Bearprint Ebike battery woes :-(

[bazwaldo]

Well I thought I would give another update for my Bearprint New City Ebike.

Just lately I have been experiencing a drop off of battery performance during my journey to and from work.
For just over a year I have been able to cycle to and back from work on 1 charge using my large 36v 16ah capacity battery.
I initially paid an extra £200 for the bigger battery realising that my 26 mile round trip would be a challenge for the smaller 10ah capacity battery.
I started to get battery cut offs near the end of the journey towards the first year of ownership and so started to use middle assistance going home.
After this I began taking my charger to work and charged the battery there from 02.11.11.

Yesterday as has been increasingly happening the battery cut off 4 times on the way to work which is a 13.4 mile distance.
It seems that particularly on any even moderately uphill sections the stress is too much for the battery and the BMS is cutting off power.
Even setting the assist level to the middle setting did not resolve the issue and I ended up having to use just low assist up the last climb into Shepton Mallet where I work.
This is not a lot of fun as it reduces the speed to 5-6 mph even on the flat.
My journey would take far too long with too much effort at this setting.

Bearprint advertise the battery as having a 2 year warranty which is one reason why I purchased their bike.

I phoned Steve and Phil at Bearprint this morning and Phil said that there is no battery in the market which can cope with the mileage I have done in a little under 13 months. I have just about 60 miles to go to bring up 6000 miles.

I pointed out that there is nothing on their website which relates the battery warranty to mileage done and he agreed that in future they may have to reduce the warranty to 1 year only.
He did say that they would have to “bite the bullet” and give a new battery under warranty if necessary but that at the moment they are out of stock of batteries having had problems with their suppliers.
It seems that the situation is so bad that the last batch of bikes were even delivered without batteries.

Bearprint also said that there have been quality control issues with large batches of faulty batteries affecting the Ebike industry. Not surprisingly I was advised that they are looking for alternative factories for battery supply.

The call ended with the agreement that I should CB after a week for more news/further discussion.

I really hope Bearprint honour the warranty which I have take at face value when purchasing the bike for £1200.
The worst thing about it is that I am probably very soon going to have to start driving to work again when I would much rather keep on enjoying my Ebike which puts a smile on my face every day I use it!

Can any other Ebike companies confirm the apparently difficult situation with battery supply and quality?

Best wishes,
Barry.

 

[Scottyf]

The 16ah battery should be more than capable of supplying the current required on full assist.
Does sound like one of the cells might have died or least having trouble and causing voltage sag.

Although with the weather getting colder and colder everyones batteries will be taknig a hit on capacity and it will only get worse. (This is the reason why I added another 5amp hr to mine).

Does the battery stay outside?

 

[NRG]

Yes, I would have thought a 16Ah more than capable for your needs. 6000/26 is 230 charge cycles so well within expected usage and utter balderdash IMHO that no battery could cope with that milage, its not the milage that kills batteries! The weather is colder so will affect performance but you should not be experiencing cutouts after 13miles...

 

[Eaglerider]

Hi Bazwaldo,

Hmm, 6000 miles, assuming say a ball park figure of £400 for a replacement battery, then the battery cost would be around 6.5 Pence per mile. Compared to a car that did say, 40mpg and a gallon of petrol cost £6.12. Accordingly the car costs £6.12 to do 40 miles, and the E-Bike does (6.5p X 40)= £2.60 for the same 40 miles.

In effective fuel costs the car is only 2.3 times more expensive than a 25Kg E-Bike because the battery depreciation is so steep. Of course, for folk who do less miles than Bazwaldo, and their battery fails over time with a greatly reduced mileage completed, the cost per mile would be even higher. I can't offer a solution to this at the moment, but it is currently the Achilles Heel of the industry.

Of course, the car has 4 seats, luggage space, a heater, a music system and considerable personal protection from environmental nasties like drunk drivers etc.

Thankfully, E-Biking is really good fun and can be most enjoyable, but I fear the low cost, save the planet aspect is fatally flawed until this situation can be remedied.

Hope you get it sorted Bazwaldo, best of luck.

 

[Scottyf]

I'd keep chasing that warranty up. Its what you paid all those extra penny's for after all.

