprised at how much better the bike feels overall.

 

[Straylight]

I'm with NRG regarding ambient temp. the difference is rather startling when you suddenly get a warm spell as we've had recently. I must say that (having been through the process myself) it's possible to get over analytical where battery performance is concerned, particularly when so many external factors can make a difference, such as headwinds, temperature, and how 'up for it' one's feeling on a given day

One thing I've found that improves consistency is charging indoors, as opposed to out in the shed where I did originally, also not letting the battery get too cold before setting off. These days the battery is the last thing to go on the bike before me.

I think that if you're not getting cut-outs under heavy load then there's little to worry about, but you could always try a conditioning cycle (full discharge then recharge). I've only done this a couple of times in over two years and five thousand miles, and my battery shows little sign of failure. I also generally only use half the capacity before recharging.

 

[hawkwind]

I did the same as Straylight, charge the battery indoors and only put it on the bike as i was ready to set off.
Learned the hard way as i left it in the garage after a frosty night and it only went a few hundred yards before i had no power.
It does make a big difference having it in a warm room for a few hours at least before setting off.

 

[allen-uk]

you could always try a conditioning cycle (full discharge then recharge).

Thanks for the very helpful thoughts.

On the full discharge: any further tips? I did try it originally, and never managed to get down below 2 lights on the Wisper. At that stage there was very little assistance left - I was riding it round and round my local quiet roads, mainly on throttle (a thing I rarely do), but I just couldn't get it all the way down on the battery indicator lights (the 4 on the battery itself).

Allen.

 

[NRG]

A 'conditioning cycle' is well worth doing. It will reset any fuel gauge present in the BMS so you can get a more accurate indication of capacity left and therefore range.

 

[lessped]

recharge

Hi there regarding running the batt. flat i always thought lithium batts. should never be let run flat .! please clarify ...thanks

 

[Mussels]

If your that far from your dealer I'm guessing you're in SE London, if you reckon there's something wrong add could have a battery swap for a couple of days and I'll let you know if yours is any different to mine.

 

[Mussels]

Hi there regarding running the batt. flat i always thought lithium batts. should never be let run flat .! please clarify ...thanks

true but most controllers will cut out before it gets to a damaging level, Wisper bikes certainly do.

 

[NRG]

Flat in this case does not mean 0v. It means when the controller detects the battery pack voltage is at ithe low voltage cutoff point. IE there will a voltage across the pack but with no or close to no remaining energy left.

 

[Straylight]

Thanks for the very helpful thoughts.

On the full discharge: any further tips? I did try it originally, and never managed to get down below 2 lights on the Wisper. At that stage there was very little assistance left - I was riding it round and round my local quiet roads, mainly on throttle (a thing I rarely do), but I just couldn't get it all the way down on the battery indicator lights (the 4 on the battery itself).

Allen.

Well, it can be a PITA, depending on how far you let yourself get from home, all I did was to estimate the range, which for me, being a lazy speed freak is around 30 miles (de-restricted throttle, on full most of the time due to scarcity of traffic where I live). I then simply kept an eye on the speedo/odo, shortening my journeys until it cut out on an incline about a mile away from home. You then realise just what the motor actually contributes, feels like someone's plonked an anvil on the back carrier , pretty much the only time I've needed first gear. For the remainder of the ride, I kept trying the throttle, to the point where none of the battery lights on the handlebars would even try to come on, ie the voltage was permanently below the controller's minimum. As others have said, this doesn't actually mean the pack is empty, just beyond the limits of the range of capacity that we use, and so the only bit we're interested in in terms of BMS calibration etc.

The way I see it, and I'm by no means an expert, is that doing this not only defines the operating range for the BMS, but also refreshes the chemical constituents of the battery, by literally getting the ions moving. It does, however, place the pack under stress that's best avoided under normal use.

Some of this could be nonsense, but battery lore is like folk lore, there seems to be different versions of the same stories, with varying interpretations, all I really know is that my pack is still healthy, and long may it remain so, as I can't afford another (well, I can, I just really don't want to!).

 

[NRG]

I hope you're putting some pennies away each week for the battery replacement rainy day!

 

[Straylight]

*sigh* I should, I know, it is enevitable.... I'm comforted though that, if memory serves, Mussels got a lot more mileage than me out of his 905, fingers crossed!

 

[Jeanette Morgan]

I'm beginning to recall and refresh my mind re batteries, however, bearing in mind my battery is guaranteed for 2 years - 14Ah Lithium for Ezee Sprint

Having done the two conditioning cycles..............

