Battery ????

[johnc461165]

Today I refitted my battery that I took off in November, it has been fully charged, ie I charged it every 2 months.

Going out tonight I travelled 1.5 miles then the bike cut out, no power, switched off with the key, switched back on power back, twisted throttle and it cut out straight away.

Do I Need to use and recharge the battery to get it back to optimum performance.

Bike is Alien Aurora 2.5 years old, battery was changed under warranty when the bike was 10 months old.

In other words HELP......

 

[flecc]

Try recharging and then running it out to empty on the bike. Then recharge again and if the battery is healthy it should be ok then. If not ok then, it may be that the battery has died regardless of your care, lithium batteries do age even when unused. It is one and two-thirds of a year old, rather young to die, but this life is by no means unusual, especially on a very powerful motor like your Aurora's one. I'm afraid less than two year battery lives are not uncommon on the moderate cost more powerful e-bikes.

 

[Deleted member 4366]

There's some anecdotal evidence that the batteries on these bikes don't last long, but I don't believe that anybody has diagnosed the actual failure mode. Often, when people don't use their bikes for a while, their batteries go out of balance, which causes a reduction in capacity. Sometimes leaving it on charge for a long time after the green light will re-balance it, so that's worth a try. If that doesn't work, you have to open it to get to the BMS connectors and measure the cell voltages. Sometimes the battery can be revived by charging individual cells to get it back in balance.

If the battery is knackered, I'd replace it with a bigger one from China, and get a new controller at the same time so that you can release a lot more power and range from your motor.

 

[johnc461165]

Thanks flecc this battery was 6 months old when removed for storage, a bit of mis info I bought the bike in July 2011 so it's only 2 years this July.

d8evh I have put the battery on charge as advised on ES if that does not work I will open it up and come back to you for further info regarding cell voltages, I never use full power only the minimum assist to help me up hills, power and range are adequate for me but thanks.

 

[johnc461165]

Battery shows 40.8 fresh off charger.

"PM Reply from dveh"

40.8v is too low. One or more cells are lower than the rest. You need to get the battery out of its case to get to the BMS. Then you can measure individual cell voltages to see which one is giving problems. Normally charging the low one on its own will bring it back to life, but you have to do a bit of wiring.

Many thanks Dave I will open up the case and investigate.

 

[johnc461165]

D8evh I have now charged the low cells (4off) and rebuilt the battery pack, at this point voltage was 41.07, put the battery back on the bike and used the lights to drop the voltage to 41.01v, recharged it and it went up to 41.9v I was wondering if a couple of conditioning cycles would possibly help to get it up a bit higher.

 

[jazper53]

Often, when people don't use their bikes for a while, their batteries go out of balance, which causes a reduction in capacity. Sometimes leaving it on charge for a long time after the green light will re-balance it, so that's worth a try. .

What would be a acceptable time to recondition/balance the battery beyond the green light state, and can one damage the battery, or charger by leaving it on charge to long ?

 

[Deleted member 4366]

What would be a acceptable time to recondition/balance the battery beyond the green light state, and can one damage the battery, or charger by leaving it on charge to long ?

It depends on which BMS you have and how it works. Also, it's assuming that there's nothing wrong with the cells in your battery.

Your battery seems to have improved now, so I think it's time to try it, and see how you get on. 41.9v is close to where it should be.

It would be nice if you could report back how much range you're getting now, so that we can see whether it's fixed , or whether the problem lies elsewhere.

 

[shemozzle999]

It seems a shame that the battery cell manufacturers go to all the effort of producing ever more efficient cells only to be repeatedly let down by the industry by hanging onto the ill conceived, economy led method of producing battery packs for electric bikes.

When the requirement for higher voltage packs for ebikes came along they decided to incorporate a cheaply built BMS inside the pack so that they could use cheap mass produced chargers originally designed for laptops.

A battery pack should be just that, only a battery.

A universal ebike charger built along the lines of the radio control chargers with the ability to maintain the accurate balance of individual cells, allow discharging to storage voltage levels and have a visual system of monitoring all the parameters of the cells including how much charge the cells have received would go a long way to help user maintain the longest life possible for their battery and show up problems with the cells to allow early maintenance to prevent failure.

This of course would come with a high initial one time cost for the new type charger but would help the image of the industry to reassure buyers that they will get value for money out of their ebike.

 

[jazper53]

Further to my previous post above. My battery has been in hibernation since November 2012 and has been charged every two months. I would like to recondition my battery on its wake up charge, and would like to know how much longer one should charge when it gets to green light. The battery is a LiFePO4 36v 9amp, I have yet to know if the battery has any problems until i venture on my first ride of the season, but would like to recondition/balance as a general precaution.

 

[Deleted member 4366]

A good suggestion for us, but the average non-technical person wouldn't know what it all means. They're balancing price against usability, and generally, they work quite well. To me, 9 out of 10 battery problems start with something like " I didn't use my bike for a few months..."

 

[johnc461165]

Quote

"Your battery seems to have improved now, so I think it's time to try it, and see how you get on. 41.9v is close to where it should be.