How old is the battery? To be honest it should easily be handling the mileage really. 16ah even at 80% would make it a 12.8ah capacity battery. Lets say it eats up 20watts per mile thats still a 23mile range. Thats using up alot of watts per mile.

It really does sound like something has broken down in the battery. I connection worked loose, a cell failing and hindering the other cells.

 

[Scottyf]

But you can get cheaper batteries made up now @ £200 for 36v 10ah.
They are out there and there not so cringe worthy prices. Making Ebikes affordable.

Its the fact most companies need to cover all bases and eventualities that anything like the above fails.

 

[Deleted member 4366]

At the time you bought your bike, they offered a 2 yr warranty. You paid in good faith, so that makes a contact, so they must honour their warranty. In any case, even the cheaper lithium batteries are supposed to last for about 900 charges, so they can't argue that your mileage is high. They state a range of up to 40 miles, so that makes 36,000 miles the expected life of the battery.

As I said in another post, the most likely cause of your problem is that a connection has broken inside due to constant severe vibration rather than the battery wearing out. If you feel competent to dismantle your battery, ask Bearprint if you can open it up to look for any obvious cause whilst still honouring the warranty as it would be the best outcome for both of you if you only have to solder a wire back on. If you're not competent, just demand a new battery under warranty. As a gesture of good will on your part, you could offer to pay them say £50 only if they send one immediately. That will give them an incentive to sort it out quickly, and I think it's fair considering all the help that they've already given you so far.

 

[steve.c]

Miles

Hi.I have a 36v 16.5v Freego Eagle and riding an average of 20 miles a day comuting and the same (or more) on my days off and I have had no problems with my battery at all and to say that no battery will put up that sort of mileage is rubbish?? I've had mine for 9 months and my mileage is around 5000 miles and it will still do 40/50 miles without a problem so if I were you I'd push for the new battery.I must mention that going to work I have it in medium but on the way home (after 12 hours) I put it in high and it fly,s. Steve

 

[bazwaldo]

Hi all, thank you for your input.
Eaglerider you are absolutely right battery performance and replacement costs are the single most important issue affecting mass take up of Ebikes.
I had hoped to get at least 2 years usage from my battery which was new with the bike and first used by me for my work commute on 21.10.10.
If the battery costs £500 a £10 per week cost of usage is just too much, £5 a week for 2 years is not so bad but still pretty expensive. I was expecting to have to charge at work during the 2nd year but the battery failing to cope with the trip in to work has surprised me happening this early in it's life.
I will give further updates as the situation unfolds.
My journey to work ended up on low assist again today after 3 cut offs in total.
The easier and slightly shorter journey home was OK with the battery cutting out just as I coasted into my drive, it was on high assist throughout which was good. Overall the climb is harder on the way to work.
As noted though things will only get worse with colder freezing weather still to come combined with stronger winds at some point.
My hope is that Bearprint will honour the warranty and that I can hold onto the original battery and somehow recycle the case and BMS with some DIY recelling using the existing bottom connector and charging 3 pin plug.
I would need to learn some new skills to do this safely though.

Barry.

 

[morphix]

I guess this is going to be a problem for the ebike industry for a while until more reliable technology emerges that can cope with the demands.. batteries are something of an unknown variable because they can vary in quality and also it depends on how users ride their bikes and how often. it must be a nightmare for manufacturers to guarantee what is a consumable product and also a significant % cost of the bike for larger batteries.

An alternative approach where practically possible, might be to use smaller battery packs with well established battery technology and swap them out as needed on route, or to look at self-maintenance and swapping out individual cells if you're able....rather than putting all your eggs in one basket so to speak in a big expensive battery which may or may not of been in the market very long. Maybe there's a whole new market here for some firms to start recycling and repairing batteries.