Keeping it at house room temperature
Removing the charger within a couple of hours of recharging
Topping up after every ride, even if only 5 miles
Leaving no more than 6 weeks (up to 8 is the max I think) between any charge
Riding the bike sporadically, ie sometimes a lot a week, other weeks hardly at all
However, the ride will always involve hills !

.......is it likely that the battery will last considerably beyond the two years?
Or will any of the above cause early decline of the battery, ie doing something differently may help improve its longevity?

Thanks

 

[flecc]

The best of today's batteries can last longer than two years. The current eZee 14 Ah battery is the same one as the current Wisper 14 Ah, different boxes of course, and one owner has just remarked his Wisper one is working well at two years old with little sign of decline.

The number of full charges claimed for this battery has increased from the former 500 to 800 now.

There's no effective special technique to making them last longer. Just use and look after them as you've already said Jeannette.
.

 

[Straylight]

The only thing that I've seen mentioned here that may improve the lifespan, is that when you're not using it for a period of weeks, you could leave it partially discharged, and somewhere cold.

I recall Flecc mentioning keeping his laptop batteries in the fridge for long term storage. The reasoning being that this slows the natural chemical decay within the pack. But do remember to warm it up (bring it indoors/take it out of the fridge for a few hours) before trying to use/charge it, as what benefits in terms of storage (IE putting it into semi-suspended animation) will impede its performance when you need it awake and working.

Oops Sorry Flecc - crossed posts - hope I'm not putting words in your mouth!

 

[flecc]

I recall Flecc mentioning keeping his laptop batteries in the fridge for long term storage. The reasoning being that this slows the natural chemical decay within the pack. But do remember to warm it up (bring it indoors/take it out of the fridge for a few hours) before trying to use/charge it, as what benefits in terms of storage (IE putting it into semi-suspended animation) will impede its performance when you need it awake and working.

Oops Sorry Flecc - crossed posts - hope I'm not putting words in your mouth!

Not at all.

Definitely on worth it for very long term storage though, not for the odd weeks of no usage. I only use my laptop on battery away from home once or twice a year, and it's battery cared for that way is well over six years old now and still with most of it's life.
.

 

[allen-uk]

If your that far from your dealer I'm guessing you're in SE London, if you reckon there's something wrong add could have a battery swap for a couple of days and I'll let you know if yours is any different to mine.

That's a tremendous offer, Mussels, but I'm right round in NW London (above Wembley), so pretty difficult journey these days.

I'll have to bite the bullet and take it down to PowaRider, I think - I had half a mind to courier it down there (no dearer than the petrol!) but it's probably fairer to Steve and his crew to see the rest of the bike at the same time.


Thanks again. I'll try the Deep Discharge route first, and report back.



Allen, Wisper 905, 2010.

 

[lessped]

flat. batt.

Hi there regarding running the batt. flat i always thought lithium batts. should never be let run flat .! please clarify ...thanks

Ok understood thaks for clearing that up for me

 

[kitchenman]

I'm a petrol-head at heart. Not by inclination, just by 40+ years.

So when I came to ebikes, I admit that I expected the battery to behave a bit like a fuel tank - fill it, use it, refill it, and so on.

I wasn't expecting a 1/4 full battery to behave any differently from a FULL battery, just to have fewer miles left in it.

Ok, I have learnt (a little) since last year.

But what I would like guidance on is this: eventually, I know, my battery will stop functioning altogether. But what are the symptoms of battery decline? Will it always be as zippy when first full? Will it just do less miles between charges? Does the '2 year' rule of thumb for battery life hold water, or can you shorten the life by frequent charging, or by (say) heavy throttle use, and by a heavy rider?

I ask as after 900 miles/9 months my Wisper SEEMS to be a little less willing than it was. I have a series of bench-mark hills which I use to assess the general fitness of me/battery, and even though the weather is no longer a factor (reasonable temperatures), they feel harder... or maybe it's just my perceptions changing. Not 100% sure.

(Like all Wisper owners I do have a standing invitation to take my bike back to my dealer; it's just that I can't really face stripping it down so that I can cram it into my smallish car, ploughing through 50 miles of London traffic (each way, and possibly on two successive days), so I'm taking the lazy route first and asking my fellow ebikers!)


Allen, Wisper 905.

Funny but my battery (NIMH) has just given up the ghost after nine months. Since I bought my CX700 I have been maintaining a spreadsheet of all my trips including all the battery activity. Time to charge, accidents, conditioning, overcharging, ... I can honestly say that I have not noticed any dip in the performance of my battery... at the moment with battery technology as it is then one day it may decide to stop working and be a complete mystery to everyone! ... However, As I keep good statistics, I was rewarded with a discounted price on a new one. I was on target to complete a years cycling on one battery which for me would have been 250 rides/cycles as I charge before every ride.