It would be nice if you could report back how much range you're getting now, so that we can see whether it's fixed , or whether the problem lies elsewhere."

Will do Dave thanks for your help. John

 

[shemozzle999]

A good suggestion for us, but the average non-technical person wouldn't know what it all means. They're balancing price against usability, and generally, they work quite well. To me, 9 out of 10 battery problems start with something like " I didn't use my bike for a few months..."

Quite the opposite actually d8veh.

There should be no need for the user to know anything.

Modern RC chargers require little or no user input if operating within normal parameters. They auto detect cell count and chemistry type.

I am sure most users would want a simple plug and play system that automatically keeps their battery in tip top condition and doesn't require them to go delving inside the pack and all the dangers that could entail.

Removing the need of the BMS from the pack would also remove the drain caused on the leading cell to power it, thus preventing the cells from going out of balance when stored for any length of time.

Like lipo's getting a bad reputation for causing fires, the majority of incidents seem to occur when misusing them outside normal parameters or bad workmanship on the part of the user

 

[Deleted member 4366]

You can check it with a volt-meter. Anything above 42v is OK. Look at your charger. It should have the voltage on it. Your battery should reach that voltage straight off the charger, but then settle down to somewhere around 42v or above.

 

[roborobo]

Today I refitted my battery that I took off in November, it has been fully charged, ie I charged it every 2 months.

Going out tonight I travelled 1.5 miles then the bike cut out, no power, switched off with the key, switched back on power back, twisted throttle and it cut out straight away.

Do I Need to use and recharge the battery to get it back to optimum performance.

Bike is Alien Aurora 2.5 years old, battery was changed under warranty when the bike was 10 months old.

In other words HELP......

How Bizarre... I have exactly the same bike (Aurora) and of roughly the same age 2+years (also hadn't used it since approx Nov)... guess what, went for about @ 2miles then cuts out, if i turn the battery key off then on the bike will power on but after 3 secs of peddling cuts out again. :-( I've found out just how heavy an Aurora is, I'm still puffing now.

Reading previous comments, does this mean a new battery ? any recommendations ?
Any 'noody' howto (hints/pictures) of checking the cell voltages ?
HELP !


Thanks
Mark

 

[Deleted member 4366]

Today I refitted my battery that I took off in November, it has been fully charged, ie I charged it every 2 months.

Going out tonight I travelled 1.5 miles then the bike cut out, no power, switched off with the key, switched back on power back, twisted throttle and it cut out straight away.

Do I Need to use and recharge the battery to get it back to optimum performance.

Bike is Alien Aurora 2.5 years old, battery was changed under warranty when the bike was 10 months old.

In other words HELP......

How Bizarre... I have exactly the same bike (Aurora) and of roughly the same age 2+years (also hadn't used it since approx Nov)... guess what, went for about @ 2miles then cuts out, if i turn the battery key off then on the bike will power on but after 3 secs of peddling cuts out again. :-( I've found out just how heavy an Aurora is, I'm still puffing now.

Reading previous comments, does this mean a new battery ? any recommendations ?
Any 'noody' howto (hints/pictures) of checking the cell voltages ?
HELP !


Thanks
Mark

If it was OK before you put it in storage, it should be possible to recover it.

First step is to open up the battery and measure the individual cell voltages.

 

[roborobo]

Hi thanks d8veh, for the prompt reply

Yes the bike had been running fine last year before its rest ;-).

When you say 'measure the individual cell voltages', I get a little nervous of doing something stupid and ending up with a load bang and a smouldering mess.

Could you describe with a little bit more detail what steps I should take to do this ? (I've never even seen inside the battery pack so don't know what to expect)

Many Thanks
Mark

 

[johnc461165]

Hi roboboro here are the cells from my battery dont worry about opening the battery 4screws each end 2 colour coded plugs each end then slide the cells out,mine was a bit stiff but still not to hard.
the cell polarity is marked on the top of the cell.
Big Roy from Alien Ocean informed me that they can do a "conditioning procedure" for this type of problem John

 

[roborobo]

Great thanks johnc461165
I will get my volt meter out tonight and check. I assume that after charging the low individual cells every thing was balanced and ok again ?

Also how did you manage to charge the individual cells ?

Thanks
Mark

 

[johnc461165]

Hi you need a 5v phone charger, Charge each Cell to 4.2v I removed the plug and connected the wires to small crocodile clips, clip onto one cell observing polarity then off you go, the copper post on the batt is neg and the alloy one is pos, depending on how low the cell is it it took mine 3 to 4 hours to come up, as the voltage reaches 4volts or just above check frequently because at that point it can rise very quickly and overcharge and damage the cell, almost forgot there is a multi pin connector on the BMS that needs to be unplugged when you are charging. (All this knowledge came from d8evh) a very clever guy who helped me.
The cell voltages came up close enough to balance the battery and allow the normal charger to charge up, I don't think the battery has acheived it's full capacity since this problem probably .3 of a volt on full charge, I still need to do a couple of full discharge/recharge cycles in the hope of getting the battery to it's best. John