 

[Kudoscycles]

Bazwaldo....if you look at my posting LifePo4 v LiMn2o4 you are experiencing in practice the degradation effects of Limn2o4 batteries,this effect is really independent of usage,we found about 14% per annum whereas the LifePo4 batteries only experiences 2% in the first year and 3% in the second year. The Limn2o4 battery has a critical minumum voltage at which point the BMS cuts the power-I suspect this is causing your dropouts-the range at which this point occurs decreases with age not usage.
The LifePo4 maintains almost the full voltage throughout it's range,giving full power up to empty...it does however have a sharp cutoff but that must be better than gradual loss of power.
It must be asked why is the LifePo4 not more popular...I am afraid you guys have a lot to blaim-you have pressured the importers to offer more power for hillclimbing,you want lighter batteries,you want longer range-to achieve this the e-bike suppliers have cranked up the amps to the controller,this uses a lot more power-so as to be able to offer an acceptable range the suppliers have had to increase the battery capacity but to maintain a reasonable weight they have had to use battery types with the maximum energy density and that means Lithium-Ion or Lithium Polymer-to use a LifePo4 to feed these hungry controllers would require a heavy battery.
But the choice to achieve maximum energy density ignores all the other advantages of the LifePo4-low cost,low self discharge,low capacity degredation,temperature tolerance,constant voltage discharge,easy maintenance etc etc.
If you want the max power at minimum weight you must continue with LiMn2o4 but you have to accept the need to replace the battery frequently and at high cost. But if you can accept a lower energy density the LifePo4 is a very cost effective alternative-I don't know why other e-bike suppliers don't offer a choice.
Dave
KudosCycles

 

[JuicyBike]

Bazwaldo....if you look at my posting LifePo4 v LiMn2o4 you are experiencing in practice the degradation effects of Limn2o4 batteries,this effect is really independent of usage,we found about 14% per annum whereas the LifePo4 batteries only experiences 2% in the first year and 3% in the second year. The Limn2o4 battery has a critical minumum voltage at which point the BMS cuts the power-I suspect this is causing your dropouts-the range at which this point occurs decreases with age not usage.
The LifePo4 maintains almost the full voltage throughout it's range,giving full power up to empty...it does however have a sharp cutoff but that must be better than gradual loss of power.
It must be asked why is the LifePo4 not more popular...I am afraid you guys have a lot to blaim-you have pressured the importers to offer more power for hillclimbing,you want lighter batteries,you want longer range-to achieve this the e-bike suppliers have cranked up the amps to the controller,this uses a lot more power-so as to be able to offer an acceptable range the suppliers have had to increase the battery capacity but to maintain a reasonable weight they have had to use battery types with the maximum energy density and that means Lithium-Ion or Lithium Polymer-to use a LifePo4 to feed these hungry controllers would require a heavy battery.
But the choice to achieve maximum energy density ignores all the other advantages of the LifePo4-low cost,low self discharge,low capacity degredation,temperature tolerance,constant voltage discharge,easy maintenance etc etc.
If you want the max power at minimum weight you must continue with LiMn2o4 but you have to accept the need to replace the battery frequently and at high cost. But if you can accept a lower energy density the LifePo4 is a very cost effective alternative-I don't know why other e-bike suppliers don't offer a choice.
Dave
KudosCycles

Barry's battery IS lithium phosphate.

 

[Kudoscycles]

Juicybike>are you sure? I have checked Bearprint's website and it lists the 36v x 16Ah battery as Lithium-Ion,manganese based. I did not see Bearprint offering a LifePo4(Lithium Phosphate) option...perhaps Barry could confirm his battery type?
Dave
KudosCycles

 

[bazwaldo]

Dave (Kudos), first of all I am very impressed with your new Ebike company and website, you do the right thing I believe by putting choice with your customers. Being able to easily buy replacement parts and batteries at reasonable prices is excellent.

I recall asking Bearprint about the 16ah battery before purchase and being told that it is Lithium Polymer - the website shows:-

"Gavin and Hector both use Lithium Ion chemistry. But what matters is their output, not their chemistry. And our batteries give you plenty of power to go up hills or to overtake safely, and have plenty of stamina to get you home."

Your other posts have explained your reasons for not offering bigger battery size than 10ah which initially I was curious about. I wonder if your bikes had been available to me and I had bought one how the battery would have coped with my 26 mile work commute?
How big and heavy would a 16 or 17ah battery be using your preferred LifePo4 type and could it be made to fit my battery case?

Bob (Juicybike) and Dave (Kudos) have you experienced problems with battery supply and quality similar to that experienced by Bearprint?
As noted several times the Freego bikes are almost identical to the Bearprint range or visa versa! I wonder if they have had similar battery issues?

From the Wisper x 2 thread I know that Wisper Bikes hope to have some terrific new batteries available in the near future and if as good as suggested it may give the Industry a real boost.

Barry.

 

[JuicyBike]

Barry, I'm fairly certain your battery is a LiFePO4. How heavy is it? (Of course we have problems )

 

[Oxygen Bicycles]

batteries - are they all the same?

From our experience I can say it is very difficult to source the right battery supplier. There are dozen of things that can go wrong with the battery pack and part of the problem are caused by the poor quality of assembly, another part by simply poor quality cells.

As for the Bearprint I'm 100% sure their big battery isn't LiFePo4 but Lithium manganese LiMn204. The battery might be cutting out because the cells might be already exhausted or one of the group of cells has died. Diffucult to say without diagnostics. On our packs it is very easy to diagnose the battery as we use o2 Micro BMS that comes with right software and pc diagnostics tool but I'm not sure if the BearPrint has that option.

all the best

Andrew

 

[Kudoscycles]

BAZWALDO>

Lithium-ion and lithium polymer batteries are basically the same. With lithium-ion the electrolyte is held in a solvent, but with lithium polymer it is held in a solid polymer. This makes the battery easier to manufacture and more rugged. Lithium polymer tends to have a greater life cycle degradation rate – 500 cycles being the norm, after that the capacity can drop below 75%.

One major problem with lithium polymer is it cannot ever be deep discharged. If deep discharge occurs the battery is irreversibly damaged and will never be able to be charged to normal capacity. The BMS system should protect the battery from deep discharging during use, however if the battery is left for a long period with low charge without recharging then the deep discharge could occur.

I weighed the lithium polymer and LiFePO4 batteries we have in stock.

36v x 10AH lithium ion 3.07kg
36v x10h LiFePO4 4.95kg

As you can see, if we increased the capacity to 16AH then the lithium ion battery would weigh about 4.9kg and LiFePO4 about 7.5kg, I think that is too heavy. There are many advantages in battery technology coming out of China and many claims for much higher energy density (lighter weight) from some battery suppliers, but I prefer to stick with what we know – our current LiFePO4 product gives us little problems.
I have another 120 bikes ready to ship from China (60 ‘Eco’ and 60 ‘King’) – my builder has not advised any battery supply problems. With regard to quality, all of my suppliers have advised the same name as a battery supplier with lots of quality problems – for obvious reasons I am not about to announce that name. However, his batteries are very cheap and numerate.

Davial Miall of Wisper and myself hold completely opposite views of our approach to batteries. He is seeking the highest density unit, lightest weight and longest range, I am respectful of his wish to push the boundaries of development – see his posts re lithium-sulphur dioxides (LiSO2) which have a whopping 250 wh/kg density. However, there are reports of only 50 cycles and £2K cost. I am equally concerned about cycle life, replacement costs and ease of maintenance. Note the LiFePO4 has a density 90-110 wh/kg but in excess of 1500 cycles . I think it is a case of ‘horses for courses’ – my customers report a solid 30 plus mile range (see ALANB and JIMOD postings) which is good for most e-bike journeys, more if you are prepared to pedal more but if you want the longest range with light weight you have to accept frequent replacements at high cost.
You pays your money and takes your choice!

Dave
Kudos Cycle

 

[Scottyf]

What is the average life of a bicycle?
Surely getting a bike to match that statistic would be useful in knowing what you should really aim at.

Maybe commuter bikes would be better with the higher weight of Lifepo4 and cheaper costs with the life cycles.
Sports models could have lower weight, less cycle life to optomise performance at the cost of frequent replacements.

 

[bazwaldo]

Barry, I'm fairly certain your battery is a LiFePO4. How heavy is it? (Of course we have problems )

Hello Bob, I weighed the battery on our Bathroom scales which showed 4.8Kg.

Barry.

 

[JuicyBike]

Hello Bob, I weighed the battery on our Bathroom scales which showed 4.8Kg.

Barry.

Wow, OK, take it all back. That's far too lightweight for a LiFePO4. The case looks so large.